Karuna Picks Up Kidney Drugs for Chance to Challenge Boehringer Ingelheim in the Brain

brain in hands

Neurological drugs developer Karuna Therapeutics is building up its pipeline with a pair of molecules initially developed for kidney disorders. It’s a small bet that could pay off in a big way by diversifying its pipeline with medicines that could compete against a Boehringer Ingelheim drug candidate addressing the same target.

The new Karuna assets come from startup Goldfinch Bio, which is shutting down. According to financial terms announced Thursday, Boston-based Karuna is paying $15 million up front for both small molecules.

Goldfinch discovered drugs with technology that analyzed anonymized human kidney data in order to identify potential drug targets. That technology identified ways to target transient receptor potential canonical (TRPC) channels 4 and 5, pathways associated with certain kidney disorders. The research yielded lead program GFB-887, which reached mid-stage testing. While activity was shown in the kidney, Karuna President of Research & Development and Chief Scientific Officer Steve Paul notes that the preclinical and clinical research also showed antidepressant and anxiety-reducing properties.

“We are fortunate to have found as advanced a clinical-stage drug candidate directed against these important [central nervous system] targets and we will now study GFB-887 in various mood and anxiety disorders where there remains a significant unmet medical need for mechanistically novel medicines,” Paul said in a prepared statement.

Going after TRPC 4/5 brings a different dimension to Karuna, which has focused its research on targeting muscarinic receptors found in the central nervous system. Lead drug candidate KarXT, an agonist of two muscarinic receptors, M1 and M4, reached Phase 3 testing in schizophrenia. After posting positive data in the study last August, the biotech said it planned to seek FDA approval in mid-2023. The remaining programs are preclinical and are in development for undisclosed targets.

Karuna said it expects to report more details on the plans for GFB-887 in the second half of this year. By then, Boehringer Ingelheim could have Phase 2 data for its drug candidate targeting TRPC4/5 in depression. A positive result in that study could read through to Karuna’s new assets, William Blair analyst Myles Minter wrote in a research note. He added that to his knowledge, Karuna now has the only other TRPC4/5 inhibitors in development for neuropsychiatric disorders and it could have a dosing edge—once daily compared to the twice-a-day dosing of the Boehringer Ingelheim drug candidate.

The $15 million upfront payment is minor for what has the potential to become a high-value asset, Minter said. Depending on the progress of the research, Karuna could pay up to $520 million in milestone payments for each TRPC4/5 drug candidate. The biotech would also pay the Goldfinch estate royalties from sales if the molecules reach the market.

Goldfinch, which spun out of venture capital firm Third Rock Ventures, initially tested GFB-887 in focal segmental glomerulosclerosis (FSGS), a rare disorder that leads to scar tissue on renal glomeruli, the parts of the kidney that filter waste from the blood. Nearly a year ago, the company reported mixed preliminary Phase 2 data for the drug. While the results showed reductions in levels of urine proteins indicative of FSGS, no treatment effect was observed in the initial group of diabetic nephropathy patients. Fierce Biotech was first to report last week that Goldfinch was shutting down. Executives told Fierce that the move follows the company’s failure to secure additional financing.

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