The US Food and Drug Administration (FDA) approved the first targeted therapy for bile duct cancer. Pemazyre (pemigatinib) is for adults with advanced bile duct cancer whose cancer has grown after at least one previous chemotherapy treatment and whose tumors have a mutation in the FGFR2 gene.

FGFRs (fibroblast growth factor receptors) are proteins on cells that help them grow and divide normally. A small portion of people with bile duct cancer have changes in the genes that make FGFRs, which result in abnormal FGFR proteins that cause cells to grow out of control and turn into cancer. Pemazyre blocks the abnormal FGFR2 protein in bile duct tumor cells and keeps them from growing.

Pemazyre is the first drug approved specifically for bile duct cancer. That’s important because most patients are diagnosed after the cancer has already spread and can’t be treated with surgery. Standard treatment has been a combination of chemotherapy drugs approved for other cancer types.

The FDA based the new approval on a clinical trial of 107 people with advanced bile duct cancer who had at least one previous chemotherapy treatment and whose tumors had an FGFR2 gene mutation. The trial measured overall response, meaning the number of patients whose tumors either shrank (partial response) or disappeared (complete response).

The overall response rate was 36%, with 2.8% of patients having a complete response and 33% having a partial response. Among the 38 patients who had a response, 24 patients (63%) had a response lasting 6 months or longer and 7 patients (18%) had a response lasting 12 months or longer.

Pemazyre was given as a tablet once a day for 14 days straight followed by 7 days off, then started again. Patients stopped taking the drug if their cancer got worse or if side effects became too severe. The most common side effects were having too much or too little phosphate in the blood, hair loss, diarrhea, constipation, nail problems, fatigue, taste changes, nausea, vomiting, dry mouth or mouth sores, loss of appetite, dry skin, dry eye or other eye problems, and joint, abdominal, or back pain.

The FDA granted Pemazyre priority review and breakthrough therapy designations. These are programs designed to make drugs for serious diseases available to patients faster. Another clinical trial will be required to confirm the results. Pemazyre also received orphan drug designation, which provides financial incentives to encourage the development of drugs for rare diseases.

Pemazyre is marketed by Incyte Corporation.