Orthopoxviral DiseasePhase 2246-SafetyNCT00907803

Safety, Tolerability, Pharmacokinetics (PK) of the Anti-Orthopox Drug, ST-246

A Phase 2 study testing ST-246 400 mg and ST-246 600 mg in people with Orthopoxviral Disease, run by SIGA Technologies at 3 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

The purpose of this study was to assess the safety, tolerability, and pharmacokinetics of two clinical doses of the anti-orthopoxvirus drug, ST-246, administered as a single daily oral dose for 14 days to healthy, fed volunteers. Read more about this study

Who is it for?: Ages 18 to 75 yearsHealthy volunteers can take part
Conditions the study is for: Orthopoxviral Disease
What is being tested?: ST-246 400 mg and ST-246 600 mg
Type of treatment: Pill or oral medicine
Could I receive a placebo?: Yes, some participants may receive a placebo
How many people: 107 participants
Where: 3 sitesUnited States
Study dates: Jun 2009to Jan 2010
Phase: Phase 2
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 to 75 years
All sexes
Healthy volunteers accepted
Adult, Older adult

Who may be able to join

18 - 75 yrs
Healthy volunteer
Ability to consent
Available for clinical follow-up for study
Not taking other medications
Adequate venous access
Using adequate birth control; negative pregnancy test
Able and willing to avoid alcohol for screening and study duration

Who cannot join

Inability to swallow study medication
Pregnant or breast-feeding
Medical condition, e.g., asthma, hypertension, angioedema, traumatic brain injury other than concussion, bleeding disorder, blood dyscrasia, idiopathic seizures, cardiac disease that limits activity, diabetes, active malignancy, Hepatitis B or C, HIV or AIDS, chronic microbial infection,
History of drug allergy that contraindicates study participation
Medical, psychiatric, social, occupational or other reason that jeopardizes the safety/rights of participant or renders he/she unable to comply with the protocol (including drug or alcohol abuse, or homelessness)
Clinically abnormal ECG

Show all 12Show fewer

Has or will participate in a clinical trial or experimental treatment within 30 days of, or during, the study
Cannot or will not do physical exercise 24 hrs before and after PK days
Will not consume grapefruit/grapefruit juice during study
Vaccination within 2 wks of screening, or planned before Day 42 of study
Treatment with prednisone or equivalent immunosuppressant/modulatory drug <3 mths before screening
Clinically significant physical exam and lab results <2weeks from 1st study drug dose

Trial locations and contacts

3 sites in 1 country.

United States3 sites

Hawaii Clinical Research Center
Honolulu, Hawaii, 96813
Orlando Clinical Research Center
Orlando, Florida, 32809
Apex Research Institute
Santa Ana, California, 92705

Other trials in United States

About this study

Official title: Double-Blind, Randomized, Placebo-Controlled, Multi-Center Trial to Assess Safety, Tolerability, and PK of the Anti-Orthopoxvirus Compound ST-246 When Administered as a Single Daily Oral Dose for 14 Days in Volunteers in the Fed State

Read the detailed description

This study is a Phase II, double-blind, randomized, placebo-controlled, multi-center (3 sites) trial to assess the safety, tolerability, and pharmacokinetics of 400 mg and 600 mg Form I ST-246 when administered as a single daily oral dose for 14 days to 107 healthy, fed volunteers between 18 and 74 years of age. Safety parameters included adverse events, vital signs, physical examinations, laboratory tests (hematology, blood chemistry, and urinalysis) and electrocardiograms.

Conditions: Orthopoxviral Disease
Being tested: ST-246 400 mg, ST-246 600 mg, Placebo
Keywords: Orthopoxvirus, Smallpox, This is a safety study only, ST-246 is being studied for treatment of Orthopoxviruses
Medical subject headings: Smallpox

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

ST-246 400 mgDrug
Also called Tecovirimat
Capsules, 400 mg daily for 14 days
ST-246 600 mgDrug
Also called Tecovirimat
Capsules, 600 mg daily for 14 days
PlaceboDrug
Capsules, once daily for 14 days

Study groups in NCT00907803
Study group	Role	What they receive
ST-246 400 mg	Experimental	ST-246 400mg (2 x 200 mg Capsules) Orally Once Daily for 14 days Receives: Drug: ST-246 400 mg
ST-246 600 mg	Experimental	ST-246 600 mg (3 x 200 mg Capsules) Orally Once Daily for 14 days Receives: Drug: ST-246 600 mg
Placebo	Placebo comparator	Matching Placebo capsules, Orally Once Daily for 14 days Receives: Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

