Axcella Therapeutics announced that patient screening is now underway in a Phase 2a trial that is investigating AXA1125, an oral product candidate, as a potential treatment for Long COVID, also known as Post COVID-19 Condition and post-acute sequelae of SARS-COV-2 infection (PASC). The Phase 2a is a randomized, double-blind, placebo-controlled trial that is evaluating the efficacy and safety of AXA1125 in patients with exertional fatigue related to Long COVID. Approximately 40 patients in the United Kingdom will be enrolled and randomized evenly to receive either 67.8 grams per day of AXA1125 or a matched placebo in two divided doses for 28 days, with a one-week safety follow-up period. The primary endpoint in this Phase 2a trial is the change from baseline to Day 28 in phosphocreatine (PCr) recovery time as measured by 31-phosphorus magnetic resonance spectroscopy (pMRS). In past clinical trials, this highly sensitive and well-established measure of mitochondrial function has been correlated with the six-minute walk test, which has been a registrational endpoint in other conditions involving fatigue, such primary pulmonary hypertension and exertional angina. Key secondary endpoints in the Phase 2a trial include lactate levels (a serum marker of mitochondrial dysfunction), six-minute walk test, fatigue scores, and safety and tolerability. Top-line data are expected to be reported from the Phase 2a trial in mid-2022.