Biotech and SPAC Stocks Plunge on Clinical Failures and Merger Volatility

Key Facts

1ArriVent BioPharma shares plunged 46.9% after its lung cancer treatment failed to meet the primary endpoint in a Phase 3 trial.

2Armada Acquisition Corp. II shares dropped 50.1% amid volatility ahead of its planned business combination with Evernorth.

3Twist Bioscience and 10x Genomics shares declined amid a broader selloff in the genomics and testing sector.

ArriVent BioPharma shares plunged 46.9% to $15.09 after its lung cancer treatment, firmonertinib, failed to meet the primary endpoint in a Phase 3 clinical trial. According to Financial Modeling Prep, Armada Acquisition Corp. II shares also dropped 50.1% to $19.20 amid volatility ahead of its planned business combination with Evernorth.

The genomics and testing sector experienced a broader selloff, causing Twist Bioscience to fall 18.6% and 10x Genomics to decline 17.5%. Regarding prior price levels, AVBP closed at $28.46 on October 5, 2026, while XRPN closed at $38.65 on the same date; SAIQ recorded a closing price of $5.16 on October 6, 2026, following a 23.7% decline.

The business combination between Armada Acquisition and Evernorth is expected to close on October 7, 2026, with the combined entity scheduled to begin trading under the ticker XRPN on October 8, 2026. Evernorth expects approximately $300 million in gross cash proceeds at the time of closing.