SLS

– Contract Research Organization for the Pivotal Phase 3 REGAL Trial of Galinpepimut-S (GPS) in Acute Myeloid Leukemia (AML) Informed the Company that 78 Events have Occurred in the Trial as of May 11, 2026; SELLAS Remains Blinded to Trial Outcomes – – Final Analysis of REGAL Trial of GPS in AML to be Conducted Following the 80th Event – – Ongoing Dosing of Patients in Phase 2 Trial of SLS009 in Newly Diagnosed First Line AML – – $107.1 Million in Cash and Cash Equivalents as of March 31, 2026; Additional $7.5 Million in Proceeds Received in Q2 2026 to Date through Warrant Exercises – NEW YORK, May 12, 2026 (GLOBE NEWSWIRE) -- SELLAS Life Sciences Group, Inc. (NASDAQ: SLS) (“SELLAS’’ or the “Company”), a late-stage clinical biopharmaceutical company focused on the development of novel therapies for a broad range of cancer indications, today reported financial results for the first quarter ended March 31, 2026, and provided a corporate update. “The first quarter of 2026 marked an important period for SELLAS as we continued to execute across our clinical programs while preparing for the anticipated pivotal Phase 3 REGAL trial data readout,” said Angelos Stergiou, MD, ScD h.c., President and Chief Executive Officer of SELLAS. “We are grateful for the ongoing commitment of the patients, caregivers, and investigators participating in the pivotal Phase 3 REGAL trial and we believe that the upcoming results, triggered by reaching the pre-specified 80th event, will be an important milestone for the Company.” “In parallel, we are generating increasingly compelling data with SLS009, including recent preclinical findings presented at AACR demonstrating potent, mechanistically driven activity in AML through suppression of key survival pathways such as MCL-1 and induction of apoptosis, including in high-risk genetic subtypes like TP53 and ASXL1 mutations. Importantly, we have begun dosing patients in our Phase 2 study of SLS009 in newly diagnosed, first-line AML, targeting high-risk populations unlikely to benefit from standard therapies, including venetoclax. With REGAL approaching its critical readout and SLS009 advancing across clinical and translational fronts, we believe that SELLAS is entering an exciting time with multiple, high-value potential catalysts that could transform the AML treatment landscape.” Recent Corporate Highlights: Phase 3 REGAL Trial of GPS: Ong...

– Continued Advancement of Pivotal Phase 3 REGAL Trial of Galinpepimut-S (GPS) in Acute Myeloid Leukemia (AML) - Final Analysis upon Reaching 80 Events – – First Patient Dosed in Phase 2 Trial of SLS009 in Newly Diagnosed First Line AML – – Reported Positive Phase 2 Data of SLS009 in Relapsed/Refractory (r/r) AML at ASH 2025 – – $71.8 Million in Cash and Cash Equivalents as of December 31, 2025; Additional $42.6 Million in Proceeds Received in Q1 2026 to Date Through Warrant Exercises – NEW YORK, March 19, 2026 (GLOBE NEWSWIRE) -- SELLAS Life Sciences Group, Inc. (NASDAQ: SLS) (“SELLAS’’ or the “Company”), a late-stage clinical biopharmaceutical company focused on the development of novel therapies for a broad range of cancer indications, today reported financial results for the full year ended December 31, 2025, and provided a corporate update. “Based upon continued progress in our GPS and SLS009 clinical programs in AML, we believe 2026 is shaping up to be a pivotal year for SELLAS,” said Angelos Stergiou, MD, ScD h.c., President and Chief Executive Officer of SELLAS. “We are advancing toward the final analysis of our Phase 3 REGAL trial evaluating GPS in AML patients who have achieved complete remission following second-line salvage therapy. Once we reach the required pre-specified 80th event, which will be announced, we will proceed with the necessary procedures towards database lock completion, statistical analysis, unblinding, and disclosure of topline results. If positive, REGAL could position GPS as a first- and best-in-class immunotherapeutic option in this AML population and serve as a significant value-inflection point for SELLAS.” Dr. Stergiou continued, “We also continue to make significant progress in our SLS009 clinical program for AML. Following the positive Phase 2 results of SLS009 in r/r AML presented at ASH, particularly in high-risk molecular subtypes, we have now dosed the first patient in the expansion cohort, which is evaluating SLS009 in newly diagnosed, first-line AML patients. Additionally, our preclinical data presented at ESMO in T-PLL demonstrated a statistically significant survival benefit of SLS009 both as monotherapy and in combination with venetoclax in a patient-derived xenograft model, further supporting the breadth of the CKD9 inhibition strategy. With a catalyst rich outlook, continued clinical execution, our strongest...

