PureTech Health’s long COVID trial has come up short. The drug candidate failed to help patients with the condition walk farther, prompting the company to drop plans for further studies in the indication.
In 2020, PureTech identified an opportunity to use its deuterated form of pirfenidone—a treatment for idiopathic pulmonary fibrosis that Roche’s Genentech sells as Esbriet—in patients with long COVID. The decision to start a clinical trial of the candidate, LYT-100, in the indication was underpinned by evidence of the prevalence of lung fibrosis in COVID-19 patients and persistence of long-term symptoms.
The phase 2 trial enrolled 177 patients who had respiratory complications after hospitalization for acute COVID-19 infection that required treatment with supplemental oxygen. Participants received LYT-100 or placebo daily for 91 days.
At the end of the treatment period, patients in the LYT-100 arm performed no better on the six-minute walk test than their counterparts who received placebo, causing the study to miss its primary endpoint. Both cohorts “meaningfully improved” their walking distance over the course of the clinical trial, the company said.
PureTech responded to the failure by stopping development of LYT-100 in long COVID. The one bright spot for the company is the lack of safety alarm bells, which leaves it clear to move the asset into studies intended to support registration in idiopathic pulmonary fibrosis later this month.
No participants suffered drug-related serious adverse events or deaths. Only one adverse event, nausea, was judged to be at least possibly related to LYT-100 and affect more than 5% of participants. The rate of nausea in the treatment arm was 8.7% compared to 2.4% in the placebo group. Headache, dizziness, fatigue and rash were deemed possibly related to LYT-100 but affected fewer than 5% of the participants.
The rate of discontinuation due to possibly treatment-related adverse events was higher in the LYT-100 arm, 8.6%, than in the placebo cohort, 2.4%. However, PureTech said “the majority of discontinuations in the LYT-100 arm were due to idiosyncratic events and not AEs commonly associated with pirfenidone.”
PureTech’s failure clears out one contender for the long COVID market. Axcella Therapeutics is still in the running, with a phase 2a clinical trial of its candidate scheduled to deliver top-line data early in the third quarter.