GRI

Phase 2a data show zero cough and 60% lower treatment-related diarrhea than placebo despite higher nintedanib use in the active arm – suggesting GRI-0621 may mitigate nintedanib-related GI-toxicities when used in combination Advancing GRI-0803 toward IND-enabling activities to expand the pipeline across autoimmune indications with high unmet need LA JOLLA, CA, May 14, 2026 (GLOBE NEWSWIRE) -- GRI Bio, Inc. (NASDAQ: GRI) (“GRI Bio” or the “Company”), a biotechnology company advancing an innovative pipeline of Natural Killer T (NKT) cell modulators for the treatment of inflammatory, fibrotic and autoimmune diseases, today announced reported financial results for the quarter ended March 31, 2026 and provided a corporate update. “The growing body of Phase 2a clinical, translational and biomarker data continues to reinforce GRI-0621’s differentiated therapeutic potential in idiopathic pulmonary fibrosis (IPF),” said Marc Hertz, PhD, Chief Executive Officer of GRI Bio. “Additional analyses in the Phase 2a study show that GRI-0621 delivered zero cough, reduced dyspnea, zero weight loss and approximately 60% less treatment-related diarrhea when added to standard of care versus standard of care alone, with no serious adverse events in the active arm – directly addressing the tolerability burdens that drive discontinuations of current IPF therapies. These data, together with improvements in lung function and consistent evidence of immune modulation, anti-fibrotic activity, and epithelial repair, give us confidence in the program. With approximately $11.0 million in cash as of March 31, 2026, supporting planned operations into the second quarter of 2027, we believe we are positioned to continue advancing GRI-0621 towards pivotal studies and progressing GRI-0803 toward IND-enabling activities with disciplined execution.” Phase 2a Data – GRI-0621 in IPF GRI-0621, the Company’s once-daily oral RARβ/γ selective agonist, was evaluated in a randomized, double-blind, placebo-controlled Phase 2a trial (GRI-0621-IPF-02; NCT06331624) in 35 patients with IPF, approximately 80% of whom were on background standard-of-care (SOC) antifibrotics. The trial met its primary safety and tolerability endpoint, with continued analyses of translational and biomarker endpoints supporting previously reported findings. Key results include: Safety and tolerability: GRI-0621 was observed to reduce important clinical features of IPF (cough/shortness of breath) and SOC-associated toxicities (diarrhea). Zero cough was observed in the active arm vs. 25% in the placebo arm; a 76% reduction in dyspnea (4% vs. 17% placebo arm); no weight loss (vs. 17% placebo arm); and a 61% reduction in diarrhea (13% vs. 33% placebo arm), despite 67% more nintedanib use in the active vs. placebo arm (nintedanib is known to be associated with higher rates of diarrhea compared to pirfenidone); no serious adverse events were reported in the active arm, and a single SAE was reported in the placebo arm. Exploratory pulmonary function: +99 mL FVC improvement overall, and +139 mL in the SOC combination subset, versus placebo + SOC at 12 weeks. MOA: Evidence across multiple, independent measures, including serum proteomics (17 analytes), whole-blood RNA-sequencing and flow cytometry suggest disease-modifying benefits, including immune rebalancing (Th2→Type 1 switch), active fibrolysis, basement membrane repair and epithelial regeneration. Patents: The Company has filed additional patent applications based, in part, on these data. First Quarter 2026 Pipeline and Corporate Highlights Advanced clinical development planning activities for GRI-0621 to support potential regulatory pathways in both the United States and Europe. Progressed GRI-0803, the Company’s type 2 diverse Natural Killer T (dNKT) agonist program for autoimmune diseases, toward IND-enabling activities. Strengthened the balance sheet through the Company’s At The Market facility, generating approximately $6.8 million in gross proceeds during the first quarter of 2026. First Quarter 2026 Financial Results Cash and cash equivalents totaled approximately $11.0 million as of March 31, 2026, compared to approximately $8.2 million as of December 31, 2025. Based on the Company’s current operating plan, GRI Bio believes existing cash resources will be sufficient to fund planned operating expenses and capital expenditure requirements into the second quarter of 2027. Research and development expenses were approximately $0.4 million for the three months ended March 31, 2026, compared to approximately $1.6 million for the same period in 2025. The decrease was primarily related to lower expenses due to the completion of the Company’s Phase 2a clinical trial of GRI-0621 in 2025. General and administrative expenses were approximately $1.6 million for the three months ended March 31, 2026, compared to approximately $1.4 million for the same period in 2025. Net loss for the quarter ended March 31, 2026, was approximately $2.0 million, compared to approximately $3.0 million for the same period in 2025. About GRI Bio, Inc. GRI Bio is a clinical-stage biopharmaceutical company focused on fundamentally changing the way inflammatory, fibrotic and autoimmune diseases are treated. GRI Bio’s therapies are designed to target the activity of Natural Killer T (“NKT”) cells, which are key regulators earlier in the inflammatory cascade, to interrupt disease progression and restore the immune system to homeostasis. NKT cells are innate-like T cells that share properties of both NK and T cells and are a functional link between the innate and adaptive immune responses. Type 1 invariant NKT (“iNKT”) cells play a critical role in propagating the injury, inflammatory response, and fibrosis observed in inflammatory and fibrotic indications. GRI Bio’s lead program, GRI-0621, is an RARβ/γ-selective agonist shown to inhibit the activity of key immune cells, such as iNKT cells, and is being developed as a novel oral therapeutic for the treatment of idiopathic pulmonary fibrosis, a serious disease with significant unmet need. The Company is also developing a pipeline of novel type 2 diverse NKT (“dNKT”) agonists for the treatment of systemic lupus erythematosus. Additionally, with a library of over 500 proprietary compounds, GRI Bio has the ability to fuel a growing pipeline. Forward-Looking Statements This press release contains “forward-looking statements” within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as “anticipate,” “believe,” “contemplate,” “could,” “estimate,” “expect,” “intend,” “seek,” “may,” “might,” “plan,” “potential,” “predict,” “project,” “target,” “aim,” “should,” “will,” “would,” or the negative of these words or other similar expressions. These forward-looking statements are based on the Company’s current beliefs and expectations. Forward-looking statements include, but are not limited to, statements regarding: the Company’s expectations with respect to development and commercialization of the Company’s product candidates, the timing of initiation or completion of clinical trials and availability of resulting data, the potential benefits and impact of the Company’s clinical trials and product candidates and any implication that the data or results observed in preclinical trials or earlier studies, topline or interim data or trials will be indicative of results of later studies or clinical trials or final data, the Company’s beliefs and expectations regarding potential shareholder value and future financial performance, the Company’s beliefs about the timing and outcome of regulatory approvals and potential regulatory approval pathways, the Company’s expected future milestones, shareholder value and the length of time the Company’s current resources will fund its planned operations (which current estimate assumes only initial preparatory activities for GRI-0621 as substantial additional capital or resources will be required to fund a Phase 2b clinical trial of GRI-0621). Actual results may differ from the forward-looking statements expressed by the Company in this press release and consequently, you should not rely on these forward-looking statements as predictions of future events. These forward-looking statements are subject to inherent uncertainties, risks and assumptions that are difficult to predict, including, without limitation risks related to: (1) the Company’s inability to maintain the listing of the Company’s common stock on The Nasdaq Capital Market and to comply with applicable listing requirements; (2) changes in applicable laws or regulations; (3) the inability of the Company to raise financing in the future; (4) the success, cost and timing of the Company’s product development activities; (5) the inability of the Company to obtain and maintain regulatory clearance or approval for its respective products, and any related restrictions and limitations of any cleared or approved product; (6) the inability of the Company to identify, in-license or acquire additional technology; (7) the inability of the Company to compete with other companies