Estimation of maximum tolerated dose and minimum efficient dose of BP-C1 in the treatment of stage IV breast cancer patients: A phase I response surface pathway designed study.
e11022 Background: The aims were to establish a treatment routine and to estimate the Maximum Tolerated Dose (MTD) and the Minimum Efficient Dose (MED) of a novel anti-cancer agent named BP-C1. Methods: The material consists of 15 Stage IV breast cancer patients with a mean age of 51 years. The study was performed as a non-randomized multi-centre trial with between patient 3-level Response Surface Pathway design. BP-C1 was given intramuscularly once daily during 32 days. The given cumulative dose window was 0.16 to 1.12 mg/kg bw, resulting in a starting dose of 0.64 mg/kg bw. The main variable was the National Cancer Institute common toxicity criteria (NCI-CTC) Bethesda. If the increase in toxicity was classified as moderate or less, the next patient in the sequence was allocated to an increased dose. In case of severe toxicity increase, the dose was reduced. Patients receiving cumulative dose of 0.96 mg/kg bw or higher was defines as the high-dose group. Results: Three of the five patients on the first design level recorded unchanged toxicity, one mild and one moderate increased Max NCI-CTC. Of the four patients receiving 0.96 mg/kg bw, three obtained no change and one a mild toxicity increase. The four patients on the third design level received the maximal dose of 1.12 mg/kg bw without any change in Max NCI-CTC. The Sum NCI-CTC increased (p= 0.07) in the low-dose group, but reduced (p=0.09) in the high-dose group. The cumulative dose of BP-C1 was found significantly (p=0.048) and negatively correlated (r = - 0.52) to the increase in toxicity. Only mild to moderate Adverse Events were reported and the prevalence was found largest in the high dose group (p=0.06). In the high-dose group 62.5% of the patients were classified as responders compared to 28.6% in the low-dose group. One of the patients in the high-dose group was classified as complete responder. The development in both Karnofsky Scale of Performance Status and patient wellbeing was found obviously better in the high-dose group. Conclusions: BP-C1 can safely be administrated continuously during a period of 32 days. The MTD seem to be at least 1.12 mg/kg bw and the MED to be 0.96 mg/kg bw.