Molecular therapy for melanoma: Useful and not useful targets

A pilot study of paclitaxel combined with gemcitabine followed by interleukin-2 and granulocyte macrophage colony-stimulating factor for patients with metastatic melanoma

It has been suggested that paclitaxel and gemcitabine modulate the immune system. This paper reports the safety and efficacy of paclitaxel plus gemcitabine followed by interleukin-2 (IL-2)and granulocyte macrophage colony-stimulating factor (GM-CSF), the PGIG chemobiotherapy, for patients with metastatic melanoma. All patients received 175 mg/m ( 2) paclitaxel on day 1 and 800 mg/m ( 2) gemcitabine on day two. IL-2 and GM-CSF were administered from day 4 to day 8 at a dosage of 2 MIU/m ( 2) and 100 μg, respectively. The PGIG chemobiotherapy was repeated every 21 d. Serum cytokine levels at baseline and at the end of the second cycle were measured via flow cytometry. Twenty-seven patients with metastatic melanoma accepted PGIG chemobiotherapy from August 2009 to March 2011. There were five patients that exhibited a partial response, 14 patients that exhibited a stable response and eight that displayed progressive disease. Therefore, the response rate was 18.5%, and the disease control rate was 70.4%. The median time to progression and median survival were 4 mo and 8 mo, respectively. The one-year and two-year survival rates were 25.9% and 18.5%, respectively. Frequent side effects included chills, fever, arthralgia, rash and pruritus. Among the 13 patients who experienced a rash and pruritus and the 14 patients who did not suffer from this side effect, the response rates and disease control rates were 30.8% vs 7.1% and 77% vs 64.2%, respectively. No relationship between serum IL-6 levels, clinical response, and either skin side effect was observed. The PGIG chemobiotherapy is safe and effective for the treatment of patients with advanced melanoma, but randomized trials are necessary to validate this effect.

New therapeutic targets in melanoma

Research into molecular targets for drug development in melanoma is starting to bear fruit. Of the drugs tested to date in patients with metastatic melanoma, those that have yielded the best results are V600E BRAF inhibitors in melanomas carrying the V600E mutation; c-kit tyrosine kinase activity inhibitors in melanomas carrying c-kit mutations; and anti-cytotoxic T lymphocyte antigen 4 (CTLA-4) antibodies, which block the mechanisms involved in immune tolerance. Many problems have yet to be resolved in these areas, however, such as the rapid development of resistance to BRAF and c-kit inhibitors and the lack of biomarkers to predict treatment response in the case of CTLA-4 blockers. We review the results of targeted therapy with these and other drugs in metastatic melanoma and discuss what the future holds for this field.