currently marketing or engaged in the development of products and services that the Company is currently developing; (8) the accuracy of the estimated size and growth potential of the markets for the Company’s products and services, and its ability to serve those markets, either alone or in partnership with others; (9) that later data or clinical trials may be inconsistent with or contrary to data and observations to date, including that later data may not indicate a patient benefit, modulate toxicities or validate a mechanism of action; (10) inaccuracy in the Company’s estimates regarding expenses, future revenue, capital requirements and needs for and the ability to obtain additional financing; (11) the Company’s ability to protect and enforce its intellectual property portfolio, including any newly issued patents and its ability to obtain any expected patent term extensions, adjustments, exclusivities or disclaimers; and (12) other risks and uncertainties indicated from time to time in the Company’s filings with the U.S. Securities and Exchange Commission (the “SEC”), including the risks and uncertainties described in the “Risk Factors” section of the Company’s most recent Annual Report on Form 10-K filed with the SEC on January 30, 2026 and subsequently filed reports. Forward-looking statements contained in this announcement are made as of this date, and the Company undertakes no duty to update such information except as required under applicable law. Investor Contact: JTC Team, LLC Jenene Thomas (908) 824-0775 [email protected]

Company reported $8.2 million in cash and cash equivalents at December 31, 2025 and raised additional $6.5 million in gross proceeds in January 2026 Balance sheet strengthened to fund operations into Q1 2027 Strong Phase 2a clinical data for GRI-0621 in idiopathic pulmonary fibrosis reinforce clinical proof-of-concept and therapeutic differentiation GRI-0803 focused on autoimmune indications with high unmet need advancing through IND-enabling activities LA JOLLA, CA, Feb. 04, 2026 (GLOBE NEWSWIRE) -- GRI Bio, Inc. (NASDAQ: GRI) (“GRI Bio” or the “Company”), a biotechnology company advancing an innovative pipeline of immune cell modulators for the treatment of inflammatory, fibrotic and autoimmune diseases today summarized recently reported Full Year 2025 financial results, provided an update on the Company’s current cash position and cash runway and summarized key clinical and corporate highlights. “In 2025, we prioritized disciplined clinical execution and balance sheet strength, delivering compelling clinical data from our lead IPF program which underscores the therapeutic differentiation of GRI-0621,” commented Marc Hertz, PhD, Chief Executive Officer of GRI Bio. “Entering 2026 with a strong cash position, we are focused on advancing GRI-0621 in IPF, progressing GRI-0803 toward the clinic and executing our clinical strategy with capital discipline to drive long-term value creation.” Recent Highlights Raised approximately $14.5 in gross proceeds in December 2025 and January 2026 Strong cash position expected to fund planned operations into the first quarter of 2027 Announced positive Phase 2a topline data from the completed Phase 2a clinical study of GRI-0621 in idiopathic pulmonary fibrosis Reported additional data demonstrating suppression of pro-fibrotic immune phenotypes, reinforcing topline data and clinical proof-of-concept Generated new RNA-sequencing gene expression data demonstrating direct impact on the core biology of fibrosis and lung repair Advanced plans to progress GRI-0803 into IND-enabling studies, expanding the Company’s pipeline in autoimmune disease Summary of Financial Results for the Year Ended December 31, 2025 As of December 31, 2025, the Company had cash and cash equivalents of approximately $8.2 million. Following the close of the quarter, the Company raised an additional $6.5 million in gross proceeds through the use of its At The Market offering. Based on the Company’s current operating plan, GRI Bio believes that its existing cash and cash equivalents will be sufficient to fund operating expenses and capital expenditure requirements into the first quarter of 2027. Net loss was $12 million for the year ended December 31, 2025. Research and development expenses were $6.8 million and $3.8 million for the years ended December 31, 2025 and 2024, respectively. The $3.0 million increase in research and development expenses was primarily due to increases of $2.9 million in expenses related to the registration development program of GRI-0621, $0.1 million in personnel expense, including stock-based compensation and a $0.1 million increase in consulting fees. General and administrative expenses were $5.2 million and $4.5 million for the years ended December 31, 2025 and 2024, respectively. The $0.7 million increase was primarily due to an increase of $0.7 million in personnel costs, including stock-based compensation expense. About GRI Bio, Inc. GRI Bio is a clinical-stage biopharmaceutical company focused on fundamentally changing the way inflammatory, fibrotic and autoimmune diseases are treated. GRI Bio’s therapies are designed to target the activity of key immune cells, such as Natural Killer T (“NKT”) cells, earlier in the inflammatory cascade to interrupt disease progression and restore the immune system to homeostasis. NKT cells are innate-like T cells that share properties of both NK and T cells and are a functional link between the innate and adaptive immune responses. Type I invariant NKT (“iNKT”) cells play a critical role in propagating the injury, inflammatory response, and fibrosis observed in inflammatory and fibrotic indications. GRI Bio’s lead program, GRI-0621, is an Immunomodulator and anti-fibrotic RARβγ agonist shown to inhibit the activity of key immune cells, like iNKT cell activity, along with anti-fibrotic and epithelial cell repair activity and is being developed as a novel oral therapeutic for the treatment of idiopathic pulmonary fibrosis, a serious disease with significant unmet need. The Company is also developing a pipeline of novel type 2 diverse NKT (“dNKT”) agonists for the treatment of serious autoimmune diseases with significant unmet need. Additionally, with a library of over 500 proprietary compounds, GRI Bio has the ability to fuel a growing pipeline. Forward-Looking Statements This press release contains “forward-looking statements” within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as “anticipate,” “believe,” “contemplate,” “could,” “estimate,” “expect,” “intend,” “seek,” “may,” “might,” “plan,” “potential,” “predict,” “project,” “target,” “aim,” “should,” “will,” “would,” or the negative of these words or other similar expressions. These forward-looking statements are based on the Company’s current beliefs and expectations. Forward-looking statements include, but are not limited to, statements regarding: the Company’s expectations with respect to development and commercialization of the Company’s product candidates, the timing of initiation or completion of clinical trials and availability of resulting data, the potential benefits and impact of the Company’s clinical trials and product candidates and any implication that the data or results observed in preclinical trials or earlier studies, topline or interim data or trials will be indicative of results of later studies or clinical trials or final data, that final data will be indicative of a proof-of-concept, the Company’s beliefs and expectations regarding potential shareholder value and future financial performance, the Company’s beliefs about the timing and outcome of regulatory approvals and potential regulatory approval pathways, the Company’s expected future milestones, shareholder value and the length of time the Company’s current resources will fund its planned operations (which current estimate assumes only initial preparatory activities for GRI-0621 as substantial additional capital or resources will be required to fund a Phase 2b clinical trial of GRI-0621). Actual results may differ from the forward-looking statements expressed by the Company in this press release and consequently, you should not rely on these forward-looking statements as predictions of future events. These forward-looking statements are subject to inherent uncertainties, risks and assumptions that are difficult to predict, including, without limitation: (1) the inability to maintain the listing of the Company’s common stock on The Nasdaq Capital Market and to comply with applicable listing requirements; (2) changes in applicable laws or regulations; (3) the inability of the Company to raise financing in the future; (4) the success, cost and timing of the Company’s product development activities; (5) the inability of the Company to obtain and maintain regulatory clearance or approval for its respective products, and any related restrictions and limitations of any cleared or approved product; (6) the inability of the Company to identify, in-license or acquire additional technology; (7) the inability of the