Objective: In recurrent ovarian cancer (ROC), there is a high demand on effective therapies with a mild toxicity profile. Treosulfan is an alkylating agent approved as oral (p.o.) and intravenous (i.v.) formulation for the treatment of recurrent ovarian cancer. Data on safety and efficacy for either formulation are rare. For the first time we conducted a randomized phase III study comparing both formulations in women with ROC.
Methods: Patients having received at least two previous lines of chemotherapy were randomly assigned to one of two treatment arms: treosulfan i.v. 7000 mg/m2 d1 q4w or treosulfan p.o. 600 mg/m2 d1-28 q8w. Primary endpoint was safety regarding hematological and gastrointestinal toxicity grade III/IV, secondary endpoints were other toxicities, clinical benefit rate (CBR), time to progression (TTP), overall survival (OS) and quality of life.
Results: 250 patients were treated with treosulfan i.v. (128) or treosulfan p.o. (122). In general treosulfan therapy was well tolerated in both treatment arms. Leukopenia grade III/IV occurred significantly more frequently in the p.o. arm (3.9% i.v. arm, 14.8% p.o. arm, p = 0.002). Other toxicities were similar in both arms. CBR was comparable between arms (41.4% i.v. arm, 36.9% p.o. arm). No difference in TTP (3.7 months i.v. arm, 3.5 months p.o. arm) or OS (13.6 months i.v. arm, 10.4 months p.o. arm, p = 0.087) occurred.
Conclusions: Given the safety and efficacy results treosulfan is an acceptable option for heavily pretreated OC patients. Regarding the toxicity profile the i.v. application was better tolerated with less grade III and IV toxicities.
Keywords: Oral versus intravenous; Ovarian cancer; Recurrent; Treosulfan.