SLS · SELLAS Life Sciences Group

The thesis

SELLAS Life Sciences is more likely to lag the S&P 500 over the next three months. Its value rests on one trial, the Phase 3 REGAL study of galinpepimut-S (GPS) in acute myeloid leukemia (AML), and the topline overall-survival result settles the shares. SELLAS said on 12 November 2026 that it expects to announce that result this month.

The shares closed at $8.03 on 12 November 2026, down 37.2% over three months from $12.78 on 14 August 2026. The market has already marked the shares down sharply into the readout, and a binary outcome with no efficacy data released leaves the shares exposed on both sides. The rating is Low because the case offers no edge over the index before the result, and a disappointing result would confirm the lag.

The third-quarter report, filed 12 November 2026, moved the timetable forward. The company said the pre-specified 80th event occurred in October 2026 and that database lock, blinded data review, statistical analysis and unblinding are under way. It gave no calendar date for any of those steps.

Bullish and bearish views on SELLAS Life Sciences Group, Inc.

The bull case on SELLAS Life Sciences Group, Inc. (SLS), in brief: the readout is close. The bear case: the shares have fallen into the readout.

Bull case

• The readout is close. CEO Angelos Stergiou said in the 12 November 2026 results release that SELLAS expects to announce REGAL topline primary-endpoint results "this month". Earlier guidance, dated 28 October 2026, was only "this quarter".
• Cash covers the work to the readout. Cash and equivalents were $134.7 million at 30 September 2026, against a third-quarter net loss of $10.1 million, or $0.05 per share (third-quarter 2026 results release). Cash was $138.3 million at 30 June 2026.
• A second asset reports data in December. SELLAS said on 4 November 2026 that it will present Phase 2 data for SLS009 (tambiciclib) in relapsed or refractory AML at the American Society of Hematology (ASH) meeting, poster abstract 5155, on 14 December 2026. The 12 November 2026 release also expects preliminary SLS009 topline data in newly diagnosed AML in the fourth quarter, with 40 of 80 planned patients enrolled.
• The company frames the upside as category-defining. Stergiou said on 28 October 2026 that positive results "could position GPS as the first- and best-in-class novel immunotherapeutic option" for certain patients. This is the company's own view, and the trial is open-label.

Bear case

• The shares have fallen into the readout. SLS closed at $10.38 on 28 October 2026, down 14.7% from $12.17 the prior session, and closed at $8.03 on 12 November 2026. The 52-week high is $15.88 (intraday, 30 June 2026).
• The result is binary. A miss on overall survival would remove the main value driver. SLS009 is in Phase 2, and SELLAS has no approved product and 13 employees.
• Spending is rising. Third-quarter research and development expense was $7.0 million, against $4.2 million in the third quarter of 2025 (results release, 12 November 2026). The company is spending more as the pivotal analysis and the SLS009 trial proceed.
• Dilution has been heavy. Shares outstanding rose from 153,103,459 on 31 December 2025 to 201,918,874 on 30 June 2026 and 203,527,833 on 30 September 2026. A positive readout could prompt another offering.
• A short seller values the shares far lower. BMF Capital's 31 August 2026 short report put $3.50 on the shares, against the $8.03 close of 12 November 2026. This is a third party's view.
• A large holder cut its stake. Company news on 5 November 2026 reported that Citigroup disclosed a reduction in its SELLAS stake.

Price setup

SLS closed at $8.03 on 12 November 2026, below its 200-day average of closes ($8.76) and well below its 50-day average ($11.15). The three-month change is −37.2%, measured from the $12.78 close of 14 August 2026.

The 52-week high is $15.88 (intraday, 30 June 2026), and the last close is 49.4% below it. The 52-week closing low is $1.39, set on 2 December 2025. In the last week of sessions the shares closed between $7.88 (5 November 2026) and $8.58 (9 November 2026).

The fall from $12.17 on 27 October 2026 to the current level came with no efficacy data from the trial. The shares have traded on the timing of the readout and on funding concerns. Published short-interest readings conflict, between roughly 55.0 million and 29.34 million shares, and FINRA's own file is the reference.

Catalysts ahead

• ~30 November 2026 (est.): REGAL topline overall-survival results; SELLAS said on 12 November 2026 it expects to announce them in November. The one result that settles the case for the shares; the company has given no exact day.
• Undated, any session: Announcement of REGAL database lock or unblinding. Either step would show how close the topline is; SELLAS has given no dates for them.
• 14 December 2026: SLS009 Phase 2 poster at the American Society of Hematology meeting (abstract 5155). The second clinical asset reports relapsed or refractory AML data; it falls after the 30-day window.
• ~31 December 2026 (est.): Fourth quarter ends; SELLAS expects preliminary SLS009 topline data in newly diagnosed AML in the fourth quarter. A second readout could move the shares if the REGAL result is delayed.

What would change the view

A daily close above $11.27, over the 50-day average of closes, which would show the shares leading again. A REGAL topline reporting a statistically significant overall-survival benefit would also show the shares leading.

What it trades with

SLS trades on its own trial news rather than with a sector group. Its sharp rises on 13 May 2026 and 20 May 2026 appeared in lists of the day's biggest gainers alongside unrelated technology and industrial names, which points to company-specific moves. Ownership is a mix of retail followers and institutions, and the selling after 28 October 2026 came with no change in the trial facts. No sector benchmark comparison is quantified here.