Undeterred by FDA setback, GSK snaps up Spero antibiotic

GSK is paying $66 million upfront to license rights to Spero Therapeutics novel antibiotic tebipenem Hbr, unswayed by the FDA's decision earlier this year not to approve the drug for adults with complicated urinary tract infections (cUTI).

The big pharma is paying $66 million upfront for rights to tebipenem in all regions, except Japan and some other Asian countries – where rights are held by Meiji Seika – and will also make a $9 million equity investment in Spero.

Another $525 million could come from development and sales milestones, including $150 million on completion of a new phase 3 trial and $150 million on the first sale of the drug in the US or Europe.

Tebipenem is the first oral drug in the carbapenem antibiotic class to reach late-stage development and, despite the desperate need for new antimicrobials, was turned down in June by the FDA, which said another clinical trial would be required to support approval.

At the time, analysts at GlobalData said the decision would raise the risk of antimicrobial resistance (AMR), on the grounds that tebipenem can be delivered at home, preventing people with cUTI from needing IV therapies in hospital where they can be exposed to other infections.

Spero will now have funding to start a new phase 3 trial of the drug – tebipenem pivoxil hydrobromide, to give it its full name – and according to GSK this will be designed based on feedback from the FDA.

The Massachusetts-based biotech sought approval of tebipenem on the strength of a phase 3 trial – called ADAPT-PO – which showed that the drug was equivalent to standard care with intravenous ertapenem in patients with cUTI and acute pyelonephritis (AP).

There were signs that Spero was expecting a negative outcome from the FDA when it halted all efforts to develop a commercial platform for the antibiotic, shed 75% of its workforce, and said it was pivoting its attention to two other pipeline drugs.

At the time, chief executive Ankit Mahadevia intimated that Spero was looking for an external partner to take the programme forward.

"With their antibiotic expertise and global commercial reach, GSK is ideally positioned to launch tebipenem HBr following regulatory approval," he said in a statement on the licensing deal.

Meanwhile, GSK's chief commercial officer Luke Miels said that tebipenem "complements GSK’s infectious disease strategy and is consistent with our commitment to find value-enhancing opportunities to build a strong late-stage portfolio."

He added that the new antibiotic has "a clear US FDA regulatory path to potential approval."