Novavax reports positive top-line data from PhII trial of RSV vaccine

Dr. Greg Glenn, Novavax SVP of R&D

There is no vaccine for respiratory syncytial virus (RSV), which causes 177,000 hospitalizations and 14,000 deaths each year in adults older than 65. But early data from Novavax's ($NVAX) Phase II trial of its RSV candidate show its promise in protecting older adults.

The company announced on Monday that its candidate prevented 64% of severe RSV cases. It fared less well in preventing all symptomatic RSV cases (44% efficacy) and RSV disease with lower respiratory tract symptoms in older adults (46% efficacy).

"These efficacy data represent a historic advance for the field. … It is clear that our RSV F Vaccine provided statistically significant efficacy in older adults, a population that historically has been difficult to protect," Novavax's R&D chief, Dr. Greg Glenn, said in a statement.

The trial enrolled 1,600 older adults at 10 sites in the U.S. It compared the unadjuvanted 135-microgram dose of the RSV F Vaccine to placebo, and it is the first trial to show efficacy of an active RSV immunization in any clinical trial population, Novavax said in the statement.

Novavax CEO Stanley Erck

"The development of an RSV vaccine has been a decades-long challenge," Stan Erck, Novavax CEO, said in the statement. "We are thrilled by the groundbreaking efficacy of our RSV F Vaccine in older adults. We are committed to pursuing an aggressive developmental timeline for this program, which includes discussions with regulatory authorities and initiation of a pivotal Phase III trial as early as the fourth quarter of this year."

The candidate is in a second Phase II trial involving pregnant women to assess its safety and immunogenicity in infants via maternal immunization.

Novavax won fast-track designation from the FDA for its candidate in November 2014 and was soon followed by AstraZeneca's ($AZN) MedImmune, whose candidate got fast-tracked in April this year. There is no vaccine or specific treatment for RSV, but AstraZeneca does market Synagis, a monoclonal antibody for use in limited cases that will go off patent in October.

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