WATERTOWN, Mass. — Enanta Pharmaceuticals Inc. said it is entering 2026 with strong momentum across its research and development portfolio, highlighting progress in respiratory syncytial virus programs, expansion of its immunology pipeline, and a financial position expected to fund operations into fiscal 2029.
The clinical-stage biotechnology company said it is continuing Phase 3–enabling activities for zelicapavir, its oral, once-daily RSV N-protein inhibitor, following positive Phase 2b results in high-risk adult patients. Enanta said it is holding discussions with the U.S. Food and Drug Administration to align on an adult Phase 3 study design and clarify the registration pathway for the drug.
“Building on the progress we achieved in our RSV and immunology portfolios this past year, we enter 2026 with strong momentum as we continue to expand our pipeline and deliver on key milestones,” said Jay R. Luly, Ph.D., president and chief executive officer of Enanta Pharmaceuticals. “We are eager to advance our RSV portfolio with the progression of both zelicapavir and EDP-323.”
Zelicapavir was most recently evaluated in the Phase 2b RSVHR study in a high-risk adult outpatient population, including elderly patients and those with asthma, chronic obstructive pulmonary disease, or congestive heart failure. Enanta reported in September 2025 that the study showed a clinically meaningful improvement in time to complete resolution of all RSV symptoms compared with placebo, including a 6.7-day benefit in the highest-risk subgroup. The drug has been dosed in more than 700 people to date and has shown a favorable safety profile.
Enanta’s second RSV candidate, EDP-323, is an oral, once-daily RSV L-protein inhibitor that may be used alone or in combination with other agents. The company said post-exposure prophylaxis data presented in October demonstrated potential for preventing RSV infection when treatment is initiated up to five days after exposure.
In immunology, Enanta announced the launch of a new discovery program focused on inhibiting MRGPRX2, a receptor involved in mast cell–driven inflammation. The company said the program is initially targeting chronic spontaneous urticaria and other type 2 immune–driven diseases with high unmet need, with plans to select a development candidate in the second half of 2026.
“Today, we are pleased to announce our third immunology program, focused on developing oral MRGPRX2 inhibitors for type 2 immune driven diseases,” Luly said. “This program represents a meaningful addition to our growing immunology portfolio.”
Enanta is also advancing EDP-978, an oral, once-daily KIT inhibitor that has been selected as a clinical candidate for chronic spontaneous urticaria and potentially other mast cell–driven diseases. The company said it remains on track to file an investigational new drug application for EDP-978 in the first quarter of 2026, with Phase 1 data expected in the fourth quarter.
In addition, Enanta is progressing EPS-3903, an oral STAT6 inhibitor nominated as a development candidate in late 2025 for atopic dermatitis and other diseases currently treated with biologics. The company plans to file an IND for EPS-3903 in the second half of 2026.
On the corporate front, Enanta said it continues to benefit from retained royalty revenues and expects its cash runway to fund operations into fiscal 2029. The company also provided an update on its patent infringement action filed in August 2025 in the Unified Patent Court of the European Union against Pfizer related to Paxlovid, with a hearing expected within the court’s 12-month target timeframe.
Looking ahead, Enanta said key 2026 milestones include aligning with the FDA on a Phase 3 RSV program, filing INDs for EDP-978 and EPS-3903, reporting early-stage clinical data, and advancing its newly launched MRGPRX2 program toward candidate nomination. The company plans to present its 2026 outlook at the J.P. Morgan Healthcare Conference on January 14.