Company to compete with other companies currently marketing or engaged in the development of products and services that the Company is currently developing; (8) the size and growth potential of the markets for the Company’s products and services, and their respective ability to serve those markets, either alone or in partnership with others; (9) that later data or clinical trials may be inconsistent with or contrary to data and observations to date, including that later data may not indicate a proof-of-concept or patient benefit; (10) inaccuracy in the Company’s estimates regarding expenses, future revenue, capital requirements and needs for and the ability to obtain additional financing; (11) the Company’s ability to protect and enforce its intellectual property portfolio, including any newly issued patents and its ability to obtain any expected patent term extensions, adjustments, exclusivities or disclaimers; and (12) other risks and uncertainties indicated from time to time in the Company’s filings with the U.S. Securities and Exchange Commission (the “SEC”), including the risks and uncertainties described in the “Risk Factors” section of the Company’s most recent Annual Report on Form 10-K filed with the SEC on January 30, 2026 and subsequently filed reports. Forward-looking statements contained in this announcement are made as of this date, and the Company undertakes no duty to update such information except as required under applicable law. Investor Contact: JTC Team, LLC Jenene Thomas (908) 824-0775 [email protected]

The Independent Data Monitoring Committee (“IDMC”) has recommended to continue the study as planned as there are no safety concerns demonstrated in the data reviewed Interim results to date demonstrate GRI-0621 to be safe and well-tolerated in the first 24 patients evaluated 6-week interim biomarker data (n=24) expected in July 2025 and topline data expected in Q3 2025 Currently available treatments for IPF are limited to only two approved drugs that come with significant side-effects, limited patient compliance and no impact on survival LA JOLLA, CA, June 26, 2025 (GLOBE NEWSWIRE) -- GRI Bio, Inc. (NASDAQ: GRI) (“GRI Bio” or the “Company”), a biotechnology company advancing an innovative pipeline of Natural Killer T (“NKT”) cell modulators for the treatment of inflammatory, fibrotic and autoimmune diseases, today reported positive 6-week interim safety results from its ongoing Phase 2a study evaluating GRI-0621 for the treatment of IPF. GRI-0621 is the Company’s small molecule RAR-βɣ dual agonist that inhibits the activity of human Type 1 Invariant NKT (“iNKT”) cells. In preliminary clinical trials to date and previous clinical trials with the oral formulation, GRI-0621 has been shown to improve fibrosis in multiple disease models and improve liver function tests and other markers of inflammation and injury in patients. The pre-planned interim analysis for 6-week safety results from the ongoing Phase 2a biomarker study demonstrated GRI-0621 (4.5mg orally once daily) to be safe and well-tolerated in the first 24 patients evaluated per protocol. There were no adverse events associated with hyperlipidemia, as assessed by LDL, HDL and triglyceride (“TG”) levels in the 24 patients assessed at the 6-week visit. There were no clinically meaningful changes in HDL, LDL or TG levels in patients receiving GRI-0621, consistent with the safety data reported after the first 12 subjects completed 2-weeks of treatment, and all subjects remained within protocol accepted ranges. The interim analysis committee recommended the study should continue as planned. The interim results show that GRI-0621’s receptor selectivity is consistent with the toxicity profile observed in earlier studies evaluating oral tazarotene in over 1,700 patients treated for up to 52 weeks. Marc Hertz, PhD, Chief Executive Officer of GRI Bio commented, “We are happy to report the IDMC confirmed no safety concerns in the first 24 subjects evaluated after 6-weeks of treatment, building upon the 2-week safety data reported earlier and adding to the large safety data available for oral tazarotene. We are encouraged by the consistent safety data and early anti-fibrotic trends previously reported and remain on track to report 6-week interim biomarker data in the coming weeks followed by topline data expected in the third quarter of this year.” The Phase 2a, randomized, double-blind, multi-center, placebo-controlled, parallel-design, 2-arm study is enrolling approximately 36 subjects with IPF. Subjects are being randomized in a 2:1 ratio for GRI-0621 4.5mg or a placebo. GRI-0621 dose of 4.5mg is being compared with a dose of placebo following once daily oral administration for 12 weeks. Concurrently, a sub-study is examining the number and activity of NKT cells in bronchoalveolar lavage (“BAL”) fluid for up to 12 eligible subjects (across various centers). The primary endpoint for the study is safety and tolerability of oral GRI-0621 as assessed by clinical labs, vital signs and adverse events after 12 weeks of treatment. Secondary endpoints are baseline changes in serum biomarkers collected at week 6 and week 12; an assessment of the pharmacokinetics (PK) of GRI-0621 at the week 12 visit of treatment (steady state); and a determination of the pharmacodynamic activity of oral GRI-0621 as measured by inhibition of iNKT cell activation in blood after 6 weeks and 12 weeks, and from BAL fluid after 12 weeks of treatment in a sub-study. Additional exploratory endpoints for the study are to assess the effect of GRI-0621 on pulmonary function at baseline and after 6 weeks and 12 weeks of treatment and flow cytometry and differential gene expression at various time points. The Company expects to report 6-week interim biomarker data in July 2025. Topline results from the Phase 2a biomarker study are expected in the third quarter of 2025. For more information about the Phase 2a study, please visit clinicaltrials.gov and reference identifier NCT06331624. About GRI Bio, Inc. GRI Bio is a clinical-stage biopharmaceutical company focused on fundamentally changing the way inflammatory, fibrotic and autoimmune diseases are treated. GRI Bio’s therapies are designed to target the activity of Natural Killer T (“NKT”) cells, which are key regulators earlier in the inflammatory cascade, to interrupt disease progression and restore the immune system to homeostasis. NKT cells are innate-like T cells that share properties of both NK and T cells and are a functional link between the innate and adaptive immune responses. Type I invariant NKT (“iNKT”) cells play a critical role in propagating the injury, inflammatory response, and fibrosis observed in inflammatory and fibrotic indications. GRI Bio’s lead program, GRI-0621, is an inhibitor of iNKT cell activity and is being developed as a novel oral therapeutic for the treatment of idiopathic pulmonary fibrosis, a serious disease with significant unmet need. The Company is also developing a pipeline of novel type 2 diverse NKT (“dNKT”) agonists for the treatment of systemic lupus erythematosus. Additionally, with a library of over 500 proprietary compounds, GRI Bio has the ability to fuel a growing pipeline. Forward-Looking Statements This press release contains “forward-looking statements” within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as “anticipate,” “believe,” “contemplate,” “could,” “estimate,” “expect,” “intend,” “seek,” “may,” “might,” “plan,” “potential,” “predict,” “project,” “target,” “aim,” “should,” “will,” “would,” or the negative of these words or other similar expressions. These forward-looking statements are based on the Company’s current beliefs and expectations. Forward-looking statements include, but are not limited to, statements regarding: the Company’s expectations with respect to development and commercialization of the Company’s product candidates, the timing of initiation or completion of clinical trials and availability of resulting data, the potential benefits and impact of the Company’s clinical trials and product candidates and any implication that the data or results observed in preclinical trials or earlier studies or trials will be indicative of results of later studies or clinical trials, the Company’s beliefs and expectations regarding potential shareholder value, the Company’s beliefs and estimates about its cash and available resources and its ability to fund its planned operations through any particular date, the Company’s beliefs about the timing and outcome of regulatory approvals and potential regulatory approval pathways, and the Company’s expected milestones in 2025. Actual results may differ from the forward-looking statements expressed by the Company in this press release and consequently, you should not rely on these forward-looking statements as predictions of future events. These forward-looking statements are subject to inherent uncertainties, risks and assumptions that are difficult to predict, including, without limitation: (1) the inability to maintain the listing of the Company’s