Mesothelioma remains one of the most difficult cancers to treat effectively. Even as improvements to the standard therapies have led to small increases in overall survival time for some patients, the disease remains without a cure and most patients diagnosed with pleural mesothelioma will die within two years of diagnosis. The introduction of pemetrexed and cisplatin combination chemotherapy represented a real advancement in the effectiveness of chemotherapy for mesothelioma, but they are approved only as first-line therapy and their use for patients with relapsed mesothelioma is unclear. In fact, very few studies have been completed on second-line chemotherapy so the role of any agent for this purpose is unclear.

In light of this question, researchers from the United Kingdom conducted a study on the use of vinorelbine for second-line chemotherapy. Vinorelbine is a chemotherapy drug commonly used to treat breast cancer and non-small cell lung cancer that previous studies have shown has some clinical activity for mesothelioma. The goal of the study was to investigate if vinorelbine was effective and well-tolerated for treating mesothelioma.

Overview of the Study

To investigate the efficacy of vinorelbine as a second-line chemotherapy agent, the researchers selected patients with histologically-confirmed pleural mesothelioma for inclusion in their study. All patients must have previously undergone chemotherapy for mesothelioma, as well as demonstrate a current performance status between 0-2 and adequate lung and organ function. Patients also had to be free of other cancers.

At the time of enrollment, patients were given a CT scan to establish disease status. If a patient presented with a pleural effusion, the effusion would be drained before starting therapy. The treatment protocol stipulated vinorelbine would be delivered on an outpatient basis, once per week. The standard dose administered was 30 mg/m² of vinorelbine in 20mL of saline; the maximum dose delivered was 60 mg/m². The patients’ weekly progress would be monitored with blood cell counts and chemistry panels. 6 administrations were considered one chemotherapy cycle and at the end of every cycle, a CT scan was completed to track treatment response.

Results

The authors enrolled 63 patients with pleural mesothelioma into their study. The average age in the cohort was 59 years-old. Most patients were male (94%) and most presented with epithelial histology. The median time between first-line chemotherapy and the start of this second-line study was 6 months.

10 patients in the study group demonstrated a partial response to the treatment. 43 patients demonstrated stable disease, which was defined in the study design as 6 consecutive months without any evidence of progression. 10 patients experienced progressive disease, but the authors noted that these 10 patients did not complete the recommended number of cycles.

Median survival for the group averaged 9.6 months.

The treatment was generally well-tolerated, but a number of patients did experience strong side effects, with the most common being neutropenia, anemia, constipation, neuropathy and phlebitis.

The authors state that there were no statistically significant differences in response or survival when controlling for histological type, stage or performance status.

Conclusion

The results of this study indicate that vinorelbine is well-tolerated and moderately effective as second-line chemotherapy for pleural mesothelioma. The authors note that median survival time was greater than would expected and they cite a number of previous studies that have also shown vinorelbine’s activity for the treatment of pleural mesothelioma. The authors conclude their article by calling for more studies on the use of vinorelbine as both a first-line and as a second-line treatment for mesothelioma.

Labels: mesothelioma