CVnCoV COVID-19 vaccine safely elicits immune response in Phase I testing

CureVac N.V. has announced positive interim data from its ongoing Phase I dose-escalation study evaluating the safety, reactogenicity and immunogenicity of CVnCoV, its investigational SARS-CoV-2 vaccine candidate.

The study enrolled more than 250 healthy individuals aged 18 to 60 years. Each was immunised intramuscularly with CVnCoV at escalating doses two, four, six, eight and 12μg on days one and 29. Per dose level, the trial included up to 10 participants who had previously tested positive for a COVID-19 infection (seropositives) to further evaluate the safety and immunogenicity of CVnCoV in this sub-population. 

According to the enterprise, CVnCoV was generally well tolerated across all tested doses and induced strong binding and neutralising antibody responses in addition to indications of T cell activation. It intends to publish a detailed overview of the Phase I data in the coming weeks. CVnCoV is currently also being investigated in a Phase IIa clinical trial in older adults in Peru and Panama. 

“We are very encouraged by the interim Phase I data. It represents a critical milestone in our COVID-19 vaccine program and strongly supports the advancement of our vaccine candidate,” said Dr Franz-Werner Haas, Chief Executive Officer of CureVac. “Following further data readouts and discussion with regulatory authorities, we remain fully committed and on track to initiate a pivotal Phase IIb/III trial before the end of 2020.” 

Geometric Mean Titers (GMTs) of binding and neutralising antibodies in study participants were compared to peak serum titers of 67 symptomatic convalescent COVID-19 patients (human convalescent sera [HCS]). The HCS panel was composed to provide a medically relevant comparator to validate CVnCoV potency, approximately 24 percent of the contributors to the panel were a severely ill COVID-19 patients who had to be hospitalised.

At 12μg, GMTs of binding antibodies increased to the level measured in the HCS panel. Analysis of T cell mediated immunity is ongoing, but the early data show indications of functional T cells. 

“These initial data show a robust and highly efficient immune response to our natural mRNA-based CVnCoV vaccine candidate, including antibody and initial T cell responses at the level of a relevant panel of symptomatic convalescent patients,” said Dr Mariola Fotin-Mleczek, Chief Technology Officer of CureVac.

The reactogenicity of CVnCoV was continuously monitored by a Data and Safety Monitoring Board. The vaccine was generally well tolerated across all tested doses with no related serious adverse events observed. At 12μg, grade three adverse events occurred mostly after administration of the second dose and included fatigue, headache, chills, muscle pain and, to a lesser extent, fever. All reported events were transient and resolved rapidly, usually within 24 to 48 hours.

About CVnCoV

CVnCoV is an mRNA-based COVID-19 vaccine candidate which encodes a prefusion stabilized full-length SARS-CoV-2 Spike protein. Its formulation is based on lipid nanoparticle (LNP) technology licensed from Acuitas Therapeutics.