Major RSV Vaccines Fail in Infants, Casting Shadow Over Chinese Biotech Giant's New Partnership

On December 10, the FDA released a briefing disclosing two RSV vaccines, mRNA-1345 and mRNA-1365, from U.S. vaccine company Moderna.Not only did it fail to alleviate the symptoms of infection, but it also worsened the condition of infants and young children.Currently, these two vaccines, as well as all RSV vaccines for children and infants,Clinical research has entered a suspended state.

RSV, or respiratory syncytial virus, causes acute lower respiratory tract infections, especially in vulnerable populations such as infants, young children, and the elderly.The threat of RSV virus can be fatal.RSV vaccines are considered to be the vaccine type with the most market potential after HPV vaccines. GlobalData analysts predict that byThe global RSV vaccine market size will reach 9 billion US dollars in 2030.

All three RSV vaccines currently marketed globally are targeted at the elderly. Pfizer's vaccine has an additional indication for active immunization in pregnant women, while no direct RSV vaccines targeting infants and young children have made progress. Some institutions estimate that the market potential for the infant and young children population is larger than that for the elderly.Accounting for 70% of the RSV vaccine market, significantly higher than that for the elderly.

Modena's vaccine ran into issues, which has dimmed the spotlight on the RSV vaccine category. In June this year, the U.S. CDC also recommended raising the age for RSV vaccination from 60 to 75, narrowing the applicable age range.

Companies in China may also be affected. On December 5, Chongqing Zhifei Biological Products Co., Ltd. had just...AndGSK Reaches Initial 10-Year Collaboration on RSV VaccineNowadays, whether this cooperation can achieve the expected results has become an uncertain question.

A Safety Threshold That's Hard to Cross

RSV vaccines have long been known for their high development difficulty, with no breakthroughs for over 50 years, until May 2023, when the FDA successively approved two RSV vaccines from GSK and Pfizer. In June this year, Moderna's RSV vaccine also successfully received FDA approval, creating a three-way competitive landscape.

But there is currently no direct vaccine for respiratory syncytial virus in infants or children,Only Pfizer's vaccine can be used for active immunization in pregnant women.The biggest issue with infant vaccines is safety. In 1966, Pfizer developed an inactivated RSV vaccine, but during clinical trials, the vaccine caused severe adverse reactions, resulting in 16 young children becoming critically ill and requiring hospitalization.Including two infant deaths. This serious adverse event led to the FDA suspending all clinical trials of RSV vaccines.

This time, the safety issues reported by Moderna regarding the RSV vaccine gave the FDA a sense of déjà vu from years past.

The FDA disclosed in the briefing,Receiving mRNA-1365 treatmentOf the 20 infants, 10 were infected with RSV,Three of them are in very serious condition.. AndIn the placebo group, 12 out of 20 infants were infected with RSV,Only 1 case with very severe conditionIt appears that vaccination not only failed to alleviate the symptoms of infection but also exacerbated the condition of infants and young children.

FDA announced that it will hold an expert meeting on December 12 to discuss the potential safety issues of RSV vaccines in infants and young children, as well as how to design future research strategies. However, scientists are not optimistic about the prospects of RSV vaccines for this population. An expert from the top international journal *Science* commented:Any early-stage RSV vaccine for children will not enter clinical trials soon.Not to mention getting approval, but we will still see what the committee's final recommendation is.

Domestic companies may be affected

RSV vaccines are also a popular variety that Chinese vaccine companies are flocking to develop. Public information shows that Alltria Bio, CSPC, Abogen Biosciences, Clover Biopharmaceuticals, and others are all developing this variety. The technical routes cover subunits, vectors, nucleic acids, etc., with most in the preclinical stage.

ADV110, developed by Aidewei Xin, is currently the fastest progressing RSV vaccine produced in China in terms of clinical research.The Phase II clinical trial was completed in August this year. The company has expressed that future research will expand from the elderly group to the infant group.

China is a country with high incidence of RSV.According to statistics, from 2009 to 2019, 16.8% of severe respiratory infection patients in China were infected with RSV, second only to the influenza virus. Among them, the incidence of RSV-related lower respiratory tract infections in children under 5 years old is about 4%, which is much higher than in developed countries. The number of related hospitalization cases is approximately 620,000 to 950,000 annually.

This corresponds to the broad imaginative space for RSV vaccines. AVIC Securities predicts,The potential market size of RSV vaccines in China by 2030 is 16-26.7 billion yuan.Behind this百亿 market, the infant and toddler population is an indispensable piece of the puzzle.

As the FDA has put a hold on the clinical trials of RSV vaccines for infants and young children,The situation for domestic followers has also become quite awkward.Under the threat of safety issues, domestic regulatory agencies in China may also follow the changes made by the FDA and tighten regulations on clinical research of RSV vaccines for infants and young children.

Whether the indication for infants and young children can be obtained will determine how high the ceiling of the RSV vaccine can reach.

Especially Chongqing Zhifei Biological Products Co., Ltd. On December 5, justInitial 10-Year Collaboration with GSK on RSV Vaccine. Many people expect the RSV vaccine to become the next blockbuster vaccine, bringing a new growth curve to the performance of Chongqing Zhifei Biological Products Co., Ltd. However, with the possible narrowing of the applicable age range for the elderly and the slow progress in developing vaccines for infants and young children,The room for imagination brought by the RSV vaccine will continue to shrink.