ECD is estimated to affect 600 to 700 patients worldwide. Approximately 54 percent of patients with ECD have the BRAF V600E mutations. The efficacy of Vemurafenib (Zelboraf) for the treatment of ECD was studied in 22 patients with BRAF-V600E-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.
Somewhat astonishing and troubling, at least for this author being concerned with individualized human drug safety issues, is the catalogue of the side effects of Vemurafenib (Zelboraf), some common and some most serious if not life-treathening, which have occurred in the very small number of 22 patients already. Thus, common side effects of in these patients included joint pain (arthralgia); small, raised bumps (maculo-papular rash); hair loss (alopecia); fatigue; change in the heart’s electrical activity (prolonged QT interval) and skin growths (papilloma). Severe side effects included the development of new cancers (skin cancer, squamous cell carcinoma or other cancers), growth of tumors in patients with BRAF wild-type melanoma, hypersensitivity reactions (anaphylaxis and DRESS syndrome), severe skin reactions (Stevens-Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN), heart abnormalities (QT prolongation), liver damage (hepatotoxicity), photosensitivity, severe reactions in the eye (uveitis), immune reactions after receiving radiation treatment (radiation sensitization and radiation recall), kidney failure and thickening of tissue in the hands and feet (Dupuytren’s contracture and plantar fascial fibromatosis). Vemurafenib (Zelboraf) can cause harm to a developing fetus; women should be advised of the potential risk to the fetus and to use effective contraception.
While the arrival of a therapy option for patients with ECD is certainly welcome, great prudence in its application seems to be necessary, both for the therapy providers and the recipients (patients) alike.