Phase 2 trial of carboplatin plus tamoxifen in platinum-resistant ovarian cancer and primary carcinoma of the peritoneum.

Objectives: A previously reported phase 2 trial suggested substantial clinical activity associated with the combination of a platinum agent and tamoxifen in the treatment of platinum-resistant ovarian cancer. We wished to confirm or refute this observation in a patient population with well-characterized platinum-resistant disease.

Methods: Patients with ovarian or fallopian tube cancers or primary carcinoma of the peritoneum whose disease had either failed to respond to a platinum-based regimen or had responded but experienced a "treatment-free interval (TFI)" of < or =3 months, or if the TFI was >3 months they had been retreated and failed a platinum-based program, were eligible for entry into this phase 2 single institution protocol. Carboplatin (AUC 5) was delivered on a q-21 day cycle. Tamoxifen was administered at a dose of 80 mg/day for the first cycle, and then reduced to 40 mg/day. Treatment was to be continued until evidence of disease progression or unacceptable toxicity.

Results: Fourteen patients were treated on this phase 2 trial. In addition to being platinum-resistant, 10 patients had cancers that were also documented to be taxane-resistant (similar criteria to that defined above for platinum). While treatment was generally well tolerated, there were no objective (measurable disease or CA-125 response criteria) or subjective responses to this treatment program.

Conclusion: In this phase 2 trial, we have been unable to confirm a meaningful level of clinical activity for the combination of carboplatin plus tamoxifen in a patient population with well-characterized platinum-resistant ovarian cancer.