It turns out FDA concerns were just the start of the problems for Crinetics Pharmaceuticals’ CRN04777. As the biotech worked to resolve a clinical hold on the rare disease drug, it learned of unrelated problems that prompted it to suspend development of the candidate.
Last year, Crinetics reported top-line data from a phase 1 trial it ran in Germany and filed to start a phase 2 study in the U.S. The FDA imposed a clinical hold on the proposed phase 2 study, prompting Crinetics to start collecting additional information and data to address the agency's concerns. As the biotech was collecting the information, new issues came to light in nonclinical studies.
“These studies uncovered findings at exposure levels that eroded anticipated therapeutic margins for CRN04777. These other findings are not related to those originally cited by the FDA for the clinical hold,” Crinetics wrote in its second-quarter results update.
“We … suffered a setback with our CRN04777 program and made the difficult decision to wind down its development,” Crinetics CEO Scott Struthers, Ph.D., said in a statement. “Our recently evolved understanding of the nonclinical profile of CRN04777 suggests that it no longer meets the high standards to which we hold all drug candidates in our pipeline.”
Crinetics decided to “suspend further significant investment into the molecule at this time” and sought to reassure investors that the concerns are specific to CRN04777. According to the biotech, the problems that torpedoed the asset are not present in nonclinical studies of its other candidates and are not more generally associated with its somatostatin receptor type 5 (SST5) mechanism of action.
The biotech identified agonism of SST5 as a way to block a step in the insulin secretion process and thereby treat congenital hyperinsulinism, a condition in which dysregulated insulin production causes life-threatening low blood glucose. Crinetics is on track to deliver phase 3 data on its lead candidate, the SST2 agonist paltusotine, in the coming months.