Fixed-dose rate gemcitabine plus carboplatin in relapsed, platinum-sensitive ovarian cancer patients: results of a three-arm Phase I study

A phase II study of gemcitabine, carboplatin and bevacizumab for the treatment of platinum-sensitive recurrent ovarian cancer

PURPOSE

The doublet gemcitabine and carboplatin is effective for the treatment of recurrent ovarian cancer, while multi-agent chemotherapy with bevacizumab may add additional benefit. This phase II study tested the efficacy and safety of a biweekly gemcitabine, carboplatin, and bevacizumab combination in patients with platinum-sensitive recurrent ovarian, peritoneal, or tubal cancer (ROC).

PATIENTS AND METHODS

Eligible patients received concurrent gemcitabine 1000 mg/m(2), carboplatin area under the curve 3, and bevacizumab 10 mg/kg administered intravenously on days 1 and 15 every 28 days for six cycles or up to 24 cycles if clinical benefit occurred. The primary end points were progression-free survival (PFS) by RECIST, and safety; the secondary end points were objective response rates and overall survival.

RESULTS

Overall, 45 patients were enrolled. The median PFS was 13.3 months (95% CI, 11.3 to 15.3). The objective response rate was 69%. Grade 4 hematologic toxicities included neutropenia (27%) and thrombocytopenia (2%). Grades 3 and 4 non-hematologic toxicities included fatigue (18%), pain (9%), and nausea/vomiting (4%). There were 2 episodes of cerebrovascular accidents, 2 noted DVTs, and no episodes of bowel perforation. Median OS was 36.1 months (95% CI, 26.7 to 45.5).

CONCLUSION

Biweekly gemcitabine, carboplatin, and bevacizumab were an effective regimen in recurrent ovarian cancer, with comparable toxicity to recently reported day 1 gemcitabine, carboplatin, bevacizumab, and day 8 gemcitabine. Response rate and PFS are improved from reported outcomes of the gemcitabine carboplatin doublet. The degree to which biweekly dosing may present a more rationale schedule for this triplet should be evaluated further.

Phase I dose-escalation study and population pharmacokinetic analysis of fixed dose rate gemcitabine plus carboplatin as second-line therapy in patients with ovarian cancer

OBJECTIVE

This phase I study of fixed dose rate (FDR) gemcitabine and carboplatin assessed the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), safety, pharmacokinetic (PK)/pharmacodynamic (PD) profile and preliminary anti-tumor activity in patients with recurrent ovarian cancer (OC).

METHODS

Patients with recurrent OC after first line treatment were treated with carboplatin and FDR gemcitabine (infusion speed 10mg/m(2)/min) on days 1, 8 and 15, every 28 days. Pharmacokinetics included measurement of platinum concentrations in plasma ultrafiltrate (pUF) and plasma concentrations of gemcitabine (dFdC) and metabolite dFdU. Intracellular levels of dFdC triphosphate (dFdC-TP), the most active metabolite of gemcitabine, were determined in peripheral blood mononuclear cells (PBMCs). Population pharmacokinetic modeling and simulation were performed to further investigate the optimal schedule.

RESULTS

Twenty three patients were enrolled. Initial dose escalation was performed using FDR gemcitabine 300 mg/m(2) (administered at infusion speed of 10 mg/m(2)/min) combined with carboplatin AUC 2.5 and 3. Excessive bone marrow toxicity led to a modified dose escalation schedule: carboplatin AUC 2 and dose escalation of FDR gemcitabine (300 mg/m(2), 450 mg/m(2), 600 mg/m(2) and 800 mg/m(2)). DLT criteria as defined per protocol prior to the study were not met with carboplatin AUC 2 in combination with FDR gemcitabine 300-800 mg/m(2) because of myelosuppressive dose-holds (especially thrombocytopenia and neutropenia).

CONCLUSIONS

FDR gemcitabine in combination with carboplatin administered in this 28 days schedule resulted in increased grade 3/4 toxicity compared to conventional 30-minute infused gemcitabine. A two weekly schedule (chemotherapy on days 1 and 8) would be more appropriate.

Inhibition of carboplatin-induced DNA interstrand cross-link repair by gemcitabine in patients receiving these drugs for platinum-resistant ovarian cancer

BACKGROUND

The potential of gemcitabine to interact with carboplatin was explored in a phase II trial in platinum-resistant ovarian cancer. Peripheral blood lymphocytes were sampled after drug administration to measure DNA interstrand cross-link formation and repair.

PATIENTS AND METHODS

Forty patients received carboplatin target area under concentration-time curve (AUC 4) followed by gemcitabine 1,000 mg/m(2) with a second dose of gemcitabine on day 8. Peripheral blood lymphocytes were obtained in 12 patients before and at intervals during the first cycle of chemotherapy. DNA cross-link formation and repair (unhooking) were measured by the single-cell gel electrophoresis (comet) assay following ex vivo incubation.

RESULTS

The global response rate was 47% (Response Evaluation Criteria in Solid Tumors rate, 29%; CA125 rate, 63%). Delays in treatment were seen in 24% of cycles largely due to myelosuppression; 15% of day 8 administration was omitted. Peak carboplatin-induced DNA cross-linking was seen by 24 hours. Significant reduction was seen in the repair of in vivo carboplatin-induced DNA cross-links following administration of gemcitabine.

CONCLUSION

An enhanced activity of carboplatin in platinum-resistant ovarian cancer may be due to synergy with gemcitabine through inhibition of repair of DNA cross-links. Future studies should explore coadministration of these drugs, as this may be a more effective schedule.