Oral cyclophosphamide in recurrent ovarian cancer

Cyclophosphamide was widely used as a single agent prior to the advent of platinum-based regimens for epithelial ovarian cancer, and, in combination with platinum, prior to the adoption of platinum and paclitaxel as standard first-line therapy. As cyclophosphamide currently has no defined role in ovarian cancer we aimed to assess its activity in women with recurrent disease.

A retrospective review was conducted of patients from three centers in Melbourne, Australia who had received oral cyclophosphamide treatment for recurrent ovarian cancer. The primary end-point was response rate to oral cyclophosphamide (150 mg p.o. day 1-14) based on Gynecologic Cancer InterGroup (GCIG) CA125 and/or Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Secondary end-points included overall and progression-free survival and toxicity.

In all, 26 patients were identified and 23 patients were evaluable for response. The median number of prior chemotherapy regimens was three (range 1-6). The response rate to oral cyclophosphamide was 44% with 10 of the 23 patients achieving a partial response (PR) based on GCIG (CA125) criteria. The median number of cycles received was three (range 1-16). Cyclophosphamide showed activity both in patients with platinum-sensitive (seven of 13 PR) and resistant or refractory disease (three of 10 PR). There was no grade 3 or 4 toxicity but two patients ceased cyclophosphamide due to less severe non-hematological toxicity.

Single agent oral cyclophosphamide is active and well tolerated in recurrent ovarian cancer. Further investigation of oral cyclophosphamide in patients with platinum-sensitive and platinum-resistant disease is warranted.