SAHPRA Authorizes ImmunityBio to Proceed with Trial of T-Cell Vaccine as Booster Against COVID-19

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ImmunityBio will proceed with a Phase I/II/III trial in South Africa of their dual-antigen T-cell vaccine as a boost in participants who were previously vaccinated against COVID-19.

ImmunityBio announced in a July 14, 2021 press release the authorization from the South Africa Health Products Regulatory Authority (SAHPRA) to proceed with the South Africa sisonke T-cell universal boost trial. Beginning in Q3 2021, the Phase I/II/III trial will evaluate hAd5 spike + nucleocapsid (S+N) as a boost for South African healthcare workers previously vaccinated with an S-only COVID-19 vaccine.

“Several peer-reviewed studies demonstrate that patients who have recovered from SARS-CoV in the 2003 outbreak possess long lasting memory T cells reactive to the nucleocapsid protein of SARS-CoV 17 years after infection,” said Patrick Soon-Shiong, founder and executive chairman of ImmunityBio, in a press release. “While antibodies block infection when present, T cells are vital for long-term immune memory. We are excited to begin this controlled, randomized trial of boosting a previously administered DNA-based viral vector vaccine with our own Ad5 dual-antigen S plus N vaccine to see if it can augment protection in participants who have received the S-based vaccine alone.”

The effect of combining vaccination by two administration routes—subcutaneous and sublingual (SL)—will be assessed in the trial. This combination has the potential to deliver protection from the virus with a single injection followed by droplets placed under the tongue.

In a separate Phase I trial in South Africa, the SL and nasal routes of administration are currently being tested. SL administration results in the most rapid absorption, while nasal spray or oral capsule delivery have the potential to provide mucosal immunity. This immunity could reduce the chance of infection and potential spread of the virus via the respiratory tract. The three formulations that don’t require an injection—SL, intranasal, and oral capsule—can be administered without a healthcare professional and are easier to transport and store.


According to the press release, this is the first randomized control trial to study a heterologous boost of an S-only vaccine with an Ad5 S+N vaccine boost versus a single S-only prime vaccine as control. The endpoints are to examine whether the boost reduces breakthrough infections currently occurring in South Africa in the sisonke T-cell boost trial.

Source: ImmunityBio