GSK Claims Patent Infringement in Suit Against Pfizer's RSV Vaccine

The RSV vaccine market is heating up, with news that GlaxoSmithKline (GSK) has filed a lawsuit against Pfizer alleging that the company knowingly infringed on 4 patents related to its respiratory syncytial virus vaccine, Arexvy.

Both companies are heavily invested in the market, with GSK's Arexvy winning FDA approval in May 2023 followed by Pfizer's Abrysvo later that month, both for the same indication in adults age 60 years and older.

The lawsuit, filed in Federal Court in Delaware, takes issue with the antigen used in the vaccines, which are the first of their kind in a burgeoning market that could exceed $10 billion, according to analysts. GSK claims they began work on their RSV program nearly 7 years before Pfizer entered the space.

GSK is seeking monetary damages and a court order to stop Pfizer from selling its vaccine. Both preventive treatments are being rolled out for the fall season, with some already available to the public at retail pharmacies. Notably, GSK said the lawsuit does not seek to limit access to pediatric-indicated shots of Abrysvo, which is pending FDA approval.

The FDA is set to make a decision by August 21st regarding Pfizer's Abrysvo as a maternal vaccine to protect infants and young children from the virus. After reviewing all available trial data during an FDA Vaccines and Related Biological Products Advisory Committee (VRBPAC) meeting in May, the committee voted 14 to 0 in favor of the efficacy of RSVpreF and 10 to 0 in favor of the safety. Through active immunization in pregnant persons, RSVpreF prevents medically attended lower respiratory tract disease (MA-LRTD) and severe MA-LRTD caused by RSV in infants from birth to 6 months of age.

In an interview with Contagion, Iona Munjal, MD, senior director of vaccine research and development at Pfizer, who was heavily involved with the phase 3 MATISSE clinical trial, shared why the vaccine's approval could be a game-changer in pediatric health.

“For infants, RSV remains the number 1 cause of inpatient hospitalizations due to respiratory illness,” Munjal said, “and to this date we have no treatment, so it’s a really frustrating time for parents. Rather than having babies get the antibody through a shot, you can actually utilize one of the oldest forms of antibody gifting, which is the placenta," noting that the vaccine helps the mother produce antibodies many folds higher than one would produce with a natural infection, which are then passed on to the fetus.

Young children may now also receive protection from severe RSV via Sanofi and AstraZeneca's nirsevimab-alip (Beyfortus), which was FDA-approved in July for the prevention of RSV in newborns and infants during their first RSV season, as well as children up to age 24 months who are at an increased risk for RSV through their second season. Earlier this week, the CDC's Advisory Committee on Immunization Practices (ACIP) endorsed the monoclonal antibody, which is not categorized as a vaccine but a therapeutic that falls under the "passive immunization" category, meaning that it does not require activation of the immune system to confer protection.

There's even more to come from the RSV drug pipeline, as Moderna recently announced key regulatory submissions for its investigational RSV vaccine mRNA-1345, which utilizes the company's messenger RNA technology and is intended to prevent RSV-associated lower respiratory tract disease in adults 60 years and older. The company submitted marketing authorization applications in July to the European Medicines Agency, as well as regulators in Switzerland and Australia, and also launched a rolling biologics license application with the FDA, who previously granted the vaccine fast track and breakthrough therapy designations.