By Chris Wack


Spero Therapeutics received written agreement from the U.S. Food and Drug Administration, under a Special Protocol Assessment, on the design and size of its pivotal Phase 3 clinical trial of tebipenem HBr in patients with complicated urinary tract infection, including acute pyelonephritis.

The biopharmaceutical company designed tebipenem in collaboration with GSK to provide a clinical path to becoming the first oral carbapenem antibiotic for treatment of cUTI, if approved.

The primary efficacy endpoint of the trial will be overall response at the test-of-cure visit. The FDA has indicated that positive and persuasive results from the trial, 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 also is eligible to receive milestone/royalty payments under the terms of its license agreement with GSK, conditional upon achievement of certain progression of milestones.

Spero could get up to an additional $120 million in development milestones as the Phase 3 clinical trial progresses; up to $150 million in potential commercial milestones based on first commercial sales; up to $225 million in potential sales-based milestones; and low-single digit to low-double digit tiered royalties on product sales of tebipenem HBr in all territories, except Japan and certain other Asian countries.

Spero shares were up 8% to $1.53 in premarket trading.


Write to Chris Wack at chris.wack@wsj.com


(END) Dow Jones Newswires

07-31-23 0836ET