It is listed here in BNTX pipeline
https://biontech.de/science/pipeline
Also From BioNTech Form S1 IPO paper
Our Rare Disease Protein Replacement mRNA Product Candidates
We
are collaborating with Genevant, in order to combine our mRNA
technology with Genevant’s LNP delivery technology, to create up to five
mRNA protein replacement therapies for the treatment of rare diseases
with high unmet medical needs. We expect our first compound from this
collaboration to enter the clinic by the second half of 2020. The first
product candidate under the Genevant
collaboration, BNT171, is currently being developed for an undisclosed
indication. Our mRNA replacement product candidate is associated with a
favorable tolerability profile and good protein expression (in mice) and
demonstrated phenotype rescue in
a mouse disease model. 
