Novavax hopes to revive RSV vaccine with a new phase 2 trial

Novavax has started a new phase 2 trial on its key respiratory syncytial virus vaccine candidate in an effort to breathe new life into a program that was hit hard last fall with disheartening late stage data.

The placebo-controlled trial will enroll up to 300 adults aged 60 or older, testing the RSV F-protein nanoparticle vaccine candidate in one or two doses with or without Novavax’s Matrix-M adjuvant. This time, subjects are to be enrolled and vaccinated in the southern hemisphere, outside of the RSV season, "to best assess immunogenicity," the company said in a release.

Last September, when the vaccine posted a phase 3 failure that decimated Novavax’s stock, R&D chief Gregory Glenn cited a sluggish RSV season as a potential reason behind the failure. Even though EvaluatePharma downgraded 2022 sales prediction for the candidate from $845 million before the failure to the most recent $549 million, the game-changing sales still make the candidate too big a temptation for Novavax to let it go without a fight.

"We expect the results from this trial … would ensure we maintain our leadership position in this very attractive market opportunity," CEO Stanley Erck said in a statement.

The FDA fast-tracked Novavax’s candidate last May as a potential means to satisfy a "significant unmet medical need," an RSV vaccine for the elderly. With a $89 million grant from the Bill & Melinda Gates Foundation, the candidate is also in a phase 3 trial that tests its ability to protect infants through maternal immunization.

After the previous phase 3 misstep, the company responded with a 30% workforce reduction as part of a restructuring plan announced with its third quarter financial results last November.

Elsewhere in RSV, AstraZeneca’s MedImmune has gained an FDA fast track for its RSV candidate, a monoclonal antibody currently being tested in phase 2 in healthy preterm infants. Bavarian Nordic also has an RSV vaccine candidate currently in phase 2, whose readout is expected in the middle of this year. In a recent interview with FiercePharma, CEO Paul Chaplin said BN's version utilizes a "differentiated approach" and "will be successful in the long run."

Novavax is also developing vaccines against flu and intends to start phase 1 trial of its Zika vaccine candidate this year. A 2016 World Preview report by EP put 2022 sales of the biotech’s influenza and RSV combo respiratory vaccine at more than $1 billion. That program is still in preclinical stages.

Editor's Note: This story has been updated with the most recent estimate for the candidate's 2022 sales from EvaluatePharma.