COVID-19 vaccine developers AstraZeneca, CanSino, Johnson & Johnson and ReiThera face multiple challenges, says GlobalData
While there has been widespread press for its COVID-19 vaccine, AstraZeneca, in collaboration with Oxford University, faces multiple challenges in the race to develop a successful product, as reported by Reynald Castañeda, Pharma Writer for the Investigative News team at GlobalData, a leading data and analytics company. CanSino, Johnson & Johnson (J&J) and ReiThera, which are also studying their own adenovirus vector vaccines, are likely to have similar hurdles.
Castañeda explains: “Although it has advantages over other vaccine technologies for COVID-19, the respective companies’ adenovirus vector vaccines are likely to be tripped up by pre-existing antibodies to the vectors used and the need for a second injection to boost protection.”
According to GlobalData, there are at least 38 companies or universities with a recombinant adenovirus-derived vaccine asset for COVID-19 from preclinical to Phase II/III stages. On 3 June, the US Federal Government’s vaccine initiative, Operation Warp Speed, named AstraZeneca’s AZD122, as one of five finalists along with Johnson & Johnson’s candidate.
Castañeda comments: “AZD1222’s recent animal data leave questions about its utility to prevent virus spread. A future booster shot could improve this aspect.
“CanSino Biologics’ Ad5-nCoV and Johnson & Johnson’s vaccines’ disadvantage is they use a human adenovirus vector. This means a significant chunk of people may already have neutralising antibodies against the vector, which decreases efficacy prospects. Phase I Ad5-nCoV data is underwhelming, which underscores this limitation. In contrast, AstraZeneca’sAZD1222 and Rome-based ReiThera’s vaccines use nonhuman vectors and so may not have this issue.”
CanSino’s Ad5-nCoV is already in a Phase II trial that has a primary completion date of January 2021. J&J’s Phase I/IIa will start in July. ReiThera will also begin clinical investigation in the summer. Phase I/II AZD1222 trial data are expected shortly, with the vaccine concurrently in a Phase II/III trial, with data timelines dependent on community viral transmission rates.
Castañeda notes: “Prior reporting has suggested that a standard trial meant for approval that starts in the summer is likely to require around 25,000–30,000 volunteers if the annualized incidence rate is 1.5%. While a human challenge trial design – where study participants would be intentionally challenged with the COVID-19 virus – could be considered to quickly gather protection data, such a trial design also has its own operational and ethical issues.”