Race is Heating Up for the First Vaccine for RSV

Development of the first vaccine for RSV is around the corner

Development of the first vaccine for RSV is around the corner 

If 2020/2021 was all about the race to develop a vaccine for COVID-19, 2022 is shaping up to be the year of the vaccine for RSV (Respiratory Syncytial Virus), and the race is coming down to its final lap. It is not a novel epidemic – in fact, RSV has been around for decades – but no vaccine currently exists and the only treatments are supportive. 

Several big pharma companies are trying to change that. In the first four places on the block: GlaxoSmithKlinePfizerJ&J, and Sanofipartnered with AstraZeneca. Next up: Moderna is in Phase I testing with an RSV vaccine of its own, based on its famed mRNA technology, and Novavax is still plugging away.

RSV, a viral infection of the respiratory tract, is the most common cause of viral pneumonia in young children and older adults. The World Health Organization states that there are 64 million infections and 160,000 deaths annually from RSV. The market is expected to be worth $4.2 billion by 2027, with a CAGR of 14.9% between 2021 and 2027. SVB Leerink thinks it will be even bigger, estimating that the RSV vaccine market will grow to around $10 billion by 2030.

What do Companies Say About Vaccine for RSV?

In October, J&J's Janssen Pharmaceutical announced that its vaccine for RSV was 80% effective in adults over 65 in Phase II. While demonstrating this level of effectiveness against lower respiratory tract disease (LRTD) caused by RSV, the experimental vaccine also exhibited 70% efficacy against any symptomatic RSV-associated acute respiratory infection. Based on these results, Janssen has initiated a Phase III confirmatory study.

"As older adults are at high risk of developing serious, potentially life-threatening illness from RSV, there is an urgent need for a vaccine to prevent the significant morbidity and mortality caused by the virus," said Dr. Penny Heaton, Janssen's global therapeutic area head for vaccines, when the results were announced.

Pfizer and GSK also have vaccines in Phase III development for older adults. In October 2020, GSK reported positive results from a Phase I/II trial for both older adults and maternal immunization. In February 2021, the British pharma giant kicked off a Phase III trial in older adults. According to GSK, LRTDs are responsible for

360,000 hospitalizations and 24,000 deaths in adults 60 and above annually in developed countries. This could be a big part of the reason why SVB Leerink estimates that adults will make up 72% of the overall market.

Will Pfizer take home first prize again? Going it alone on this one, the American multinational kicked off its own Phase III trial in September, dosing the first patients with its investigational RSV bivalent prefusion F subunit vaccine candidate (RSVpreF). The study is expected to enroll 30,000 adults 60 and older.

A Pfizer spokesperson noted that the company expects to share data from its Phase IIa challenge study in the adult program in 2022.

Pfizer also has a maternal vaccine for RSV in Phase III development. This type of vaccine works by protecting the mother, who passes the protection on to the baby through the placenta. This is particularly important as infants under 6 months are especially vulnerable to RSV infection.  

"RSV is a major cause of respiratory disease in infants. It is the leading cause of hospitalization of infants in developed countries and a very important cause of infant mortality in lower-income countries," Dr. Philip Dormitzer, M.D., Ph.D., vice president and chief scientific officer, RNA and viral vaccines at Pfizer told BioSpace in a previous interview.

Dormitzer also noted that early efforts to develop a vaccine for RSV have failed because the wrong antigen shape was being used. Working in collaboration with the National Institutes of Health, Pfizer stabilized the correct shape and has seen early success. 

"We are hopeful that we're going to have something that can offer protection to infants from this disease through immunizing their mothers during pregnancy," he shared.

Sanofi and AstraZeneca are also in the race on this end of the age spectrum. In April 2021, the partners announced their Phase III trial of nirsevimab, a prophylactic monoclonal antibody for infants, hit its primary endpoint. In June, they reported that nirsevimab had demonstrated positive safety and tolerability in another Phase II/III study of approximately 925 preterm infants or infants with chronic lung disease or congenital heart disease.

"We believe nirsevimab has the potential to become an important and innovative routine immunization for all infants—those born prematurely or at term, healthy or with health conditions," Jean-François Toussaint, Sanofi Pasteur's global head of research and development, said at the time.

For its part, GSK reported positive Phase I/II data for its maternal vaccine for RSV candidates in July. The showing was not as successful for its pediatric counterpart. GSK made the call to discontinue this program when an assessment showed the target efficacy profile was unlikely to be met.

Another big COVID-19 player, Novavax, hasn't had the smoothest path to success with its RSV vaccine candidate, ResVax. The aluminum adjuvanted RSV fusion (F) protein recombinant nanoparticle vaccine failed to hit its Phase III primary endpoint in February 2019, sending the Maryland-based company's stock reeling. But it wasn't all bad news. While ResVax failed to meet the primary objective of preventing medically significant RSV LRTI through the first 90 days of life, it did reduce hospitalization by 25% and LRTI-related severe hypoxemia by 39% throughout the baby's first 6 months. 

Novavax has been quiet on the RSV front as of late, as the company focuses on getting its COVID-19 vaccine to the finish line. Novavax's luck hasn't been a lot greater in this space, as it continues to push back an application for emergency use authorization in the U.S. However, it recently submitted regulatory applications to both the U.K. Medicines and Healthcare products Regulatory Agency (MHRA) and Health Canada.

Meanwhile, Moderna received FDA Fast Track designation for its single-dose mRNA vaccine for RSV candidate in August for adults over 60. A phase I study of mRNA-1345 in older adults, younger adults and children is ongoing.

With a potential approval expected in 2023, BioSpace will continue to track the race to the RSV vaccine finish line.   

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