CureVac said it has decided to stop developing its first-generation mRNA Covid-19 vaccine candidate, CVnCoV, due to disappointing efficacy in phase 3 clinical trials and focus on a more promising second-generation vaccine with GSK.
The company expected to get approval for CVnCoV in the second quarter of 2022 at the earliest, given the results of a recent review of the European Medicines Agency (EMA).
By then, however, its second-generation vaccine for Covid-19 will enter the late clinical development stage, which might overlap with the first-generation candidate under development, according to company officials.
As a result of CureVac's decision, the European Commission will also suspend its pre-purchase agreement of CVnCoV to address urgent pandemic demand, they said.
CureVac and GSK are strengthening their partnership, committing additional resources and expertise to speed up the development and production of their second-generation vaccines. The two companies plan to begin clinical development in the next few months to release an improved Covid-19 vaccine in the market next year.
According to the pre-clinical results, the second-generation CV2CoV showed strong potential compared to the previous vaccine. Animal studies have shown up to 10 times higher immunogenicity in CV2CoV. On the other hand, the first-generation CVnCoV showed only a 48 percent overall efficacy rate in phase 2 and 3 clinical trials.
CureVac acknowledged that the spread of Covid-19 variants might have affected study results.
"The global fight against Covid-19 continues, and we are working to make a difference with a safe and effective vaccine," CureVac CEO Franz-Werner Haas said. "The goal has not been changed, but the requirements to effectively addressing the virus and new variants have."
Haas added that the company's decision to withdraw the CVnCoV approval process and focus on second-generation mRNA vaccine reflects the shifting public needs CV2CoV might be able to address in the ongoing transition from the Covid-19 pandemic to an endemic.
CureVac said it plans to use lessons learned from CVnCoV development and infrastructures to focus on developing second-generation vaccines with GSK.
"We welcome CureVac's decision to focus on the second-generation mRNA vaccine as it has shown a strong improvement compared to CVnCoV in pre-clinical testing," GSK Head of Vaccines R&D said. "We have also begun the development of modified mRNA technologies as part of our collaboration to complement second-generation non-modified mRNA vaccine."