Pemetrexed shows survival benefit in patients with pleural mesothelioma

Pemetrexed shows survival benefit in patients with pleural mesothelioma

May 20, 2002

Patients with cancer of the lining of the lung, known as pleural mesothelioma, live longer and have less pain and shortness of breath if they receive the new chemotherapy drug pemetrexed (Alimta R, Eli Lilly), according to the results of a Phase III global study.

The study was presented May 20, 2002, at the annual meeting of the American Society for Clinical Oncology.

Mesothelioma patients who were treated with pemetrexed plus the commonly used chemotherapy drug cisplatin lived for about a year after their diagnosis, nearly three months longer than patients who received only cisplatin, the researchers found. The two-drug combination also caused the cancer to shrink in 41% of patients, compared to 17% of patients who received only cisplatin, and was more effective at reducing pain and shortness of breath, symptoms commonly experienced by patients with this type of cancer.

"The results are very encouraging and significant because mesothelioma patients and their families now have proof that this new chemotherapy drug offers real and tangible benefits," said Nicholas J. Vogelzang, MD, Fred C. Buffett Professor and Director of the University of Chicago Cancer Research Center.

Mesothelioma is most commonly caused by asbestos exposure. Pemetrexed is a cousin of one of the earliest chemotherapy drugs, methotrexate, used for the treatment of other types of cancer. While methotrexate blocks one enzyme necessary for cell division and tumor growth, pemetrexed blocks three such enzymes.

The Phase III randomized study is the largest mesothelioma trial ever conducted, involving 456 patients. Patients were selected at random to receive pemetrexed plus cisplatin or cisplatin alone.

Shortly after the study began, the researchers found that many of the patients were deficient in the vitamins folic acid and B12. The deficiencies, which were presumably caused by the cancer and a poor appetite, decreased the ability of normal cells to repair and produce new DNA. The vitamin-deficient patients who received pemetrexed were more likely to experience severe toxicity (such as very low white blood cell counts [severe neutropenia], severe diarrhea, and severe mouth ulcers [stomatitis] which could lead to death) than patients who received only cisplatin.

Following this observation, all patients in the study received folic acid and vitamin B12 as a standard part of their treatment. This reduced the toxic side effects associated with pemetrexed, and more patients benefited from the drug.