Ziopharm Oncology, a biopharmaceutical company, has reported positive interim data from the multicenter randomized Phase II trial of palifosfamide treating patients with unresectable or metastatic soft tissue sarcoma.
As previously announced, having achieved the study-specified efficacy milestone following planned safety and efficacy review by the Data Committee, a panel of international sarcoma experts, and the company's medical advisory board, it was determined that the data are compelling and sufficient to proceed to a pivotal study in support of product registration and to conclude enrollment in the trial.
The randomized Phase II trial treats patients with unresectable or metastatic soft tissue sarcoma in the front- and second-line setting. Patients are randomized either to doxorubicin or to palifosfamide in combination with doxorubicin. As of the October 5, 2009 cut-off date, there were 67 patients randomized to the trial, with 65 treated and 61 eligible for analysis.
The 61 patients were evaluated for progression-free survival (PFS) with 20 documented PFS events. With this analysis of all randomized and eligible patients, the hazard ratio is 0.63 favoring palifosfamide + doxorubicin, statistically supporting that palifosfamide prolongs PFS by at least 50%.
The median PFS for doxorubicin is 4.4 months, the median PFS for palifosfamide + doxorubicin has not yet been reached; the first quartile PFS was 1.5 months for doxorubicin compared to 3.5 months for palifosfamide + doxorubicin.
The arms of the trial were very well-balanced by predetermined stratification in terms of age and pre-selected histopathological subtypes. In addition, and consequently, this also resulted in balance between front- and second-line patients. The company is in the process of finalizing a registration trial plan in soft tissue sarcoma for review by the appropriate US and international regulatory authorities.
Lawrence Einhorn, distinguished professor at the Simon Cancer Center of Indiana University Medical Center, Lance Armstrong Foundation chair in oncology and also a member of medical advisory board at Ziopharm, said: "These data are not only encouraging for sarcoma but hopefully palifosfamide may also work in treating other cancers. This is particularly interesting if the oral form is successful in the clinic."