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SPR720

Phase 2

Nontuberculous Mycobacterial Pulmonary Disease (NTM-PD) | Small molecule | Respiratory |Spero Therapeutics, Inc.|Trials Updated: Oct 9, 2025

SPR720 development status

Highest phase Phase 2
Registered trials 3 across 1 sponsor since Sep 2020

SPR720 target and mechanism

Molecular targetDNA gyrase B
Target classProtein
ModalitySmall molecule

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLED
Total Trials1
Total Enrollment25

FDA Designations

No designations recorded

SPR720 clinical trials

SPR720 · 1 trial · 1 indication

Phase 2 1
NCT05496374A Study to Evaluate the Efficacy, Safety, Tolerability, and Pharmacokinetics of SPR720 as Compared With Placebo for the Treatment of Participants With Mycobacterium Avium Complex (MAC) Pulmonary DiseaseNontuberculous Mycobacterial Pulmonary Disease (NTM-PD)
COMPLETED25 Analytics
PHASE2COMPLETED
A Study to Evaluate the Efficacy, Safety, Tolerability, and Pharmacokinetics of SPR720 as Compared With Placebo for the Treatment of Participants With Mycobacterium Avium Complex (MAC) Pulmonary Disease
Nontuberculous Mycobacterial Pulmonary Disease (NTM-PD)Unlock trial analytics

Study Endpoints

Primary Endpoints

Slope of the Weekly Sputum Log10 Colony Forming Units Per Millilitre (CFU/mL) Change From Day 1 Through 56 in micro-Intent to Treat (m-ITT) Population
Days 1 through 56 (end of the treatment [EOT])

Secondary Endpoints

Slope of the Weekly Sputum Log10 CFU/mL Change From Days 1 Through 28 in micro-ITT Population
Days 1 through 28
Slope of the Time to Positivity (TTP) using Mycobacteria Growth Indicator Tube (MGIT) on Samples of Induced Sputum From Days 1 Through 56 (EOT) in micro-ITT Population
Days 1 through 56 (EOT)
Change from Baseline in the Sputum Log10 CFU/mL in the micro-ITT Population
Days 1 through 56 (EOT)
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Investigator Blind: PlaceboPLACEBO_COMPARATORParticipants received SPR720 matching-placebo capsules, orally, once daily (QD) for 56 days.
Investigator Blind: SPR720 500 mgEXPERIMENTALParticipants received SPR720 500 mg (250 mg × 2) capsules along with 2 SPR720 matching- placebo capsules, orally, QD for 56 days.
Investigator Blind: SPR720 1000 mgEXPERIMENTALParticipants received SPR720 1000 mg (250 mg × 4) capsules, orally, QD for 56 days.
Open-label: SPR720 1000 mgEXPERIMENTALParticipants received SPR720 1000 mg (250 mg × 4) capsules, orally, QD for 56 days.
Open-label: SPR720 500 mgEXPERIMENTALParticipants received SPR720 500 mg (250 mg × 2) capsules, orally, twice daily (BID) for 56 days.

Interventions

NameTypeDescription
PlaceboDRUGPlacebo-matching capsules was administered orally.
SPR720 500 mgDRUGSPR720 500 mg (250 mg × 2 capsules) was administered orally.
SPR720 1000 mgDRUGSPR720 500 mg (250 mg × 4 capsules) was administered orally.
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites28

Inclusion Criteria: 1. Has a prior diagnosis of NTM-PD due to MAC according to American Thoracic Society (ATS) criteria 2. Has at least one prior lower respiratory culture (sputum or bronchoalveolar lavage \[BAL\]) positive for MAC in the 12 months prior to consent 3. Has an induced sputum culture ...

Countries:United States
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Frequently asked questions about SPR720

What is SPR720?

SPR720 is an investigational oral small molecule being developed by Spero Therapeutics, Inc. for nontuberculous mycobacterial pulmonary disease (NTM-PD), a chronic lung infection. It is in Phase 2 clinical development and has not been approved by the FDA. It is also referred to as SPR720 500 mg.

What is SPR720 used for in NTM-PD?

SPR720 is being developed to treat nontuberculous mycobacterial pulmonary disease (NTM-PD), specifically Mycobacterium avium complex (MAC) pulmonary disease. The Phase 2 trial enrolled adults with this condition. SPR720 is investigational and has not been approved for any indication.

What does SPR720 target?

SPR720 targets DNA gyrase B, a bacterial enzyme involved in DNA replication. By inhibiting this target, SPR720 is designed to interfere with mycobacterial DNA processes. DNA gyrase B is a protein target, and SPR720 is a small molecule therapeutic.

Who is developing SPR720?

SPR720 is being developed by Spero Therapeutics, Inc., which trades under the ticker SPRO. The company is the sponsor of the clinical program evaluating SPR720 in nontuberculous mycobacterial pulmonary disease.

What phase is SPR720 in?

SPR720 is in Phase 2 clinical development. It is an investigational drug and has not been approved by the FDA. The completed Phase 2 trial evaluated its efficacy, safety, tolerability, and pharmacokinetics in patients with Mycobacterium avium complex pulmonary disease.

What clinical trials is SPR720 in?

SPR720 has been studied in one Phase 2 trial, NCT05496374, titled a study to evaluate the efficacy, safety, tolerability, and pharmacokinetics of SPR720 compared with placebo for Mycobacterium avium complex pulmonary disease. The trial was completed, enrolled 25 participants, was randomized, double-blind, and placebo-controlled, and was conducted in the United States.