common stock on The Nasdaq Capital Market and to comply with applicable listing requirements; (2) changes in applicable laws or regulations; (3) the inability of the Company to raise financing in the future; (4) the success, cost and timing of the Company’s product development activities; (5) the inability of the Company to obtain and maintain regulatory clearance or approval for its respective product candidates, and any related restrictions and limitations of any cleared or approved product candidates; (6) the inability of the Company to identify, in-license or acquire additional technology; (7) the inability of the Company to compete with other companies currently marketing or engaged in the development of products and services that the Company is currently developing; (8) the size and growth potential of the markets for the Company’s products and services, and their respective ability to serve those markets, either alone or in partnership with others; (9) the failure to achieve any milestones or receive any milestone payments under any agreements; (10) inaccuracy in the Company’s estimates regarding expenses, future revenue, capital requirements and needs for and the ability to obtain additional financing; (11) the Company’s ability to protect and enforce its intellectual property portfolio, including any newly issued patents; and (12) other risks and uncertainties indicated from time to time in the Company’s filings with the U.S. Securities and Exchange Commission (the “SEC”), including the risks and uncertainties described in the “Risk Factors” section of the Company’s most recent Annual Report on Form 10-K filed with the SEC on March 14, 2025 and subsequently filed reports. In particular, the data discussed in this release is interim data and additional study and additional favorable results will be needed for development of GRI-0621 to continue; this interim data may not be indicative of later or final data for this trial. Forward-looking statements contained in this announcement are made as of this date, and the Company undertakes no duty to update such information except as required under applicable law. Investor Contact: JTC Team, LLC Jenene Thomas (908) 824-0775 [email protected]

Data presented at the 2025 American Thoracic Society (ATS) International Conference Pre-clinical and interim clinical results underscore GRI-0621’s potential to have both anti-inflammatory and anti-fibrotic effects in pulmonary fibrosis Results from 6-week interim analysis (n=24) in ongoing Phase 2a study of GRI-0621 for the treatment of Idiopathic Pulmonary Fibrosis (IPF) anticipated in Q2 2025 LA JOLLA, CA, May 22, 2025 (GLOBE NEWSWIRE) -- GRI Bio, Inc. (NASDAQ: GRI) (“GRI Bio” or the “Company”), a biotechnology company advancing an innovative pipeline of Natural Killer T (“NKT”) cell modulators for the treatment of inflammatory, fibrotic and autoimmune diseases, today announced the presentation of positive preclinical data demonstrating its lead program GRI-0621 has anti-inflammatory and anti-fibrotic effects in pulmonary fibrosis. The data was presented by Marc Hertz, PhD, Chief Executive Officer of GRI Bio in the poster titled, “Inactivation of iNKT Cells After the Inflammatory Phase Leads to Significant Inhibition of Fibroblast Activation and Fibrosis in a Model of Pulmonary Fibrosis,” as part of the D21 - IMMUNOLOGICAL INSIGHTS IN LUNG INFLAMMATION AND REPAIR session at the 2025 ATS International Conference held on Wednesday, May 21, 2025. “We continue believe GRI-0621 is a promising potential treatment option for IPF, an indication where there remains significant unmet need. Our growing body of pre-clinical results continue to bolster our understanding of the role of iNKT cell activity in driving pulmonary fibrosis and further support our ongoing Phase 2a study examining the safety and tolerability of GRI-0621 and its effect on various biomarkers in IPF patients. We remain encouraged by the progress made in our Phase 2a biomarker study and look forward to reporting additional data this year,” commented Marc Hertz, PhD, Chief Executive Officer of GRI Bio. The presented data highlights results from biochemical, qPCR and immunohistochemistry analyses, used to investigate whether iNKT cell inactivation during the fibrotic phase resolves lung injury, fibroblast activation, and fibrosis in the murine bleomycin model of pulmonary fibrosis. Key Highlights In a therapeutic regimen of the bleomycin-induced fibrosis model, orally administered GRI-0621 after completion of the inflammatory phase (Day 7), significantly inhibits lung injury and several important fibrotic cellular and molecular drivers of lung disease, including fibroblast activation and fibrosis. In a therapeutic regimen of the bleomycin-induced fibrosis model, orally administered GRI-0621 after completion of the inflammatory phase (Day 7), significantly inhibits lung injury and several important fibrotic cellular and molecular drivers of lung disease, including fibroblast activation and fibrosis. GRI-0621 demonstrated to impact key innate and adaptive cell activity, cytokine production, myofibroblast activation, and ECM deposition and fibrosis. GRI-0621 demonstrated to impact key innate and adaptive cell activity, cytokine production, myofibroblast activation, and ECM deposition and fibrosis. GRI-0621 inhibition of iNKT cell activity is therapeutic in treatment models of pulmonary fibrosis and performs as well or better than the approved drug nintedanib. GRI-0621 inhibition of iNKT cell activity is therapeutic in treatment models of pulmonary fibrosis and performs as well or better than the approved drug nintedanib. GRI Bio’s lead program, GRI-0621, is a small molecule RAR-βɣ dual agonist that inhibits the activity of human iNKT cells. GRI-0621 is currently being assessed in a 12-week, double-blind, randomized, placebo-controlled study in patients with IPF to assess the safety and tolerability of GRI-0621. In addition, the effect of GRI-0621 on a number of biomarkers both from the blood and bronchoalveolar lavage (BAL) will be evaluated. These include several biomarkers associated with disease progression, NKT cell and other immune cell numbers and activity, differential gene expression, as well as pulmonary function tests. As previously announced, the pre-planned interim analysis for 2-week safety results from the ongoing Phase 2a biomarker study demonstrated GRI-0621 (4.5mg orally once daily) to be safe and well-tolerated in the first 12 patients evaluated per protocol. Hyperlipidemia, as assessed by LDL, HDL and triglyceride (TG) levels, was not seen in the 12 patients assessed at the 2-week visit. There were no meaningful changes in HDL, LDL or TG levels in patients receiving GRI-0621. The interim analysis committee recommended the study should continue as planned. The interim results show that GRI-0621’s receptor selectivity is consistent with the toxicity profile observed in earlier studies evaluating oral tazarotene in over 1,700 patients treated for up to 52 weeks. Additionally, interim biomarker results from the first 12 subjects at 2 weeks were reviewed by the IDMC and determined that the change from baseline in PRO-C3 of GRI-0621-treated patients compared to placebo patients is suggestive of anti-fibrotic effect. Based on the available interim data reviewed, the IDMC has recommended the Phase 2a study evaluating GRI-0621 to continue as planned as there are no safety concerns seen to date. Topline results from the Phase 2a biomarker study are expected in the third quarter of 2025. For more information about the Phase 2a study, please visit clinicaltrials.gov and reference identifier NCT06331624. About GRI Bio, Inc. GRI Bio is a clinical-stage biopharmaceutical company focused on fundamentally changing the way inflammatory, fibrotic and autoimmune diseases are treated. GRI Bio’s therapies are designed to target the activity of Natural Killer T (“NKT”) cells, which are key regulators earlier in the inflammatory cascade, to interrupt disease progression and restore the immune system to homeostasis. NKT cells are innate-like T cells that share properties of both NK and T cells and are a functional link between the innate and adaptive immune responses. Type I invariant NKT (“iNKT”) cells play a critical role in propagating the injury, inflammatory response, and fibrosis observed in inflammatory and fibrotic indications. GRI Bio’s lead program, GRI-0621, is an inhibitor of iNKT cell activity and is being developed as a novel oral therapeutic for the treatment of idiopathic pulmonary fibrosis, a serious disease with significant unmet need. The Company is also developing a pipeline of novel type 2 diverse NKT (“dNKT”) agonists for the treatment of systemic lupus erythematosus. Additionally, with a library of over 500 proprietary compounds, GRI Bio has the ability to fuel a growing pipeline. Forward-Looking Statements This press release contains “forward-looking statements” within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as “anticipate,” “believe,” “contemplate,” “could,” “estimate,” “expect,” “intend,” “seek,” “may,” “might,” “plan,” “potential,” “predict,” “project,” “target,” “aim,” “should,” “will,” “would,” or the negative of these words or other similar expressions. These forward-looking statements are based on the Company’s current beliefs and expectations. Forward-looking statements include, but are not limited to, statements regarding: the Company’s expectations with respect to development and commercialization of the Company’s product candidates, the timing of initiation or completion of clinical trials and availability of resulting data, the potential benefits and impact of the Company’s clinical trials and product candidates and any implication that the data or results observed in preclinical trials or earlier studies or trials will be indicative of results of later studies or clinical trials, the Company’s beliefs and expectations regarding potential shareholder value and future financial performance, the Company’s beliefs and estimates about its cash and available resources and its ability to fund its planned operations through any particular date, the Company’s beliefs about the timing and outcome of regulatory approvals and potential regulatory approval pathways, the Company’s expected milestones in 2025, and the Company’s beliefs and expectations regarding the sufficiency of its existing cash and cash equivalents to fund its planned operations, its ability to raise additional funds, which may not be available to the Company on acceptable terms, or at all, and capital expenditure requirements. Actual results may differ from the forward-looking statements expressed by the Company in this press release and consequently, you should not rely on these forward-looking statements as predictions of future events. These forward-looking statements are subject to inherent uncertainties, risks and assumptions that are difficult to predict, including, without limitation: (1) the inability to maintain the listing of the Company’s common stock on The Nasdaq Capital Market and to comply with applicable listing requirements; (2) changes in applicable laws or regulations; (3) the inability of the Company to raise financing in the future; (4) the success, cost and timing of the Company’s product development activities; (5) the inability of the Company to obtain and maintain regulatory clearance or approval for its respective products, and any related restrictions and limitations of any cleared or approved product; (6) the inability of the Company to identify, in-license or acquire additional technology; (7) the inability of the Company to compete with other companies currently marketing or engaged in the development of products and services that the Company is currently developing; (8) the size and growth potential of the markets for the Company’s products and services, and their respective ability to serve those markets, either alone or in partnership with others; (9) the failure to achieve any milestones or receive any milestone payments under any agreements; (10) inaccuracy in the Company’s estimates regarding expenses, future revenue, capital requirements and needs for and the ability to obtain additional financing; (11) the Company’s ability to protect and enforce its intellectual property portfolio, including any newly issued patents; and (12) other risks and uncertainties indicated from time to time in the Company’s filings with the U.S. Securities and Exchange Commission (the “SEC”), including the risks and uncertainties described in the “Risk Factors” section of the Company’s most recent Annual Report on Form 10-K filed with the SEC on March 14, 2025 and subsequently filed reports. In particular, the data discussed in this release is interim data and additional study and additional favorable results will be needed for development of GRI-0621 to continue; this interim data may not be indicative of later or final data for this trial. Forward-looking statements contained in this announcement are made as of this date, and the Company undertakes no duty to update such information except as required under applicable law. Investor Contact: JTC Team, LLC Jenene Thomas (908) 824-0775 [email protected]

Positive interim 2-week safety and biomarker results from its ongoing Phase 2a study evaluating GRI-0621 for the treatment of Idiopathic Pulmonary Fibrosis (“IPF”) Continued momentum with completed patient enrollment for the 6-week interim analysis (n=24) and over two-thirds enrollment completed for the overall trial Cash runway expected to fund operations through Q3 2025 LA JOLLA, CA, May 15, 2025 (GLOBE NEWSWIRE) -- GRI Bio, Inc. (NASDAQ: GRI) (“GRI Bio” or the “Company”), a biotechnology company advancing an innovative pipeline of Natural Killer T (“NKT”) cell modulators for the treatment of inflammatory, fibrotic and autoimmune diseases, today reported its financial results for the quarter ended March 31, 2025 and provided a corporate update. “We continue to make very encouraging progress with our ongoing Phase 2a trial of our lead program, GRI-0621. Based on the positive interim safety and biomarker data observed in the first 12 patients at 2 weeks, the current momentum with patient enrollment, and the additional data readouts anticipated this year, we believe we are well-positioned to build near- and long-term value for shareholders,” commented Marc Hertz, PhD, Chief Executive Officer of GRI Bio. Recent Highlights Reported interim biomarker data demonstrating a positive trend towards an anti-fibrotic effect of GRI-0621 in first 12 patients of ongoing Phase 2a study in IPF; Reported interim biomarker data demonstrating a positive trend towards an anti-fibrotic effect of GRI-0621 in first 12 patients of ongoing Phase 2a study in IPF; Completed patient enrollment for the 6-week interim analysis (n=24) and completed over two-thirds of enrollment for the overall trial; Completed patient enrollment for the 6-week interim analysis (n=24) and completed over two-thirds of enrollment for the overall trial; Reported encouraging interim safety results from its ongoing Phase 2a study evaluating GRI-0621 for the treatment of IPF; Reported encouraging interim safety results from its ongoing Phase 2a study evaluating GRI-0621 for the treatment of IPF; Announced its abstract was selected for poster discussion at the 2025 American Thoracic Society (ATS) International Conference; Announced its abstract was selected for poster discussion at the 2025 American Thoracic Society (ATS) International Conference; Bolstered global intellectual property portfolio with granting of patents in Europe and Japan; and Bolstered global intellectual property portfolio with granting of patents in Europe and Japan; and Extended cash runway with closing of $5.0 million public offering. Extended cash runway with closing of $5.0 million public offering. Clinical Program Update GRI-0621: Type 1 Invariant NKT (“iNKT”) Antagonist in Development for the Treatment of IPF IPF is a rare chronic progressive pulmonary disease with abnormal scarring of the lung blocking the movement of oxygen into the bloodstream. Currently available treatments for IPF are limited with only two approved drugs that come with significant side-effects, limited compliance and no impact on overall survival1, leaving significant opportunity to augment IPF treatment with a new therapeutic. GRI Bio’s lead program, GRI-0621, is a small molecule RAR-βɣ dual agonist that inhibits the activity of human iNKT cells. In preliminary trials to date and previous trials with the oral formulation, GRI-0621 has been observed to improve fibrosis in multiple disease models and improve liver function tests and other markers of inflammation and injury in patients. As previously announced, the pre-planned interim analysis for 2-week safety results from the ongoing Phase 2a biomarker study demonstrated GRI-0621 (4.5mg orally once daily) to be safe and well-tolerated in the first 12 patients evaluated per protocol. Hyperlipidemia, as assessed by LDL, HDL and triglyceride (TG) levels, was not seen in the 12 patients assessed at the 2-week visit. There were no meaningful changes in HDL, LDL or TG levels in patients receiving GRI-0621. The interim analysis committee recommended the study should continue as planned. The interim results show that GRI-0621’s receptor selectivity is consistent with the toxicity profile observed in earlier studies evaluating oral tazarotene in over 1,700 patients treated for up to 52 weeks. Additionally, interim biomarker results from the first 12 subjects at 2 weeks were reviewed by the Independent Data Monitoring Committee (IDMC) and determined that the change from baseline in PRO-C3 of GRI-0621-treated patients compared to placebo patients is suggestive of anti-fibrotic effect. Based on the available interim data reviewed, the IDMC has recommended the Phase 2a study evaluating GRI-0621 to continue as planned as there are no safety concerns seen to date. Topline results from the Phase 2a biomarker study are expected in the third quarter of 2025. For more information about