Doublet regimen active, more convenient in ovarian cancer

TAMPA — A doublet regimen of carboplatin and pemetrexed was well tolerated and active in platinum-sensitive recurrent ovarian cancer, according to recent data.

“Platinum doublets have been found to improve both progression-free survival and overall survival compared with single-agent platinum in this setting,” Ursula Matulonis, MD, assistant professor of medicine, Harvard Medical School, said during her presentation. “However, significant toxicities occur in both of the standard regimens.”

Forty-four patients were enrolled into the phase-2 study. Patients received pemetrexed (Alimta, Lilly) followed immediately by carboplatin every 21 days for up to six cycles. The researchers assessed the cancer every two cycles. Toxicities were graded every two cycles.

There were no complete responses, but 52.3% of patients had confirmed partial responses, and 32% had stable disease. Two patients had unconfirmed partial responses, and two patients developed progressive disease. The median progression-free survival was 7.57 months. The median overall survival has not yet been reached.

Toxicities were primarily hematologic; 42% of patients had grade-3 or grade-4 neutropenia, 23% had grade-3 or grade-4 thrombocytopenia and 9% had grade-3 anemia. Sixteen patients had a carboplatin reaction, and 11% had grade-3 fatigue.

The strengths of this study are pretty obvious. There was a very high rate of response and a large clinical benefit rate. The regimen was well tolerated and offers a favorable treatment schedule. It is very exciting that the progression-free survival and overall survival were similar to the standard platinum regimens. However, a third of the patients had a reaction to the carboplatin, which is pretty significant. Also, there were no complete responses; in previous studies, carboplatin alone has demonstrated complete response rates of 6% to 35%. The researchers make sense of the overall survival data, but there was not enough information, such as the number of events. There are not a lot of data with pemetrexed in ovarian cancer, but existing data in other models show synergism between carboplatin and pemetrexed.

– Paul Haluska, MD

Assistant Professor of Oncology
Mayo Clinic, Rochester, Minn.

For more information:

Matulonis U, Richard P, Campos S, et al. #50. Presented at: the Society of Gynecologic Oncologists 39th Annual Meeting on Women’s Cancer; March 9-12; Tampa, Fla.