Vemurafenib Effective Against Metastatic Melanoma
According to a study led by an international team of researchers from the United States and Australia and researchers at Moffitt Cancer Center in Tampa, vemurafenib (PLX4032), an oral BRAF inhibitor, prolongs lives of patients with metastatic melanoma. After Phase II clinical trial, patients with the BRAF mutation had a higher response rate.
Malignant melanoma is an aggressive form of cancer that arises either from a mole or nevus, either from clinically normal skin. The incidence is increasing lately and it seems that solar radiation is one of the causes of this cancer. Other factors incriminated in the occurrence of this cancer are burns, trauma, ionizing radiations. It is important to note that this type of cancer cells occurs when a mole changes its shape, color, or when it begins itching or bleeding.
Melanoma has a high capacity to metastasize, both via lymphatic and hematogenous pathway. Excision of tumor in oncologic safety limits, with or without lymphadenectomy is considered the most important therapeutic gesture.
Vemurafenib is a drug approved by FDA in August 2011 as monotherapy for the treatment of metastatic melanoma in patients with BRAF V600 mutation. Important to note that vemurafenib is not indicated if patients do not express this mutation. Paradoxically, vemurafenib cause tumor growth in such cases. Regarding side effects, there were reported arthralgia, skin rash and photosensitivity.
According to study co-author Jeffrey S. Weber, MD, Ph.D., director of the Donald A. Adam Comprehensive Melanoma Research Center at Moffitt, about 50% of patients with melanoma have threonine protein kinase B-RAF mutation, which means therapeutic options for these patients are limited. Dr. Weber said that few patients with this mutation respond to treatment and the average survival is 10 months. However, study results are positive so far because it demonstrates extended survival of patients with more than six months.
Researchers conducted a multicenter Phase II study on 132 patients aged over 18 years, diagnosed with stage IV melanoma who had at least one previous systemic therapy. The response rate was 56% and was higher than the rate of response to previous therapies such as monoclonal antibody with impilimumab. Dr. Weber pointed out that the study clearly showed that vemurafenib has antitumoral activity in metastatic melanoma and response rates are higher than the therapies used so far.
The study authors added that one of the main problems is the appearance of cancer resistance to treatment. Therefore, scientists seek to develop new strategies in order not resistance to this drug.