Phase I trial of intraperitoneal pemetrexed, cisplatin, and paclitaxel in optimally debulked ovarian cancer

This phase I trial evaluated intraperitoneal (i.p.) pemetrexed, cisplatin, and paclitaxel in optimally debulked ovarian cancer.

Dose escalation of day 1 i.p. pemetrexed accrued three patients to each of five dose levels (60-1,000 mg/m(2)), along with day 2 i.p. cisplatin (75 mg/m(2)) and day 8 i.p. paclitaxel (60 mg/m(2)). The goals were to determine maximum tolerated dose (MTD), 18-month progression-free survival (PFS), and pharmacokinetics of i.p. pemetrexed.

Cycles, given every 21 days, had an 80% 6-cycle completion rate. There was minimal grade III toxicity in the first 4 dose levels and remarkably an almost complete absence of peripheral neuropathy and alopecia. At the highest dose level, two of three patients experienced ≥ grade III and dose-limiting toxicity (DLT; hematologic, infection, gastrointestinal). There was a pharmacokinetic advantage for i.p. pemetrexed with an intraperitoneal:plasma area under the concentration-time curve ratio of 13-fold. Neither analysis of pharmacokinetic nor homocysteine levels explains the unexpected severity of toxicity in those two patients. On the basis of plasma C(24h) levels, the 42 cycles at ≥ 500 mg/m(2) i.p. pemetrexed without DLT, the MTD appears to be 500 mg/m(2). Median PFS is 30.1 months; 18-month PFS is 78.6% (median follow-up 22.4 months).

This i.p.-only regimen in front-line ovarian cancer is feasible with PFS in line with recent literature. We suggest phase II trials of this regimen in this population with i.p. pemetrexed at 500 mg/m(2). The favorable toxicity profile at doses <1,000 mg/m(2), which needs to be confirmed, appears to compare well with standard combination i.v./i.p. platinum/taxane chemotherapy in this disease.