Revertant and potentiating activity of lonidamine in patients with ovarian cancer previously treated with platinum

Lonidamine (LND) is an energolytic derivative of indazol-carboxylic acid that has been shown to enhance cisplatin (CDDP) activity in both sensitive (A2780) and resistant (A2780/Cp8) ovarian cancer cell lines. The aim of this study was to confirm the potentiating or reverting activity of LND on CDDP activity obtained in experimental models in a phase II study of advanced ovarian cancer patients previously treated with platinum-based regimens.

Twenty-seven consecutive women with histologically proven and measurable ovarian cancer previously treated with platinum compounds were treated with CDDP plus LND. CDDP was administered at 1 mg/kg intravenously (IV) once weekly for 6 weeks and every 3 weeks thereafter until disease progression or toxicity. LND was administered at 450 mg daily (1 tablet every 8 hours) for the entire period of therapy starting 3 days before the first CDDP administration. In addition, a higher LND dosage was provided on the day of CDDP administration in an attempt to maximize the synergy of this drug with CDDP.

Ten patients achieved a complete response (CR) or partial response (PR) for an overall response rate of 37% (95% confidence interval [CI], 19% to 55%). In particular, responses were observed in five of 18 (28%) refractory or early relapsed patients (one CR and four PRs) and in five of nine patients (55%) in the late-relapsed group (two CRs and three PRs). Grade 3 or 4 anemia, leukopenia, and thrombocytopenia were observed in 19%, 15%, and 11% of patients, respectively, whereas seven of 27 patients (26%) showed LND-related myalgia. Grade 3 renal toxicity was observed in two patients (8%). Neurotoxicity, often concealed by LND-related myalgia, was recorded as grade 1 or 2 in six patients (22%) and as grade 3 in one (4%).

The 37% response rate observed in this study (28% in refractory or early-relapsed patients), suggests that the synergism between CDDP and LND observed in vitro against ovarian cancer cell lines can be clinically confirmed. However, larger series and randomized studies are needed to assess definitely the revertant activity of LND on CDDP-refractory patients.