CHICAGO—There is minimal toxicity associated with the use of thalidomide in malignant pleural mesothelioma (MPM); however, there is also no evidence of benefit in progression free survival (PFS) or overall survival (OS), according to researchers at the American Society of Clinical Oncology’s 2011 Annual Meeting. Standard chemotherapy treatment does not lead to long-term survival, and studies such as this are aiming to find new treatment approaches.
MPM is known for its high vessel count and levels of vascular growth factors. Paul Baas, MD, PhD and colleagues from Netherlands Cancer Institute, Amsterdam, believe that adding thalidomide in the maintenance setting may suppress the neovasculature and lead to improved PFS. After obtaining informed consent, patients on pemetrexed (500mg/m2) and carboplatin (AUC 5) or cisplatin (75mg/m2) every 3 weeks for four or more courses with no signs of progression were eligible and randomized to receive either oral thalidomide 100mg/day for 2 weeks that was increased to 200mg/day if tolerated or no treatment. Physical examination and CT scanning of the thorax was performed every 2 months or earlier. Patient PFS and OS were calculated from start of randomization and a number of 190 events were required to show and improvement of 50% in PFS.
Investigators included 222 patients (median age: 64 years [range 41–82]; 86% epithelial type; 215 WHO 0–1; and 6 WHO 2) from May 2004 until December 2009 from eight Dutch and four Australian centers. The PFS was HR 1.0 [0.7-1.2]; P=0.71 and OS was HR 1.2 [0.9-1.6]; P=0.30. Few patients showed grade 3/4 toxicities.
Dr. Baas et al concluded that in this largest maintenance study in patients with MPM reported so far, there is also no evidence of benefit in PFS or OS and thalidomide as switch maintenance treatment in MPM is not effective. However, a dose of 200mg/day is manageable with limited toxicity. Investigators concluded that further data mining with translational research is necessary.