This year, the Digital International Liver Congress took place online from August 27-29, thanks to COVID-19. During the conference, biopharmaceutical company Mirum Pharmaceuticals announced data from its Phase 2 INDIGO clinical trial. Their analysis tracked 5-year survival rates, particularly transplant-free survival rates, for patients with progressive familial intrahepatic cholestasis type 2 (PFIC2) being treated with maralixibat. According to the data, the therapy significantly and meaningfully improves transplant-free survival rates. More importantly, this offers a less invasive treatment option than liver transplants. You can find the full presentation here.
Considered generally well-tolerated, maralixibat is an orally-administered, investigational drug developed to treat patients with rare liver disorders. In addition to PFIC2, maralixibat is also being investigated for patients with Alagille syndrome and biliary atresia. The therapy inhibits the apical sodium dependent bile acid transporter (ASBT). As a result, more bile acids are removed through fecal matter. Thus, there are lower levels of bile acids in the body, preventing liver damage. So far, less than 2,000 patients have been treated with maralixibat. However, the results from studies are promising, highlighting lower levels of bile acids and pruritus (extreme itching). In fact, maralixibat received the Breakthrough Therapy Designation for pruritus.
In the Phase 2 INDIGO trial, researchers analyzed the safety, efficacy, and tolerability of maralixibat over an extended period of time. Overall, 19 patients with BSEP gene mutations enrolled in the study. They received 280 µg/kg of the therapy up to 2x daily. Researchers discovered a significant reduction in bile acids (up to 75%). Additionally, patients experienced longer periods of transplant-free survival. Of the participants, 7 (37%) were transplant-free after 5 years. Side effects were mild and included vomiting, diarrhea, abdominal discomfort, fever, and a cough.
Progressive Familial Intrahepatic Cholestasis (PFIC)
Caused by gene mutations, progressive familial intrahepatic cholestasis (PFIC) is a group of liver disorders caused by biliary epithelial transporter defects. Normally, biliary epithelial transporters help transport bile out of the liver. When these are not working properly, it causes a number of health issues. PFIC2 may also be known as bile salt export pump (BSEP). Generally, PFIC symptoms appear in infancy or early childhood (before 2 years old). However, in rare cases, PFIC onset may occur in adolescence. Symptoms include:
- Failure to thrive
- Bile obstruction
- Jaundice (yellowing of the skin)
- Severe issues
- Vitamin deficiencies
- Vision difficulties
- Suicidal ideation
Learn more about PFIC.