FDA Expands Approval of Roche’s Zelboraf as First Treatment Rare Blood Cancer

Rare Daily Staff

The U.S. Food and Drug Administration said it expanded the approval of Roche’s  Zelboraf to include the treatment of certain adult patients with Erdheim-Chester disease, the first treatment for the rare blood cancer.

“This FDA decision means people living with Erdheim-Chester disease will now, for the first time, have an FDA-approved treatment option,” said Sandra Horning, Roche’s Chief Medical Officer and Head of Global Product Development.

Zelboraf is indicated to treat patients whose cancer cells have a specific genetic mutation known as BRAF V600. Zelboraf is a kinase inhibitor that works by blocking certain enzymes that promote cell growth.

ECD is a slow-growing blood cancer that originates in the bone marrow. It causes an increased production of histiocytes, a type of white blood cell. Excess histiocytes can result in tumors infiltrating many organs and tissues throughout the body, including the heart, lungs, brain and others.

An estimated 600 to 700 patients worldwide suffer from ECD. Approximately 54 percent of patients with ECD have the BRAF V600 mutation. Patients with ECD have very limited life expectancies.

 “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, director of the FDA’s Oncology Center of Excellence and acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research.

The FDA first approved Zelboraf in 2011 to treat certain patients with melanoma that harbor the BRAF V600E mutation. The FDA granted this application Priority Review and Breakthrough Therapy designations for this indication. Zelboraf also received Orphan Drug designation as a treatment ECD.

The efficacy of Zelboraf for the treatment of ECD was studied in 22 patients with BRAF-V600-mutation positive ECD. The trial measured the percent of patients who experienced a complete or partial reduction in tumor size (overall response rate). In the trial, 11 patients (50 percent) experienced a partial response and 1 patient (4.5 percent) experienced a complete response.

Common side effects of Zelboraf in patients with ECD include joint pain, rash, hair loss, fatigue, change in the heart’s electrical activity, and skin growths.

Severe side effects of Zelboraf include the development of new cancers, growth of tumors in patients with BRAF wild-type melanoma, hypersensitivity reactions, severe skin reactions, , heart abnormalities, liver damage, photosensitivity, severe reactions in the eye, immune reactions after receiving radiation treatment, kidney failure, and thickening of tissue in the hands and feet. Because Zelboraf can cause harm to a developing fetus, women should be advised of the potential risk use effective contraception.