Ziopharm Oncology said today it is putting into place a restructuring plan "to align staffing to current objectives and to marshal its resources toward achieving success with its synthetic biology programs," following its decision to terminate development of its palifosfamide (ZIO-201) for first-line metastatic soft tissue sarcoma.
The restructuring follows the failure of the bi-functional DNA alkylating agent to meet its primary endpoint of progression-free survival in a Phase III trial. Palifosfamide failed the PICASSO 3 trial, in which a total of 447 patients with metastatic soft tissue sarcoma were randomized to receive either intravenous palifosfamide plus doxorubicin (150 mg/m2 3 days every 21 days for a maximum of 6 cycles, followed by 75 mg/m2 1 day every 21 days for a maximum of 6 cycles) or doxorubicin alone (75 mg/m2 1 day every 21 days for a maximum of 6 cycles).
PICASSO 3 was conducted at more than 150 clinical centers in North America, Europe, South America, Australia, Israel, and Asia.
In pulling the plug on palifosfamide, Ziopharm went against its own independent data monitoring committee, which recommended that patients be followed for overall survival, the trial’s key secondary endpoint. Other secondary endpoints included quality of life assessments, and the safety and tolerability of the therapy combination in patients.
Ziopharm said it will instead immediately place its exclusive strategic focus on its synthetic biology programs, which are being developed in partnership with Intrexon. The lead therapeutic candidate, Ad-RTS IL-12, is now being tested in two Phase II studies—one for advanced melanoma, and the other for nonresectable recurrent or metastatic breast cancer in combination with palifosfamide.
"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," Jonathan Lewis, M.D., Ph.D., Ziopharm’s CEO, said in a statement.
Ziopharm’s DNA synthetic biology platform employs an inducible gene delivery system designed to enable controlled delivery of genes that produce therapeutic proteins to treat cancer. Ad-RTS IL-12 enables controlled delivery of therapeutic interleukin-12 (IL-12), a protein that plays a key role in immune response to cancer. Controlled delivery is achieved by turning expression of IL-12 on and off through Intrexon's biological "switch," the RheoSwitch Therapeutic System® (RTS).
Following announcement of the Phase III failure and planned restructuring, shares of Ziopharm on NASDAQ plunged more than 60% from its $5.13 per share close yesterday, to $1.92 per share at the start of trading this morning, then to $2.01 per share as of 9:45 a.m. today. Shares had traded as high as $5.95 earlier this month.