Phase I trial of fenretinide Lym-X-Sorb oral powder in adults with solid tumors and lymphomas

Background: The synthetic retinoid fenretinide (N-(4-hydroxyphenyl) retinamide, 4-HPR) has shown promising anticancer activity in preclinical studies, but its limited oral bioavailability has hindered clinical assessment. A novel lipid matrix, Lym-X-Sorb (LXS), was evaluated to improve fenretinide bioavailability and attain higher plasma concentrations. Patients and Methods: Adults with refractory malignancies were administered fenretinide/LXS oral powder in 2 divided doses over 24 h for 7 consecutive days every 21 days in a standard phase I dose-escalation study with pharmacokinetic analysis. Results: The principal toxicities observed were diarrhea, reversible night blindness, and allergic reaction. The maximum tolerated dose regimens were 1,000 mg/m ²/day divided into 2 daily doses for 7 days, every 21 days, and 800 mg/m ²/day divided into 3 daily doses for 7 consecutive days, every 21 days. Conclusion: Better fenretinide formulations are needed to improve adult patient acceptability and compliance and to achieve the consistent systemic exposures associated with activity in preclinical models.