aibioRapport Therapeutics prices $250 million stock offering at $26.00 a share
Tickers RAPP
Rapport priced 9,615,385 shares at $26.00 the day after reporting Phase 2a epilepsy data for RAP-219, with net proceeds of about $234.7 million. The data came from 30 treated patients and were tested against fixed null rates, not a placebo group.
Key facts
- Company
- Rapport Therapeutics, Inc. (NASDAQ: RAPP)
- News type
- Financings
- Primary source
- Rapport Therapeutics, Inc. 424B5 (2025-09-08)
The pricing
Rapport Therapeutics, Inc. signed an underwriting agreement on September 9, 2025 with Goldman Sachs & Co. LLC, Jefferies LLC, TD Securities (USA) LLC and Stifel, Nicolaus & Company, Incorporated. The underwriters agreed to buy 9,615,385 shares of common stock at $26.00 a share. The underwriting discount is $1.56 a share, or $15,000,000.60 in total, leaving $235,000,009.40 before expenses. The company estimates net proceeds of about $234.7 million, or about $270.0 million if the underwriters use their 30-day option to buy up to 1,442,307 more shares.
The preliminary prospectus supplement, filed September 8, described a $250,000,000 offering and cited a last reported sale price of $14.36 on September 5. The final supplement, dated September 9, cites $28.03 on that day. All of the shares are sold by the company, and delivery was expected on or about September 11. After the sale, 46,113,062 shares would be outstanding, or 47,555,369 if the option is exercised in full.
The data behind the jump
On September 8, Rapport announced topline results from its Phase 2a trial of RAP-219 in patients with drug-resistant focal onset seizures. RAP-219 is an AMPA receptor negative allosteric modulator that the company says targets a protein, TARP g 8, found in the brain regions where focal seizures often start. Thirty patients were dosed. The primary endpoint, long episodes tracked through patients' implanted RNS devices, was analyzed in 27 patients in a modified intent-to-treat group. In that group, 85.2% had at least a 30% reduction in long episodes from baseline, and the median reduction was 71.0%. For clinical seizures, analyzed in 25 patients, 72.0% had a reduction of at least 50% and 24.0% were seizure free during the 8-week treatment period.
The results come with limits. The prospectus says the p-values were calculated against fixed null rates, 10% for the primary responder measure, not against a placebo group. Statistical comparisons were not made for other cut points. Four patients discontinued during treatment, three because of adverse events: worsening of preexisting memory impairment, a panic attack and worsening of preexisting anxiety. Dizziness was reported in 26.7% of patients, headache in 16.7% and fatigue in 13.3%. No serious adverse events were reported, and the company says rage or aggression was not observed. The 8-week follow-up period is still running, with further analyses expected in 2026.
What comes next for RAP-219
The company plans an end-of-Phase 2 meeting with the FDA in the fourth quarter of 2025 and says it plans two Phase 3 pivotal trials starting in the third quarter of 2026. A Phase 2 trial in bipolar mania is enrolling, with topline results expected in the first half of 2027.
The forward-looking statements in the prospectus still list the company's ability to resolve the FDA's clinical hold on the Phase 2a proof-of-concept trial of RAP-219 in diabetic peripheral neuropathic pain. The prospectus gives no reason for the hold. It says an update on the plan for a Phase 2 trial in that pain indication is expected later in 2025.
Dilution and cash runway
At June 30, 2025, Rapport had net tangible book value of approximately $263.2 million, or $7.21 per share, on 36,497,677 shares. After this sale the as adjusted figure is $497.9 million, or $10.80 per share. New investors face immediate dilution of $15.20 per share.
Rapport intends to use the proceeds, with its existing cash, cash equivalents and short-term investments, mainly to fund ongoing and planned RAP-219 trials, other research and development, working capital and general corporate purposes. The prospectus says that money should fund operations into the second half of 2029, but the company says that estimate rests on assumptions that may prove wrong and it could use its capital sooner than expected.
Counsel and the shelf
Goodwin Procter LLP of Boston passes on the validity of the shares for Rapport, and its opinion is Exhibit 5.1 to the 8-K. Cooley LLP of New York is counsel for the underwriters. The sale was made under a Form S-3 shelf registration statement, File No. 333-288444, filed July 1, 2025 and declared effective July 9, 2025.