Exhibit 99.1 SELLAS Life Sciences Reports First Quarter 2025 Financial Results and Provides Corporate Update – 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– NEW YORK, NY May 13, 2025 -- SELLAS Life Sciences Group, Inc. (NASDAQ: SLS) ("SELLAS'' or the "Company"), a late-stage clinical biopharmaceutical ...

– 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 ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 ________________________________ FORM 10-Q ________________________________ ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number: 001-33958 7 Times Square, Suite 2503, New York, NY 10036 (646) 200-5278 (Address, including zip code, and tele ...

New Data Suggest SLS009 (tambiciclib) May Overcome Resistance to Azacitidine-Venetoclax Regimen and Trigger Apoptosis of TP53 Mutated AML CellsNEW YORK, April 28, 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 announced that preclinical efficacy of SLS009 in TP53 mutated Acute Myeloid Leukemia (AML) cells are being ...

- ASCO Presentation to Highlight Preclinical Efficacy of SLS009 (tambiciclib) in ASXL1 Mutated Colorectal Cancer -NEW YORK, April 23, 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 announced that preclinical efficacy of SLS009 in ASXL1 mutated colorectal cancer lines will be presented at the 2025 American Society of ...

- 8.9 Months Median Overall Survival (mOS) in Patients with AML-Myelodysplasia-Related Changes (AML-MRC) and 8.8 mOS in All Relapsed or Refractory to Venetoclax-Based Regimens Patients; Surpassing Historical Benchmark of 2.5 Months - - Overall Response Rate (ORR) of 67% Achieved in Patients with AML-MRC (Target Patient Population of SLS009 in r/r AML) – Exceeding Targeted 20% ORR - - Trial Continues with Full Data and FDA Regulatory Path Feedback Expected in 1H 2025 – NEW YORK, April 08, 2025 (GLOBE NEWSWIR ...

Exhibit 99.1 SELLAS Life Sciences Reports Full Year 2024 Financial Results and Provides Corporate Update NEW YORK, NY March 20, 2025 -- 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 ...

– 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 ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 ________________________________ FORM 10-K ________________________________ (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from _________ to _________ Commission File Number: 001-33958 SELLAS Life Sciences G ...

HIGHLIGHTS: Solaris has formed an Inter-Institutional working group with the Arutam Shuar People (“PSHA”), ratified through the signing of a Letter of Intent (“LOI”) The Company has formed an Inter-Institutional working group with the PSHA, together with our host communities of Warints and Yawi and the Ecuadorian StateThe PSHA and its Governing Council ratified this process through the signing of a LOI aimed at advancing dialogue in order to reach a future cooperation agreement Expanded Infill resource dri ...