Temozolomide and thalidomide combination effective against malignant melanoma spread to the central nervous system

The non-randomised phase II trial, published in the online journal ecancermedicalscience, investigated the combination of thalidomide and temozolomide. It is the first phase II study combining a new cyclic regimen of temozolomide (150mg /m2 daily, 7 days on 7days off) and thalidomide, for patients with malignant melanoma suffering from brain metastases, to show a meaningful response rate.

Melanoma is the third most common cause of metastases in the central nervous system. Thalidomide is known to prevent new blood vessels growing from pre-existing vessels and thus inhibit tumour growth, and is also known to adjust the body’s immune response. Temozolomide is a chemotherapy alkylating agent commonly used for primary brain tumours, but also active in melanoma.

The researchers observed a response rate of 17.5% for temozolomide and thalidomide combined, around twice the response rate of the standard schedule of temozolomide alone (6-9% established in a previous study).

A statistically significant correlation was found between efficacy and lymphopenia (lowered white blood cell count).

Lead author Dr Lene Vestermark concluded: “The combination of temozolomide using the dose-intense schedule and thalidomide at 100-200 mg/day is a safe regimen leading to clinical efficacy in patients with brain metastases from malignant melanoma.

Most importantly it seems that patients who develop lymphopenia during therapy have a higher chance of obtaining objective response. The potential immunologic mechanism behind this will be the subject of future investigations, focusing on the potential benefit of regulatory T Cell down-regulation. The correlation between lymphopenia and objective response needs further investigation.”

Further evaluations using larger patient numbers and including different therapy schedules will be considered for the future.