The company said that 10 of 34 evaluable patients (29%) enrolled to date in the ongoing, single-arm, Simon two-stage design study evaluating the combination of Zybrestat and chemotherapy (carboplatin and paclitaxel) had partial responses as measured by tumor imaging and/or ovarian cancer biomarker (CA-125) criteria.
An additional unconfirmed partial response was observed in a patient lost to follow up, and stable disease responses were observed in an additional nine patients. The combination regimen of Zybrestat and chemotherapy was observed to be well-tolerated.
Data reported are based on a preliminary analysis of 34 evaluable patients enrolled to date in the Phase II trial. Per the study design, total enrollment in the trial is anticipated to be 43 patients. Patients in the study had received between one and seven prior lines of chemotherapy and were confirmed to have platinum-resistant ovarian cancer. Platinum resistance is defined as disease relapse within six months of completing treatment with platinum-based therapy, and the patients enrolled in the study would therefore not be expected to respond to further treatment with platinum-based therapy.
Patients in the study were given a 10-minute infusion of Zybrestat, followed by standard doses of carboplatin and paclitaxel within 18-22 hours. This combination was repeated every three weeks for up to six cycles. The combination regimen of Zybrestat, carboplatin and paclitaxel appeared to be well-tolerated, with the most frequently reported side-effects being transient nausea, fatigue and tumor pain.
In December 2007, OXiGENE reported that the study met the primary efficacy endpoint of stage one of the Simon two-stage study. In the first stage, five of the 18 patients responded to Zybrestat. A total of 25 patients are expected to be enrolled in the second stage of the study. The company expects final data from this study in the first half of 2009.
Patricia Walicke, chief medical officer of OXiGENE, said: “The data presented are consistent with the overall results we have seen in approximately 350 patients to date indicating that Zybrestat appears to be well-tolerated and has clinical activity against a variety of tumor types, including difficult-to-treat malignancies such as platinum-resistant ovarian cancer and anaplastic thyroid cancer.”