YS Biopharma's rabies vaccine bests approved competitor in interim phase 3 readout

China’s YS Biopharma has a good feeling about a phase 3 trial of its investigational PIKA rabies vaccine if a glimpse at the interim data is anything to go by.

The biotech has been putting the vaccine, which uses YS Biopharma's PIKA adjuvant technology, up against a “globally marketed comparator” in a 4,500-participant trial in the Philippines and Pakistan.

The primary immunogenicity endpoints of the study are geometric mean titers (GMTs) of rabies virus neutralizing antibodies (RVNA) and RVNA seroconversion rate at Day 14 in the first 900 participants. Based on the interim data, YS Biopharma sounds confident that its vaccine has delivered the goods.

“The interim results indicate that the PIKA rabies vaccine has successfully met the primary endpoints of the trial and has the potential to achieve best-in-class accelerated protection and meet the WHO's goal of a one-week rabies vaccine regimen to replace the conventional three- or four-week regimens,” the company explained in an April 9 release.

The interim readout showed that the RVNA seroconversion rate of the PIKA rabies vaccine was double that of the approved comparator vaccine at Day 7. “This accelerated and higher seroconversion rate came at no cost to safety, with the safety profile of the PIKA rabies vaccine remaining highly tolerable,” the biotech noted.

The secondary immunogenicity endpoints of the trial are RVNA seroconversion rate and GMTs of RVNA at days 28, 42, 90 and 180 in the same 900 participants, as well as RVNA seroconversion rate at Day 7 and Day 365 in all the study’s participants.

YS Biopharma, also known as Yisheng Biopharma, already markets a conventional rabies vaccine in China. The biotech has designed its PIKA rabies vaccine to produce a more robust immune response in an accelerated time span compared to existing rabies vaccines on the market.

“The interim results of the pivotal phase 3 trial provide compelling evidence of the robust immunogenicity and favorable safety profile of the PIKA rabies vaccine,” YS Biopharma Chief Medical Officer Zenaida Mojares said in the release.

“At present, the long and inconvenient regimen length for existing rabies vaccines represents a major barrier to treatment completion, and we are eager to see how the enhanced speed of the PIKA rabies vaccine might have a positive impact on patients,” Mojares added. “We are proud of our team for the hard work and dedication which got us to this point, and we are excited to see how our advances will contribute to the ongoing global fight against rabies.”

The FDA has already granted the PIKA candidate an orphan-drug tag, but YS Biopharma CEO David Shao, Ph.D., name-checked the Philippines, Pakistan, Singapore and China as countries where the biotech is already “working closely with drug regulatory agencies.”