Bharat Biotech COVID-19 vaccine: Testing underway at CDL-Kasauli, volunteer enrolment begins

Once CDL clears the batches, the vaccine candidate will be given to human volunteers within a day or two as part of Phase I and II human clinical trials.

The Central Drugs Laboratory (CDL) at Kasauli in Himachal Pradesh is testing experimental batches of Bharat Biotech's COVID-19 vaccine Covaxin on a priority basis, sources told Moneycontrol.

"Once CDL clears the batches, the vaccine candidate will be given to human volunteers within a day or two as part of Phase I and II human clinical trials," the sources said.

"It is expected to take a few more days," said a person privy to the matter.

A letter issued by the Indian Council of Medical Research (ICMR) to 12 principal investigators, instructing them to fast-track approvals to initiate clinical trials of Bharat Biotech's COVID-19 vaccine with an aim to launch it by August 15, had become controversial.

Many experts raised serious concerns, calling the timelines unprecedented and unrealistic.

While ICMR has softened the stand on August 15 deadline, sources said the government is keen on getting the vaccine out as fast as possible.

Why is CDL-Kasuali testing important?

The CDL at Kasuali conducts testing on every vaccine batch meant for human use in India.

CDL will be conducting a battery of tests on Bharat Biotech Covaxin to confirm its identity, purity, potency and stability to ensure that each batch is consistent and safe before it is given to humans.

For example, in potency test - the vaccine would be tested using in vitro (test tube) followed by mice. The mice will be given the COVID-19 vaccine, and are checked whether they are producing neutralising antibodies. In some protocols, there is also a mice challenge model, wherein the vaccinated mice are exposed to SARS-CoV-2 virus. It is not known whether that applies here or not.

"They may repeat certain tests to verify data submitted by Bharat Biotech,"  said a second person who didn't want to be named.  The company submits a docket to CDL, documenting the entire process of vaccine development work and manufacturing process.

Enrolment underway

Even as these tests at CDL are going on, some of the clinical trial sites where the Bharat Biotech vaccine will be tested have begun enrolling volunteers.

As per the Clinical Trials Registry of India (CTRI) website, as on July 9, out of 12 medical institutions, ethics committees of six institutions have given the go-ahead; these include Prakhar Hospital - Kanpur, Gillurkar Hospital - Nagpur, Jeevan Rekha Hospital - Belgavi, PGIMS - Rohtak, Rana Hospital - Gorakhpur and Redkar Hospital - Goa. For the remaining institutions, approvals are under review.

For instance - the Nijam Institute of Medical Sciences (NIMS) in Hyderabad, which is one of the 12 clinical trial sites where Bharat Biotech COVID-19 vaccine will be tested, is seeing enquiries from people willing to enroll not just from Telangana but from adjoining states such as Karnataka and Maharashtra, said a person who didn't want to be named.

To be sure, not everyone enrolled will be recruited to get a shot of the vaccine, as volunteers have to be healthy. The clinical trial protocol determines the health parameters of the participant.

The randomised double-blind control study is designed to evaluate the safety, reactogenicity, tolerability, and immunogenicity of three groups of healthy volunteers who receive two intramuscular doses of Covaxin.

Out of a total sample size of 1,125 healthy volunteers, 375 volunteers are in the phase 1 study and 750 volunteers are in the phase 2 study. Out of five arms, four arms would get the vaccine and one arm called as control will get the Japanese Encephalitis vaccine. The vaccine which is given in three formulations in ascending dose order will be two doses at an interval of 14 days. The CTRI on July 9 showed that the date of first enrollment for the vaccine is July 13.

The trial is expected to take a month to complete, after which the interim data will have to be submitted to the Drug Controller General of India (DCGI). There will be independent agencies that will audit the trial. The DCGI will take a call on the next step on the basis of the data.


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