In a previous study, 50 patients with prostatic
carcinoma were given continuous oral
estramustine phosphate at a dose of 15 mg/kg/day. All patients had progressed on prior standard treatment. The objective and subjective response rates were 19% and 36% respectively. Seven of the 50 patients are still receiving treatment after 1-3 years. One patient who was given
estramustine phosphate therapy for 1 year achieved a complete response, which included disappearance of osteoblastic
metastasis. He still continues in unmaintained remission despite the fact that
estramustine phosphate therapy was stopped because of gastrointestinal toxicity. No serious side effects related to the
drug have been seen.
Estramustine phosphate may be given safely for a prolonged period and has a place in the treatment of advanced
prostatic cancer refractory to hormonal
therapy. Twenty-one patients with stage D prostatic
adenocarcinoma who failed hormonal
therapy were treated with a combination of
estramustine phosphate (600 mg/m2/day) plus
prednimustine (Leo-1031) (15 mg/m2/day) in daily oral doses. Fifteen patients have been treated with
prednimustine alone. The preliminary results of the combination
therapy (after 2-9 months) are as follows: five patients (24%) had an objective response and nine patients (44%) had subjective improvement. Only five (24%) did not benefit from the
drug and seven (33%) are stable. Of the 16 patients treated with
prednimustine alone, one patient has had an unequivocal objective response and one experienced a considerable objective improvement. These preliminary results indicate the possible advantage of adding an
alkylating agent (
prednimustine) to
estramustine phosphate in advanced prostatic
carcinoma.