Spero Accepts GSK’s $66 Million to Save its Rejected Antibiotic

GSK offered $66 million upfront for Spero Therapeutics’ complicated urinary tract infection (cUTI) antibiotic, tebipenem pivoxil hydrobromide (tebipenem HBr), after the FDA rejected Spero’s New Drug Application (NDA) submission in June. Following a meeting with the FDA, Spero published a press release highlighting the need for an external partnership to advance the development and potential commercialization of the drug. GSK stepped up to the plate, presenting Spero the upfront payment and up to $525 million in milestones.

Salvaging a Once-Promising Program

Spero put years of research into developing tebipenem HBr to treat cUTI because of the drug’s potential as an effective carbapenem antibiotic. Carbapenems are a class of highly effective antibiotics used to treat serious infections. Currently, there are no FDA-approved oral carbapenem antibiotics, making tebipenem HBr a promising candidate to provide an alternative to intravenous treatments. Spero says tebipenem HBr could prevent unnecessary hospitalizations or ease the transition from hospital to at-home treatments with its oral tebipenem HBr. 

Despite tebipenem HBr’s potential benefits, the FDA denied Spero’s April NDA submission for the drug, citing insufficient data. Spero published Phase 3 trial results alongside its NDA submission, with tebipenem HBr demonstrating non-inferior results compared to intravenous ertapenem, another carbapenem antibiotic used to treat cUTI. 

In light of the rejection, Spero met with the FDA to clarify a potential path forward to approve the drug. The FDA indicated that Spero would need to perform an additional Phase 3 trial with tebipenem HBr to meet the FDA’s standards for approval. After spending so much time and resources on the project, Spero announced it would seek an external partnership for the additional Phase 3 trial and potential product commercialization.

It only took a few weeks for GSK to answer the call, pledging $66 million upfront for near global rights to the drug and the promise to purchase $9 million worth of Spero shares. GSK also offered the potential for up to $525 million in development and commercial milestones. The announcement resulted in a jump in Spero’s stock price, which has drastically declined over the last year. 

Related Article: Spero Therapeutic Lays Off 75% of Employees Resulting in Stock Plummet

Hope for Tebipenem HBr’s Future

With a solid partner backing the project, Spero can breathe a sigh of relief before hitting the ground running to start the additional Phase 3 trial next year. 

Ankit Mahadevia, M.D., Chief Executive Officer of Spero, said, “We are thrilled to collaborate with GSK on developing tebipenem HBr for patients suffering from complicated urinary tract infections. With their antibiotic expertise and global commercial reach, GSK is ideally positioned to launch tebipenem HBr following regulatory approval as the first oral treatment for complicated urinary tract infections, providing patients with an alternative to in-hospital intravenous therapy.”

If the drug meets the FDA’s expectations after the next Phase 3 trial, GSK will have global rights excluding Japan and certain Asian countries. Spero partner, Meiji Seika, will retain rights to Japan, where tebipenem HBr is approved for pediatric infections limited to pneumonia, otitis media, and sinusitis. 

GSK’s decision to pay $66 million for Spero’s tebipenem HBr provides immense relief for Spero, which was running out of options after the drug’s FDA rejection. With a renewed regulatory approval path, the two companies have a shot at bringing tebipenem HBr to the market as the first FDA-approved oral carbapenem antibiotic to treat cUTI. 

Author

Reed Slater