Janux Therapeutics (JANX) said Tuesday it started an underwritten public offering of $300 million of shares or pre-funded warrants to buy shares.

Underwriters will be given a 30-day option to buy up to an additional $45 million of shares, the company said.

The offering is subject to market conditions, and there's no assurance as to whether or when it may be completed, its actual size or terms, Janux said.

Net proceeds will be used to advance the clinical development of the company's product pipeline and for general corporate purposes, according to the company.