the Phase 2a study, please visit clinicaltrials.gov and reference identifier NCT06331624. Expected GRI-0621 Upcoming Milestones Q2 2025: Report 6-week interim results from Phase 2a biomarker study Q2 2025: Report 6-week interim results from Phase 2a biomarker study Q3 2025: Report topline results from Phase 2a biomarker study Q3 2025: Report topline results from Phase 2a biomarker study Summary of Financial Results for First Quarter 2025 Net loss was $3.0 million for the three months ended March 31, 2025. Research and development expenses were $1.6 million and $0.9 million for the three months ended March 31, 2025 and 2024, respectively. General and administrative expenses were $1.4 million and $1.0 million for the three months ended March 31, 2025 and 2024, respectively. As of March 31, 2025, the Company had cash and cash equivalents of approximately $3.3 million. Subsequent to the end of the quarter, the Company closed a public offering for aggregate gross proceeds of $5.0 million. Based on the Company’s current operating plan, the Company believes that its existing cash and cash equivalents will be sufficient to fund its operating expenses and capital expenditure requirements through Q3 2025. About GRI Bio, Inc. GRI Bio is a clinical-stage biopharmaceutical company focused on fundamentally changing the way inflammatory, fibrotic and autoimmune diseases are treated. GRI Bio’s therapies are designed to target the activity of Natural Killer T (“NKT”) cells, which are key regulators earlier in the inflammatory cascade, to interrupt disease progression and restore the immune system to homeostasis. NKT cells are innate-like T cells that share properties of both NK and T cells and are a functional link between the innate and adaptive immune responses. Type I invariant NKT (“iNKT”) cells play a critical role in propagating the injury, inflammatory response, and fibrosis observed in inflammatory and fibrotic indications. GRI Bio’s lead program, GRI-0621, is an inhibitor of iNKT cell activity and is being developed as a novel oral therapeutic for the treatment of idiopathic pulmonary fibrosis, a serious disease with significant unmet need. The Company is also developing a pipeline of novel type 2 diverse NKT (“dNKT”) agonists for the treatment of systemic lupus erythematosus. Additionally, with a library of over 500 proprietary compounds, GRI Bio has the ability to fuel a growing pipeline. Forward-Looking Statements This press release contains “forward-looking statements” within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as “anticipate,” “believe,” “contemplate,” “could,” “estimate,” “expect,” “intend,” “seek,” “may,” “might,” “plan,” “potential,” “predict,” “project,” “target,” “aim,” “should,” “will,” “would,” or the negative of these words or other similar expressions. These forward-looking statements are based on the Company’s current beliefs and expectations. Forward-looking statements include, but are not limited to, statements regarding: the Company’s expectations with respect to development and commercialization of the Company’s product candidates, the timing of initiation or completion of clinical trials and availability of resulting data, the potential benefits and impact of the Company’s clinical trials and product candidates and any implication that the data or results observed in preclinical trials or earlier studies or trials will be indicative of results of later studies or clinical trials, the Company’s beliefs and expectations regarding enrollment momentum and future enrollment, potential shareholder value and future financial performance, the Company’s beliefs and estimates about its cash and available resources and its ability to fund its planned operations through any particular date, the Company’s beliefs about the timing and outcome of regulatory approvals and potential regulatory approval pathways, the Company’s expected milestones in 2025, and the Company’s beliefs and expectations regarding the sufficiency of its existing cash and cash equivalents to fund its planned operations, its ability to raise additional funds, which may not be available to the Company on acceptable terms, or at all, and capital expenditure requirements. Actual results may differ from the forward-looking statements expressed by the Company in this press release and consequently, you should not rely on these forward-looking statements as predictions of future events. These forward-looking statements are subject to inherent uncertainties, risks and assumptions that are difficult to predict, including, without limitation: (1) the inability to maintain the listing of the Company’s common stock on The Nasdaq Capital Market and to comply with applicable listing requirements; (2) changes in applicable laws or regulations; (3) the inability of the Company to raise financing in the future; (4) the success, cost and timing of the Company’s product development activities; (5) the inability of the Company to obtain and maintain regulatory clearance or approval for its respective products, and any related restrictions and limitations of any cleared or approved product; (6) the inability of the Company to identify, in-license or acquire additional technology; (7) the inability of the Company to compete with other companies currently marketing or engaged in the development of products and services that the Company is currently developing; (8) the size and growth potential of the markets for the Company’s products and services, and their respective ability to serve those markets, either alone or in partnership with others; (9) the failure to achieve any milestones or receive any milestone payments under any agreements; (10) inaccuracy in the Company’s estimates regarding expenses, future revenue, capital requirements and needs for and the ability to obtain additional financing; (11) the Company’s ability to protect and enforce its intellectual property portfolio, including any newly issued patents; (12) the risk that interim or preliminary data or analysis is on representative of final data or analysis as addition clinical testing is required to evaluate safety and efficacy; and (13) other risks and uncertainties indicated from time to time in the Company’s filings with the U.S. Securities and Exchange Commission (the “SEC”), including the risks and uncertainties described in the “Risk Factors” section of the Company’s most recent Annual Report on Form 10-K filed with the SEC on March 14, 2025 and subsequently filed reports. In particular, the data discussed in this release is interim data and additional study and additional favorable results will be needed for development of GRI-0621 to continue; this interim data may not be indicative of later or final data for this trial. Forward-looking statements contained in this announcement are made as of this date, and the Company undertakes no duty to update such information except as required under applicable law. Investor Contact: JTC Team, LLC Jenene Thomas (908) 824-0775 [email protected] 1 T. M. Maher et al., Global incidence and prevalence of idiopathic pulmonary fibrosis. Respir Res 22, 197 (2021)

The Independent Data Monitoring Committee (IDMC) has recommended to continue study as planned as there are no safety concerns seen in the data reviewed Interim results demonstrate GRI-0621 to be safe and well-tolerated in the first 12 patients evaluated Interim biomarker data on track for Q2 2025 and topline results expected Q3 2025 Currently available treatments for IPF are limited to only two approved drugs that come with significant side-effects, limited patient compliance and no impact on survival LA JOLLA, CA, April 01, 2025 (GLOBE NEWSWIRE) -- GRI Bio, Inc. (NASDAQ: GRI) (“GRI Bio” or the “Company”), a biotechnology company advancing an innovative pipeline of Natural Killer T (“NKT”) cell modulators for the treatment of inflammatory, fibrotic and autoimmune diseases, today reported interim safety results from its ongoing Phase 2a study evaluating GRI-0621 for the treatment of Idiopathic Pulmonary Fibrosis (“IPF”). GRI-0621, is the Company’s small molecule RAR-βɣ dual agonist that inhibits the activity of human Type 1 Invariant NKT (“iNKT”) cells. In preliminary clinical trials to date and previous clinical trials with the oral formulation, GRI-0621 has been shown to improve fibrosis in multiple disease models and improve liver function tests and other markers of inflammation and injury in patients. The pre-planned interim analysis for 2-week safety results from the ongoing Phase 2a biomarker study demonstrated GRI-0621 (4.5mg orally once daily) to be safe and well-tolerated in the first 12 patients evaluated per protocol. Hyperlipidemia, as assessed by LDL, HDL and triglyceride (TG) levels, was not seen in the 12 patients assessed at the 2-week visit. There were no meaningful changes in HDL, LDL or TG levels in patients receiving GRI-0621, and all subjects remained within normal ranges. The interim analysis committee recommended the study should continue as planned. The interim results show that