ZIOPHARM Oncology, Inc. (Nasdaq: ZIOP) announced guidance today regarding the Company's planned pivotal Phase III trial for palifosfamide in metastatic soft tissue sarcoma, including details of the proposed study's design, timing and regulatory review.
Following reporting of favorable interim results from its Phase II randomized controlled trial of palifosfamide plus doxorubicin vs. doxorubicin in patients with metastatic or unresectable soft tissue sarcoma (PICASSO), the Company obtained input on the protocol design for a pivotal Phase III trial from the U.S. Food and Drug Administration (FDA) in an end of Phase II meeting in January. In that meeting, the Company also discussed its intention to seek Special Protocol Assessment (SPA) in which the Company is currently engaged.
The Company has proposed that the pivotal trial, known as PICASSO III, be based upon PICASSO. The Company recently presented additional results from the PICASSO study at the 46th Annual American Society of Clinical Oncology Meeting. The additional results for the primary endpoint, progression-free survival (PFS), demonstrated that, in 62 evaluable patients, a hazard ratio of 0.43 favoring the palifosfamide combinations Syndrome.
As designed, the Company's PICASSO III study is a randomized, double-blinded, placebo-controlled, pivotal Phase III trial. Patients with metastatic soft tissue sarcoma in the front-line setting will be randomized either to doxorubicin plus placebo or to doxorubicin in combination with palifosfamide. Progression-free survival is designated as the primary endpoint for accelerated approval, while overall survival is the primary endpoint for full approval.
In a recent communication, FDA has indicated that the Company could conduct the pivotal trial as designed without SPA and that approvability would be determined by the data, balanced with risks and benefits. FDA presently considers the endpoints as designated for the proposed pivotal trial as not supportive of SPA in this disease setting, although they would grant SPA with modified endpoints. The Company intends to request a meeting with FDA, regarding the proposed designation of study endpoints while it weighs the advisability of moving forward with the current design. Therefore the Company expects enrollment in PICASSO III to begin in the third quarter rather than this month, as previously disclosed.
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