A phase 3 trial of GSK’s linerixibat in a liver disease has hit its primary endpoint, keeping the drugmaker on track to launch the first treatment for the relentless itching experienced by some patients.
The study enrolled 238 people with primary biliary cholangitis (PBC) and cholestatic pruritus, a medical term for relentless itch. GSK said 510,000 people will have been diagnosed with PBC by 2030 and close to half of those patients will experience relentless itch requiring treatment. PBC treatments are available, even after the setback to Intercept Pharmaceuticals’ Ocaliva, but they are unable to reduce itching.
GSK identified the inhibition of ileal bile acid transporter (IBAT) as a way to alleviate the PBC symptom. Bile flow is disrupted in people with PBC, increasing the level of bile acids in circulation. The excess bile acids cause itches that cannot be relieved by scratching. Linerixibat is designed to block the resorption of bile acids in the small intestine, decreasing levels of itch-driving bile acids in circulation.
The drugmaker put the idea to the test in a phase 3 trial that randomized PBC patients with moderate to severe itch to receive linerixibat or placebo. GSK included people on stable doses of anti-itch medicines, treatment-naïve patients and participants who had previously tried therapies in the trial.
After 24 weeks, GSK saw a statistically significant reduction in monthly itch score in the linerixibat cohort compared to the placebo arm, causing the trial to hit its primary endpoint. The company is yet to share the data behind the primary endpoint hit or any details about the secondary endpoints. GSK said the preliminary safety results were generally consistent with the data from earlier studies of linerixibat.
The press release lacks details of GSK’s plans for seeking approval of the candidate. GSK rescheduled the timeline for market access talks in the U.K. earlier this year, resulting in the anticipated start date of the appraisal moving to late September 2025.
GSK said that “linerixibat has the potential to be the first global therapy indicated to treat itch in PBC.” Ipsen sells the IBAT inhibitor Bylvay in other indications. Mirum Pharmaceuticals is running a phase 2 trial to test another IBAT inhibitor, volixibat, as a treatment for itch associated with PBC.