Halozyme Therapeutics, Inc. (NASDAQ: HALO), a biotechnology company developing novel oncology and drug-delivery therapies, today announced interim findings from the ongoing phase 2 clinical study of its investigational new drug PEGPH20 for the potential treatment of patients with metastatic pancreatic cancer.
The encouraging interim data was presented today at the American Society of Clinical Oncology annual meeting in an oral presentation by Principal Investigator Sunil Hingorani, M.D., Ph.D., Associate Member of the Fred Hutchinson Cancer Research Center and Associate Professor at University of Washington School of Medicine.
The trial included 135 treated patients in stage 1, of whom a total of 44 patients -- 23 receiving PEGPH20 in combination with ABRAXANE® and gemcitabine (PAG treatment arm) and 21 receiving ABRAXANE and gemcitabine alone (AG treatment arm) -- had available biopsies that were determined in a retrospective analysis to have high levels of hyaluronan (HA). PEGPH20 targets HA to help improve cancer therapy access to tumor cells. Results reported include:
- A more than doubling of median progression-free survival of 9.2 months versus 4.3 months in high HA patients treated with PAG vs. AG (hazard ratio of 0.39; p-value of 0.05);
- A more than doubling of overall response rate of 52 percent versus 24 percent (p-value of 0.038) and a duration of response of 8.1 months compared to 3.7 months in high HA patients treated with PAG versus AG;
- In the 30 high HA patients (15 PAG treatment arm versus 15 AG treatment arm) who were evaluated for response prior to the April 2014 clinical hold and subsequent PEGPH20 treatment discontinuation, the overall response rate was 73 percent versus 27 percent (p-value of 0.01), respectively, consistent with findings presented in January;
- A trend toward improvement in median overall survival of 12 months compared to 9 months in high HA patients treated with PAG versus AG (hazard ratio of 0.62) despite discontinuation of PEGPH20 in more than half of the PAG-treated patients at the time of the clinical hold in April 2014.
Data was also presented on the rate of thromboembolic (TE) events in 55 patients treated in stage 2 of the trial, which is currently randomizing patients at a 2:1 ratio of PAG versus AG. Stage 2 began after a protocol amendment in July 2014, excluding patients at high risk of TE events and adding prophylaxis with low molecular weight heparin (enoxaparin) to all patients in both treatment arms. Reported results included:
- A TE event rate of 13 percent in 38 patients treated with PAG versus 18 percent in 17 patients receiving AG;
- In the 20 PAG patients receiving 1 mg/kg/day of enoxaparin, no TE events have been reported to date.
"The interim results from the ongoing study are very encouraging," said Dr. Hingorani. "We have a high unmet need in pancreas cancer and the trend we observed toward longer survival rates and the slowing of disease progression are noteworthy in a cancer that has seen very few therapeutic developments in the past several years."
"We remain very encouraged by the interim data presented today from our ongoing phase 2 study, including the positive trend in overall survival, and we continue to plan for the first-quarter 2016 initiation of our phase 3 study," said Dr. Athena Countouriotis, senior vice president and chief medical officer.
HA is a glycosaminoglycan – or chain of natural sugars throughout the body – that can accumulate around cancer cells inhibiting other therapies. PEGPH20 is designed to degrade HA to improve the access to tumor cells for chemotherapy, monoclonal antibodies and other immuno-therapy agents.
Halozyme previously announced it plans to proceed in Q1 2016 with a phase 3 clinical study (Study 301) of PEGPH20 in patients with metastatic pancreatic cancer, using a design allowing for potential marketing application based on either progression-free survival or overall survival. The use of progression-free survival as the basis for marketing approval will be subject to the overall benefit and risk profile associated with PEGPH20 combined with ABRAXANE and gemcitabine therapy, including the:
- Magnitude of the progression-free survival treatment effect observed;
- Toxicity profile; and
- Interim overall survival data.
Halozyme Therapeutics, Inc.