Biotech Rally Fueled by Merck Acquisition Buzz and Clinical Wins: After-Hours Winners Deliver Strong Momentum

Biotech stocks staged an impressive after-hours performance on Thursday, with a wave of positive developments spurring investor enthusiasm across the sector. The action was headlined by acquisition speculation surrounding a major pharma player, clinical breakthroughs, and strategic company initiatives.

Merck Deal Speculation Ignites Revolutionary Run

Revolution Medicines Inc. (RVMD) emerged as the session’s standout performer, jumping 15.1% to reach $123.65 in extended trading, adding $16.26 to its value. The explosive move was triggered by Financial Times reporting that Merck is exploring an acquisition of the company. Fueling this rally, RVMD also announced that its lead candidate, zoldonrasib—a RAS(ON) G12D-selective inhibitor—received FDA Breakthrough Therapy Designation. This approval applies to treating adult patients with KRAS G12D-mutated locally advanced or metastatic NSCLC who have exhausted anti-PD-1/PD-L1 and platinum-based chemotherapy options. The stock had already climbed 5% during regular trading hours, but momentum accelerated sharply following the breakthrough designation announcement.

AI-Driven Strategy Propels SXTC Higher

China SXT Pharmaceuticals, Inc. (SXTC) vaulted 13.6% to $1.42, gaining $0.17 per share after revealing its newly launched Strategic Artificial Intelligence Insights Initiative. The program aims to embed AI-powered analytics into product development planning and competitive intelligence, positioning the company to transform into a data-centric, innovation-focused player in the modern traditional Chinese medicine space.

Clinical Data and Operational Momentum Drive Multi-Stock Rebound

KalVista Pharmaceuticals, Inc. (KALV) jumped 14.0% to $18.04, up $2.22, following disclosure of preliminary unaudited global net product revenue figures for Q4 and full-year 2025, alongside positive operational metrics that resonated with investors.

Sagimet Biosciences Inc. (SGMT) advanced 7.7% to $6.00, gaining $0.43, after confirming plans to unveil findings at the 10th Annual MASH-TAG Conference in Park City, Utah. The company will showcase anti-fibrotic efficacy data from its Phase 2b FASCINATE-2 trial, which evaluated denifanstat—a fatty acid synthase (FASN) inhibitor—in F3 and stage 4 MASH patients, reinforcing the mashtag event’s importance for advancing fatty acid synthase research.

Zentalis Pharmaceuticals, Inc. (ZNTL) ticked up 8.1% to $3.07, adding $0.23, likely sustained by lingering positive sentiment from its January 6 corporate briefing, which detailed development milestones and anticipated momentum for azenosertib throughout 2026.

Momentum-Driven Gains Without Fresh Catalysts

BriaCell Therapeutics Corp. (BCTX) gained 7.3% to $7.81, up $0.53, despite the absence of new company-specific announcements, reflecting momentum trading activity. Equillium, Inc. (EQ) posted a more modest 4.4% gain to $1.18, a $0.05 increment, as the stock attracted buying interest despite no fresh developments disclosed on the day.

The after-hours session underscored investor appetite for biotech exposure amid strong clinical pipelines and strategic corporate moves, with acquisition speculation and regulatory milestones continuing to drive sector sentiment.