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SmallpoxPhase 4NCT04485039

Drug-drug Interaction Study of TPOXX When Co-administered With Phosphate Binders

A Phase 4 study testing Tecovirimat, sevelamer carbonate oral tablet and sucroferric oxyhydroxide chewable tablet in people with Smallpox, run by SIGA Technologies at 1 site 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

An open-label, drug-drug interaction study with TPOXX and phosphate binders. Read more about this study

Who is it for?
Ages 18 to 50 yearsHealthy volunteers can take part
Conditions the study is for
Smallpox
What is being tested?
Tecovirimat, sevelamer carbonate oral tablet and sucroferric oxyhydroxide chewable tablet
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
44 participants
Where
1 siteUnited States
Study dates
8 Jun 2022to 23 Apr 2023
Phase
Phase 4
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 50 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • Each subject must meet all of the following criteria to be enrolled in this study:
  • Subject is male or female 18 to 50 years of age, inclusive.
  • Phosphorus levels within normal laboratory reference range.
  • Women of childbearing potential have a negative human chorionic gonadotropin pregnancy test (serum) at the screening visit and a confirmatory negative serum pregnancy test on Day -1 of each period before receipt of study drug, and meet one of the following criteria:
  • The subject or their partner has undergone surgical sterilization
  • The subject is postmenopausal, defined as 12 consecutive months with no menses without an alternative medical cause and has a documented plasma follicle-stimulating hormone level >40 IU/mL

