BioNTech, which is flush with cash, is expanding its business operations despite falling COVID shot sales.

Germany's BioNTech, which is Pfizer's partner on COVID-19 vaccines, announced on Monday that its net income for the first quarter had plummeted due to decreasing demand for the shots as the company broadens its work on cancer and other diseases.

BioNTech, which stated at the end of March that it had accumulated an 18.6 billion euro ($20.55 billion) balance of cash and receivables, has pursued a series of takeovers and allianc....