Following disappointing results for an antibiotic candidate whose development program is now being suspended, Spero Therapeutics is looking to extend its cash runway while it focuses on other assets in its pipeline.
As part of a restructuring following the suspension of its development program for an antibiotic candidate, Spero Therapeutics will lay off about 39% of its workforce, the company announced Oct. 29. The clinical-stage biopharma expects to mostly complete the cuts by end of the year, according to an Oct. 29 SEC filing.
As of Dec. 31, Spero had 46 employees, 30 of whom were mostly handling R&D activities, as noted in a March 13 SEC filing. If the Cambridge, Massachusetts, business has the same number of employees now, the cuts could affect about 18 people.
Regarding its antibiotic candidate, Spero shared that an interim analysis of the Phase IIa study of SPR720, a treatment being investigated for nontuberculous mycobacterial pulmonary disease, did not meet the primary endpoint. The company noted that while there was antimicrobial activity associated with SPR720, the analysis did not show sufficient separation from placebo. In addition, the data highlighted potential dose-limiting safety issues in subjects dosed at 1,000 milligrams orally once daily, including three cases of reversible grade 3 hepatotoxicity.
Spero’s restructuring is expected to extend the company’s cash runway and support operations into mid-2026, according to the announcement. During this time, the biopharma will focus on advancing tebipenem HBr in an ongoing global Phase III trial and preparing for a Phase II trial for SPR206, contingent on continued nondilutive funding. Tebipenem HBr is an oral carbapenem antibiotic meant to treat complicated urinary tract infections. SPR206 is an intravenously administered next-generation polymyxin that has shown antibiotic activity against multidrug-resistant Gram-negative pathogens, according to the company.
Tebipenem HBr is tied to a previous layoff at Spero. In 2022, the company cut about 75% of its workforce as part of a restructuring ahead of an expected FDA rejection of the antibiotic. According to a May 3, 2022, SEC filing, those layoffs reduced Spero’s full-time staff from 146 to 35 employees.
The FDA did reject the drug, and in September 2022, GlaxoSmithKline announced it would license tebipenem HBr as part of a $66 million licensing deal.