– Hosted Virtual R&D Day Highlighting GPS and SLS009 Programs in AML – – Positive Phase 2 Data for SLS009 in R/R AML Accepted for Presentation at ASH 2025; Initiation of Trial Including Newly Diagnosed First-Line AML Patients Expected in Q1 2026 – – $44.3 Million in Cash and Cash Equivalents as of September 30, 2025; Additional $29.1 Million in Proceeds Received in October 2025 through Warrant Exercises – NEW YORK, Nov. 12, 2025 (GLOBE NEWSWIRE) -- SELLAS Life Sciences Group, Inc. (NASDAQ: SLS) (“SELLAS’’ or the “Company”), a late-stage clinical biopharmaceutical company focused on the development of novel therapies for a broad range of cancer indications, today reported financial results for the third quarter ended September 30, 2025, and provided a corporate update. “We remain highly encouraged by the continued, strong execution across our programs and the expanding body of clinical and preclinical data reinforcing the strength of our AML-focused pipeline,” said Angelos Stergiou, MD, ScD h.c., President and Chief Executive Officer of SELLAS. “The Phase 3 REGAL trial of GPS is advancing as planned as highlighted by the key opinion leaders at our recent R&D event. Momentum around SLS009 also continues to build—our positive Phase 2 data were accepted for presentation at the upcoming ASH Annual Meeting, and we recently presented preclinical results at ESMO demonstrating clear survival benefits in T-PLL.” Dr. Stergiou continued, “Our recent R&D Day was a resounding success and provided an excellent opportunity to share program updates and hear directly from leading experts who expressed genuine enthusiasm for both GPS and SLS009. These achievements highlight the breadth and promise of our pipeline and underscore the complementary potential of our two programs to meaningfully improve outcomes for patients with AML and other hematologic cancers. With a strong financial foundation following the recent warrant exercises and multiple catalysts ahead, we believe SELLAS is entering a transformative period of growth and value creation.” Recent Corporate Highlights: Phase 3 REGAL Trial of GPS: Following the positive IDMC recommendation announced in August to continue the trial without modification, the Phase 3 REGAL trial of GPS in patients with acute myeloid leukemia (AML) who have achieved complete remission following second-line salvage therapy (CR2) remains on track...

- Positive IDMC Recommendation to Continue Pivotal Phase 3 REGAL Trial of Galinpepimut-S (GPS) in AML Without Modification; Final Analysis Anticipated by Year-end 2025 – - Reported Positive Phase 2 Results of SLS009 in Relapsed/Refractory (r/r) Acute Myeloid Leukemia (AML) with Trial Meeting All Primary Endpoints; Full Data Presentation Expected Later This Year - - Alignment with FDA to Advance SLS009 in a First-Line AML Trial with Enrollment Anticipated by Q1 2026 - - $25.3 million in Cash and Cash Equivalents as of June 30, 2025; Additional $4.0 million Proceeds Received in July 2025 for Warrant Exercises - NEW YORK, Aug. 12, 2025 (GLOBE NEWSWIRE) -- SELLAS Life Sciences Group, Inc. (NASDAQ: SLS) (“SELLAS’’ or the “Company”), a late-stage clinical biopharmaceutical company focused on the development of novel therapies for a broad range of cancer indications, today reported financial results for the second quarter ended June 30, 2025, and provided a corporate update. “We continue to make significant progress in advancing our AML-focused pipeline, as demonstrated by the positive Phase 2 results evaluating our novel CDK9 inhibitor, SLS009, for the treatment of r/r AML,” said Angelos Stergiou, MD, ScD h.c., President and Chief Executive Officer of SELLAS. “The Phase 2 trial met all primary endpoints, achieving a 44% response rate among patients with Acute Myeloid Leukemia-Myelodysplasia-Related Changes (AML-MRC), which at the optimal dose level, nearly tripled the median overall survival compared to a historical benchmark. Based on the strength of these data, we conducted an end-of-Phase 2 meeting and the FDA recommended advancing SLS009 into the front-line setting for AML. We are now preparing an 80-patient trial that is focused on newly diagnosed and early refractory to venetoclax and azacitidine AML patients, with enrollment anticipated to begin by Q1 2026.” Dr. Stergiou continued, “During the quarter, we also presented promising preclinical data at ASCO supporting SLS009 as a potential targeted therapy for ASXL1 mutated colorectal cancer and strengthened our scientific leadership with the addition of three world-class oncology experts to our Scientific Advisory Board. With the final pivotal Phase 3 REGAL data of GPS in AML expected by year-end, positive Phase 2 data of SLS009 in r/r AML, and our upcoming ESMO presentation showcasing SLS009’s impact in T-PL...

