Based on investigator assessments, patients treated with bavituximab plus carboplatin and paclitaxel demonstrated a current median PFS estimate of 5.8 months versus 4.6 months in patients treated with carboplatin and paclitaxel alone, a 26% improvement. These results are consistent with a prior phase II single-arm study testing the same bavituximab combination in front-line NSCLC patients which showed a 6.1 month median PFS and with several prior published studies with carboplatin and paclitaxel in front-line patients that showed approximately a 4.5 month median PFS. Based on independent central imaging reads, patients demonstrated a current median PFS estimate of 6.7 months for the bavituximab-containing arm and 6.4 months for the chemotherapy-only arm. Peregrine expects to report median overall survival (OS) from this trial in the second half of 2012.
"We are pleased that the PFS results for the bavituximab-containing arm by both local and central image interpretation actually met or exceeded our expectations going into the study. While the data from the investigator assessments were in alignment with previous published reports for carboplatin and paclitaxel and suggested an encouraging difference between the treatment arms, the unexpected long PFS estimate for the control arm based on central reads confounds our ability to fully interpret this secondary efficacy endpoint," said
Further data from the study showed that based on an independent central imaging review of eligible patients, patients treated with bavituximab plus carboplatin and paclitaxel demonstrated an ORR of 25%, versus 23% in patients treated with carboplatin and paclitaxel alone. Investigator-determined response rates were 32% for bavituximab plus carboplatin and paclitaxel versus 31% for carboplatin and paclitaxel alone.
"We continue to be enthusiastic about the bavituximab program and look forward to the upcoming data from seven ongoing clinical studies in multiple solid tumor indications including the OS data from this study. While we had hoped the PFS results in this study would be more consistent, we are encouraged by what we have seen so far in the trial and now look forward to the final and perhaps most important endpoint from the study, median OS," said
Bavituximab is currently being tested in seven clinical studies including three randomized Phase II trials in front-line and second-line non-small cell lung cancer (NSCLC), front-line pancreatic cancer and four investigator-sponsored trials (ISTs) in additional oncology indications with clinical data from each study expected in 2012.
About Peregrine's Randomized Phase II Front-Line NSCLC Trial
This randomized trial is designed to compare the ORR of carboplatin and paclitaxel with or without bavituximab in 86 patients with front-line, Stage IIIb/IV NSCLC. This analysis was performed on 83 protocol eligible patients (per protocol population) and ORR was determined by both investigators and independent central imaging review using RECIST (Response Evaluation Criteria in Solid Tumors). Secondary objectives of the study include median PFS, duration of response, median OS, and safety parameters. More information about this trial can be found at http://www.clinicaltrials.gov/ct2/show/NCT01160601?term=bavituximab&rank=4.
Bavituximab is a first-in-class phosphatidylserine (PS)-targeting monoclonal antibody that represents a new approach to treating cancer. PS is a highly immunosuppressive molecule usually located inside the membrane of healthy cells, but "flips" and becomes exposed on the outside of cells that line tumor blood vessels, creating a specific target for anti-cancer treatments. PS-targeting antibodies target and bind to PS and block this immunosuppressive signal, thereby enabling the immune system to recognize and fight the tumor.
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