Parabilis Medicines has priced an upsized initial public offering of 33.5 million shares at $20 per share, the company said Tuesday.

Underwriters have been granted a 30-day option to purchase up to about 5 million additional shares.

The company said it expects to begin trading on the Nasdaq this Wednesday, under the ticker symbol, "PBLS." The offering is set to close Thursday.

In addition to the IPO, Parabilis has agreed to sell 4.2 million shares at $18 per share in a concurrent private placement to Regeneron Pharmaceuticals (REGN), the company said.

Gross proceeds from the offerings are expected to total about $745 million.