Why Did SLS, MRNA, ABCL Stocks Surge To 52-Week Highs Last Week?

• Sellas Life Sciences hit a 52-week high of $12.43 as record short interest, buyout speculation and anticipation for its Phase 3 AML trial boosted the stock. 
• Moderna’s Science Day presentation highlighted advances across its cancer, autoimmune and rare disease pipeline. 
• AbCellera Biologics stock climbed to a more than two-year high of $7.40 on momentum from its partnership with Jazz Pharmaceuticals.

Sellas Life Sciences (SLS), Moderna (MRNA), and AbCellera Biologics (ABCL) ended Friday at 52-week highs, highlighting investor confidence in biotech companies backed by business and clinical catalysts, suggesting that investors are favoring companies with identifiable near-term events and validation over broader speculative momentum.

Sellas Life Sciences surged 17%, Moderna ended the session 12% higher and AbCellera Biologics gained over 10%. 

SLS Nears Key Clinical Event

Sellas Life Sciences' stock hit a new 52-week high of $12.43 on Friday as short interest reached a record high. The stock also gained on renewed speculation that the company could be acquired after it updated executive severance agreements. Investors are also waiting for a key update from the company's acute myeloid leukemia (AML) clinical trial. 

The company filed updated employment agreements for top executives on Thursday. The revised terms increase severance benefits and accelerate stock vesting if leadership is let go after a change in control, fueling investor speculation about a possible acquisition or licensing deal. 

Investor optimism has also centered on the company's Phase 3 REGAL study evaluating Galinpepimut-S (GPS) as a maintenance treatment for AML patients in second complete remission. The event-driven trial requires 80 patient deaths before final analysis can begin. The company previously disclosed that 78 events had occurred, leaving the study close to its final data analysis and topline results.

On Stocktwits, retail sentiment around the stock remained in ‘extremely bullish’ territory. 

MRNA Pipeline Expands Across Cancer And Autoimmune Diseases 

Moderna stock extended its strong 2026 rally on Friday, hitting a 52-week high of $69.29 after its Science Day presentation on Thursday, where the company highlighted progress across several therapeutic areas. 

The biotechnology company highlighted progress across cancer, autoimmune and rare disease therapies while emphasizing its growing use of artificial intelligence, automation and robotics to speed drug discovery.

Moderna highlighted several oncology programs in development, including experimental cancer therapies targeting solid tumors, Lynch syndrome and metastatic cancers. The company also reported continued progress with mRNA-2808, an investigational T-cell engager for multiple myeloma. 

Retail sentiment around the stock remained in ‘neutral’ territory. 

ABCL Secures Major Partnership

AbCellera Biologics stock hit a two-year high of $7.40 as investors cheered its research collaboration with Jazz Pharmaceuticals (JAZZ) focused on multispecific T-cell engager antibodies for gastrointestinal cancers. 

The agreement includes $56 million in upfront, non-dilutive funding for the first two programs, with another $28 million tied to a third program. The deal also creates the potential for milestone and commercialization payments if development goals are achieved.

Retail sentiment around the stock remained in ‘bullish’ territory. 

So far this year, SLS stock has soared 228%, while MRNA  and ABCL stocks have surged 128% and 115%, respectively. 

Also See: Why Retail Traders Couldn’t Take Their Eyes Off These Stocks Last Week: AAPL, MU, MSFT, INFQ, RKLB

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