Number of Study Participants Who Tolerated a Single Daily Oral ST-246 Dose as Determined by Safety Parameter Changes According to the DAIDS (Division of Acquired Immunodeficiency Syndrome) Adverse Events (AE) Grading Table.
Subjects were administered a single, daily oral dose of ST-246 (400 or 600 mg)and changes in safety parameteres were monitored. Safety parameters included adverse events, vital signs, physical examinations, laboratory tests (hematology, blood chemistry, and urinalysis) and electrocardiograms. The DAIDS AE grading table is a list of common terms and severity (intensity) of parameters used to describe adverse events occurring in NIAID-sponsored clinical studies/trials.
Measured: Days 1 to 14; then 24, 48, 72, 96 and 120 hours and 4 weeks after final dose

Secondary outcomes (7)

Evaluation of Pharmacokinetic Parameters to Assess Interventions: Cmax
Cmax: Maximum drug concentration in plasma determined directly from individual concentration-time data
Measured: Day 1 post-dose
Evaluation of Pharmacokinetic Parameters to Assess Interventions: Cmax
Cmax: Maximum drug concentration in plasma determined directly from individual concentration-time data
Measured: Day 14 post-dose
Evaluation of Pharmacokinetic Parameters to Assess Interventions: Tmax
Tmax: Time to reach maximum drug concentration in plasma calculated from [plasma] versus time profiles
Measured: Day 1 post-dose
Evaluation of Pharmacokinetic Parameters to Assess Interventions: Tmax
Tmax: Time to reach maximum drug concentration in plasma calculated from [plasma] versus time profiles
Measured: Day 14 post-dose
Evaluation of Pharmacokinetic Parameters to Assess Interventions: AUCtau
AUCtau: Area under the plasma concentration-time curve for each dosing interval (from time 0 to 24 hours sample) determined using the linear trapezoidal rule
Measured: Day 1 post-dose
Evaluation of Pharmacokinetic Parameters to Assess Interventions: AUCtau
AUCtau: Area under the plasma concentration-time curve for each dosing interval (from time 0 to 24 hours sample) determined using the linear trapezoidal rule
Measured: Day 14 post-dose
Evaluation of Pharmacokinetic Parameters to Assess Interventions: t½
t½: Observed terminal elimination half-life determined after the last dose on Day 14
Measured: Day 14 post-dose

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

Jun 2009Jan 2010

First posted25 May 2009 (estimated)
Study startJun 2009
Primary completionJan 2010
Study completionJan 2010

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for Orthopoxviral DiseaseStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 2
Primary purpose: Other
Allocation: Randomised
Intervention model: Parallel groups
Masking: Double blind
Who is masked: Participant, Investigator
Enrolment: 107 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT00907803
Sponsor's protocol ID: SIGA-246-004
Other IDs: HHSN261002600014C
Acronym: 246-Safety
Status last verified: Sep 2010
First submitted: 21 May 2009
Last updated: 11 Sep 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: Yes

Study at a glance

From the registry record, last updated by the sponsor on 11 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Double-Blind, Randomized, Placebo-Controlled, Multi-Center Trial to Assess Safety, Tolerability, and PK of the Anti-Orthopoxvirus Compound ST-246 When Administered as a Single Daily Oral Dose for 14 Days in Volunteers in the Fed State
ClinicalTrials.gov ID: NCT00907803
Acronym / sponsor ID: 246-Safety / SIGA-246-004
Conditions: Orthopoxviral Disease
Keywords: Orthopoxvirus, Smallpox, This is a safety study only, ST-246 is being studied for treatment of Orthopoxviruses
Phase: Phase 2
Study type: Interventional
Recruitment status: Completed
Enrolment: 107 participants (actual)
Lead sponsor: SIGA TechnologiesIndustry (pharma, biotech, devices)
Collaborators: National Institutes of Health (NIH)
Study start: Jun 2009
Primary completion: Jan 2010 (actual)
Study completion: Jan 2010 (actual)
First posted: 25 May 2009 (estimated)
Results: Posted 27 Aug 2010

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Primary purpose: Other
Allocation: Randomised
Intervention model: Parallel groups
Masking: Double blind (participant, investigator)
Number of arms: 3

Arm	Type	Receives
ST-246 400 mg	Experimental	Drug: ST-246 400 mgST-246 400mg (2 x 200 mg Capsules) Orally Once Daily for 14 days
ST-246 600 mg	Experimental	Drug: ST-246 600 mgST-246 600 mg (3 x 200 mg Capsules) Orally Once Daily for 14 days
Placebo	Placebo comparator	Drug: PlaceboMatching Placebo capsules, Orally Once Daily for 14 days

Who may qualify

Ages: 18 to 75 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult, Older adult

Key inclusion criteria (8 listed)

18 - 75 yrs
Healthy volunteer
Ability to consent
Available for clinical follow-up for study
Not taking other medications

