Peregrine Pharmaceuticals (NASDAQ:PPHM) announced the presentation of promising new data from its Phase III SUNRISE trial of bavituximab in patients with previously treated locally advanced or metastatic non-squamous non-small cell lung cancer (NSCLC). Presented results demonstrated that patients in the study’s bavituximab treatment arm who had low baseline PD-L1 expression levels had a statistically significant improvement in median overall survival (mOS) as compared to patients in the same treatment arm who had higher baseline levels of PD-L1.  Data were presented by Peregrine scientists at the Annual Meeting of the American Society of Clinical Oncology (ASCO), being held June 2 – 6, 2017 in Chicago.

Data presented demonstrated that patients in the study’s docetaxel plus bavituximab (D+B) treatment arm with a pre-treatment PD-L1 expression level on tumor cells of < 1% (TC0) had a mOS of 12.1 months compared to a mOS of 6.1 months for patients with PD-L1 expression ≥1% (TC1/2/3) (HR = 0.42 p=0.007).  There was no difference in mOS based on PD-L1 expression levels observed in the study’s docetaxel plus placebo (D+P) control arm (10.7 months for TC0 vs. 11.1 months for TC1/2/3; HR = 0.87; p=0.609).

“We believe that these latest observations from the SUNRISE trial further support the hypothesis that bavituximab, through its immune modulating mechanism, may have more effect on tumors without pre-existent immunity.  These ‘cold’ tumors suppress normal anti-tumor immune response and are categorized by very low to no PD-L1 expression on tumor cells,” said Joseph Shan, vice president of clinical and regulatory affairs at Peregrine. “These latest findings, along with other recently announced clinical and preclinical data from our PS-targeting program, inform our clinical development strategy going forward and provide additional rationale for combining bavituximab with checkpoint inhibitors.”

As part of the SUNRISE clinical study protocol, researchers requested but did not require that patients provide a tumor tissue sample at the time of diagnosis.  In total, tissue samples were collected from 129 of the trial’s 597 patients and were assessed retrospectively for baseline PD-L1 expression levels on tumor cells.  Of the 129 tissue samples collected, 122 were evaluable for PD-L1 expression on tumor cells (54 in D+B arm and 68 in D+P control arm). Of the evaluable samples in the D+B arm, 69% demonstrated PD-L1 expression levels < 1%, as compared to 59% in the D+P arm.

Bavituximab is an investigational immune-modulatory monoclonal antibody that targets phosphatidylserine (PS). PS inhibits the ability of immune cells to recognize and fight tumors. Bavituximab is believed to reverse PS-mediated immunosuppression by blocking the engagement of PS with its receptors as well as by sending an alternate immune activating signal.  PS-targeting antibodies have been shown to shift the functions of immune cells in tumors, resulting in multiple signs of immune activation and anti-tumor immune responses.

Peregrine’s clinical development strategy for bavituximab currently focuses on small, early-stage, proof-of-concept trials evaluating the drug in combination with other cancer treatments.  This approach includes grants awarded by the National Comprehensive Cancer Network (NCCN) to support three different clinical trials of bavituximab treatment combinations.  These trials will evaluate novel bavituximab combinations in glioblastoma, head and neck cancer, and hepatocellular carcinoma including an immunotherapy combination.  Additionally, Peregrine continues to advance its pre-clinical collaboration with Memorial Sloan Kettering Cancer Center (MSK) with the goal of evaluating combinations of PS targeting antibodies with checkpoint inhibitors and other immune stimulatory agents.  Peregrine’s intent behind this strategy is to focus its research and development spending to further validate bavituximab’s combination potential as the company seeks to advance the program though a pharmaceutical or biotechnology partner.

Shares of Peregrine closed last Friday at $0.595, up $0.03 or 4%. PPHM has a 1-year high of $0.77 and a 1-year low of $0.28. The stock’s 50-day moving average is $0.59 and its 200-day moving average is $0.48.

Peregrine Pharmaceuticals, Inc. is a biopharmaceutical company that engages in the provision of monoclonal antibody therapeutics. It operates through Peregrine and Avid segments. The Peregrine segment refers to research and development of monoclonal antibodies for the treatment and diagnosis of cancer. The Avid segment provides contract management services for peregrine and third-party customers on a fee-for-services basis.