What happened

Shares of BioNTech (BNTX -2.55%) were falling 7.3% as of 11:24 a.m. EDT on Tuesday. The German biotech didn't announce any news. The most likely reason behind the decline was that Sanofi (SNY -0.31%) is expanding its collaboration with Translate Bio (TBIO) to develop messenger RNA (mRNA) vaccines. The new deal between the two companies could be worth up to $1.9 billion.

So what

The expansion of the relationship between Sanofi and Translate Bio underscores the increased competition that is emerging in the arena of mRNA vaccines. Moderna is also developing mRNA vaccines, including a highly publicized COVID-19 vaccine.

Gloved hand holding COVID-19 vaccine syringe

Image source: Getty Images.

But the sell-off of BioNTech could be overdone. The company already has two big partners for its mRNA COVID-19 vaccine -- Pfizer and Chinese drugmaker Fosun Pharma. BioNTech has also teamed up with Pfizer, Genmab, and Roche on other mRNA programs.

In addition, BioNTech has a big head start with its COVID-19 vaccine compared to Translate Bio. While Sanofi and Translate Bio don't expect to advance their COVID-19 vaccine candidate into early-stage testing until the fourth quarter of 2020, BioNTech began a phase 1/2 clinical study of its COVID-19 vaccine in Germany in April with a U.S. clinical trial starting in early May.

Now what

The main thing to watch with BioNTech is the clinical progress for its COVID-19 vaccine candidate. BioNTech expects to report preliminary results from phase 1 studies by July. Positive news from these studies should provide a big catalyst for the biotech stock.