FDA Issues Complete Response Letter for UTI Therapy

The FDA has issued a complete response letter (CRL) for Spero Therapeutics’ new drug application (NDA) seeking approval for tebipenem HBr oral tablets. Spero was seeking an indication as a treatment of adult patients with complicated urinary tract infection (cUTI), including pyelonephritis, which is a UTI that has traveled to one of the kidneys.

In the CRL, the FDA indicated that Spero’s phase 3 study, ADAPT-PO, was insufficient to support approval and that an additional clinical study would be required. Spero officials said they intend to request a Type A meeting with the FDA to gain further insights as to the pathway forward for regulatory approval.

Ankit Mahadevia, M.D.

“We are disappointed with the FDA’s decision, but we look forward to our continued dialogue, addressing the agency’s concerns and outlining a clear path forward for tebipenem HBr,” Ankit Mahadevia, M.D., chief executive officer of Spero Therapeutics, said in a press release.

The CRL was anticipated based on feedback the company had received from the FDA in May 2022, in which the agency said there were potential deficiencies in the application.

The company also announced in May that, as a result of the FDA’s feedback, it was reducing its workforce by about 75% and a restructuring of its operations to reduce operating costs and reallocate resources toward the clinical development programs of SPR720 and SPR206, while continuing engagement with the FDA on the appropriate path forward for tebipenem HBr.

SPR720 is a novel oral therapy candidate for the treatment of a rare, orphan pulmonary disease caused by non-tuberculous mycobacterial infections. A phase 2 trial for this indication is expected to begin in the second half of 2022.

SPR206 is aimed at treating MDR gram-negative bacterial infections. Company officials said SPR206’s phase 1 data support further development in complicated urinary tract infection, hospital-acquired and ventilator-associated bacterial pneumonia, and bloodstream infections. A phase 2, cross-indication resistant pathogen study is expected to begin in the second quarter of 2023.