Newly announced results of a Phase I dose-escalation study show CureVac’s COVID-19 vaccine candidate, CVnCoV, generates noticeable immune responses in healthy volunteers.
CureVac formulated CVnCoV based on state-of-the-art lipid nanoparticle (LNP) technology which was licensed from the company’s long-term partner Acuitas Therapeutics. The vaccine candidate’s mode of action mimics the body’s natural immune response to infection documented in patients who have recovered from COVID-19.
CureVac’s Phase I study enrolled over 250 healthy volunteers between the ages of 18 and 60. Participants received intramuscular injections of CVnCoV at escalating doses of 2, 4, 6, 8 and 12µg on days one through 29. Up to 10 participants who previously tested positive for COVID-19 were included per dose level to assess the safety and immunogenicity of the vaccine in seropositive individuals.
The immunogenicity from the CureVac study show the CVnCoV candidate induced binding antibody titers, or relevant titers of virus neutralizing antibodies. These antibodies were observed at all dose levels.
In a subanalysis which pitted Geometric Mean Titers (GMTs) of binding and neutralizing antibodies from healthy study volunteers against 67 symptomatic convalescent patients with COVID-19, an applied human convalescent sera panel was found to be “highly representative of the immune activation of seriously ill patients with multiple symptoms of whom approximately 24% were hospitalized,” according to CureVac’s statement of the findings.
Overall, the vaccine was generally well tolerated by the study participants. At time of the interim analysis, there were no reported serious adverse events (AEs) related to the vaccine. Transient grade III AEs, which occurred at the 12µg dose level and mostly followed the second dose, included fatigue, headache, chills, muscle pain and (to a lesser extent) fever.
Currently, the German biotech firm is conducting an ongoing analysis of T cell mediated immunity. The company stated that the early trial data suggest indications of functional T cells confirming activation of cellular immune response. In addition, a Data and Safety Monitoring Board is continuously monitoring CVnCoV’s reactogenicity.
“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,” CureVac’s chief technology officer, Dr. Mariola Fotin-Mleczek, said in a statement. “We are grateful to all study volunteers who are helping to enable the development of a vaccine that will provide the best possible protection for people.”
The positive interim Phase I trial data mark a critical milestone in CureVac’s COVID-19 vaccine program and may support the advancement of the candidate at its highest dose level of 12µg into larger-scale trials, according to a statement made by CureVac’s chief executive officer, Dr. Franz-Werner Haas. “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.”
In late September, CureVac announced it had dosed its first participant in a Phase IIa clinical trial of its COVID-19 vaccine candidate. The study, which is being conducted in Peru and Panama, is enrolling up to 690 participants, including older adults. Similar to the Phase I trial, CureVac’s South American trial is evaluating the safety, reactogenicity and immunogenicity associated with CVnCoV.
“The start of the clinical Phase IIa trial in Peru and Panama represents an important step forward in our COVID-19 clinical study program,” said Dr. Fotin-Mleczek, in a statement. “This trial is designed to further confirm the selection of the dose of our vaccine candidate and to confirm that we can provide a safe and tolerable vaccine, also to older adults, who are at a higher risk of experiencing serious impacts from COVID-19.”