CHICAGO -- Maintenance therapy with pemetrexed (Alimta) appears to significantly extend progression-free survival in patients with advanced nonsquamous non-small cell lung cancer -- although the difference when compared with placebo is modest.
The median period without disease progression following induction therapy was 2.8 months among patients treated with placebo on top of best supportive care and 4.1 months for patients who were treated with pemetrexed plus best supportive care -- about a 40-day difference (P=0.00006), said Luis Paz-Ares, chief of oncology at Seville University Hospital, Spain.
Paz-Ares, in a press briefing at the annual meeting of the American Society of Clinical Oncology, said his study shows that continuing maintenance therapy with a drug used in the inductive phase of therapy can be accomplished without diminishing response.
"These results suggest that patients can still continue to benefit from the use of the same drug rather than 'use up' an alternative early in the course of treatment," he said. "This could change the standard of care for these patients, at least in terms of maintenance treatment."
In the phase III trial, patients diagnosed with nonsquamous non-small-cell lung cancer, who had no previous systemic treatment for the disease, underwent induction therapy with 500 mg/m2 pemetrexed plus 75 mg/m2 cisplatin for four 21-day cycles. If at the end of induction therapy, the patients had achieved complete response, partial response or stable disease, they were randomly assigned to receive pemetrexed plus best supportive care or placebo plus supportive care.
The 359 patients on pemetrexed did not progress for a median of 4.1 months when they were assessed by the trial investigators compared with 2.8 months for the 180 patients on placebo, which translated to a 38% relative risk reduction of the chance of experiencing disease progression.
The investigators also asked independent reviewers to assess whether the patients progressed. They determined that the median time to progression was 3.9 months for the 319 charts examined of those on pemetrexed compared to 2.6 months in the scans of 166 patients on placebo, also a 1.3 month difference that still achieved statistical significance (P=0.0002), which was a relative risk reduction of 36% in the chance of progression.
Mark Kris, MD, chief of the thoracic oncology service at Memorial Sloan-Kettering Cancer Center, in New York City, suggested that despite the cost of pemetrexed, he believed doctors would prescribe the treatment in the maintenance phase of therapy for advanced non-small cell lung cancer.
"The reason is that the patients in this study have received the drug, have demonstrated in their own lives that the drug is tolerable, and they remain cancer free. I would say the cost is a cost worth spending," Kris, who moderated the ASCO press briefing, told MedPage Today.
Pemetrexed therapy costs about $4,000 per cycle, Amy Sousa, a spokesman for Eli Lilly, the sponsor of the trial, told MedPage Today.
Costs aside, David Carbone, MD, professor of medicine at Vanderbilt University, Nashville, said that he was not on the bandwagon for prescribing pemetrexed as maintenance therapy.
"I don't believe in it and I don't use it," Carbone told MedPage Today. "I mention it to my patients but I recommend they don't take it. These patients often have a limited life expectancy and the prospect of getting stuck with needles to achieve a very small incremental benefit in progression-free survival does not seem worthwhile."
He would like to see studies that compared maintenance dosing to treatment at the time of recurrence to determine if that would have any impact on survival. Paz-Ares noted the survival data have not yet matured.