GRI-0621’s receptor selectivity is consistent with the toxicity profile observed in earlier studies evaluating oral tazarotene in over 1,700 patients treated for up to 52 weeks. Marc Hertz, PhD, Chief Executive Officer of GRI Bio commented, “While preliminary, in the first 12 subjects evaluated these results are encouraging and in line with our expectations. We believe these results, particularly the safety data, underscore GRI-0621’s potential to provide a much needed safe and effective treatment option for the treatment of IPF, where there remains significant unmet need. The two ant-fibrotic drugs currently approved for the treatment of IPF can slow the decline of lung function but are not curative, do not improve overall survival, and both come with significant side effects which limit their use. Based on the trends seen in these interim results, as well as the consistent toxicity profile with tazarotene, we believe GRI-0621 will continue to demonstrate that the molecule is safe and inhibits NKT cell activity in this patient population, providing much needed benefit to patients. Our team remains focused on driving enrollment and treatment in the study and we look forward to reporting topline data in the third quarter of 2025.” The Phase 2a, randomized, double-blind, multi-center, placebo-controlled, parallel-design, 2-arm study will enroll approximately 36 subjects with IPF whom will be randomized in a 2:1 ratio for GRI-0621 4.5mg or a placebo. GRI-0621 dose of 4.5mg will be compared with a dose of placebo following once daily oral administration for 12 weeks. Concurrently, a sub-study will examine the number and activity of NKT cells in bronchoalveolar lavage (“BAL”) fluid for up to 12 eligible subjects (across various centers). An interim analysis will be performed when 24 subjects (of which approximately 8 will be placebo subjects) complete 6 weeks of treatment. The primary endpoint for the study is safety and tolerability of oral GRI-0621 as assessed by clinical labs, vital signs and adverse events after 12 weeks of treatment. Secondary endpoints are baseline changes in serum biomarkers collected at week 6 and week 12; an assessment of the pharmacokinetics (PK) of GRI-0621 at the week 12 visit of treatment (steady state); and a determination of the pharmacodynamic activity of oral GRI-0621 as measured by inhibition of iNKT cell activation in blood after 6 weeks and 12 weeks, and from BAL fluid after 12 weeks of treatment in a sub-study. Additional exploratory endpoints for the study are to assess the effect of GRI-0621 on pulmonary function at baseline and after 6 weeks and 12 weeks of treatment and flow cytometry and differential gene expression at various time points. The Company expects to report interim biomarker data in Q2 2025. Topline results from the Phase 2a biomarker study are expected in the third quarter of 2025. For more information about the Phase 2a study, please visit clinicaltrials.gov and reference identifier NCT06331624. About GRI Bio, Inc. GRI Bio is a clinical-stage biopharmaceutical company focused on fundamentally changing the way inflammatory, fibrotic and autoimmune diseases are treated. GRI Bio’s therapies are designed to target the activity of Natural Killer T (“NKT”) cells, which are key regulators earlier in the inflammatory cascade, to interrupt disease progression and restore the immune system to homeostasis. NKT cells are innate-like T cells that share properties of both NK and T cells and are a functional link between the innate and adaptive immune responses. Type I invariant NKT (“iNKT”) cells play a critical role in propagating the injury, inflammatory response, and fibrosis observed in inflammatory and fibrotic indications. GRI Bio’s lead program, GRI-0621, is an inhibitor of iNKT cell activity and is being developed as a novel oral therapeutic for the treatment of idiopathic pulmonary fibrosis, a serious disease with significant unmet need. The Company is also developing a pipeline of novel type 2 diverse NKT (“dNKT”) agonists for the treatment of systemic lupus erythematosus. Additionally, with a library of over 500 proprietary compounds, GRI Bio has the ability to fuel a growing pipeline. Forward-Looking Statements This press release contains “forward-looking statements” within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as “anticipate,” “believe,” “contemplate,” “could,” “estimate,” “expect,” “intend,” “seek,” “may,” “might,” “plan,” “potential,” “predict,” “project,” “target,” “aim,” “should,” “will,” “would,” or the negative of these words or other similar expressions. These forward-looking statements are based on the Company’s current beliefs and expectations. Forward-looking statements include, but are not limited to, statements regarding: the Company’s expectations with respect to development and commercialization of the Company’s product candidates, the timing of initiation or completion of clinical trials and availability of resulting data, the potential benefits and impact of the Company’s clinical trials and product candidates and any implication that the data or results observed in preclinical trials or earlier studies or trials will be indicative of results of later studies or clinical trials, the Company’s beliefs and expectations regarding potential shareholder value and future financial performance, the Company’s beliefs and estimates about its cash and available resources and its ability to fund its planned operations through any particular date, the Company’s beliefs about the timing and outcome of regulatory approvals and potential regulatory approval pathways, the Company’s expected milestones in 2025, and the Company’s beliefs and expectations regarding the sufficiency of its existing cash and cash equivalents to fund its planned operations, its ability to raise additional funds, which may not be available to the Company on acceptable terms, or at all, and capital expenditure requirements. Actual results may differ from the forward-looking statements expressed by the Company in this press release and consequently, you should not rely on these forward-looking statements as predictions of future events. These forward-looking statements are subject to inherent uncertainties, risks and assumptions that are difficult to predict, including, without limitation: (1) the inability to maintain the listing of the Company’s common stock on The Nasdaq Capital Market and to comply with applicable listing requirements; (2) changes in applicable laws or regulations; (3) the inability of the Company to raise financing in the future; (4) the success, cost and timing of the Company’s product development activities; (5) the inability of the Company to obtain and maintain regulatory clearance or approval for its respective products, and any related restrictions and limitations of any cleared or approved product; (6) the inability of the Company to identify, in-license or acquire additional technology; (7) the inability of the Company to compete with other companies currently marketing or engaged in the development of products and services that the Company is currently developing; (8) the size and growth potential of the markets for the Company’s products and services, and their respective ability to serve those markets, either alone or in partnership with others; (9) the failure to achieve any milestones or receive any milestone payments under any agreements; (10) inaccuracy in the Company’s estimates regarding expenses, future revenue, capital requirements and needs for and the ability to obtain additional financing; (11) the Company’s ability to protect and enforce its intellectual property portfolio, including any newly issued patents; and (12) other risks and uncertainties indicated from time to time in the Company’s filings with the U.S. Securities and Exchange Commission (the “SEC”), including the risks and uncertainties described in the “Risk Factors” section of the Company’s most recent Annual Report on Form 10-K filed with the SEC on March 14, 2025 and subsequently filed reports. In particular, the data discussed in this release is interim data and additional study and additional favorable results will be needed for development of GRI-0621 to continue; this interim data may not be indicative of later or final data for this trial. Forward-looking statements contained in this announcement are made as of this date, and the Company undertakes no duty to update such information except as required under applicable law. Investor Contact: JTC Team, LLC Jenene Thomas (908) 824-0775 [email protected]

