FDA Grants Priority Review for Rare Blood Disease Drug

Approval sought for vemurafenib (Zelboraf) to treat Erdheim-Chester disease with BRAF V600 mutation.

The FDA on Monday granted Priority Review and Breakthrough Therapy Designation to vemurafenib (Zelboraf) for the treatment of Erdheim-Chester disease (ECD) with BRAF V600 mutation.

Vemurafenib is designed to inhibit mutated forms of BRAF, and is indicated to treat metastatic melanoma, according to a press release.

Included in the supplemental New Drug Application were data from the open-label, phase 2 VE-BASKET study.

The non-randomized, basket study investigated the use of vemurafenib in patients with BRAF V600 mutation-positive cancers and other diseases, including ECD.

The results of the study showed that 22 patients with ECD who received vemurafenib achieved a best overall response rate of 54.5%. The median duration of response, progression-free survival, and overall survival were not reached at the median follow-up of 26.6 months.

The most common adverse events grade 3 or higher were new skin cancers, high blood pressure, rash, and joint pain.

“This first potential treatment submitted to the FDA for this rare disease was identified by an innovative trial studying Zelboraf across different diseases with the same genetic mutation,” Sandra Horning, MD, chief scientific officer and head of Global Development, Genentech, said in the release. “We are committed to bringing new treatment options to people with rare diseases and hope to see Zelboraf approved for Erdheim-Chester disease as soon as possible.”

The FDA is expected to decide on approval by December 7, 2017.

ECD is a serious, rare blood disorder characterized by the abnormal multiplication of histiocytes. Currently, there are no FDA-approved treatments for ECD. It is estimated that there are fewer than 500 cases of ECD in the United States.