Synagis (palivizumab)
Company: AstraZeneca
Disease: Monoclonal antibody to prevent respiratory syncytial virus infection in infants
Global 2013 sales: $1.1 billion
Patent expiration date: October 2015

Synagis is already struggling ahead of a looming patent expiry, making it a not particularly tempting target for a biosimilar. Its sales were only $375 million during the first half of 2014, down 10% from the same period a year earlier.

In July, for the fifth time, the American Academy of Pediatrics (AAP) guidelines recommended less usage because the drug isn't particularly effective for any children other than the most premature infants. Respiratory syncytial virus (RSV) causes mild, coldlike symptoms; children are commonly infected by two years of age. But it is the leading cause of pneumonia in infants.

The drug was approved in 1998 for use in certain "high-risk" children, such as premature infants born at 35 weeks or earlier.

Only 20% of hospitalized infants are actually suitable for Synagis treatment, Dr. H. Cody Meissner, a member of an AAP committee involved in drafting the new guidance and a professor of pediatrics at Tufts University School of Medicine, told The Wall Street Journal for a July article.

The most recent AAP guidance calls for use of the drug in infants born before 29 weeks, older preemies with chronic lung disease or certain heart problems and certain other at-risk children younger than two years old. AstraZeneca ($AZN) estimated that previous restrictions eliminated about 100,000 infants from eligibility, while these new ones took out 40,000 more.

Synagis has been shown in studies to reduce the risk of hospitalization but not to reduce hospital stays or chances for long-term complications or death.

Despite the difficulties of the biosimilar pathway in the U.S., at least one company, iBio ($IBIO), has a preclinical palivizumab biosimilar. The micro-cap company says it has a deep pipeline of large-molecule drugs dependent on a biosimilar regulatory pathway. The costly Synagis is priced at about $1,000 for each of 5 required monthly injections.

For more:
AstraZeneca rolls out preemie newspaper ads to fight Synagis limits
AstraZeneca CEO jumps into asset-sale fray to 'focus on what we do well'
iBio shares jump with flu shot clinical trial
Motavizumab failure shifts spotlight to RSV vaccines

-- Stacy Lawrence (email | Twitter)