Third Rock, J&J neuroscience spinout Rapport is first biotech to outline summer IPO plans

The new year burst of biotech IPOs may have sputtered out months ago, but Rapport Therapeutics is a reminder that companies are still willing to test the waters of the public markets.

Rapport launched from the Third Rock conveyor belt in March 2023 armed with $100 million in funds and a clinical-stage seizure disorder asset born in Johnson & Johnson’s labs. Five months later, the company had already secured $150 million in fresh funds from a raft of new investors as well as existing backers Third Rock Ventures, Arch Venture Partners and Johnson & Johnson Innovation – JJDC.

At the time, CEO Abe Ceesay told Fierce Biotech that he expected the biotech's list of investors would stick around for a couple more financing rounds at least. But, now, the company has decided to make the jump to the Nasdaq.

The Boston- and San Diego-based company was set up by Third Rock and JJDC as a vehicle to take forward the research of molecular neuroscientist David Bredt, M.D., Ph.D., who headed up neuroscience research at both Eli Lilly and J&J before becoming Rapport’s chief scientific officer.

Bredt discovered receptor-associated proteins (RAPs), which play a key role in modulating receptor expression. By harnessing genomics, protein science and brain imaging technologies to identify RAPs for use in precision neuromedicines, Rapport believes it can home in on receptors—such as α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs)—in the specific neuroanatomical regions causing various conditions.

In a Friday evening Securities and Exchange Commission filing, Rapport didn’t set out its estimated share price nor how much money it expects to bring in from the listing but said it would use part of the proceeds to advance the clinical development of RAP-219 into phase 2. The TARPg8 AMPAR program has already completed two phase 1 trials in healthy volunteers in preparation for assessing the candidate in focal epilepsy, peripheral neuropathic pain and bipolar disorder, with more indications planned.

Part of these plans include conducting a second multiple-ascending dose trial of a long-acting injectable formulation of RAP-219. The IPO proceeds will also be used to take another TARPg8 AMPAR program, RAP-199, into the clinic for the first time.

Further back in the pipeline, the company has preclinical nicotinic acetylcholine receptor discovery programs being considered for both chronic pain and hearing disorders.

Clearly, the company’s management hasn’t been put off by the mixed fortunes of this year’s first wave of publicly listed biotechs. While most of the January and February crop received a warm reaction from the markets initially, their valuations have dropped off since.

A Fierce analysis of data from S&P Capital IQ shows that only one—CG Oncology—is still trading above its IPO price. It’s an even more impressive feat for CG considering the bladder-cancer-focused company was not only the first biotech to go public this year but also brought in the most money via its significantly upsized $380 million offering.

Rapport’s IPO intentions back up the predictions of Medicxi Partner Francesco De Rubertis, who told Fierce earlier this month that he expected the biotech IPO window to reopen this summer.