Broad pneumococcal vaccine meets targets in first phase 3
The VAX-31 candidate generated at least comparable immune responses to two existing vaccines in a large adult trial, but has not yet been approved.
US manufacturer Vaxcyte has reported positive results for VAX-31, a candidate vaccine against pneumococcal disease. The first of three planned phase 3 trials met its prespecified targets; independent assessment and approval are still pending.
VAX-31 is designed to provide protection against 31 serotypes of the bacterium Streptococcus pneumoniae. The bacterium can cause pneumonia, meningitis and bloodstream infections, among other conditions. Existing vaccines from Pfizer and Merck target 20 and 21 serotypes respectively.
More than 3,500 adults took part in the OPUS-1 study. Participants received VAX-31 or one of the existing comparator vaccines. The researchers focused mainly on the amount of antibodies produced against different serotypes after vaccination, rather than on a direct difference in the number of cases of disease.
According to the results reported by Vaxcyte, VAX-31 produced an immune response at least comparable to that of the existing vaccines against the 28 serotypes shared with one or both products. The company reported stronger responses against three serotypes found only in VAX-31 and against serotype 20B.
Reuters reports that the candidate vaccine also met a prespecified safety target. According to the manufacturer, its safety profile was comparable to that of the two existing vaccines in the age groups studied. No serious adverse events were directly linked to the vaccines.
The results do not yet amount to marketing authorisation. Vaxcyte expects data from two other phase 3 trials in the first half of 2027 and plans to submit an application for authorisation in the United States in the first half of 2028. Regulators still have to assess the full data, product quality and risks.
The outcome is therefore encouraging for the development of broader protection, but it is not the same as proven better protection in everyday practice. The study reports mainly immune responses and preliminary results from the manufacturer. The full publication, independent analysis and any authorisation will ultimately determine how significant the findings are for patients and vaccination programmes.
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The reported phase 3 targets, the comparison with existing vaccines and the remaining authorisation steps were described by the manufacturer, Reuters and STAT. The article calls the outcome encouraging but avoids the incorrect conclusion that VAX-31 is already available or has been proven to provide better protection against disease.
- confirmed VAX-31 met the prespecified targets in the OPUS-1 phase 3 study. — Vaxcyte reports this in its topline results; Reuters and STAT describe the same outcome. source
- confirmed More than 3,500 adults took part in the study. — STAT mentions slightly more than 3,500 participants in the adult study. source
- confirmed VAX-31 targets 31 serotypes and is compared with vaccines against 20 and 21 serotypes. — These figures appear in the company statement and independent reporting. source
- confirmed The results mainly show immune responses and no direct difference in the number of cases of disease. — The primary endpoints are immunogenicity and safety; Reuters describes the study as a comparison of immune responses. source
- confirmed The vaccine has not yet been approved and additional phase 3 results are expected in 2027. — Vaxcyte cites the planned OPUS-2 and OPUS-3 results and a later application to the FDA. source
Editor's note
The phase 3 results were reported by the manufacturer as topline data on 5 October and independently described by Reuters and STAT. The vaccine has not been approved, the full study data have not yet been published, and the study mainly shows immune responses, not a proven reduction in cases of disease.Sources
More on this in Dutch media
- De Telegraaf — „vaccin pneumokokken”
- AD — „vaccin pneumokokken”
- de Volkskrant — „vaccin pneumokokken”