PROSPECTUS SUMMARY
This summary highlights information contained elsewhere in this prospectus or incorporated by reference in this prospectus, and does not
contain all of the information you should consider before making your investment decision. You should carefully read this prospectus, any applicable prospectus supplement and the information incorporated by reference in this prospectus and any
applicable prospectus supplement before you invest in our common stock.
Company Overview
We are a clinical-stage biopharmaceutical company focused on the discovery, development and commercialization of next generation targeted
therapies for womens cancers. We are advancing our pipeline of novel therapies by leveraging our deep understanding of endocrine-driven cancers, nuclear receptors, and mechanisms of acquired resistance. Our lead product candidate, palazestrant
(OP-1250), is a novel orally-available small molecule with dual activity as both a complete estrogen receptor, or ER, antagonist, or CERAN, and a selective ER degrader, or SERD, currently being investigated in
patients with recurrent, locally advanced or metastatic ER-positive, or ER+, human epidermal growth factor receptor 2-negative, or HER2-, breast cancer. In preclinical
models, palazestrant binds and completely blocks ER-driven transcriptional activity in both wild-type and mutant forms of metastatic ER+ breast cancer including activity in central nervous system, or CNS,
metastases models. In clinical studies across more than 400 patients, palazestrant has demonstrated strong anti-tumor activity, attractive pharmacokinetics and prolonged drug exposure, favorable tolerability, and combinability with CDK4/6 inhibitors
with no significant drug-drug interaction. Palazestrant is being evaluated as a single agent in an ongoing Phase 3 clinical trial, OPERA-01, and in Phase 1/2 combination studies with a CDK4/6 inhibitor
(palbociclib or ribociclib), a phosphatidylinositol 3 kinase alpha, or PI3Ka, inhibitor (alpelisib), and a Phase 1b/2 combination study with an mTOR inhibitor (everolimus).
Private Placement
On November 29,
2024, we entered into a Securities Purchase Agreement, or the Purchase Agreement, with the selling stockholders named in this prospectus, pursuant to which we issued and sold to the selling stockholders in a private placement, or the Private
Placement, (i) 19,928,875 shares of our common stock at a purchase price of $9.08 per share of common stock and (ii) pre-funded warrants to purchase up to an aggregate of 7,604,163 shares of our common
stock at a purchase price of $9.0799 per pre-funded warrant, which represents the per share purchase price of the shares of common stock, less the $0.0001 per share exercise price for each pre-funded warrant. The aggregate gross proceeds from the Private Placement at the closing of the Private Placement, before deducting placement agent fees and other offering expenses, were approximately
$250.0 million, which does not include any proceeds that may be received upon exercise of the pre-funded warrants issued in the Private Placement. The closing of the Private Placement occurred on
December 4, 2024.
Each pre-funded warrant has an exercise price of $0.0001 per share. The pre-funded warrants were exercisable immediately upon closing of the Private Placement, and may be exercised at any time until all of the pre-funded warrants are exercised in
full. A holder (together with its affiliates and other attribution parties) may not exercise any portion of a pre-funded warrant to the extent that immediately prior to or after giving effect to such exercise
the holder would own more than 9.99% of our outstanding common stock immediately after exercise, which percentage may be changed at the holders election to a lower or higher percentage not in excess of 9.99% (or such higher percentage up to
19.99%, at the election of the holder) upon 61 days notice us subject to the terms of the pre-funded warrants.
The shares of common stock and pre-funded warrants issued to the selling stockholders in connection
with the Private Placement were not initially registered under the Securities Act or any state securities laws. We relied on the exemption from the registration requirements for transactions by an issuer not involving any public