CureVac ramps up COVID-19 mRNA vaccine effort as Moderna analysts raise questions about animal data

With all the excitement surrounding Moderna’s fast-moving mRNA vaccine for COVID-19, it’s no surprise that another mRNA vaccine player, CureVac, has been overlooked. But CureVac is making it clear it intends to compete in this race, too—and it has rolled out preclinical results in anticipation of launching a phase 1/2a clinical trial this June.

CureVac said late last week that its lead COVID-19 vaccine candidate generated “high levels” of virus-neutralizing titers in animal models and that it “has the potential to induce a strong immunologic response to neutralize SARS-CoV-2,” the virus that causes the illness. The company is prepared to manufacture “several hundred million doses per year” at its facility in Germany, it added.

Even as CureVac’s vaccine moves into clinical trials, Wall Street analysts will likely show interest in its preclinical results—and how they compare to those reported by Moderna, which saw its stock skyrocket 23% on Monday on news of positive data from a mouse trial and small human study of its COVID-19 vaccine candidate, mRNA-1273.

CureVac said a low dose of its vaccine candidate—two micrograms—protected animals from COVID-19 infection. That result was similar to what the company has seen with mRNA vaccines it is studying for rabies, flu and respiratory syncytial virus (RSV). In fact, CureVac said that in a phase 1 study of its rabies vaccine, a dose of one microgram produced immune responses in healthy volunteers.

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But when it comes to COVID-19, how much can animal models really tell us about the protective power of mRNA vaccines? That was a question Moderna’s executives fielded several times during a conference call with analysts Monday morning. One wondered what the company would need to see to gain confidence that the antibody levels produced by mRNA-1273 are truly protective. Another asked if the scientists who completed the mouse research measured responses from the immune system’s T cells to gauge the effectiveness of the doses studied.

Vaccines based on mRNA technology carry strands of mRNA that encode disease-specific proteins, with the goal of stimulating the immune system to produce antibodies against the disease. The COVID-19 vaccines from both Moderna and CureVac are centered around the spike protein that allows the novel coronavirus to infect healthy cells.

Moderna’s chief medical officer, Tal Zaks, M.D., Ph.D., said he had no T-cell data to share from the newly disclosed animal trial. But generally speaking, the company’s past mRNA studies have shown T cell activity in both preclinical and clinical studies. “You would expect that based on the fundamental scientific principles of how an mRNA vaccine works because it teaches the body’s own cells to make the protein from within the cell.”

As for what level of protection mRNA vaccines will provide, Zaks expressed confidence in the signals seen in the mouse study. After just a priming dose, “the mouse was already protected. And so we’re getting a comfortable margin here to know that we’re at the right level that one needs to be in to protect people.”

Both Moderna and CureVac have attracted considerable support for their mRNA efforts. Moderna is allied with the National Institutes of Health and recently partnered with Lonza to manufacture mRNA-1273.

CureVac has funding from the likes of the Bill & Melinda Gates Foundation and the U.S. Department of Defense. The company has seen its share of turmoil, however: Its former CEO, Daniel Menichella, mysteriously left earlier this year after meeting with President Donald Trump, who reportedly pressured CureVac to move its COVID-19 R&D to the U.S.

Now CureVac’s chief operating officer and acting CEO, Franz Werner-Haas, Ph.D., is trying to turn the spotlight back on the science behind the company’s mRNA vaccine candidate. “We are convinced that with our expertise and advanced technology we are well-positioned to fight viral outbreaks such as the current one and that our approach may provide the best chance to protect many people from SARS-CoV-2 and other health threats," he said in a statement.