SLS Stock Hits Over 4-Year High: CEO Eyes FDA Talks, ‘Whole Gamut’ Of Cancer Uses For GPS

• CEO Angelos Stergiou said survival in the Regal study appeared “unexpectedly long” and reiterated his bullish view on the probability of a successful outcome.
• Stergiou also outlined a potential FDA pathway, saying Sellas could pursue a pre-BLA meeting and filing shortly after positive topline data are announced.
• Investors are also watching Sellas’ second drug, SLS009, following encouraging Phase 2 data and its “extraordinary synergy” with venetoclax in patients with resistant AML.

Shares of Sellas Life Sciences Group (SLS) surged to their highest level in over four years on Wednesday as investors bet the company’s acute myeloid leukemia (AML) study may be nearing a major breakthrough, with CEO Angelos Stergiou discussing potential FDA talks and broader expansion plans for GPS.

SLS stock jumped 18% on Wednesday, on track to post its fourth straight week of gains. 

Strong GPS Survival Fuels SLS Optimism

The rally comes as Sellas approaches the final analysis stage of its Phase 3 Regal study evaluating galinpepimut-S (GPS) in AML patients who entered second remission after salvage therapy. The company recently disclosed that the study had reached 78 events as of May 11, leaving only two events remaining before the trial reaches the threshold required for topline data release.

Speaking at A.G.P.’s Annual Virtual Healthcare Conference on Wednesday, Stergiou said that survival in the Regal study appeared stronger than initially expected: “Indeed, survival times in the REGAL study appear unexpectedly long,” Stergiou said.

The CEO reiterated that the delayed timing to the final event may improve the probability of a successful outcome. “Every passing month, as I've often said, may increase the probability of a successful study due to a potential GPS effect,” he said.

The company previously said that Regal would be considered successful if GPS extends median overall survival to 12.6 months compared with 8.1 months for patients receiving standard treatment.

Sellas CEO: Regal Timing Has 'Surpassed' Expectations

The A.G.P. conference is the second summit Sellas is participating in this week, following the Stifel 2026 Targeted Oncology Virtual Forum, where Stergiou acknowledged that the Regal timeline has already extended well beyond the company’s original assumptions.

“The initial assumption was, once the last patient was enrolled, which happened around March of 2024, we expected between 12 and 15 months or so to hit the 80th event. Obviously, that has surpassed the timing,” Stergiou said.

Stergiou noted that Sellas remains blinded to the Regal results but said, “My personal belief is that there's a very good chance that GPS will mimic survival data, what we had seen in the phase II study, and potentially even better.” 

Sellas Maps Out Potential FDA Path

At the recent A.G.P. conference, Stergiou also outlined potential next regulatory steps if Regal delivers positive data. “With top-line data available, we will do the necessary work for a pre-BLA meeting with the agency, and assuming positive outcome, we'll be in a position to file shortly thereafter,” he said.

Stergiou added that a successful Regal outcome could make GPS the first approved maintenance immunotherapy in AML patients after second remission. 

Beyond the upcoming AML catalyst, Stergiou also highlighted a potentially larger opportunity for GPS from Wilms’ Tumor 1 (WT1), the cancer target the therapy is designed to attack. “GPS targets the number one-ranked cancer antigen by the NCI, Wilms’ Tumor 1,” Stergiou said. He added that WT1 is expressed across multiple cancer types beyond leukemia.

“There are about 20 tumor types that have this WT1 expression,” he said. “Assuming positive data, GPS could potentially be developed in other WT1-expressing tumor types as well.” Stergiou added: “There’s obviously a whole gamut of indications that one could go after.”

The company has already evaluated GPS in ovarian cancer, mesothelioma and multiple myeloma, while Sellas also hinted at potential in combination with bone marrow transplant and checkpoint inhibitors.

Sellas’ Next Big Catalyst

While Regal remains the company’s main near-term focus, investors are also tracking Sellas’ second AML candidate, SLS009, a selective CDK9 inhibitor currently in Phase 2 development. 

During the A.G.P. conference, Stergiou discussed updated Phase 2 data previously presented at the American Society of Hematology meeting, in which SLS009 showed responses in 44% of patients with refractory AML/myelodysplasia overall and 58% of patients with 1 prior treatment regimen. Sellas also said venetoclax-resistant patients treated with SLS009 achieved a median overall survival of 8.9 months compared with a historical benchmark of 2.4 months. 

At the Stifel conference, Stergiou said the drug’s activity in resistant AML was “quite astonishing” and positioned it as a potential option for patients who stop responding to venetoclax-based treatment. “There are also no patients who do not develop resistance to venetoclax at some point,” Stergiou said during the Stifel event.

“SLS009 interestingly exhibits an extraordinary synergy with venetoclax and has the ability to both improve response to venetoclax or even convert complete resistance to venetoclax into a strong response,” he added. Sellas expects topline SLS009 data later this year and is evaluating potential accelerated approval pathways.

How Do Retail Traders Feel About SLS?

On Stocktwits, retail sentiment for SLS was ‘extremely bullish’ amid ‘extremely high’ message volume.

One user said, “SLS has every reason to be 50 bucks a share right now…we have an AWESOME OUTLOOK.”

Another user said, “Our stock will be in the 30s on the day of shareholders meeting [June 16] which would be more accurate pending on the imminent 80th event!!! We should be bought for 150+  LFG!!!” 

SLS stock has surged 362% over the past year. 

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