What happened

Shares of Pfizer (PFE) rose 3.2% on Wednesday after the pharmaceutical giant released promising early results from its COVID-19 vaccine trials. 

So what 

Pfizer is working with German biotech BioNTech (BNTX -1.44%) to develop a novel coronavirus vaccine. On Wednesday, the two companies said that one of their vaccine candidates, labeled BNT162b1, produced neutralizing antibodies in all 24 participants who received two doses (of either 10 or 30 micrograms) of the experimental drug. Health officials are hopeful that neutralizing antibodies could help to build immunity to COVID-19.

A person wearing safety gear holding a liquid-filled vile.

Pfizer and BioNTech released positive preliminary data from their coronavirus vaccine study on Wednesday. Image source: Getty Images.

Notably, Pfizer and BioNTech said the levels of neutralizing antibodies were 1.8 times to 2.8 times higher than in patients who recovered from COVID-19.

"We are encouraged by the clinical data of BNT162b1, one of four mRNA constructs we are evaluating clinically, and for which we have positive, preliminary, topline findings," Pfizer Head of Vaccine Research & Development Kathrin Jansen said in a press release.

Now what 

Pfizer and BioNTech intend to begin a global Phase 2b/3 safety and efficacy trial in late July, pending regulatory approval. That study would be much larger, with as many as 30,000 participants.

If the vaccine proves both safe and effective, Pfizer and BioNTech would seek to produce up to 100 million doses by the end of this year and possibly more than 1.2 billion doses by the end of 2021.