The Drug Controller General of India (DCGI) has instructed Pune-based Serum Institute of India (SII) to submit a revised protocol for conducting clinical trials in India for the Covid-19 vaccine candidate developed by the University of Oxford.

SII has signed an agreement with British-Swedish multinational AstraZeneca to manufacture the ChAdOx1 nCoV-19 coronavirus vaccine doses if the trials are successful.

Official sources in DCGI told Businessline that SII had submitted a protocol for conducting phase II and III clinical trials for the vaccine in India, which includes enrolling at least 1,600 human volunteers.

The proposal was discussed by the DCGI Subject Expert Committee (SEC) on July 28. “After detailed deliberation, the committee recommended amendments to the protocol and has asked SII to submit a revised protocol,” the source said. The panel has made eight observations for the revision of the protocol. It has asked for clinical trial sites of the vaccine candidate to be distributed across India.

Objective of the study

It has also asked for the role of the country’s apex health reach body, Indian Council of Medical Research, to be specifically mentioned along with a copy of Memorandum of Understanding. The committee has questioned whether immunogenicity —the ability of a vaccine to provoke an immune response — is the primary or the secondary objective of the study.

The committee has also asked SII to demarcate phase II and III in the trial protocol. According to the University of Oxford trial protocol, while phase II involves expanding the age range in which people will be assessed to check immune responses to the vaccine and variation in how well the immune system responds in older people or children, phase III involves assessing how the vaccine works in a large number of people over 18 years of age as well as assessing how well the vaccine works to prevent people from becoming infected or unwell with Covid-19.

SEC has stated that the drop-out rate of 41 per cent proposed by SII in the protocol should be revised to keep the rate at par with other vaccine studies. “Also, the basis of sample size calculation for safety and immunogenicity cohorts should be mentioned,” the committee has pointed out.

The DCGI panel has stated that SII should look at cellular immunity — a protective immune response that involves activation of immune cells in response to the virus — as part of it’s immunogenicity assessment, which should be carried out only after the 58th day of administering the vaccine.

On July 20, scientists in Oxford University stated that the vaccine appears safe and induces strong immune responses after doses were given to 1,077 healthy adults between 18 and 55 years of age in April and May as part of phase II clinical trials.

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