Pfizer has shared positive phase 3 results for its respiratory syncytial virus (RSV) vaccine, Abrysvo, in immunocompromised adults who are at risk of developing severe RSV-associated lower respiratory tract disease.
RSV is a common contagious virus characterised by several mild, cold-like symptoms. Although most people recover within a week or two, the virus can cause severe illness in certain groups, including older adults, infants and those with immunocompromising conditions.
Pfizer’s RSV vaccine is already approved in major markets, such as the US and EU, to protect older adults as well as infants through maternal immunisation. However, there are currently no RSV vaccines approved for adults aged 18 to 59 years in the US.
A substudy of the ongoing MONeT trial was conducted to evaluate the safety and immunogenicity of two doses of Abrysvo, given one month apart, in four groups of immunocompromised adults aged 18 years and older.
This included those with non-small cell lung cancer, those on haemodialysis due to end-stage renal disease, those with autoimmune inflammatory disorder receiving active immunomodulator therapy, and solid organ transplant recipients.
Abrysvo was found to be well-tolerated, demonstrating a safety profile consistent with findings from previous studies of the vaccine.
The top-line results also showed that, while Pfizer evaluated two doses of Abrysvo, a single 120µg dose generated a strong neutralising response against both RSV-A and RSV-B across all cohorts and age groups.
The company said it is planning to share the findings at an upcoming scientific conference and publish them in a peer-reviewed scientific journal, as well as submit the data to the regulatory agencies for review.
Annaliesa Anderson, senior vice president and chief scientific officer, vaccine research and development at Pfizer, said: “Immunocompromised adults, such as patients with cancer or autoimmune disorders, have a substantially increased risk of experiencing severe complications from RSV, yet there are currently no vaccines approved for those aged 18 to 59 in the US.
“We are encouraged by the positive top-line data from this study, which provide important evidence that Abrysvo has the potential to address a significant unmet need in this vulnerable population.”