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TPOXX

Phase 4FDA approved 2018

Smallpox | Small molecule | Infectious Disease |SIGA Technologies Inc.|Trials Updated: Sep 14, 2026

TPOXX development status

FDA approval Jul 13, 2018
Approval holderSiga Technologies
ApplicationNDA208627
Highest phase Phase 4 (NCT04392739)
Phase scored for SIGAPhase 3
Registered trials 6 across 2 sponsors since Jun 2015

Label indication TPOXX is an inhibitor of the orthopoxvirus VP37 envelope wrapping protein and is indicated for the treatment of human smallpox disease in adults and pediatric patients weighing at least 3 kg. ( 1.1 ) Limitations of Use: The effectiveness of TPOXX for treatment of smallpox disease has not been determined in humans because adequate and well-controlled field trials have not been feasible, and inducing smallpox disease… FDA label

TPOXX target and mechanism

ModalitySmall molecule

Also known as tecovirimat

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMC
Total Trials3
Total Enrollment1,016

FDA Designations

No designations recorded

TPOXX clinical trials

TPOXX · 3 trials · 1 indication

Phase 3 2Phase 2 1
NCT04971109Safety, Tolerability and Pharmacokinetics of TPOXX When Administered Orally for 28 DaysSmallpox
COMPLETED467 Analytics
NCT02474589A Trial to Assess the Safety, Tolerability, and Pharmacokinetics of the Anti-Orthopoxvirus Compound TecovirimatSmallpox
COMPLETED449 Analytics
PHASE3COMPLETED
Safety, Tolerability and Pharmacokinetics of TPOXX When Administered Orally for 28 Days
SmallpoxUnlock trial analytics
PHASE3COMPLETED
A Trial to Assess the Safety, Tolerability, and Pharmacokinetics of the Anti-Orthopoxvirus Compound Tecovirimat
SmallpoxUnlock trial analytics

Study Endpoints

Primary Endpoints

Cmin
28 days

Cmin - Minimum TPOXX concentration in plasma

Cmax
28 days

Peak exposure when administered TPOXX

AUC(0-last) - Total Systemic TPOXX Exposure
28 days

Total systematic exposure when administered TPOXX

Time To Maximum TPOXX Exposure
28 days

Median hours post dose when administered TPOXX

To Determine the Number of Participants With Adverse Events
45 days

To determine the safety and tolerability of oral tecovirimat

Adverse Events
59 Days

Number of participants with adverse events when TPOXX or TPOXX Placebo is coadministered with JYNNEOS

Immunogenicity
Day 43

Least squared geometric mean

Secondary Endpoints

Adverse Events
58 Days
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Study Design & Arms

AllocationRANDOMIZED
MaskingDOUBLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
TPOXXACTIVE_COMPARATORTreatment Group 1: An oral dose of 600 mg (3 x 200 mg capsules)TPOXX
TPOXX PlaceboPLACEBO_COMPARATORTreatment Group 2: An oral dose of placebo (3 capsules identical to TPOXX)
ActiveACTIVE_COMPARATOR600 mg tecovirimat capsules BID to assess safety and tolerability and pharmacokinetics of the anit-orthopoxvirus compound Tecovirimat when administered orally in healthy subjects
PlaceboPLACEBO_COMPARATORmatching placebo capsules BID to assess safety and tolerability and pharmacokinetics of the anit-orthopoxvirus compound Tecovirimat when administered orally in healthy subjects
JYNNEOS + TPOXXACTIVE_COMPARATORAn oral dose of 600 mg (3 × 200 mg capsules) TPOXX BID (every 12 hours \[±30 minutes\]) for 28 days and a single AM SC dose of 0.5 mL JYNNEOS on Day 1 and Day 29. JYNNEOS will be administered with TPOXX concomitantly on Day 1
JYNNEOS + matching TPOXX placeboPLACEBO_COMPARATORAn oral dose of placebo (3 capsules identical to TPOXX) BID (every 12 hours \[±30 minutes\]) for 28 days and a single AM SC dose of 0.5 mL JYNNEOS on Day 1 and Day 29. JYNNEOS will be administered with TPOXX placebo concomitantly on Day 1.

Interventions

NameTypeDescription
TPOXXDRUGStudy is based on Animal Regulatory Rule
TPOXX PlaceboOTHERDoes not apply
tecovirimatDRUGStudy is based on Animal Regulatory Rule
PlaceboOTHERDoes not apply
Smallpox and Mpox VaccineDRUGvaccine
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Eligibility Criteria

Age Range18 Years to 80 Years
SexALL
Healthy VolunteersYes
Study Sites9

Inclusion Criteria: 1. Subject is male or female between 18 and 80 years of age, inclusive. 2. Subject is available for clinical follow-up for the duration of the study. 3. Women of childbearing potential have a negative beta human chorionic gonadotropin pregnancy test (serum) at the screening visi...

Countries:United States
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Recent Changes (Last 90 Days)

MEDIUMOct 12, 2026NCT02474589TRIAL_REMOVED: changed
MEDIUMOct 12, 2026NCT04971109TRIAL_REMOVED: changed
MEDIUMOct 12, 2026NCT02474589TRIAL_REMOVED: changed
MEDIUMOct 12, 2026NCT04971109TRIAL_REMOVED: changed
MEDIUMOct 12, 2026NCT02474589TRIAL_REMOVED: changed
MEDIUMOct 12, 2026NCT04971109TRIAL_REMOVED: changed
LOWSep 15, 2026NCT04957485lastUpdatePostDate: changed
LOWSep 15, 2026NCT04957485lastUpdatePostDate: changed
LOWSep 15, 2026NCT04957485lastUpdatePostDate: changed

Frequently asked questions about TPOXX

What is TPOXX used for?

TPOXX is an investigational small molecule drug being developed for smallpox. It is currently in Phase 3 clinical development. TPOXX is being studied for its safety, tolerability, and pharmacokinetics when administered orally for 28 days.

Who makes TPOXX?

TPOXX is being developed by SIGA Technologies Inc., a company traded under the ticker symbol SIGA. The drug is currently in Phase 3 clinical development for the treatment of smallpox.

What phase is TPOXX in?

TPOXX is in Phase 3 clinical development. It is an investigational drug and has not been approved by regulatory authorities. One Phase 3 clinical trial has been completed, with no active trials currently ongoing.

What clinical trials is TPOXX in?

TPOXX has one completed Phase 3 clinical trial with the identifier NCT04971109. This trial studied the safety, tolerability, and pharmacokinetics of TPOXX when administered orally for 28 days. The trial enrolled 467 participants in the United States.

Is TPOXX FDA approved?

TPOXX is not FDA approved. It is an investigational drug currently in Phase 3 clinical development for smallpox. A Phase 3 clinical trial has been completed, but the drug remains under investigation and has not received regulatory approval.