SLS Stock Jumps Premarket: US Investor Dagco Boosts Stake By 78% Ahead Of Fresh Cancer Drug Data Reveal

• Dagco added 451,240 shares, making Sellas its second-largest holding at 1.01% of portfolio weight.
• The stake increase comes ahead of AACR presentation of preclinical data on SLS009, Sellas’ CDK9 inhibitor targeting acute myeloid leukemia (AML).
• Investor focus remains centered on the Phase 3 Regal trial of GPS, with 72 of 80 required survival events recorded as of Dec. 26, moving the study closer to topline analysis.

Shares of Sellas Life Sciences Group, Inc. (SLS) jumped 5% in premarket trading on Monday after U.S. investment manager Dagco increased its stake by 78% ahead of a major AACR leukemia data catalyst and the closely watched Regal survival trigger.

SLS stock snapped four sessions of gains on Monday to end over 4% lower at $4.99.

Dagco Loads Up Ahead Of SLS009 AACR Data

Data compiled by Quiver Quantitative showed that Dagco added 451,240 shares on Tuesday, bringing its total holdings to 1.03 million shares valued at $4.35 million as of March 31. The position now represents its second biggest holding at 1.01% of Dagco’s disclosed portfolio, placing Sellas among its healthcare bets alongside larger pharma holdings such as Merck, Thermo Fisher Scientific and Johnson & Johnson.

The stake increase comes just as Sellas prepares to present new preclinical findings on SLS009, its CDK9 inhibitor for acute myeloid leukemia (AML), during a poster session at AACR in San Diego on Tuesday.

According to the company, lab studies showed that SLS009 triggered leukemia-cell death by increasing activity of caspase-3, a protein involved in the body’s natural cell-death process, while lowering survival signals such as MCL-1 and survivin that help cancer cells persist. The drug also showed stronger potency with repeated exposure, with early biological effects appearing within hours and becoming more pronounced over 24 hours.

Notably, SLS009 remained active in AML carrying ASXL1 and TP53 mutations, which are genetic subtypes associated with treatment resistance and poorer outcomes. 

Regal Survival Countdown In Focus

While the AACR presentation represents a near-term catalyst, investor attention remains firmly centered on the company’s ongoing Phase 3 Regal trial evaluating GPS, an immunotherapy targeting the Wilms Tumor-1 antigen, as a maintenance treatment for AML patients whose disease returned but later entered remission after additional therapy.

The event-driven study will begin final analysis once 80 overall-survival events are recorded. Sellas previously said 72 events had been logged as of Dec. 26, bringing the trial closer to the threshold required to initiate topline analysis.

CEO Angelos Stergiou previously said that slower accumulation of survival events in oncology trials can sometimes indicate patients are living longer than expected compared with historical assumptions. Once the 80th event occurs, the company plans to proceed with database lock, statistical analysis, trial unblinding and disclosure of topline results.

How Do Retail Traders Feel About SLS?

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

One user noted Diagco’s stake and said, “It's likely clearly see the asymmetric upside with the margin of safety of no REGAL downside.”

Another user said, “Can't wait to get update on 009, since GPS has been put on hold for an 80th event that might happen from old age.”

SLS stock has surged over 280% over the past year. 

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