With plans in place to launch global pivotal testing of GH-001, its inhaled version of psychedelic mebufotenin (5-MeO-DMT), in treatment-resistant depression in 2026, GH Research plc reported the lifting of a U.S. FDA clinical hold, enabling U.S. subject enrollment. The firm now will seek a meeting with the agency to discuss trial design.

Abbvie Inc. signed a $1.1 billion New Year’s Eve deal with China’s Zelgen Biopharmaceuticals Co. Ltd., gaining ex-China rights to Zelgen’s lead oncology asset, alveltamig (ZG-006), a trispecific T-cell engager targeting delta-like ligand 3. Under terms of the deal, Abbvie will pay Zelgen an up-front fee of $100 million, and Zelgen is eligible to receive $60 million in near-term milestones and could receive up to $1.075 billion in additional development, regulatory and commercial milestones, alongside tiered royalties on net sales outside China. Zelgen retains full rights in China.

December 2025 was a big month for announcements from Psithera Inc. The Watertown, Mass.-based newco announced its name change from Psivant Therapeutics, having come out from under the Roivant Sciences Ltd. umbrella – thus the dropping of the “-vant” name. The company also announced a $47.5 million series A financing and disclosed that Eric Shaff had started as the company’s new president and CEO.

Receiving a third complete response letter (CRL) from the U.S. FDA for its bevacizumab formulation, ONS-5010, to treat wet age-related macular degeneration, Outlook Therapeutics Inc. watched its stock (NASDAQ:OTLK) plummet nearly 62% to a 52-week low of 60 cents on Jan. 2.

On the last day of the year, shares of Axsome Therapeutics Inc. rose 22% on news that the U.S. FDA accepted and granted priority review of the company’s supplemental NDA for AXS-05 to treat Alzheimer’s disease agitation, a $1 billion-plus opportunity, scheduling the PDUFA date for April 30.

The U.S. FDA dashed hopes that Corcept Therapeutics Inc. might be able to launch its selective glucocorticoid receptor antagonist in two indications in 2026, issuing a complete response letter for relacorilant for use in patients with hypertension secondary to hypercortisolism, also known as Cushing syndrome. Focus is now on the July 2026 PDUFA date, as Corcept seeks approval for the same drug as a treatment for patients with platinum-resistant ovarian cancer.

The U.S. FDA has approved its first pharma treatment in more than 40 years for motion sickness. The green light for Nereus (tradipitant), from Vanda Pharmaceuticals Inc., was based on three clinical studies, all pivotal, including two phase III real-world trials with patients on boats and another supporting study.

If the 2025 U.S. life sciences regulatory scene were to be summed up in one word, it would have to be uncertainty. Two words might be more definitive – chaotic uncertainty.