German immunotherapy specialist BioNTech SE (NASDAQ:BNTX), which is collaborating with Pfizer (NYSE:PFE) on a potential coronavirus vaccine, on Wednesday received regulatory permission to begin phase 1/2 clinical trials of its lead candidates in Germany.

It was just over a month ago, on March 17, that Pfizer and BioNTech agreed to join forces to attempt to develop a vaccine for SARS-CoV-2, the coronavirus that causes COVID-19. Now, the Paul-Ehrlich-Institut -- which is both a research institute and one of Germany's medical regulators -- has given them the go-ahead to conduct human studies of the experimental vaccines from their BNT162 program. A similar green light to begin trials in the U.S. is expected shortly.

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The BNT162 program is actually a collection of four experimental coronavirus vaccines, all of which use different messenger RNA (mRNA) formats to produce one of two selected target antigens. Two of the candidates employ mRNA strands that function as templates for the production of the big spikes found on the surface of SARS-CoV-2. The other two help patients produce copies of a smaller (but hopefully more recognizable) region of the coronavirus spike protein.

A good deal

On April 9, Pfizer handed BioNTech an upfront payment of $185 million and promised it up to $563 million in potential milestone payments. If the BNT162 program produces a successful vaccine, the partners will split the costs of development and commercialization. If the vaccine never reaches commercialization, though, Pfizer will pay for 100% of the development costs.

In the first part of the planned trial in Germany, investigators will inject around 200 healthy patients with one of the four candidates in doses ranging from 1 microgram to 100 micrograms. But at this early trial stage, the researchers are largely looking to determine the optimal dosage, whether the vaccines are safe, and whether they generate the hoped-for immune system response. The question of whether any of them effectively prevents COVID-19 transmission will have to wait for larger, later-stage trials. And while the partners are moving at top speed on this vaccine project, it could be a long time before that question is answered.