ImmunityBio is set to initiate a Phase I clinical trial of its novel subcutaneous Covid-19 vaccine candidate, hAd5 T-cell, in South Africa, where the 501Y.V2 strain of SARS-CoV-2 was found.

The latest development comes after the company secured the South Africa Health Products Regulatory Authority (SAHPRA) authorisation to begin the trial.

HAd5-COVID-19 targets both the mutation-prone outer spike protein (S) and the more stable inner nucleocapsid (N) protein. It can activate antibodies, memory B cells and T-cells against the virus.

The vaccine candidate administered subcutaneously and as a room temperature stable oral capsule formulation can potentially act as a universal T-cell boost to existing vaccines or address mutations where others could fail, such as the 501Y.V2 variant.

It is currently being analysed in a similar Phase I trial in the US, with no safety concerns noted so far.

ImmunityBio chairman and CEO Patrick Soon-Shiong said: “Unlike antibody-based vaccines, T-cell-based vaccines kill the infected cell, preventing virus replication and could provide long-term immune memory to recipients.

“Pursuing a vaccine that does not rely solely on targeting the S protein where the mutations are occurring is of critical importance as multiple variants of the SARS-CoV-2 virus have appeared globally, with concentrated outbreaks beginning in South Africa.

“After leveraging this concept in our novel Covid-19 oral vaccines, we saw complete protection to a viral challenge in our non-human primate data.”

ImmunityBio noted that recruitment for this trial of subcutaneous doses of the vaccine will start next month in Cape Town, South Africa. It will be followed by trials using sublingual doses as well as room temperature stable oral capsules.

Last month, ImmunityBio reported that a challenge study showed its Covid-19 vaccine candidate provided complete protection of nasal and lung airways of non-human primates against the SARS-CoV-2 virus.