CureVac to Move COVID-19 Vaccine Into Late-Stage Testing on Positive Early Data

CureVac reported interim phase 1 study data on Monday showing that its experimental COVID-19 vaccine triggered strong binding and neutralizing antibody responses, and also gave a “first indication” that T-cells had been activated in a cohort of healthy adult volunteers. The company said the findings support a decision to advance the 12-mcg dose of CVnCoV in the upcoming pivotal phase 2b/3 study, which is on track to start before the end of this year.

“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,” commented chief technology officer Mariola Fotin-Mleczek.

The phase 1 trial, which was cleared by regulators in June to get under way in Germany and Belgium, has so far enrolled more than 250 individuals aged 18 to 60 years who were vaccinated intramuscularly with CVnCoV at escalating dose levels ranging from 2 mcg to 12 mcg. CureVac noted that at each of the five dose levels tested, the trial included up to 10 people who had previously tested positive for COVID-19, in order to further evaluate the safety and immunogenicity of CVnCoV in this sub-population.

‘Indications’ of functional T-cells

According to CureVac, immunogenicity data showed induction of binding antibody titers that translated into relevant titers of virus neutralising antibodies at all tested dose levels. At the 12-mcg dose, geometric mean titers of binding antibodies increased to the level measured in a convalescent sera panel consisting of peak serum titers from 67 symptomatic convalescent COVID-19 patients. The company noted that the panel was “highly representative” of the immune activation seen among seriously ill patients, of whom approximately 24% were hospitalized. Meanwhile, analysis of T-cell-mediated immunity is ongoing, but “early data show indications of functional T cells, confirming activation of cellular immune response,” CureVac said.

The company added that the vaccine was generally well tolerated, and none of the participants experienced serious adverse events. It noted that side effects seen for the 12-mcg dose occurred mostly after the second injection, and included fatigue, headache, chills and muscle pain, as well as fever to a lesser extent, with all reported events resolving rapidly, usually within 24 to 48 hours.

The company intends to provide a detailed Phase I data overview and publication in a scientific journal “in the coming weeks.” CVnCoV, which is based on lipid nanoparticle technology licensed from Acuitas Therapeutics, is currently also being investigated in a phase 2a trial of 690 participants, including adults ages 61 years and older, in Peru and Panama.

Other mRNA-based frontrunners

Two frontrunners in the race to develop a COVID-19 vaccine, including Moderna and an alliance between Pfizer and BioNTech, are also testing mRNA-based candidates, with CureVac CEO Franz-Werner Haas noting that as no such vaccine has ever been approved, a win for rivals can only be good news for his company as well. Haas suggested this technology is “not only for the COVID-19… In five years, [it may also be beneficial] for the COVID-25, or whatever it is.” The approach, he added, could in fact “revolutionise the entire prophylactic vaccine field.”

In June, the German government agreed to acquire a 23% stake in the company for €300 million euros ($349 million).