A new human rabies antibody was noninferior to a currently administered immunoglobulin product for post-exposure prophylaxis, or PEP, researchers said.
In fact, the geometric mean concentration (GMC) of rabies antibodies (RVNA) in patients who were given the new antibody (SII RMAb) — which was developed by recombinant DNA technology — was more than four times that of those receiving human rabies immunoglobulin (HRIG), they wrote in Clinical Infectious Diseases.
“This pivotal study demonstrated that a PEP regimen of SII RMAb and rabies vaccine produced RVNA activity on day 14 that was noninferior to that of HRIG and rabies vaccine,” researcher Nithya J. Gogtay, MD, a professor in the clinical pharmacology department of King Edward Memorial Hospital and Seth Gordhandas Sunderdas Medical College in Mumbai, India, and colleagues wrote. “There were no significant differences in [rabies virus neutralizing antibody (RVNA)] levels at earlier or later measured time points, suggesting that SII RMAb interfered less with RVNA responses to early doses of the rabies vaccine and provided comparable neutralizing activity after the fourth and fifth doses.”
SII RMAb was developed as an alternative to HRIG, which is rarely used to treat severe bites in India and is often very expensive for patients.
Gogtay and colleagues conducted their phase 2/3 study at five Indian hospitals from June 2012 to March 2015. It included patients with bites from animals suspected to have rabies. In all, 101 patients were randomly assigned to receive SII RMAb along with rabies vaccine, and 98 were randomly assigned to receive HRIG with the vaccine.
At 14 days after the start of treatment, the GMC ratio of those receiving SII RMAb to those receiving HRIG was 4.23. Specifically, the GMC in the SII RMAb group was 24.9 IU/mL, compared with 5.88 IU/mL in the HRIG group.
The GMCs were not significantly different on days 28, 42 and 84 after treatment initiation, the researchers said. Most local injection site and systemic adverse reactions in both groups were mild to moderate, they added. – by Joe Green
Disclosures: Gogtay reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.