What happened

Shares of Tricida (TCDA) are down 30% at 1:33 p.m. EST today after the Food and Drug Administration denied the company's appeal of a complete response letter (CRL) that the agency issued for Tricida's marketing application for veverimer as a treatment for chronic kidney disease.

So what

A CRL, like the one Tricida received in August 2020, is essentially a rejection letter from the FDA with instructions on what data the agency would need to see for the drug to eventually get approved. Tricida was trying to get veverimer approved under the accelerated approval pathway, which uses surrogate endpoints, such as biomarkers, to predict clinical outcomes. In Tricida's case, it wanted to use change in serum bicarbonate levels to predict future kidney function in patients with chronic kidney disease.

Rather than address the issues and resubmit the marketing application with more clinical data, which would take awhile, Tricida appealed the FDA's decision, arguing that the change in serum bicarbonate seen in the one clinical trial run by the company was sufficient for accelerated approval.

Not surprisingly, the agency stuck with its belief that the magnitude of change in serum bicarbonate wasn't likely to predict clinical benefit in patients with chronic kidney disease. The agency is also concerned that a majority of the sites for the clinical trial were in Eastern Europe, where the different diets and treatments prescribed to patients might make the results less applicable to the U.S. patient population.

Doctor showing a report to a patient

Image source: Getty Images.

Now what

While the FDA's denial of the appeal is certainly bad news for Tricida, the company still has a pathway to gain approval for veverimer.

Tricida is currently running a second clinical trial, the Valor-CKD study, which theoretically could produce the data on changes in serum bicarbonate that the FDA wants. But Tricida warned that the data might not be strong enough for the agency to give veverimer an accelerated approval.

Fortunately, the Valor-CKD study is also measuring the function of patients' kidneys, so the results could be used for a full approval. Unfortunately for Tricida, it takes awhile for patients with chronic kidney disease to progress, so a final readout isn't expected until the first half of 2024. If veverimer works really well, the clinical trial could produce data during one of two interim readouts expected in the second half of 2021 and the middle of 2022.