SLS Stock Clocks Three Straight Weeks Of Gains On Cancer Vaccine Spillover, REGAL Trial Data Anticipation

• The rally draws key context from Wednesday’s advance, when SLS gained about 6% after Maxim Group analysts linked the stock to strong late-stage results from Moderna and Merck’s individualized mRNA cancer vaccine in melanoma.
• SELLAS’s lead candidate, galinpepimut-S (GPS), is in the pivotal late-stage REGAL study for patients with acute myeloid leukemia in second complete remission.
• By May, 78 of the 80 required events for final analysis had already occurred, with the company stating that analysis would begin once the 80th event was reached.

Shares of Sellas Life Sciences Group Inc (SLS) jumped 15% on Friday, building on recent gains and reflecting growing optimism that positive developments in the broader cancer vaccine space could signal upside for the company’s late-stage pipeline.

The stock has gained nearly 21% in the past five days, marking its best week since late June and its third consecutive week of price appreciation. 

Positive Spillover From Moderna-Merck Results

The rally draws key context from Wednesday’s advance, when SLS gained about 6% after Maxim Group analysts linked the stock to strong late-stage results from Moderna and Merck’s individualized mRNA cancer vaccine in melanoma. That trial met its primary goal of prolonging recurrence-free survival when combined with the popular cancer drug Keytruda. Maxim called the outcome a “win for cancer vaccines,” arguing similar enthusiasm could lift SELLAS if its own GPS program succeeds, while maintaining a Buy rating and $30 price target. 

Earlier this month, Alliance Global Partners also raised its target on SLS to $35 from $25, maintaining a Buy rating, citing pipeline strength ahead of the GPS readout. 

Anticipation Builds For REGAL Trial

SELLAS’s lead candidate, galinpepimut-S (GPS), is in the pivotal late-stage REGAL study for patients with acute myeloid leukemia in second complete remission. By May, 78 of the 80 required events for final analysis had already occurred, with the company stating that analysis would begin once the 80th event was reached. Topline results remain event-driven and could arrive soon. Management stays blinded but plans to enter a quiet period after the 80th event announcement until analysis. 

Sellas is also advancing SLS009 (tambiciclib) in newly diagnosed first-line AML. Data from the ongoing mid-stage trial of the candidate is expected in the fourth quarter of 2026.

How Did Retail Traders React?

On Stocktwits, retail sentiment around SLS stock rose from ‘bullish’ to ‘extremely bullish’ over the past 24 hours, while message volume remained ‘high.’

Stocktwits users see the announcement of the 80th event and subsequent commencement of analysis driving the stock as high as $40.

Another user said that there is too much bottled-up pressure waiting to drive the stock higher on a positive data release from the REGAL trial.

A third user, however, recommended selling to make profits as the stock rallies, stating that the stock would go down when the 80th event announcement doesn’t materialize. 

According to Koyfin data, SLS has a 12-month average price target of $32.50, implying potential upside of over 100% from the stock’s current trading level.

SLS stock has rallied over 300% year-to-date.

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