Pemetrexed single agent for "continuation maintenance" therapy in patients with advanced nonsquamous nonsmall-cell lung cancer (NSCLC)

October 28, 2011 — The European Commission has approved pemetrexed (Alimta, Eli Lilly) for use as a single agent for "continuation maintenance" therapy in patients with advanced nonsquamous nonsmall-cell lung cancer (NSCLC), the company announced today. Pemetrexed is the first chemotherapy agent to be approved in Europe for continuation maintenance therapy, according to Eli Lilly. Continuation maintenance therapy refers to the first-line use of a therapy and then its ongoing use in nonprogressors. Other maintenance regimens are currently available for NSCLC, according to a company press statement, but they involve "switch maintenance," in which nonprogressing patients are switched from their first-line treatment to another drug during the maintenance phase. Continuation maintenance therapy is not for every NSCLC patient who responds to first-line treatment, according to a pemetrexed investigator. "Some may have significant toxicity during induction treatment, and it may be worth having a treatment break. [However], a patient who is having a good response in the absence of significant toxicity may be a good candidate for maintenance therapy," said Luis Paz-Ares, MD, PhD, from the Seville University Hospital in Spain, in a press statement at the 2011 annual meeting of the American Society of Clinical Oncology (ASCO). Dr. Paz-Ares was the lead author of the study on which the European approval is based. That phase 3 study, known as PARAMOUNT, is the first large trial to demonstrate that using continuation maintenance therapy can increase progression-free survival in this setting. The study results were first presented at the 2011 ASCO meeting, and were reported by Medscape Medical News at that time. In an earlier study, pemetrexed was found to increase progression-free survival and overall survival, compared with placebo, in this same patient population when used in switch maintenance. In PARAMOUNT, 939 patients were given the standard 4 courses of first-line induction treatment with pemetrexed and cisplatin to induce disease remission. Nonprogressors with a good performance status were then randomized (in a 2:1 ratio) to either maintenance pemetrexed (n = 359) or placebo (n = 180). Median progression-free survival was 4.1 months in the pemetrexed group and 2.8 months in the placebo group. Continuation maintenance therapy with pemetrexed resulted in a significant 38% reduction in the risk for disease progression (hazard ratio, 0.62; P = .00006). Pemetrexed is approved in Europe and the United States for 3 indications in patients with advanced nonsquamous NSCLC — first-line treatment in combination with cisplatin, second-line treatment, and maintenance treatment for patients whose disease does not progress immediately after platinum-based chemotherapy. Maintenance therapy is a controversial treatment strategy in lung cancer and has been discouraged in certain patients by various experts.