The designation is granted by the FDA’s Office of Orphan Products Development (OOPD) to investigational therapies intended to treat rare diseases that affect fewer than 200,000 people in the U.S., or that are not expected to make a profit.
Orphan drug status confers several benefits to the pharmaceutical company, including the possibility of market exclusivity for seven years if the therapy is approved, tax credits for subsequent clinical trials, and waivers for prescription medicine user fees.
“While the potential applications for SRF231 in oncology are quite broad, we are particularly excited about the opportunity to provide benefits to patients with multiple myeloma,” Rob Ross, MD, chief medical officer of Surface Oncology, said in a press release.
“We have already demonstrated the ability of our antibody to increase phagocytosis of myeloma cells and to shrink tumors in preclinical models,” he said. “Receiving orphan designation for SRF231 represents an important milestone as we continue to progress the program in the clinic in multiple myeloma and other cancer types.”
SRF231 is an antibody designed to block the activity of CD47. This protein is present in high levels in many types of cancer cells, allowing them to escape and avoid being targeted by macrophages, a type of white blood cell that engulfs and digests foreign invaders.
Recently, Surface started a multi-center, open-label Phase 1/1b trial (NCT03512340) to investigate the safety and efficacy of SRF231 for the treatment of advanced solid tumors and blood cancers, including myeloma, based on positive data from preclinical studies.
The study will be conducted in two parts. Part A will enroll 48 patients with advanced disease or who have failed prior therapies, to determine the safety and tolerability of SRF231.
Primary outcomes of this part include the study of dose-limiting toxicity, non-tolerated dose, maximum tolerated dose, and number of adverse events. Researchers are also hoping to identify the recommended dose for further testing.
Part B will continue to evaluate SRF231’s safety and will also examine patients for signs of efficacy — including overall response rate, duration of response, disease control rate, and the time a patient lives without disease progression — as secondary outcomes.
This part will include 100 patients who demonstrated progressive disease after the most recent treatment regimen.
The Phase 1 trial is currently recruiting participants. More information about the trial and how to participate is available here.