CureVac has reported second interim analysis results from the global Phase IIb/III HERALD study, where its Covid-19 vaccine candidate, CVnCoV, failed to meet prespecified statistical success criteria.

Data showed that CVnCoV had an interim vaccine efficacy of 47% against Covid-19 of any severity.

CVnCoV is a non-chemically modified messenger ribonucleic acid (mRNA), which encodes the prefusion stabilised full-length spike protein of SARS-CoV-2. It is formulated within lipid nanoparticles.

The trial, which was carried out in partnership with Bayer, enrolled nearly 40,000 subjects in ten countries across Latin America and Europe.

About 134 Covid-19 cases that occurred at least two weeks from the second dose administration were included in the second interim analysis.

Initial analyses of the trial indicate age and strain-dependent efficacy of the vaccine, and the data has been shared with the European Medicines Agency (EMA).

A favourable safety profile of the vaccine was confirmed by the Data Safety Monitoring Board (DSMB).

The trial is underway to conduct the final analysis in the coming weeks and the complete data will be evaluated to determine the most suitable regulatory pathway, CureVac noted.

CureVac CEO Dr Franz-Werner Haas said: “While we were hoping for a stronger interim outcome, we recognise that demonstrating high efficacy in this unprecedented broad diversity of variants is challenging.

“As we are continuing toward the final analysis with a minimum of 80 additional cases, the overall vaccine efficacy may change.”

In December last year, CureVac initiated a Phase III clinical study of CVnCoV in healthcare workers at the University Medical Center Mainz, Germany.

Apart from CVnCoV, CureVac is developing second-generation Covid-19 vaccine candidates in collaboration with GlaxoSmithKline (GSK).

CureVac and GSK anticipate advancing the second-generation vaccine candidate into the clinic in the third quarter of this year.

The companies intend to launch the vaccine next year on obtaining the necessary regulatory approval.