May 8 (Reuters) - The U.S. Food and Drug Administration has approved Partner Therapeutics' drug for adults with a rare form of bile duct cancer as part of a new fast-track review program, the agency said on Friday.

Here are some details:

• The antibody drug, branded Bizengri, is the first treatment approved for adults with ​advanced cholangiocarcinoma, whose tumors carry a rare genetic ​mutation and whose disease has worsened after prior ⁠treatment, the FDA said.

• The approval is the seventh granted under the FDA commissioner's National Priority Voucher pilot program to expedite reviews for treatments for rare diseases with few or no options.

• In a study of 19 patients, 36.8% saw their tumors shrink with Bizengri. Responses lasted from 2.8 months to 12.9 months, the FDA said.

• Approval comes just two days after the privately held company was granted the fast-track voucher for the drug.

• Bizengri is already approved for certain adults with ​advanced lung and pancreatic cancers whose disease has progressed after prior treatment.

• The FDA said serious side effects can include infusion reactions, lung inflammation and heart-related problems.

• Common side effects include diarrhea, pain, fatigue, nausea, shortness of breath and rashes.