Spero to receive $30 million development milestone payment from GSK

Spero Therapeutics, Inc. (Nasdaq: SPRO), a multi-asset clinical-stage biopharmaceutical company, focused on identifying, developing and commercializing treatments in areas of high unmet need involving rare diseases and multi-drug resistant (MDR) bacterial infections, announced today that it received written agreement from the U.S. Food and Drug Administration (FDA), under a Special Protocol Assessment (SPA), on the design and size of PIVOT-PO, a pivotal Phase 3 clinical trial of tebipenem HBr in patients with complicated urinary tract infection (cUTI), including acute pyelonephritis (AP).

“PIVOT-PO was designed in collaboration with GSK to provide tebipenem HBr with a clinical path to becoming the first oral carbapenem antibiotic for treatment of cUTI, if approved,” said Dr. Kamal Hamed, Chief Medical Officer of Spero. “With increasing prevalence of antibiotic-resistant bacteria, cUTI patients often have no choice but to receive an intravenous (IV) carbapenem antibiotic in a hospital setting. The goal of our tebipenem HBr program is to provide appropriate patients with an efficacious oral option for the treatment of cUTI. We believe that tebipenem HBr has the potential to deliver strong value to the healthcare system.”

PIVOT-PO is a global, randomized, double-blind, pivotal Phase 3 clinical trial of oral tebipenem HBr vs. IV imipenem cilastatin, in hospitalized adult patients with cUTI/AP. The primary efficacy endpoint will be overall response (composite of clinical cure plus microbiological eradication) at the test-of-cure visit. The primary analysis for the trial will be an assessment of non-inferiority (NI) in the microbiological intention-to-treat population, based on a 10% NI margin, which is consistent with FDA guidance for non-inferiority studies in cUTI/AP. The FDA has indicated that positive and persuasive results from PIVOT-PO, along with previously completed studies, could be sufficient to support approval of tebipenem HBr as a treatment for cUTI, including pyelonephritis, for a limited use indication.

Spero is also eligible to receive the following milestone/royalty payments under the terms of its license agreement with GSK, conditional upon achievement of certain progression of milestones: (1) up to an additional $120 million in development milestones as the Phase 3 clinical trial progresses; (2) up to $150 million in potential commercial milestones based on first commercial sales; (3) up to $225 million in potential sales-based milestones; and (4) low-single digit to low- double digit (if sales exceed $1 billion) tiered royalties on net product sales of tebipenem HBr in all territories, except Japan and certain other Asian countries.