SELLAS Life Sciences Group (NASDAQ: SLS) ended the trading day today with a gain in excess of 14% as investors speculated about a potential acquisition of the clinical-stage cancer drug developer.

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The speculation followed a LinkedIn post from CEO Angelos Stergiou marking the company's 15th anniversary. Stergiou discussed SELLAS' progress developing two experimental cancer treatments, galinpepimut-S (GPS) and SLS009, and expressed optimism about the company's future.

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Some retail investors interpreted the message as a possible signal that a major announcement could be approaching.

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On Stocktwits, investors floated potential acquisition valuations ranging from $40 billion to $120 billion, with some predicting share prices as high as $540. To be sure, those numbers are highly speculative. SELLAS hasn't announced an acquisition agreement, confirmed that it's negotiating a sale, or disclosed any offer from a potential buyer.

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The real catalyst is a Phase 3 leukemia trial

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SELLAS is approaching a critical milestone in its Phase 3 REGAL trial, which is evaluating GPS in patients with acute myeloid leukemia (AML). If you’re unfamiliar, AML is an aggressive form of blood cancer that begins in the bone marrow. Even after successful treatment, the disease frequently returns, leaving patients with limited options.

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GPS is an experimental immunotherapy designed to stimulate the immune system to recognize cancer cells expressing a protein called WT1. The REGAL trial is evaluating whether GPS can extend overall survival in patients who have achieved a second remission following additional treatment.

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Unlike clinical trials that conclude after a predetermined period, REGAL is event-driven. Its final analysis is triggered after 80 patient deaths. As of May 11, 2026, SELLAS had reported 78 deaths, leaving just two additional events needed to trigger the final analysis.

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The company has not publicly confirmed that the 80-event threshold has been reached.

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Another leukemia treatment is advancing

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SELLAS also has SLS009, an experimental drug designed to inhibit CDK9, an enzyme involved in regulating the growth and survival of certain cancer cells.

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The company is evaluating SLS009 in a Phase 2 trial involving patients with newly diagnosed AML whose disease becomes resistant to standard treatment. The 80-patient study is expected to produce additional data in the fourth quarter of 2026.

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Having two clinical-stage programs gives SELLAS more than one opportunity to demonstrate the potential of its cancer treatments. However, neither drug has received regulatory approval, and both still face clinical and commercialization risks.

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Could SELLAS become an acquisition target?

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A successful Phase 3 REGAL trial could substantially improve SELLAS' position.

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Positive overall survival data would strengthen the company's case for regulatory approval and could make GPS more attractive to larger pharmaceutical companies looking to expand their oncology portfolios.

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Investors are also watching the American Society of Hematology's annual meeting in December, where SELLAS plans to exhibit alongside several major pharmaceutical companies.

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Some traders have interpreted the company's conference presence as another possible indication of acquisition interest. But exhibiting at an industry conference isn't evidence of an impending buyout. Nor does an optimistic anniversary message from management indicate that acquisition negotiations are underway.

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For now, the company's clinical results offer a more credible basis for evaluating its prospects than the extraordinary buyout valuations circulating on social media.

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