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Spero Therapeutics
Spero Therapeutics focuses on carbapenem-resistant infections, with SPR720 in Phase 2 for NTM pulmonary disease and tebipenem HBr funded by a BARDA award.
Spero Therapeutics
Spero Therapeutics launched in 2014 with a rare disease antibiotic platform licensed from Massachusetts General Hospital, targeting the kind of gram-negative pathogens that land patients in the ICU with few pharmaceutical options left. The founding thesis assumed a narrow path: develop treatments for multi-drug resistant infections, win regulatory designations that compress timelines, then partner with larger commercial players for distribution. That model produced tebipenem HBr, an oral carbapenem designed to replace IV-only hospital stays for complicated urinary tract infections, and SPR206, an IV polymyxin for MDR gram-negative infections. Spero's pipeline splits between the SPR720 oral DNA gyrase inhibitor — in Phase 2 for nontuberculous mycobacterial pulmonary disease under Fast Track and Orphan Drug designations — and tebipenem HBr, where a 2024 BARDA contract funded a pivotal trial for cUTI. The company out-licensed ex-US rights for tebipenem to GSK for Japan and certain Asian territories, while retaining full US commercial optionality. SPR206 wrapped Phase 1 testing with a safety profile that avoided the nephrotoxicity historically seen in polymyxins. The portfolio spans gram-negative pathogen coverage, mycobacterial disease, and adjunctive therapies for cystic fibrosis-related infections — all in pre-revenue stage. Headcount stood at 86 as of early 2026 (per SEC filing, 2026). Spero operates from Cambridge, Massachusetts, with a research infrastructure that emerged from the Partners Innovation Fund and a network of Boston-area academic medical centers. The May 2025 restructuring — reducing non-tebipenem spending and refocusing toward SPR720 — came after a Type A meeting with the FDA confirmed a path for a single Phase 3 trial, compressing the timeline and shifting capital allocation toward the pulmonary indication. Spero's architecture departs from the typical late-stage biotech in one visible way: it does not intend to build a US commercial sales force. The GSK partnership for tebipenem ex-US is structured as a territorial out-license, and management has telegraphed a similar approach for US commercialization — making Spero an R&D engine that monetizes through milestone payments and royalties rather than in-market operations. That R&D-centric posture has attracted non-dilutive funding from BARDA and maintains a balance sheet with $105.5M in cash against a small, focused late-stage pipeline.
General information
Firm type
Asset Manager
Year founded
2014
AUM
Undisclosed
Location
Region
North America
Country
United States
City
Cambridge
Corporate office
Cambridge, MA, United States
Principals
Ankit Mahadevia
Chief Executive Officer
Timothy Keutzer
Chief Development Officer
Sector focus
Frequently asked questions
What does Spero Therapeutics develop?
Spero develops treatments for multi-drug resistant bacterial infections and rare pulmonary diseases. Its lead programs are tebipenem HBr, an oral carbapenem for complicated urinary tract infections, and SPR720, an oral DNA gyrase inhibitor targeting nontuberculous mycobacterial pulmonary disease. A third candidate, SPR206, is an IV polymyxin for gram-negative hospital infections. All three address pathogens on the WHO critical-priority list.
Why did Spero restructure in May 2025?
The restructuring followed a Type A meeting with the FDA that confirmed a single Phase 3 trial could support tebipenem HBr approval, compressing the regulatory pathway. Spero reallocated spending toward the tebipenem pivotal trial and the ongoing SPR720 Phase 2 study in NTM-PD, reducing headcount and non-core programs. The decision preserved the $105.5M cash balance to fund through key data readouts.
How is Spero funded?
Spero has relied on a mix of equity financing, non-dilutive government awards, and licensing proceeds. BARDA awarded the company up to $46.2M in 2024 to support tebipenem HBr development. GSK paid an upfront fee for ex-US rights to tebipenem in Japan and select Asian territories. Spero has also received funding from the National Institute of Allergy and Infectious Diseases and the Cystic Fibrosis Foundation for SPR720.
Does Spero have a commercial sales force?
Spero does not maintain a commercial sales force and has indicated it does not plan to build one for the US market. The company has partnered ex-US rights for tebipenem to GSK and has signaled a similar territorial out-licensing approach for US commercialization if tebipenem receives FDA approval. Spero's model monetizes through milestone payments and royalties.
What partnership does Spero have with GSK?
GSK holds exclusive rights to tebipenem HBr for all territories outside the United States, with an initial focus on Japan and certain Asian markets. The deal was structured as a license agreement with an upfront payment, development milestones, and tiered royalties on net sales. Spero retains full US rights and is conducting the pivotal trial independently with BARDA support.
What is SPR720 targeting?
SPR720 is an oral DNA gyrase inhibitor in Phase 2 clinical development for nontuberculous mycobacterial pulmonary disease, a chronic lung infection with no currently approved therapy in the United States. The FDA granted both Fast Track and Orphan Drug designations. Spero is also evaluating SPR720 as an adjunctive therapy in cystic fibrosis patients with chronic NTM infections.
How many programs does Spero have in clinical development?
Spero has two programs in clinical development: tebipenem HBr, now in a pivotal Phase 3 trial for complicated urinary tract infections, and SPR720, in a Phase 2 dose-ranging trial for NTM pulmonary disease. A third candidate, SPR206, completed Phase 1 and remains available for partnership or government-funded advancement against multi-drug resistant gram-negative infections.
Profile maintained by Altss using OSINT (open-source intelligence), regulatory filings, licensed data partners, and verified direct submissions. Read the methodology. Last updated: . Continuous refresh with full update cycles at least every 30 days.
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