Ziopharm Oncology, a biopharmaceutical company focused on the development and commercialization of new cancer therapies, announced that its phase III trial of palifosfamide (ZIO-201) for the treatment of metastatic soft tissue sarcoma in the first-line setting (PICASSO 3) did not meet its primary endpoint of progression-free survival (PFS).

With this outcome, Ziopharm has made the decision to immediately terminate the development of palifosfamide in metastatic soft tissue sarcoma and place exclusive strategic focus on its synthetic biology programs, which are being developed in partnership with Intrexon.

"We are disappointed that the PICASSO 3 study did not meet its primary endpoint of progression-free survival," said Jonathan Lewis, M.D., Ph.D., CEO of Ziopharm. "We sincerely thank the trial investigators, clinical sites and the Ziopharm team for conducting a highly rigorous study, and are deeply appreciative to the cancer patients and their families for their participation in this trial."

The study's independent data monitoring committee has recommended that patients be followed for overall survival (OS), the study's secondary endpoint, however Ziopharm does not expect to continue follow up for OS. Palifosfamide was well tolerated, with a safety profile in combination with doxorubicin observed in the study comparable with other palifosfamide clinical trials in soft tissue sarcoma. Full data from PICASSO 3 will be submitted for publication in a scientific journal.

"It is imperative that the Company rapidly focus its resources and efforts on our highly promising synthetic biology programs, employing therapeutic motifs that represent the next-generation in biotechnology,” said Lewis.

The lead therapeutic candidate in the program with Intrexon is Ad-RTS IL-12, a DNA therapeutic to enable controlled delivery of therapeutic interleukin-12 (IL-12), a protein important for an immune response to cancer. This is achieved by placing IL-12 under the control of Intrexon's proprietary biological "switch" (the RheoSwitch Therapeutic System) to turn on/off the therapeutic protein expression. Ad-RTS IL-12 is currently being tested in two phase II studies, the first for the treatment of advanced melanoma, and the second in combination with palifosfamide for the treatment of non-resectable recurrent or metastatic breast cancer.

A highly focused team within the Company will be deployed in support of these programs. As a result, a restructuring plan is immediately being put into place to align staffing to current objectives and to marshal its resources toward achieving success with its synthetic biology programs.