Combination reduces PSA levels in men with advanced PCa

A combination of samarium SM-153 lexidronam injection (Quadramet) and docetaxel (Taxotere) appears to reduce PSA levels in patients with progressive hormone-refractory prostate cancer, according to a phase II study involving 29 patients.

In the study, known as TAXSAM1, mean PSA level at baseline was 838.0 ng/mL. Docetaxel was administered as a 30-minute infusion at a dose of 30 mg/m2 weekly for 5 weeks. Eighteen to 24 hours prior to the fourth administration of docetaxel, the approved palliative dose of samarium SM-153 lexidronam injection was administered. Patients received a second cycle of the combination regimen at PSA and/or clinical progression.

Within 12 weeks after the start of the first cycle, the researchers noted PSA declines greater than 50% and 75% in 34% and 21% of patients, respectively. The time from start of the regimen until PSA declines greater than 50% and 75% was 38 and 34 days, respectively. PSA progression was seen in 69% of the patients, with a median time to PSA progression of 126 days.

After the second cycle, received in 17 patients with a mean PSA level of 880.0 ng/mL, PSA declines greater than 50% and 75% were seen in 18% and 6% of patients, respectively, with the time from start of the regimen until PSA declines greater than 50% and 75% being 40 and 34 days, respectively. PSA progression was seen in 65% of patients, with a median time to PSA progression of 151 days, reported lead investigator Anders Widmark, MD, of Umea University, Sweden.

The research was presented at the Prostate Cancer Foundation annual scientific retreat in Phoenix.