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Three principal investigators dispute phase 2 trial claim

ICMR, doctors at odds on vaccine

Debate over phase 2 status
Phase 1 safety studies examine whether a vaccine candidate has any adverse side-effects on the volunteers who receive it.

G.S. Mudur   |   New Delhi   |   Published 05.08.20, 05:01 AM

The head of India’s apex health research agency said on Tuesday that both indigenous vaccine candidates against the coronavirus disease had completed phase 1 safety studies and were undergoing phase 2 efficacy studies, but doctors conducting the trials contradicted the claim.

The director-general of the Indian Council of Medical Research (ICMR), Balram Bhargava, said the inactivated virus-based candidate developed by the Hyderabad-based Bharat Biotech and the DNA-based candidate developed by the Ahmedabad-based Zydus Cadila had “completed phase 1” studies.

Phase 1 safety studies examine whether a vaccine candidate has any adverse side-effects on the volunteers who receive it. Successful completion would be an early yet significant milestone followed by phase 2 efficacy studies that examine whether the candidate can generate an immune response.

“The inactivated virus vaccine… has completed phase 1 study in 11 sites and started its phase 2 study,” Bhargava said at a briefing called by the Union health ministry.  “Similarly, for the DNA vaccine… India has completed phase 1 and has embarked on phase 2 studies at 11 sites. That is also progressing well.”

But three senior doctors who are principal investigators in the clinical trials — one in Bharat’s trials, two in Zydus’ trials — said phase 2 studies had not started yet. The doctors said data analysis for safety assessment was underway and volunteers had not received any dose under phase 2.

“We have yet to take blood samples from the volunteers to analyse their blood counts, liver function and kidney function parameters after the second dose of the vaccine,” one of the principal investigators told The Telegraph. These tests, he said, are routinely done as part of assessing candidate vaccines for adverse side-effects.

Another investigator said sites had started screening volunteers for phase 2 studies. Bharat’s vaccine will be evaluated in 1,125 volunteers, while Zydus’s vaccine will be evaluated in 1,048 volunteers, according to protocols submitted to the ICMR and the country’s drug regulatory authority.

The ICMR, in response to a query from this newspaper, issued a clarification late Tuesday evening that said: “Recruitment of volunteers for phase 1 is over and phase 2 has commenced. Both are combined.”

Clinical researchers familiar with the trials’ protocols said both clinical trials had combined phase 1 and phase 2 components in an effort to fast-track the assessment effort. One protocol is even titled “an adaptive seamless phase 1 followed by phase 2”.

Bhargava has asserted there will be no compromise in science or safety during the development effort.

But his claim on Tuesday that phase 1 studies have been completed and phase 2 have started has evoked afresh criticism from sections of medical experts who said they are puzzled over why the ICMR chief has once again issued a misleading comment relating to Covid-19.

“In June, the DG had claimed at an official briefing that India has no community transmission — even after the ICMR’s own survey had produced evidence for it,” a professor at the All India Institute of Medical Sciences, New Delhi, who requested not to be named, said.

In early July, Bhargava had stunned sections of the medical community by writing to the doctors engaged in the vaccine trials to fast-track the studies and envisioning a target date of August 15 to launch the vaccine. The ICMR later issued a clarification saying the letter was only intended to “cut unnecessary red tape without bypassing any necessary processes”.

India on Tuesday recorded 52,050 new Covid-19 cases, raising the total number of lab-confirmed infections to more than 1.85 million, of whom 586,298 patients are under medical supervision, more than 1.23 million have recovered and 38,938 have died.


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