A phase 1 study of daily oral perifosine (P) with every 3-week paclitaxel (T)
13134 Background: Perifosine is a novel alkylphospholipid that has been shown to affect multiple signal transduction pathways including Akt, MAPK and JNK (Kondapaka, Mol. Canc. Ther 2: 1093–1103. 2003). Treatment with a taxane initially activates Akt, and persistent activation increases resistance to the drug (Vanderweele, Mol. Canc. Ther. 3: 1605–13, 2004). Methods: Twelve patients (pts) were enrolled on this study. T was given at a dose of 175 mg/m2 on day 8 (after 7 days of perifosine) of a 21 day cycle; this was to obtain a steady state level of P at the tumor before exposure to T. The intent of the protocol was to determine if full dose P could be delivered with 50 mg of perifosine given orally 1, 2 or 3 times a day on days 1–14 of each cycle. Results: Disease sites included lung 3, thyroid 3, breast 1, esophagus 1 and other 4, Median age was 66 (range 45 - 83); 6 pts were male and median ECOG performance status was 1 (range 0–2). All pts had received prior chemotherapy (median 2 regimens); 3 had prior treatment with a taxane. Three pts were entered at each dose level and the cohort expanded to 6 pts if 2 or more pts experienced a grade 3/4 non-hematologic toxicity (DLT) during cycle 1. A dose level was toxic if 4 or more pts experienced a DLT during cycle 1. A total of 30 cycles and a median of 2 cycles (range 1–11) per patient were delivered. There were no grade 3/4 hematologic toxicities. Full dose T was given in all treatment cycles. P dose reductions were required in 6% of cycles (50 mg - 7%, 100 mg - 0%, 150 mg - 7%). One patient missed one dose due to nausea and one pt was stopped due to diarrhea. The grade 3 toxicities for each cohort are given in the table below. The elevated glucose value was 321. Nine pts were evaluable for response; two pts with thyroid cancer had stable disease by the RECIST criteria for 9 and 10+ months. Conclusions: In this study the usual single agent doses of P (150 mg daily) & T (175 mg/m2 q 3 weeks) were given together without increasing the toxicities that would be expected from using each drug alone. Phase II studies are warranted to define activity of the combination. [Table: see text] [Table: see text]