To date, few large studies have been reported of patients with peritoneal mesothelioma, and treatment of this disease has been largely extrapolated from the treatment of pleural disease. Hence, it was considered important to study and report on this specific patient population. Before the regulatory approval of pemetrexed, an expanded access program (EAP) provided access to eligible patients with malignant pleural or peritoneal mesothelioma.
Patients received pemetrexed 500 mg/m2 alone or in combination with cisplatin 75 mg/m2 once every 21 days for > or = 6 cycles. All patients received folic acid, vitamin B12, and steroid prophylaxis. Serious adverse events (SAEs) were compiled in a pharmacovigilance database, which included all patients in the EAP with pleural or peritoneal mesothelioma. From June 12, 2002 to February 18, 2004, 1056 patients with malignant mesothelioma were enrolled and received > or = 1 dose of treatment at 462 sites in the United States. Of these patients, 98 (9.3%) had peritoneal mesothelioma (57 previously treated, 38 chemotherapy-naive, and 3 with missing data).
Response data were available for 73 patients (43 previously treated, 28 chemotherapy-naive, and 2 not classified), indicating response rates of 23.3% for previously treated patients (0 complete responses [CRs], 10 partial responses [PRs], 21 cases of stable disease [SDs], 12 cases of progressive disease [PDs]) and 25% for chemotherapy-naive patients (3 CRs, 4 PRs, 12 SDs, and 9 PDs). Median survival was 13.1 months for previously treated patients and has not been reached for chemotherapy-naive patients. The most commonly reported SAEs for the total EAP were dehydration (7.2%), nausea (5.2%), and vomiting (4.9%).
Pemetrexed with or without cisplatin had a favorable safety profile, and the disease control rate (CR + PR + SD) of 71.2% in the subset of patients with peritoneal mesothelioma indicated activity in this patient population.