The Omicron-targeted boosters are coming. Almost 250 days since Omicron became the dominant variant in the US, Pfizer and BioNTech on Monday officially announced that they’ve requested an Emergency Use Authorization (EUA) from the US Food and Drug Administration for their booster dose of an Omicron BA.4/BA.5-adapted bivalent vaccine for those 12 and older.

The application’s submission comes as BioNTech said earlier this month that it expects to begin delivering Omicron-adapted vaccines as early as October, subject to regulatory approval.

The FDA’s vaccine advisory committee in late June gave the thumbs up — by a vote of 19-2 — to requiring an Omicron-related component in this season’s booster dose; both Pfizer/BioNTech and Moderna have been working on such boosters over the past few months.

The EUA for Pfizer/BioNTech’s booster would be based on preclinical data showing that it generated a strong neutralizing antibody response against the BA.4/BA.5 variants, as well as safety, tolerability and immunogenicity data from a Phase II/III trial of a 30-µg booster dose of the companies’ other, Omicron BA.1-adapted bivalent vaccine candidate.

A clinical study investigating the safety, tolerability and immunogenicity of the Omicron BA.4/BA.5-adapted bivalent vaccine in individuals 12 years of age and older is expected to start this month, Pfizer and BioNTech said.

FDA to Pfizer: Test another course of Paxlovid for those rebounding

In other COVID-related drug developments, the FDA earlier this month quietly called on Pfizer to test another course of its Covid-19 antiviral Paxlovid for those who have rebounded and tested positive after an initial dose.

On Aug. 5, the FDA reissued its EUA letter for Paxlovid to include additional post-authorization requirements, including calling on Pfizer “to conduct a clinical trial in patients with ‘COVID-19 rebound’ and a clinical trial evaluating different durations of treatment in immunocompromised patients with mild-to-moderate Covid-19.”

Pfizer told Bloomberg News that it is “working with the FDA to finalize a protocol to study patients who may be in need of retreatment,” and the trial protocol is expected to be finalized this month.

FDA expands Novavax EUA for teenagers

Additionally, US teenagers looking for an option outside of the mRNA Covid-19 vaccines will now be able to turn to Novavax’s Covid-19 vaccine which won an expanded EUA on Friday from the FDA.

Those aged 12 through 17 will gain access to the Novavax vaccine after the company submitted data from an ongoing pediatric expansion of its Phase III trial of 2,247 adolescents within that same age range across 75 sites in the US.

The company said that in this population the vaccine achieved its primary efficacy endpoint, with clinical efficacy of about 78% (95% CI: 37.55%, 92.45%) overall, at a time when the Delta variant was the predominant circulating variant. The efficacy analysis was supported by assessment of antibody titers that were shown to be higher in adolescents than in young adults, Novavax added.

Canada buys 12M doses of Moderna’s Omicron-targeted booster

Meanwhile, mRNA powerhouse Moderna said Monday that Canada’s government has exercised its option to purchase an additional 4.5 million doses of an Omicron-containing bivalent vaccine booster candidate, in addition to moving forward the scheduled delivery of 1.5 million doses of the bivalent vaccine candidate from 2023 to 2022.

Moderna and Canada also agreed to shift six million doses of the current vaccine to the Omicron-containing vaccine, subject to regulatory approval, with doses scheduled for delivery this year. The vaccine is expected to be ready for deployment in the US in October.

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This article was first published by Endpoints News.

Image Credits: Flickr – World Economic Forum.