Key exclusion criteria (12 listed)

Inability to swallow study medication
Pregnant or breast-feeding
Medical condition, e.g., asthma, hypertension, angioedema, traumatic brain injury other than concussion, bleeding disorder, blood dyscrasia, idiopathic seizures, cardiac disease that limits activity, diabetes, active malignancy, Hepatitis B or C, HIV or AIDS, chronic microbial infection,
History of drug allergy that contraindicates study participation
Medical, psychiatric, social, occupational or other reason that jeopardizes the safety/rights of participant or renders he/she unable to comply with the protocol (including drug or alcohol abuse, or homelessness)

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
ST-246 400 mgAlso: TecovirimatCapsules, 400 mg daily for 14 days	Drug	ST-246 400 mg
ST-246 600 mgAlso: TecovirimatCapsules, 600 mg daily for 14 days	Drug	ST-246 600 mg
PlaceboCapsules, once daily for 14 days	Drug	Placebo

Primary outcome

Number of Study Participants Who Tolerated a Single Daily Oral ST-246 Dose as Determined by Safety Parameter Changes According to the DAIDS (Division of Acquired Immunodeficiency Syndrome) Adverse Events (AE) Grading Table.
Time frame: Days 1 to 14; then 24, 48, 72, 96 and 120 hours and 4 weeks after final dose
Subjects were administered a single, daily oral dose of ST-246 (400 or 600 mg)and changes in safety parameteres were monitored. Safety parameters included adverse events, vital signs, physical examinations, laboratory tests (hematology, blood chemistry, and urinalysis) and electrocardiograms. The DAIDS AE grading table is a list of common terms and severity (intensity) of parameters used to describe adverse events occurring in NIAID-sponsored clinical studies/trials.

7 secondary outcomes

Evaluation of Pharmacokinetic Parameters to Assess Interventions: Cmax
Time frame: Day 1 post-dose
Evaluation of Pharmacokinetic Parameters to Assess Interventions: Cmax
Time frame: Day 14 post-dose
Evaluation of Pharmacokinetic Parameters to Assess Interventions: Tmax
Time frame: Day 1 post-dose
Evaluation of Pharmacokinetic Parameters to Assess Interventions: Tmax
Time frame: Day 14 post-dose
Evaluation of Pharmacokinetic Parameters to Assess Interventions: AUCtau
Time frame: Day 1 post-dose
Evaluation of Pharmacokinetic Parameters to Assess Interventions: AUCtau
Time frame: Day 14 post-dose
Evaluation of Pharmacokinetic Parameters to Assess Interventions: t½
Time frame: Day 14 post-dose

Results and safety

Results posted to the registry on 27 Aug 2010, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
ST-246 400 mg	45	42
ST-246 600 mg	46	43
Placebo	16	16

Primary outcome: Number of Study Participants Who Tolerated a Single Daily Oral ST-246 Dose as Determined by Safety Parameter Changes According to the DAIDS (Division of Acquired Immunodeficiency Syndrome) Adverse Events (AE) Grading Table.

Time frame: Days 1 to 14; then 24, 48, 72, 96 and 120 hours and 4 weeks after final dose. Number. Unit: Participants

Measure	ST-246 400 mg n = 45	ST-246 600 mg n = 46	Placebo n = 16
Value	34	38	15

Population analysed: As per protocol. During the study, a total of 6 withdrawals occurred. These were due to adverse events (2) and consent withdrawal (1) in the 400 mg group, and subject request (1), lost to follow-up (1) and protocol violation (1) in the 600 mg group.

7 secondary outcomes are reported in the full results.

Adverse events

Time frame: 6 weeks. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
ST-246 400 mg	0 of 45 (0%)	11 of 45 (24.4%)	Not reported
ST-246 600 mg	0 of 46 (0%)	8 of 46 (17.4%)	Not reported
Placebo	0 of 16 (0%)	1 of 16 (6.3%)	Not reported

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 11 Sep 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.

Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Thomas Marbury, MD principal investigator

Orlando Clinical Research Center

Erik Ross, MD principal investigator

Apex Research Institute

Jon Ruckle, MD principal investigator

Hawaii Clinical Research Center

3 sites in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing ST-246 400 mg and ST-246 600 mg in people with Orthopoxviral Disease, run by SIGA Technologies at 3 sites in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 8 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 11 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 3 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 27 Aug 2010). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Number of Study Participants Who Tolerated a Single Daily Oral ST-246 Dose as Determined by Safety Parameter Changes According to the DAIDS (Division of Acquired Immunodeficiency Syndrome) Adverse Events (AE) Grading Table. (time frame: Days 1 to 14; then 24, 48, 72, 96 and 120 hours and 4 weeks after final dose). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT00907803.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 Sep 2026.