Rapport Therapeutics, a company whose neuroscience technology comes from Johnson & Johnson, joined the public markets Friday, raising $154 million for proof-of-concept testing of a lead program in development for a common form of epilepsy.
Rapport had revealed its plans to go public last month. Late Thursday, the biotech priced its offering of 8 million shares at $17 apiece, which was the midpoint of the price range it set earlier this week. At that price, the Boston-based company’s IPO raised $136 million. Concurrent with the stock offering, Rapport raised another $18 million in a private placement, bringing total proceeds to $154 million.
Shares of Rapport now trade on the Nasdaq under the stock symbol “RAPP.” In Rapport’s first day of trading, its shares closed at $20.80 apiece, up 22.3% from the IPO price.
Lead Rapport drug candidate RAP-219 is being developed as a treatment for focal epilepsy, a form of the disorder caused by intermittent abnormal electrical activity in certain parts of the brain. An estimated 1.8 million people in the U.S. have focal epilepsy, accounting for 60% of epilepsy patients, Rapport said in its IPO filing. Focal epilepsy can be treated with anti-seizure medicines that hit the AMPA receptor. But this receptor is found throughout the brain, so hitting it can lead to serious side effects that lead many patients to stop using AMPA-targeting drugs.
Rapport aims to more selectively hit AMPA receptors, which could vastly improve the side effect profile. The company’s small molecule drugs target receptor associated proteins (RAPs), proteins that regulate receptor expression and function. RAP-219 targets a RAP for the AMPA receptor found only in certain regions of the brain. In the IPO filing, Rapport says this approach offers the potential for a wider therapeutic index, the range of doses in which a therapy is effective without causing unacceptable adverse effects. The company is also exploring other neurological indications for its lead molecule.
RAP-219 and the RAP platform technology that developed the drug were licensed from Janssen, a Johnson & Johnson subsidiary. The biotech is preparing to advance its lead drug candidate to a Phase 2a proof-of-concept test. The company’s pipeline also includes RAP-199, a drug that targets the same RAP as RAP-219, but in a way that offers different chemical and pharmacokinetic properties.
Since its 2022 launch, Rapport had raised about $250 million prior to the IPO, the prospectus shows. Founding investors Third Rock Ventures and Johnson & Johnson Innovation—JJDC respectively own 22.9% and 7% post-IPO stakes of the company, according to the filing. Arch Venture Partners owns a 10.5% stake in Rapport. The private placement consists of 1.06 million shares sold at the IPO price. The buyers are Sofinnova Ventures and Goldman Sachs, the filing shows. As of the end of the first quarter of this year, Rapport reported a $193.2 million cash position. Rapport said it expects that money, together with the new capital raised, will support the company through the end of 2026.
Rapport will put its new capital to work right away on RAP-219’s mid-stage clinical trial, expected to start in the second half of this year. The company has budgeted $100 million to take this program through the completion of proof-of-concept trials in focal epilepsy, peripheral neuropathic pain, and bipolar disorder. Another $40 million is earmarked for a second multiple-ascending dose study and positron emission tomography trial, and for advancing development of a long-acting version of RAP-219. The company also plans to advance RAP-199 through Phase 1 development.
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