Interim data and topline data readouts from Phase 2a biomarker study expected in Q2 2025 and Q3 2025, respectively Cash runway expected to fund operations into Q2 2025, including interim data readout from GRI-0621 LA JOLLA, CA, March 17, 2025 (GLOBE NEWSWIRE) -- GRI Bio, Inc. (NASDAQ: GRI) (“GRI Bio” or the “Company”), a biotechnology company advancing an innovative pipeline of Natural Killer T (“NKT”) cell modulators for the treatment of inflammatory, fibrotic and autoimmune diseases, has reported its financial results for the fiscal year ended December 31, 2024 and today provided a corporate update. “Over the last year, we made significant progress on the development of our lead program GRI-0621 for the treatment of IPF. We continue to make strides towards our anticipated interim data readout and topline data readout which remain on track for the second and third quarter of 2025, respectively. We remain confident that the data observed to date, and the additional data readouts anticipated this year, will position us to build momentum and drive value for shareholders in the near and long term,” commented Marc Hertz, PhD, Chief Executive Officer of GRI Bio. Recent Highlights Presented positive preclinical data demonstrating its lead program GRI-0621 reduces important inflammatory and fibrotic drivers in IPF at the 8th Annual Antifibrotic Drug Development Summit; and Presented positive preclinical data demonstrating its lead program GRI-0621 reduces important inflammatory and fibrotic drivers in IPF at the 8th Annual Antifibrotic Drug Development Summit; and Granted European patent covering GRI-0803 and the Company’s library of 500+ proprietary compounds. Granted European patent covering GRI-0803 and the Company’s library of 500+ proprietary compounds. GRI-0621: Type 1 Invariant NKT (“iNKT”) Antagonist in Development for the Treatment of IPF. IPF is a rare chronic progressive pulmonary disease with abnormal scarring of the lung blocking the movement of oxygen into the bloodstream. Currently available treatments for IPF are limited with only two approved drugs that come with significant side-effects, limited compliance and no impact on overall survival1, leaving significant opportunity to augment IPF treatment with a new therapeutic. GRI Bio’s lead program, GRI-0621, is a small molecule RAR-βɣ dual agonist that inhibits the activity of human iNKT cells. In preliminary trials to date and previous trials with the oral formulation, GRI-0621 has been shown to improve fibrosis in multiple disease models and improve liver function tests and other markers of inflammation and injury in patients. The Company plans to leverage the 505(b)(2) regulatory pathway for this candidate. For more information about the Phase 2a study, please visit clinicaltrials.gov and reference identifier NCT06331624. Expected GRI-0621 Upcoming Milestones Q2 2025: Report interim data from Phase 2a biomarker study Q2 2025: Report interim data from Phase 2a biomarker study Q3 2025: Report topline results from Phase 2a biomarker study Q3 2025: Report topline results from Phase 2a biomarker study Summary of Financial Results for Full Year 2024 Net loss was $8.2 million for the year ended December 31, 2024. Research and development expenses were $3.8 million and $3.2 million for the years ended December 31, 2024 and 2023, respectively. The $0.6 million increase in research and development expenses was primarily due to increased expenses related to the registrational development program of GRI-0621. General and administrative expenses were $4.5 million and $8.2 million for the years ended December 31, 2024 and 2023, respectively. The $3.7 million decrease was primarily due to a decrease of $3.4 million in accounting, legal, investment banking and other fees related to the merger with Vallon Pharmaceuticals, Inc. in April 2023. As of December 31, 2024, the Company had cash and cash equivalents of approximately $5.0 million. Based on the Company’s current operating plan, the Company believes that its existing cash and cash equivalents will be sufficient to fund its operating expenses and capital expenditure requirements into the second quarter of 2025. About GRI Bio, Inc. GRI Bio is a clinical-stage biopharmaceutical company focused on fundamentally changing the way inflammatory, fibrotic and autoimmune diseases are treated. GRI Bio’s therapies are designed to target the activity of NKT cells, which are key regulators earlier in the inflammatory cascade, to interrupt disease progression and restore the immune system to homeostasis. NKT cells are innate-like T cells that share properties of both NK and T cells and are a functional link between the innate and adaptive immune responses. iNKT cells play a critical role in propagating the injury, inflammatory response, and fibrosis observed in inflammatory and fibrotic indications. GRI Bio’s lead program, GRI-0621, is an inhibitor of iNKT cell activity and is being developed as a novel oral therapeutic for the treatment of idiopathic pulmonary fibrosis, a serious disease with significant unmet need. The Company is also developing a pipeline of novel type 2 diverse NKT agonists for the treatment of systemic lupus erythematosus. Additionally, with a library of over 500 proprietary compounds, GRI Bio has the ability to fuel a growing pipeline. Forward-Looking Statements This press release contains “forward-looking statements” within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as “anticipate,” “believe,” “contemplate,” “could,” “estimate,” “expect,” “intend,” “seek,” “may,” “might,” “plan,” “potential,” “predict,” “project,” “target,” “aim,” “should,” “will,” “would,” or the negative of these words or other similar expressions. These forward-looking statements are based on the Company’s current beliefs and expectations. Forward-looking statements include, but are not limited to, statements regarding: the Company’s expectations with respect to development and commercialization of the Company’s product candidates, the timing of initiation or completion of clinical trials and availability of resulting data, the potential benefits and impact of the Company’s clinical trials and product candidates and any implication that the data or results observed in preclinical trials or earlier studies or trials will be indicative of results of later studies or clinical trials, the Company’s beliefs and expectations regarding potential shareholder value and future financial performance, the Company’s beliefs and estimates about its cash and available resources and its ability to fund its planned operations through any particular date, the Company’s beliefs about the timing and outcome of regulatory approvals and potential regulatory approval pathways, the Company’s expected milestones in 2025, and the Company’s beliefs and expectations regarding the sufficiency of its existing cash and cash equivalents to fund its planned operations, its ability to raise additional funds, which may not be available to the Company on acceptable terms, or at all, and capital expenditure requirements. Actual results may differ from the forward-looking statements expressed by the Company in this press release and consequently, you should not rely on these forward-looking statements as predictions of future events. These forward-looking statements are subject to inherent uncertainties, risks and assumptions that are difficult to predict, including, without limitation: (1) the inability to maintain the listing of the Company’s common stock on The Nasdaq Capital Market and to comply with applicable listing requirements; (2) changes in applicable laws or regulations; (3) the inability of the Company to raise financing in the future; (4) the success, cost and timing of the Company’s product development activities; (5) the inability of the Company to obtain and maintain regulatory clearance or approval for its respective products, and any related restrictions and limitations of any cleared or approved product; (6) the inability of the Company to identify, in-license or acquire additional technology; (7) the inability of the Company to compete with other companies currently marketing or engaged in the development of products and services that the Company is currently developing; (8) the size and growth potential of the markets for the Company’s products and services, and their respective ability to serve those markets, either alone or in partnership with others; (9) the failure to achieve any milestones or receive any milestone payments under any agreements; (10) inaccuracy in the Company’s estimates regarding expenses, future revenue, capital requirements and needs for and the ability to obtain additional financing; (11) the Company’s ability to protect and enforce its intellectual property portfolio, including any newly issued patents; and (12) other risks and uncertainties indicated from time to time in the Company’s filings with the U.S. Securities and Exchange Commission (the “SEC”), including the risks and uncertainties described in the “Risk Factors” section of the Company’s most recent Annual Report on Form 10-K filed with the SEC on March 14, 2025 and subsequently filed reports. Forward-looking statements contained in this announcement are made as of this date, and the Company undertakes no duty to update such information except as required under applicable law. Investor Contact: JTC Team, LLC Jenene Thomas (908) 824-0775 [email protected] 1 T. M. Maher et al., Global incidence and prevalence of idiopathic pulmonary fibrosis. Respir Res 22, 197 (2021)