Zura Bio’s 247-Participant Trial Fails, Prompting Halt to Hidradenitis Treatment Development
Key Facts
Zura Bio said its Phase 2 TibuSHIELD trial of tibulizumab did not meet its primary endpoint and decided to stop developing the drug for hidradenitis suppurativa. The trial included 247 adults with moderate to severe disease, randomly assigned in a 1:1:1 ratio to two drug doses or placebo. The study was randomized, double-blind and placebo-controlled. The primary endpoint measured the percentage change from baseline in the total number of abscesses and inflammatory nodules at week 16. The company’s filing with the U.S. Securities and Exchange Commission confirmed that neither the 300 mg nor the 150 mg dose met the endpoint.
Results showed a reduction in abscesses and nodules at week 16 of 56.0% among participants who received the 300 mg dose and 58.1% with the 150 mg dose. The placebo group recorded a 52.5% reduction over the same period. Reductions in both treatment groups were therefore higher than with placebo, but the difference between the results remained limited and did not translate into meeting the trial’s defined primary endpoint. The company said the outcome was measured by the change from baseline in the total number of lesions, the criterion that neither dose met. The result ends the drug program in this disease, while Zura has decided to continue its other trial programs.
The two secondary endpoints, HiSCR50 and HiSCR75, were also not met, according to the company’s update. The HiSCR50 response rate was about 48.0% with the 300 mg dose, compared with 52.7% with the 150 mg dose. The placebo group recorded a response rate of 45.5% on the same measure. The figures show similar response rates in the drug and placebo groups at week 16, alongside similar reductions in lesion counts. The secondary results did not provide grounds to continue developing tibulizumab for hidradenitis suppurativa, in line with the company’s decision to stop the program for this indication.
Chief Executive Sandeep Kulkarni attributed the difficulty in interpreting the trial results to the challenges of developing treatments for the disease, pointing to “the high variability in placebo group responses.” He said the company was conducting a full analysis of the data to understand its biological implications. Safety data through week 16 showed one serious adverse event related to treatment in the 300 mg dose group, with no similar events recorded in the other two groups. One death was also reported in that dose group during the study, and the company’s filing said the site investigator determined it was unrelated to treatment. The filing attributed the death to cardiac arrest in a participant with multiple cardiovascular risk factors.
In its second-quarter update, Zura said enrollment in the TibuSURE trial for systemic sclerosis was complete, with 91 participants, and that it expected topline results in the first half of 2027. The company continued this trial after deciding to stop the hidradenitis suppurativa program, keeping the expected data timing in the first half of 2027. It also plans to proceed with the NEXUS-PMR trial for polymyalgia rheumatica, with data expected in the fourth quarter of 2028. In August 2026, the company had set the end of the year as its target to start NEXUS-PMR. In that update, it estimated that more than 700,000 people in the United States had the disease and said the average time to permanent discontinuation of glucocorticoids was about 6 years.
The third-quarter filing showed cash and cash equivalents of $187.652 million on September 30, 2026, compared with $109.407 million on December 31, 2025. The filing provides the latest cash figure reported by the company, alongside the continuation of its systemic sclerosis and polymyalgia rheumatica programs. In its second-quarter update, Zura had expected TibuSHIELD data in the fourth quarter of 2026, before announcing that the primary endpoint had been missed. The next timelines announced by the company center on TibuSURE results in the first half of 2027 and NEXUS-PMR data in the fourth quarter of 2028. The available information did not include a reliable share price or market reaction that could be attributed to the trial results announcement.