New York, June 3, 2026, 16:07 (EDT)
- Spero traded at $2.80, off 1.1%. The SPDR S&P Biotech ETF gained 1.5%.
- FDA is expected to make a decision on tebipenem HBr by June 18.
- Spero finished March holding $56.1 million in cash and maintained its guidance for runway into 2028.
Spero Therapeutics shares slipped late Wednesday, missing gains seen in the wider biotech sector. Traders watched for a June 18 U.S. decision on tebipenem HBr, Spero’s antibiotic that’s partnered with GSK. The stock changed hands at $2.80, off 1.1%, giving the company a market cap around $151 million. The SPDR S&P Biotech ETF was ahead 1.5%.
Spero shares traded with a clear catalyst ahead. The biotech said the Food and Drug Administration gave a June 18 PDUFA date for tebipenem HBr’s new drug application. That’s the target for an FDA decision on whether to approve the drug.
Tebipenem HBr is in development for complicated urinary tract infections, or cUTIs, including kidney infections like pyelonephritis. It’s an oral carbapenem antibiotic. Carbapenems are typically used as strong infection drugs delivered by IV for these cases.
Spero President and CEO Esther Rajavelu told investors last month the company was making “solid progress” on its program with GSK. She said Spero was preparing for an FDA decision in June. Spero has given GSK exclusive rights to sell tebipenem HBr in most markets, except for some Asian regions where Meiji controls rights. GlobeNewswire
Spero shares barely moved after the company said its Phase 3 PIVOT-PO trial would stop early in 2025 for efficacy. The company’s latest update showed the study hit non-inferiority against IV imipenem-cilastatin in hospitalized cUTI patients, meaning Spero’s drug wasn’t worse than the comparator by the set margin. Investors were left with a tight regulatory picture.
Balance sheet figures are in focus as well. Spero posted a net loss of $7.2 million for the first quarter, better than the $13.9 million net loss a year ago. Revenue came in at $258,000, most of it from collaborations. Cash and equivalents totaled $56.1 million at the end of March. The company still says current cash should last into 2028.
Wockhardt this week got FDA approval for Zaynich, an IV antibiotic for adults with complicated UTIs like pyelonephritis. That adds more competition in the drug-resistant Gram-negative infection market. Spero is pushing a different angle. It has an oral option in the works aimed at cutting down hospital IV use if it gets approved.
GSK is leading the filing, which eases launch costs for Spero but keeps the smaller firm dependent on GSK’s handling. Reuters said last year that Spero shares jumped after the companies announced the late-stage trial hit its primary goal and revealed no new safety issues other than those already seen.
But the risk is clear. Spero’s filing notes it hasn’t made any product sales and approval for its candidates might never come. It also says the FDA could ask for more trials, put restrictions on labeling or reject a drug altogether. Fast-track, qualified infectious disease product and priority-review benefits aren’t a sure thing for approval, the company said.
Nasdaq ran its normal session Wednesday, with no holiday schedule. The exchange’s calendar puts the following 2026 closure on June 19 for Juneteenth, and regular trading stays at 9:30 a.m. to 4 p.m. Eastern. Spero shares stayed in the regular tape, as focus stays on the June 18 FDA decision.
