Clinical trials on five-year olds and above to start soon: Zydus
Ahmedabad-based pharmaceutical major Cadila Healthcare (Zydus Cadila) is planning to start clinical trials soon on children aged five years and above for its deoxyribonucleic acid (DNA) plasmid technology-based Covid-19 vaccine, claimed a senior executive.
Meanwhile, the company is awaiting approval from the Drugs Controller General of India (DCGI) for its vaccine ZYCOV-D. It has sought approval for use in children above 12 years, and has already submitted safety and tolerability data from the Phase 2 clinical trials. It has generated the data on 1,000 adolescents (between 12 years and 18 years) from its Phase 3 trials as well. The 1,000volunteer data will be submitted to the regulator soon.
“We plan to start trials on children aged five years and above if the regulator approves,” said Sharvil Patel, managing director of Zydus Cadila. So far, no other vaccine has been approved globally for children below 12 years. India’s Bharat Biotech is now in the middle of conducting clinical trials on children above two years for the Covaxin.
If things go well, ZYCOV-D could be the first approved vaccine for adolescents
in India. Zydus has also claimed that its vaccine works against the Delta variant. Trials carried out in more than 50 clinical sites spread across the country and during the peak of the second wave of Covid-19 have shown the vaccine’s efficacy against the new mutant strains, especially the Delta variant.
At the moment, the DCGI and its expert committee are reviewing the data submitted by Zydus from a 28,000-people Phase 3 efficacy trial. According to sources, the subject expert committee is likely to take up the review of ZYCOVD this week. So far, the regulator and experts have been studying the data submitted.
ZYCOV-D has shown 66.6 per cent efficacy in interim analysis of Phase 3 trials, and can be stored at 25 degrees Celsius for three months. It is a three-dose vaccine given on Day Zero, Day 28, and Day 56. No moderate case of Covid disease was observed in the vaccine arm after administration of the third dose — suggesting 100 per cent efficacy for moderate disease. No severe cases or deaths due to Covid occurred in the vaccine arm after administration of the second dose of the vaccine, the company claimed. Meanwhile, Zydus has also submitted the immunogenicity data from a two-dose regimen (using 3 milligram doses) trial to the DCGI, which shows ‘equivalent immunogenicity’ with that of the three-dose regimen. Patel is thus hopeful that there will be a ‘good discussion point’ with the regulator for approval for a two-dose regimen.
Conventional active vaccines are made from a killed or weakened form of the infectious agent. DNA plasmid vaccine is a relatively new approach, where a piece of DNA containing the genes for the antigens is injected. The body then learns to develop an immune response against the antigen, and when the actual pathogen attacks, the body is able to generate the specific antibodies against it.
DNA vaccines, Zydus has claimed, have been shown to stimulate sustained immune responses.
ZYCOV-D efficacy is in the range of Johnson & Johnson’s single-dose vaccine, which uses a human adenovirus vector Ad26 — a 66.3 per cent efficacy in preventing Covid illness.
As for the Oxford-astrazeneca vaccine, the World Health Organization notes on its website, “The AZD1222 vaccine against Covid19 has an efficacy of 63.09 per cent against symptomatic SARS-COV-2 infection.”
Bharat Biotech’s Covaxin has shown 77.6 per cent efficacy against symptomatic Covid illness from interim analysis of Phase 3 trials, while Russia’s Sputnik V has shown 97.8 per cent efficacy against severe Covid disease in an 81,000-subject trial in the UAE recently.