Sound Biologics is launching a Phase 1 trial to test its candidate immunotherapy PSB205 in relapsed or refractory solid tumor patients, after the U.S. Food and Drug Administration cleared its investigational new drug (IND) application.
The product is a combination of antibodies against the PD-1 and CTLA-4 factors — two proteins used by cancer cells to evade the immune system — produced by a single cell line, which allows researchers to have a well-controlled ratio of both antibodies.
According to the company, PSB205 is expected to be better tolerated by patients than current combinations of anti-PD-1 and anti-CTLA-4 antibodies.
“We’re pleased to take this critical step toward providing cancer patients with a better therapeutic option for blockade of two key immunotherapy pathways,” Wei Yan, PhD, CEO of Sound Biologics, said in a press release.
Cancer cells often develop strategies to evade the host’s immune system, including the use of immune checkpoint proteins — like PD-1 and CTLA-4 — that cause immune cells to “think” that cancer cells are not harmful.
Researchers have long been focusing on blocking these signals as a means to boost immune responses against cancers, with several immune checkpoint blockade therapies already approved for multiple cancer types.
These include the PD-1 inhibitors Opdivo (nivolumab) and Keytruda (pembrolizumab); the PD-L1 inhibitors Tecentriq (atezolizumab) and Bavencio (avelumab); and the CTLA-4 inhibitor Yervoy (ipilimumab).
Combinations of immune checkpoint inhibitors also have shown promise as cancer therapies, with some already approved for melanoma. But patients often experience severe side effects as a result of overactive immune systems.
Bi-specific antibodies — those that target two distinct proteins — are also being investigated, but they imply that a similar amount of each antibody type is used.
Sound Biologics is working to counteract these problems and, using their proprietary MabPair technology, developed a cell line that produces both anti-PD-1 and anti-CTLA-4 antibodies in a controlled ratio, allowing researchers to use the optimal amount of each antibody when treating patients.
“PSB205 represents the first product to contain two antibodies expressed from one cell line,” Yan added. “We’re excited to be the first to explore this innovative approach to biologic combinations and look forward to reviewing the initial clinical data in late 2019.”
