Cadila Healthcare (Zydus Cadila) said it has completed enrolment and dosing of 1,000 volunteers in phase-2 clinical trials of its potential Covid-19 vaccine, ZyCoV-D, and plans to submit the data to the Drug Controller General of India (DCGI) this month.
“At present the immunogenicity evaluation is going on,” said Sharvil Patel, Managing Director of Zydus Cadila, in an update to analysts during the company’s earnings call on Monday.
Immunogenicity refers to the ability of the vaccine to provoke an immune response in the human body.
“We will have a readout (of phase 2) by the end of November, and immediately we will apply for phase-3 permission,” Patel added.
The Zydus Cadila MD said that based on the regulator’s response, the company plans to begin a larger phase-3 trial in December, and expects to have final data by March-April 2021.
Frequently Asked Questions
A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.
There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.
Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.
Zydus Cadila initiated Phase–1 and 2 trials in July. The company plans to test the ZyCoV-D vaccine on about 15,000-20,000 people in Phase-3. The launch of the vaccine is expected in the first half of 2021.
Patel said no safety concerns were observed in phase-1. He added that cellular and humoral immunity response studies are under progress, along with neutralisation antibody testing related to phase-1.
The company has taken a novel approach to its potential Covid-19 vaccine, using the DNA route. The DNA vaccine consists of genetic material of SARS-CoV-2 proteins. The genetic material instructs human cells to make SARS-CoV2 antigen, eliciting an immune response.
The company says that this approach is easily replicable and scalable, requiring just Biosafety Level (BSL)-1, as the vaccine doesn’t use any live virus.
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Biosafety level 1 applies to laboratory settings and manufacturing plants in which personnel work with low-risk microbes that pose little to no threat of infection in humans.
“We don't have any infectious agent as part of delivery technology, DNA vaccines have a very clear pathway both by the WHO and USFDA in terms of requirements for safety and efficacy,” Patel said.
He added that the ZyCoV-D vaccine can be stored at 2-8 degrees temperature, making it a good fit for the existing cold chain infrastructure. The vaccine is delivered through the intradermal (injected into the epidermis) route, which is much easier to administer compared to intramuscular injection, which requires training of healthcare workers.
Patel declined to provide an indication of the vaccine’s pricing, but said it would be affordable, given the inherent advantages of the technology used to develop it.
Pursuit of vaccine deals
Patel said the company is making conscious efforts to collaborate with multinational companies to manufacture and distribute their Covid-19 vaccines in India and emerging markets.
“We are making conscious efforts to collaborate with various multinational organisations to make their vaccines available in India and emerging markets,” Patel explained.
“We have different platforms for (vaccine) manufacturing because we do multiple vaccines. So, some of them already have capabilities to manufacture vaccines at small scale or initial scale. And if the vaccine is successful we can scale up those plants. There will be some investment, but we can start technology transfer and initiate scaling up the process as the vaccines go through clinical phases,” he added.Patel noted that it takes about 4-6 months to scale up a vaccine from pilot scale to commercial manufacturing.