Phase I trial of fenretinide (4-HPR) intravenous emulsion for hematologic malignancies

Abstract

13007 Background: 4-HPR is a retinoid cytotoxic for cancer cell lines. In clinical trials, oral capsule 4-HPR had limited bioavailability and activity. An intravenous intralipid emulsion formulation of 4-HPR (ILE 4-HPR) was developed to increase bioavailability. The objectives of this phase I trial were to determine a maximally tolerated dose (MTD) of ILE 4-HPR, and to assess toxicities, pharmacokinetics (PK), and preliminary response data. Methods: We used an accelerated titration Simon design 2 dose escalation schema with 100% increase in ILE 4-HPR per dose level tested until moderate toxicity was observed in 2 patients or DLT in one. Ten dose levels were planned with a starting dose of 80 mg/m2/day (continuous i.v. x 5 days q 3 weekly), increasing until Dose level 10 at 1,810 mg/m2. A De-escalation to 1,240 mg/m2/day Dose level 9 was added when DLT was observed in 2 patients at 1,810 mg/m2 dose level 10. Results: To date, 11 patients have been enrolled. At dose level 10 (1,810 mg/m2/day), 2 pts experienced a DLT of grade IV hypertriglyceridemia with grade 2 pancreatitis. A de-escalation to dose level 9 (1,280 mg/m2/day) has enrolled 4 pts, 1 had grade IV hypertriglyceridemia; enrollment is ongoing. We observed a transient response in a patient with NHL at 320 mg/m2 and a continued partial response in one patient with NHL on dose level 10 (1,810 mg/m2). PK showed a linear relationship of dose to plasma level, with steady-state levels of 54 μM (1,280 mg/m2)and 62 μM (1,810 mg/m2). Conclusions: ILE 4-HPR was given via continuous infusion to a dose of 1,810 mg/m2/day x 5 days. 1 patient with NHL had a transient partial response and a second patient with chemotherapy-refractory NHL had a partial response sustained on treatment for > 6 months. The DLT of hypertriglyceridemia is likely related to the intralipids delivered. Enrollment continues at a dose of 1,280 mg/m2/day. ILE 4- HPR can be safely administered and obtained plasma levels 6 to 7 times higher than previously obtained by oral capsule 4-HPR, with clinical activity in hematologic malignancies. No significant financial relationships to disclose.