RAPP

8-K

false 0002012593 0002012593 2026-10-28 2026-10-28

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): October 28, 2026

Rapport Therapeutics, Inc.

(Exact name of Registrant as Specified in Its Charter)

Delaware

001-42121

88-0724208

(State or Other Jurisdiction of Incorporation)

(Commission

File Number)

(IRS Employer Identification No.)

99 High Street

Suite 2100

Boston, Massachusetts

02110

(Address of Principal Executive Offices)

(Zip Code)

Registrant’s Telephone Number, Including Area Code: (857) 321-8020

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐

Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐

Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐

Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐

Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which registered

Common Stock, $0.001 par value per share

RAPP

The Nasdaq Global Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 1.01 Entry into a Material Definitive Agreement.

Underwriting Agreement in Respect of Common Stock and Pre-Funded Warrants

On October 28, 2026, Rapport Therapeutics, Inc. (the “Company”) entered into an underwriting agreement (the “Equity Underwriting Agreement”) with Morgan Stanley & Co. LLC, Leerink Partners LLC and Evercore Group L.L.C. as representatives of the several underwriters (collectively, the “Equity Offering Underwriters”), related to an underwritten public offering (the “Common Stock Offering”) of (i) 8,333,334 shares (the “Firm Shares”) of the Company’s common stock, par value $0.001 per share (“Common Stock”) and (ii) in lieu of Common Stock to certain investors, pre-funded warrants to purchase an aggregate of up to 1,190,476 shares of Common Stock (the “Pre-Funded Warrants” and the Common Stock issuable upon exercise of the Pre-Funded Warrants, the “Pre-Funded Warrant Shares”). In addition, the Company has granted the Equity Offering Underwriters an option, exercisable in whole or in part at any time for a period of 30 days from the date of the Underwriting Agreement, to purchase, at the offering price, less the underwriting discounts and commissions, up to an additional 1,428,571 shares of Common Stock (the “Option Shares,” and, together with the Firm Shares, the “Shares”). Each Share was offered and sold at a public offering price of $21.00 (the “Offering Price”), and each Pre-Funded Warrant was offered and sold at a public offering price of $20.999, which is equal to the Offering Price less the $0.001 exercise price of each Pre-Funded Warrant. On October 28, 2026, the Equity Offering Underwriters exercised their option in full to purchase 1,428,571 Option Shares.

Each Pre-Funded Warrant has an initial exercise price per share of $0.001, subject to certain adjustments. The Pre-Funded Warrants are exercisable immediately and may be exercised at any time until all of the Pre-Funded Warrants are exercised in full. Under the Pre-Funded Warrants, the Company may not effect the exercise of any Pre-Funded Warrant, and a holder will not be entitled to exercise any portion of any Pre-Funded Warrant (i) if immediately prior to the exercise, holder (together with its affiliates), beneficially own an aggregate number of shares of Common Stock greater than 4.99% (the “Maximum Percentage”) of the total number of issued and outstanding shares of Common Stock of the Company without taking into account any Pre-Funded Warrant Shares, or (ii) to the extent that immediately following the exercise, the holder (together with its affiliates) would beneficially own in excess of the Maximum Percentage of the number of shares of Common Stock outstanding immediately after giving effect to the issuance of such shares of Common Stock, which such percentage may be changed at the holder’s election to a higher or lower percentage not in excess of 19.9

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EX-99.1

2 rapp-ex99_1.htm

EX-99.1

EX-99.1

Exhibit 99.1

Rapport Therapeutics Reports First Quarter 2026 Financials and Provides Business Update

Phase 2a follow-up period data for RAP-219 in focal onset seizures (FOS) demonstrated sustained seizure reduction, including a 90% median reduction in clinical seizures over baseline in weeks 9-12

RAP-219 Phase 2 trial in bipolar mania topline results now expected in the fourth quarter of 2026, ahead of previous 1H 2027 guidance

RAP-219 Phase 3 program in FOS remains on track for initiation in the second quarter of 2026