– Announced Positive Overall Survival in Cohort 3 from the Ongoing Phase 2 Trial of SLS009 (tambiciclib) in Relapsed/Refractory (r/r) Acute Myeloid Leukemia (AML) Demonstrating 8.9 mOS in AML-MRC and 8.8 mOS in All r/r to Venetoclax-Based Regimens Patients – – SLS009 Shows Promising Efficacy in Pediatric Acute Lymphoblastic Leukemia (ALL) Xenograft Models – – Final Analysis of Pivotal Phase 3 REGAL Trial of Galinpepimut-S (GPS) in AML Anticipated in 2025 – – $28.4 million in Cash and Cash Equivalents as of March 31, 2025; Additional $4.0 million Proceeds received in April 2025 through Warrant Exercises – NEW YORK, May 13, 2025 (GLOBE NEWSWIRE) -- SELLAS Life Sciences Group, Inc. (NASDAQ: SLS) (“SELLAS” or the “Company”), a late-stage clinical biopharmaceutical company focused on the development of novel therapies for a broad range of cancer indications, today reported financial results for the first quarter ended March 31, 2025, and provided a corporate update. “We are very encouraged by the strong momentum across our pipeline,” said Angelos Stergiou, MD, ScD h.c., President and Chief Executive Officer of SELLAS. “The positive overall survival data in cohort 3 from the ongoing Phase 2 trial of SLS009 in r/r AML, showing a median OS that exceeds all historical benchmarks by over 3 times, further underscores the transformative potential of SLS009 for many underserved patients. In parallel, our new preclinical findings demonstrating the ability of SLS009 to overcome TP53-driven resistance, along with the promising clinical efficacy from the ongoing Phase 2, give us renewed optimism for patients across different genetic AML mutations. We look forward to presenting further data on SLS009 at ASCO, highlighting its preclinical efficacy in ASXL1-mutated colorectal cancer lines. With the full topline Phase 2 data of SLS009 anticipated soon, and the final analysis of our Phase 3 pivotal REGAL trial of GPS in AML expected later this year, we are well-positioned for an exciting and meaningful 2025.” Recent Corporate Highlights: Announced Positive Overall Survival in Cohort 3 from the Ongoing Phase 2 Trial of SLS009 in r/r AML: The data demonstrated that patients with AML-Myelodysplasia-Related Changes (AML-MRC) achieved a mOS of 8.9 months, while all relapsed or refractory to venetoclax-based regimens patients receiving 30 mg BIW achieved a mOS of 8.8 months, far surpas...

– Announced Positive Outcome of Interim Analysis for its Pivotal Phase 3 REGAL Trial of Galinpepimut-S (GPS) in Acute Myeloid Leukemia (AML) with Next and Final Analysis Planned Upon Reaching 80 Events, Anticipated in 2025 – – Reported Positive Overall Survival and Overall Response Rate Data from the Ongoing Phase 2 Trial of SLS009 (Tambiciclib) in r/r AML – Full Data and FDA Regulatory Path Feedback Expected in 1H 2025 – – Raised $25 Million in Gross Proceeds in a Registered Direct Offering in January 2025 – NEW YORK, March 20, 2025 (GLOBE NEWSWIRE) -- SELLAS Life Sciences Group, Inc. (NASDAQ: SLS) (“SELLAS’’ or the “Company”), a late-stage clinical biopharmaceutical company focused on the development of novel therapies for a broad range of cancer indications, today reported financial results for the full year ended December 31, 2024, and provided a corporate update. “We are pleased with the progress of our pipeline as we continue to advance our two key assets through clinical development,” said Angelos Stergiou, MD, ScD h.c., President and Chief Executive Officer of SELLAS. “The most anticipated milestones in 2025 will be the final analysis of our Phase 3 pivotal REGAL trial of GPS in acute myeloid leukemia (AML) and the full topline Phase 2 data of SLS009 in AML, both of which represent significant opportunities and offer hope to AML patients in need. If successful, the REGAL trial provides a pathway for regulatory approval in AML, and GPS could become a transformative treatment for patients in their second complete remission. Furthermore, the promising data from the ongoing Phase 2 trial of SLS009 has shown a 56% overall response rate (ORR) in AML patients with myelodysplasia-related changes (AML MRC) prospectively enrolled in two expansion cohorts, exceeding the prespecified target ORR of 33%. In the optimal dosing regimen of 30 mg BIW, the median overall survival (mOS) has not been reached but exceeds 7.7 months at the latest follow-up, where the expected mOS is historically approximately 2.5 months.” Dr. Stergiou continued, “We are especially encouraged by the multiple regulatory designations granted to our programs in 2024, including three FDA Rare Pediatric Disease Designations, one FDA Fast Track Designation, and two EMA Orphan Drug Designations, which reflect the significant potential impact of our therapies and provide valuable regulatory benefit...