ImmunityBio has received approval from the South Africa Health Products Regulatory Authority (SAHPRA) to assess its dual-antigen T-cell vaccine for Covid-19 in Phase I/II/III South Africa Sisonke T-Cell Universal Boost clinical trial.

The trial is scheduled to commence in the third quarter of this year to evaluate the safety, efficacy and immunogenicity of the hAd5 viral-vector vaccine.

It will study the Spike (S) plus Nucleocapsid (N) vaccine as a booster in healthcare workers who previously received an S-only vaccine.

ImmunityBio’s vaccine is designed to target S and N proteins of SARS-CoV-2 to elicit B and T cell memory against these antigens. It also potentially offers durable immunity against the virus.

The vaccine leverages a second-generation hAd5 platform, which could induce immune responses to SARS-CoV-2 in people who are Ad-immune, indicating that individuals can take the vaccine several times, based on the requirement.

Furthermore, the vaccine is available as a subcutaneous (SC) injection, sublingual (SL) drops, intranasal spray and a room-temperature-stable oral capsule, allowing various routes of administration.

The Phase I/II/III trial is intended to test the ability of the T-cell-based vaccine to prevent breakthrough Covid-19 infections by the Delta variant in healthcare workers who previously received inoculation.

With its vaccine, the company aims to offer more protection and durable immunity to the different SARS-CoV-2 variants and third-wave infections that South Africa and other countries are presently fighting.

A combination of SC and SL formulations of the vaccine will be assessed during the trial to potentially protect with a single shot and subsequent droplets placed under the tongue.

ImmunityBio chief operating officer Leonard Sender said: “We are encouraged by the preliminary safety findings in our ongoing Phase I studies in both the US and South Africa.

“In addition, our US data show that just a single prime subcutaneous vaccination with our Covid-19 vaccine candidate induces a ten-fold increase in T cell response – equivalent to T cell responses from patients previously infected with SARS-CoV-2.”

In April 2021, the company reported initial data from the Phase I trial of the vaccine, which stimulated the T cell reactive to vaccine-delivered S and N protein antigens in healthy subjects.