The US Food and Drug Administration (FDA) has lifted the clinical hold placed on the Phase II clinical trial of Spero Therapeutics’ investigational oral therapy candidate, SPR720, to treat nontuberculous mycobacterial (NTM) disease.

A new type of antibacterial therapeutic, SPR720, which is currently being developed, acts on enzymes needed for the replication of bacterial DNA.

The FDA placed a hold on the trial of the SPR720 programme last February after analysing results from a non-human primate (NHP) toxicology study.

In this study, deaths with inconclusive causality to the therapy were reported.

Spero Therapeutics CEO Ankit Mahadevia said: “We are very pleased with the FDA’s decision and eager to bring SPR720 back into the clinic.

“Extensive analyses, together with prior clinical and non-clinical data, support our belief that SPR720 has the potential to offer a new, well-tolerated, oral treatment option for patients suffering from NTM-PD.”

The latest move comes after the company presented a comprehensive study report, which included a thorough assessment from the NHP toxicology study.

In the first quarter of this year, Spero intends to hold talks with the FDA on the restart of the Phase II trial of SPR720 in individuals with NTM-pulmonary disease (NTM-PD).

The trial is anticipated to commence in the second half of next year.

Spero Therapeutics chief medical officer David Melnick said: “Current treatments for nontuberculous mycobacteria are often ineffective and involve lengthy and complex combination regimens that include injectable and/or inhalable antibiotics.

“Through SPR720’s clinical development and potential future marketing approval, we aim to provide appropriate NTM-PD patients with a once-daily oral therapy, in conjunction with existing therapeutic regimens.”

A common environmental pathogen, NTM can cause gradual damage to the lungs and lead to respiratory failure, especially in immunocompromised people or those with underlying pulmonary ailments.

Spero started the Phase I trial of SPR720 to treat NTM infections in January 2019.