Phase II evaluation of maytansine in patients with metastatic lung cancer

A phase II evaluation of MAYT was performed in patients with advanced lung cancer, the majority of whom had had prior chemotherapy and poor PS. The overall tumor regression rate was 8%. Regressions were seen in patients with ACA, LGC, and SQC, but not in patients with SMC. Of the 47 patients treated, 21 progressed after the first course of chemotherapy. Only 26 received a second course of treatment, seven a third course, and only one a fourth course. Consequently, little can be said about the chronic toxicity. The severe constipation and unrelenting peripheral neurotoxicity seen in a minority of patients was the most troubling. We were especially concerned about our inability to prevent or ameliorate toxicity despite dose reduction or drug discontinuation. This, coupled with the 45% immediate progression rate, leads us to believe that more frequent treatment would not be more beneficial. The conclusion is that MAYT is an agent with some, but very limited, activity in lung cancer. Until the pharmacokinetics of the drug are better understood, we feel that further MAYT treatment of lung cancer employing the schedule described in this study is not warranted.