Pilot trial of the safety, tolerability, and retinoid levels of N-(4-hydroxyphenyl) retinamide in combination with tamoxifen in patients at high risk for developing invasive breast cancer.

OBJECTIVE

N-(4-hydroxyphenyl) retinamide (¿4-HPR, Fenretinide; R.W. Johnson Pharmaceutical Research Institute, Springhouse, PA) and tamoxifen (TAM) have synergistic antitumor and chemopreventive activity against mammary cancer in preclinical studies. We performed a pilot study of this combination in women at high risk for developing breast cancer.

METHODS

Thirty-two women were treated with four cycles of 4-HPR, 200 mg orally (PO) for 25 days of each 28-day cycle, and TAM, 20 mg PO once daily for 23 months beginning after 1 month of 4-HPR alone. Tolerability, dark adaptometry, tissue biopsies, and retinoid plasma concentrations (Cp) were evaluated.

RESULTS

Symptomatic reversible nyctalopia developed in two patients (6%) on 4-HPR, but 16 (73%) of 22 patients had reversible changes in dark adaptation, which correlated with relative decrease in Cp retinol (P

CONCLUSIONS

TAM administration did not affect Cp 4-HPR or 4-MPR. Reversible nyctalopia correlated with relative decrease in Cp retinol but was not symptomatic for most patients. TAM + 4-HPR has acceptable tolerability for this high-risk cohort.