33,500,000 Shares

Common Stock
This is an initial public offering of shares of common stock of Parabilis Medicines, Inc. We are offering 33,500,000 shares of our common stock.
Following this offering, we will have two classes of common stock: the voting common stock offered hereby and non-voting common stock. For a description of the rights of the voting common stock and non-voting common stock, see the section titled “Description of Capital Stock” beginning on page 202 of this prospectus. We are offering voting common stock in this offering, and unless otherwise noted, all references in this prospectus to our “common stock,” “common shares” or “shares” refer to our voting common stock.
Prior to this offering, there has been no public market for our common stock. The initial public offering price per share is $20.00. Our common stock has been approved for listing on The Nasdaq Global Select Market under the symbol “PBLS”.
We are an “emerging growth company” and “smaller reporting company” as defined under the U.S. federal securities laws and, as such, we have elected to comply with certain reduced public company reporting requirements in this prospectus and future filings.
Investing in our common stock involves a high degree of risk. See the section titled “Risk Factors” beginning on page 15 to read about factors you should carefully consider before deciding to invest in shares of our common stock.
Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.
|
|
Per Share |
|
Total |
||
Initial public offering price |
|
$ |
20.00 |
|
$ |
670,000,000 |
Underwriting discounts and commissions (1) |
|
$ |
1.40 |
|
$ |
46,900,000 |
Proceeds, before expenses, to Parabilis Medicines, Inc. |
|
$ |
18.60 |
|
$ |
623,100,000 |
We have granted the underwriters the option to purchase up to an additional 5,025,000 shares of common stock from us, at the initial public offering price, less the underwriting discounts and commissions.
In connection with our strategic research collaboration, Regeneron Pharmaceuticals, Inc. (“Regeneron”) has agreed to purchase approximately $75.0 million of shares of our common stock in a concurrent private placement exempt from the registration requirements of the Securities Act of 1933, as amended, at a per share price equal to 90% of the initial public offering price (or 4,166,666 shares). The private placement will close concurrently with, and is contingent and conditioned upon consummation of, this offering; however, this offering is not contingent on the consummation of the concurrent private placement. In connection with the concurrent private placement, we have entered into a stock purchase agreement with Regeneron. The underwriters of this offering will not receive any fee in connection with the concurrent private placement.
The underwriters expect to deliver the shares against payment on or about June 11, 2026.
Leerink Partners |
BofA Securities |
Evercore ISI |
Guggenheim Securities |
LifeSci Capital |
Prospectus dated June 9, 2026










































