In a field littered with failures, positive data prompt speedy US, EU review of AstraZeneca’s long-acting RSV drug

The complex molecular structure of the respiratory syncytial virus (RSV) has largely thwarted drugmakers from developing a vaccine or treatment for an infection that afflicts most American infants before their second birthday. But AstraZeneca — the original maker of the only preventative treatment, Synagis, for serious lower respiratory tract infections (LRTI) caused by RSV in infants and young children — has now been offered an expedited review from US and EU regulators for its long-acting RSV drug, MEDI8897.

MEDI8897 is under development for prevention of LRTI for a broader patient population than standard-of-care Synagis, which in the US is only approved for high-risk infants. Synagis is also injected monthly in the typically five-month RSV season, while MEDI8897 is designed to be given as a solitary dose.

For most older healthy children and adults, RSV causes little discomfort beyond a common cold, but in high-risk groups with compromised immune systems such as infants and the elderly, it can lead to more serious lung and airway infections. But efforts to thwart the infection have culminated in a litany of failures. Most recently, J&J $JNJ terminated Phase IIb trials of its RSV drug lumicitabine and Regeneron $REGN abandoned its RSV drug after a late-stage failure. Novavax $NVAX, whose RSV vaccine failed a Phase III trial in older adults, is expected to report data from another late-stage trial later this quarter of the vaccine’s performance in infants, after their mothers were given the vaccine in the latter stages of their pregnancy.

On Tuesday, the FDA granted MEDI8897 breakthrough therapy status, and the treatment also secured access to the EMA’s PRIME (PRIority MEdicines) scheme on the basis of a positive primary analysis of a Phase IIb trial in healthy preterm infants. MEDI8897 is also being evaluated in a late-stage trial in late preterm and healthy full-term infants, and the British drugmaker intends to conduct a separate trial testing the drug in Synagis-eligible pediatric patients to generate additional data for use in this population.

In 2017, AstraZeneca $AZN and Sanofi $SNY agreed to jointly develop MEDI8897. Last November, as part of a deal in which AstraZeneca offloaded the Synagis’ US rights to to Swedish Orphan Biovitrum AB (Sobi) for $1.5 billion, Sobi also won the right to participate in AstraZeneca’s share of US profits and losses related to MEDI8897. Sales of Synagis outside the US is the responsibility of AbbVie $ABBV.

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Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT
Director of Operations
Atlas Venture Cambridge, MA

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