(CNN) The biotechnology company Novavax now plans to apply for emergency use authorization of its Covid-19 vaccine in the US in the third quarter of this year, CEO Stanley Erck told CNN in a phone interview on Monday.
The American biotech firm previously announced plans to apply in the second quarter, but a delay in getting manufacturing data involving quality, consistency, and stability tests for manufacturing and storage of vaccine has pushed back the timeline, Erck said.
"The hard part of the regulatory filings for us right now is getting all the manufacturing data put together, getting all the very complex biologic assays that we have to do developed -- they have to be qualified and then validated, which are two sequential processes, and it's just taking us longer than we wanted," Erck told CNN.
"I don't believe we're going to be able to make it by the end of June. Therefore we have to push off the guidance until third quarter," Erck said. "Obviously, it will be in everybody's benefit for us to get it done as early in the third quarter as possible, but we're not putting a date on it right now."
Novavax also announced on Monday that it intends to file for authorization with the UK Medicines and Healthcare products Regulatory Agency and the European Medicines Agency in Europe in the third quarter of 2021.
Erck said that the company is currently "stockpiling inventory" and has made "tens of millions of doses" of its vaccine, which is administered as two injections, 21 days apart.
Currently, three vaccines have emergency use authorization in the US -- those made by Moderna, Pfizer/BioNtech and Johnson & Johnson's Janssen vaccine arm.
As part of its applications for authorization, Novavax will include data from its clinical trials. The company expects to see results from a Phase 3 study of its Covid-19 vaccine in the United States and Mexico "in a few weeks," Erck told CNN.
That trial has enrolled 30,000 volunteers, among which 13% are older adults, across more than 100 locations. Previously, the Maryland-based company announced that it was on track to have the trial results sometime in April.
"We're still unblinding in the second quarter -- that hasn't changed. It's just not in April, obviously, and so it'll be in a few weeks," Erck said in Monday's phone interview.
The new timeline "gives us the ability to count more cases," Erck said. "It gives us a bit more robust data, hopefully, and allows us to catch more severe events, and also take a closer look at what variants were infecting our population."
Erck added that the trial data will reveal the efficacy level of the vaccine in the United States and Mexico as well as which variants were circulating at the time of the trial and what the efficacy of the vaccine will be against those variants.
"We've seen the rapid rise of the B.1.1.7 strain. This variant now accounts for over 60% of the US cases," Dr. Gregory Glenn, president of research and development at Novavax, said during an investors call on Monday.
In March, Novavax announced that a final analysis of a separate Phase 3 trial in the United Kingdom confirmed its Covid-19 vaccine had an efficacy of 96% against the original coronavirus strain and 86% against the B.1.1.7 variant first identified in the UK.
In the United States, Novavax's coronavirus vaccine could be used as a booster shot later this year for people who have already been vaccinated against Covid-19, Erck said.
"In the US, I think it will be the booster for everyone, particularly if we get it out late in the third quarter," Erck said in the phone interview. "It's going to be time to start boosting -- whether it's six months or at a year point."
Currently, the US Centers for Disease Control and Prevention says vaccine types and brands are not interchangeable for the initial immunization, and there has been no decision either in the US or globally on the need for booster doses yet, let alone which vaccine might be appropriate for any booster.
But the CDC noted in January that its guidance may be updated as new information and new types of vaccines become available.