Pipeline programs, including RAP-219 long-acting injectable formulation, RAP-219 in primary generalized tonic-clonic seizures, and α6β4 nAChR in chronic pain and migraine, continue to advance

Strategic collaboration and license agreement entered into with Tenacia Biotechnology to develop and commercialize RAP-219 in Greater China across indications

Ended the first quarter of 2026 with $476.8 million in cash, cash equivalents and short-term investments, excluding restricted cash, expected to fund operations into the second half of 2029

BOSTON and SAN DIEGO, May 7, 2026 -- Rapport Therapeutics, Inc. (Nasdaq: RAPP) (“Rapport” or the “Company”), a clinical-stage biotechnology company dedicated to the discovery and development of small molecule precision medicines for patients with neurological or psychiatric disorders, today reported financial results for the quarter ending March 31, 2026, and provided a business update.

“We entered 2026 with strong momentum across the RAP-219 development program, highlighted by compelling new follow-up Phase 2a data recently presented at AAN that further reinforces RAP-219’s treatment effect in focal onset seizures and builds confidence as we enter our Phase 3 trials,” said Abraham N. Ceesay, chief executive officer of Rapport. “With multiple important development milestones ahead, including continued advancement of our epilepsy franchise, progress in bipolar mania, and development of our long-acting injectable formulation, we believe we are well positioned to continue building value across our pipeline.”

CORPORATE HIGHLIGHTS

RAP-219 in Epilepsy

• Positive Phase 2a Follow-up Period Data Reinforces RAP-219’s Sustained Activity in Focal Onset Seizures. In April 2026, Rapport presented new 8-week follow-up period data from its Phase 2a trial of RAP-219 in patients with drug-resistant FOS at the American Academy of Neurology (AAN) Annual Meeting.

➢ Therapeutic levels of RAP-219 were sustained, resulting in continued biomarker and clinical responses in the 8-week follow-up period (weeks 9-16).

➢ RAP-219 continued to demonstrate clinically meaningful improvements in long episodes (LEs) and clinical seizures during the follow-up period, with an 80% median reduction in LEs and 90% median reduction in clinical seizures compared to baseline in weeks 9-12

and a 68% median reduction in LEs and 59% median reduction in clinical seizures compared to baseline in weeks 13-16.

➢ Based on pharmacokinetic (PK) data collected across the Company’s Phase 1 and Phase 2 trials and further supported by population PK modeling, RAP-219 is now estimated to have a 22-day half-life, compared to the prior reported estimate of 14 days.

• Phase 3 Program in FOS. Following feedback from an end-of-Phase 2 meeting with the U.S. Food and Drug Administration (FDA) in December 2025, the Company accelerated the initiation of its Phase 3 program in FOS, which is on track to begin in the second quarter of 2026.

• Open-label Trial Initiated. The Company is enrolling patients from its Phase 2a FOS trial into an open-label, long-term safety trial. Data from the trial is expected to be released in the second half of 2026.

• Expansion into Primary Generalized Tonic-Clonic Seizures (PGTCS). Building on the robust clinical data generated in FOS, Rapport plans to initiate a Phase 3 trial of RAP-219 in PGTCS in the first half of 2027, expanding its epilepsy franchise into the most common type of generalized seizure.

Additional Pipeline Updates

• Bipolar Mania Phase 2 Trial Topline Results Expected Ahead of Plan. Enrollment in the Phase 2 trial is progressing well and topline results are now expected in the fourth quarter of 2026, ahead of the previous guidance of first half of 2027. Additionally, the Company modified the trial’s statistical analysis plan and increased target enrollment, enabling the trial to potentially be considered as confirmatory evidence of effectiveness. Following completion of the Phase 2 trial, and subject to the results, the Company plans to engage with the FDA in an End-of-Phase 2 meeting to align on the design of a potential Phase 3 program to support a New Drug Application for the treatment of bipolar mania.

• Long-Acting Injectable Formulation Development Continues. Development of RAP-219’s long-acting injectable formulation continues to advance, with IND-enabling activities underway and initial Phase 1 pharmacokinetic