Rectify Pharma bets on proteins that need a helping hand

A protein can be present and still be useless. It may have the wrong shape. It may never reach the membrane where it belongs. Or it may arrive at its post and perform poorly. To a drug hunter, these are three different troubles wearing the same disguise. Rectify Pharma was founded around the possibility that a small molecule could help such proteins get back to work.

The idea has a distinguished relative. Jonathan Moore, Rectify’s founder, was a founding scientist at Vertex Pharmaceuticals, where he worked on precision treatments targeting CFTR in cystic fibrosis. CFTR belongs to the ATP-binding cassette, or ABC, family. There are 48 human family members. The interesting question was whether the lesson from one could be carried to others.

Forty-eight relatives, one family resemblance

Moore founded Rectify with Atlas Venture in 2020. At its public launch the following year, it was still operating from Atlas’s Cambridge incubator. The company already had a $100 million Series A from Atlas, Omega Funds, Forbion and Longwood Fund. Its stated destination for that capital was the first human proof-of-concept studies. That is financing for an experiment, rather than the price of a finished medicine.

Rectify calls its compounds Positive Functional Modulators, or PFMs. The name contains the argument: increase useful function. Much familiar small-molecule drug discovery looks for ways to block activity. Rectify pursues membrane proteins whose activity needs restoring or enhancing. Its proposed audience spans rare genetic diseases and common conditions in which normal, or wild-type, proteins are doing too little.

That broader scope matters. A business tied exclusively to particular mutations has one set of possible patients. A platform that can enhance wild-type proteins has another. In a 2024 interview, CEO Rajesh Devraj and chief medical officer Pol Boudes described the genetic evidence, structural biology and cellular testing underpinning that ambition. The same principle travels; each disease still needs its own proof.

Bile needs a better recipe, and an exit

Consider primary sclerosing cholangitis, or PSC. In this disease, bile ducts become inflamed, scarred and narrowed. Bile has difficulty moving through them. Care can address symptoms, obstructions and complications; liver transplantation may become necessary. The clinical problem leaves room for a medicine that changes progression. Rectify’s lead candidate, RTY-406, attempts to intervene in the chemistry and movement of bile.

It targets two transporters. ABCB4 moves phospholipids into bile, helping make its composition less damaging. BSEP, also called ABCB11, exports bile acids. Rectify’s proposal is to improve both composition and flow. Imagine attending to what runs through a pipe as well as how readily it runs. The analogy is imperfect, but it explains why two targets sit at the center of this program.

The two-target detail is easy to misunderstand. RTY-406 is a single molecule, rather than a combination of two separate agents. That means one compound to formulate and scale. At ACS Fall 2026, Rectify reported cryo-EM structures confirming that the compound series binds directly to ABCB4 and BSEP. Mouse-model results included dose-dependent improvements in markers of inflammation and fibrosis. The company also reported that RTY-406 was being evaluated in Phase 1.

Earlier, at EASL 2025, Rectify had presented hepatobiliary data on RTY-694. The current lead is RTY-406. The important progression in the public record is toward human testing. In May 2026, Rectify described mouse efficacy findings and proof-of-mechanism results in non-human primates, including changes in liver-related blood markers. Those findings support asking the clinical question. They do not answer whether patients will live better or avoid transplantation.

The second wager runs through the kidney

Rectify’s other conspicuous program concerns ABCC6 and vascular calcification. The rationale runs through inorganic pyrophosphate, abbreviated PPi, which inhibits calcification. Enhancing ABCC6 function may help maintain this protective system. In chronic kidney disease, pathological calcium deposits and cardiovascular complications give the hypothesis practical urgency.

At ERA 2025, the company reported results for RTY-822 in rat models of kidney disease. Treatment reduced vascular calcification and improved markers including creatinine and cystatin C. These were animal experiments, with defined diets and treatment periods. An improved laboratory marker in a rat is useful evidence for development; a patient benefit remains a separate proposition.

In December 2025, Boehringer Ingelheim signed a research and licensing agreement for the ABCC6 program. Rectify receives an undisclosed upfront payment, can earn up to $448 million through specified milestones, and may receive tiered royalties on future sales. The word “can” does substantial work. Milestone totals describe conditional opportunities, and should never be counted as cash already received.

First, build a test that asks the right question

The early obstacle was methodological. Chief scientific officer Robert Hughes describes building a platform capable of finding the desired mechanism, then developing disease models to connect protein activity with useful effects. Candidate compounds also had to survive familiar practical filters, including solubility and developability. His account gives a sequence of challenges rather than a romantic tale of one disastrous prototype.

“Our hepatobiliary program could become a disease-modifying treatment, but we have to prove that clinically.”Robert Hughes · Pharmaceutical Online · June 2026

There is a lesson readers can borrow: design the measurement around the change you want. Rectify measures protein location and function, then looks for downstream effects. Its manufacturing discussion also makes the limits plain. Potency, delivery, safety and interactions still matter. Restoring function requires a protein that can respond, and beneficial biology must translate into tolerable exposure and meaningful clinical outcomes.

Commercially, Rectify is a drug developer with a licensing partner. Patients are its intended beneficiaries; the lead compound remains investigational. Boehringer contributes complementary development expertise to the kidney effort. Vertex supplies a scientific precedent, while existing PSC care and competing investigational approaches define the clinical comparison. Rectify’s place in that market will depend on what its trials establish.