FDA Approves Zelboraf for Erdheim-Chester Disease

Today, the FDA approved an expanded indication of vemurafenib (Zelboraf) to include adults with Erdheim-Chester Disease (ECD), a rare blood cancer.

Vemurafenib is a kinase inhibitor indicated to treat patients with ECD with BRAF V600 mutations. This is the first drug approved to treat this rare form of cancer, according to a press release.

“Today’s approval of Zelboraf for patients with ECD demonstrates how we can apply knowledge of the underlying genetic characteristics of certain malignancies to other cancers,” said Richard Pazdur, MD, director of the Oncology Center of Excellence and acting director of the Office of Hematology and Oncology Products in the Center for Drug Evaluation and Research, FDA.

EDC is a slow-growing blood cancer that causes an amplified production of histiocytes. The overproduction of the white blood cells results in cancer spreading to numerous organs, including the heart, lungs, and brain, according to the FDA.

Current estimates indicate that up to 700 patients have the disease worldwide, with 54% harboring BRAF V600 mutations, according to the release. The FDA reported that patients with this rare disease have limited survival.

The efficacy of vemurafenib was evaluated in a clinical trial of 22 patients with BRAF-600-mutation positive ECD. The study investigated how many patients achieved a complete or partial reduction in tumor size.

The researchers discovered that 50% of patients achieved a partial response, while 1 patient achieved a complete response, according to the FDA.

Common side effects include arthralgia, maculo-papular rash, alopecia, fatigue, prolonged QT interval, and papilloma.

The FDA warns that severe side effects of vemurafenib can occur and include:

• Development of new cancers
• Tumor growth in those with BRAF wild-type melanoma
• Hypersensitivity reactions
• Severe skin reactions
• Heart abnormalities
• Liver damage
• Photosensitivity
• Uveitis
• Immune reactions after radiation therapy
• Kidney failure
• Thickening of tissue in the hands and feet

Vemurafenib previously received priority review, breakthrough therapy, and orphan drug designations for the treatment of ECD.

“This product was first approved in 2011 to treat certain patients with melanoma that harbor the BRAF V600E mutation, and we are now bringing the therapy to patients with a rare cancer with no approved therapies,” Dr Pazdur said.