Who cannot join

  • Subjects meeting any of the following criteria will be excluded from the study:
  • Subject is a female who is pregnant or breastfeeding or planning to become pregnant within 3 months after the last dose of study drug.
  • Subject has a history of any clinically significant conditions including:
  • Asthma treated with oral systemic steroids within the past 6 months
  • Diabetes mellitus (type 1 or 2), with the exception of gestational diabetes
  • Hypertension that is poorly controlled (repeat readings >140 mm Hg systolic and/or >90 mm Hg diastolic)
Show all 52Show fewer
  • Thyroidectomy or thyroid disease that required medication within the past 12 months
  • Serious angioedema episodes within the previous 3 years or requiring medication in the previous 2 years
  • Head trauma resulting in a diagnosis of traumatic brain injury other than concussion
  • Frequent episodes of headache.
  • Subject has received treatment in another clinical study of an investigational drug (or medical device) within 30 days or 5 half-lives (whichever is longer) before the first dose of study drug.
  • Subject has a history of relevant drug and/or food allergies (ie, allergy to TPOXX or excipients, or any significant food allergy that could preclude a standard diet in the study site).
  • Subject has any condition possibly affecting drug absorption (eg, previous surgery on the gastrointestinal tract, including removal of parts of the stomach, bowel, liver, gallbladder, or pancreas, with the exception of appendectomy).
  • Subject has evidence or history of clinically significant allergic (except for untreated, asymptomatic, seasonal allergies at time of the first dose of study drug), hematological, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, or neurological disease. Exceptions to these criteria (eg, stable, mild joint disease unassociated with collagen vascular disease) may be made following discussions with the medical monitor.
  • Subject has a history of cardiac disease, symptomatic or asymptomatic arrhythmias, syncopal episodes, or risk factors for torsades de pointes (eg, heart failure, hypokalemia).
  • Subject has a family history of sudden cardiac death not clearly due to acute myocardial infarction.
  • Subject has a seizure disorder or history of seizures (does not include childhood febrile seizures) or a past history that increases seizure risks such as significant head injury that caused loss of consciousness or other changes in the subject's daily function, concussion, stroke, central nervous system infection or disease, or alcohol or drug abuse or family history of idiopathic seizures.
  • Subject has a history of a peptic ulcer or significant gastrointestinal bleeding.
  • Subject has a bleeding disorder diagnosed by a doctor (eg, factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with blood draws.
  • Subject has a malignancy that is active, or treated malignancy for which there is not reasonable assurance of sustained cure, or malignancy that is likely to recur during the period of the study (subject should be in complete remission for at least 5 years).
  • Subject has neutropenia or other blood dyscrasia determined to be clinically significant by the investigator.
  • Subject has used any of the following prohibited medications from within 7 days (or 5 half lives, whichever is longer) before the first dose of study drug: antidiabetic medication; anticoagulants; anticonvulsants; substrates of the breast cancer resistance protein transporter including methotrexate, mitoxantrone, imatinib, irinotecan, lapatinib, rosuvastatin, sulfasalazine, and topotecan; substrates of CYP2C8 including repaglinide, paclitaxel, Montelukast, pioglitazone, rosiglitazone; and substrates of CYP2C19 including S-mephenytoin, clobazam, diazepam, rabeprazole, voriconazole, lansoprazole, and omeprazole. Medications not listed here that are known (or thought) to be CYP3A4 substrates may be allowed at the investigator's discretion, after consultation with the medical monitor, if administration poses little to no risk to the subject.
  • Subject has a history of drug or alcohol abuse or dependency within the last year before screening.
  • Subject has a current or recent (<30 days before screening) history of clinically significant bacterial, fungal, or mycobacterial infection.
  • Subject has a current clinically significant viral infection.
  • Subject has a known clinically significant chronic viral infection (eg, human T cell lymphotropic virus I or II).
  • Subject has consumed grapefruit or grapefruit juice, Seville orange or Seville orange containing products (eg, marmalade), or caffeine- or xanthine containing products within 48 hours before the first dose of study drug.
  • Subject has used any prescription (excluding hormonal birth control) or over the counter medication (including herbal or nutritional supplements) within 14 days before the first dose of study drug.
  • Subject demonstrates long-term use (≥14 consecutive days) of glucocorticoids including oral or parenteral prednisone or equivalent (>20 mg total dose per day) or high-dose inhaled steroids (>800 mcg/day of beclomethasone dipropionate or equivalent) within the preceding 1 month (low-dose [≤800 mcg/day of beclomethasone dipropionate or equivalent] inhaled and topical steroids are allowed).
  • Subject has donated >450 mL blood or blood components within 30 days before the first dose of study drug. The investigator should instruct subjects who participate in this study to not donate blood or blood components for 4 weeks after the completion of the study.
  • Subject is a smoker or has used nicotine or nicotine containing products (eg, cigarettes, electronic vapor cigarettes, cigars, chewing tobacco, snuff, nicotine patches, or nicotine gum) within 6 months before the first dose of study drug.
  • Subject has consumed pomegranate or pomegranate juice, pomelo fruits or pomelo juice, or alcohol within 72 hours before the first dose of study drug.
  • Subject reports participation in strenuous activity or contact sports within 24 hours before the first dose of study drug.
  • Subject has known hepatitis B or C infection or positive test for hepatitis B surface antigen, hepatitis C virus antibody, or human immunodeficiency virus type 1 or 2 antibodies at screening.
  • Subject has a positive test result for amphetamines (including methamphetamines and ecstasy/methylenedioxymethamphetamine), barbiturates, benzodiazepines, cannabinoids (including tetrahydrocannabinol), cocaine metabolites, opiates (including heroin, codeine, and oxycodone), or alcohol at screening or check-in.
  • Subject has any of the following laboratory test results within 28 days before the first dose of study drug:
  • Estimated serum creatinine clearance (Cockcroft-Gault) <70 mL/min
  • Creatinine in males >1.7 mg/dL and in females >1.4 mg/dL (1.3 times the upper laboratory reference range)
  • Hemoglobin ≤10% of the lower laboratory reference range
  • White blood cell count considered to be clinically significant by the investigator
  • Absolute neutrophil count <1000 cells/mm3
  • Platelets not within ±10% of laboratory reference range
  • Alanine aminotransferase >2.0 times above the upper laboratory reference range
  • Aspartate aminotransferase >2.0 times above the upper laboratory reference range
  • Alkaline phosphatase >20% above the upper laboratory reference range
  • Hemoglobin A1c ≥7.0%
  • Cholesterol ≥300 mg/dL and low density lipoprotein ≥190 mg/dL.
  • Subject has a blood pressure considered to be clinically significant by the investigator. Blood pressure may be retested twice in the sitting position at 5 minute intervals.
  • Subject has a resting heart rate of <40 beats per minute or >110 beats per minute at screening.
  • Subject has an abnormal ECG at screening that is determined by the investigator to be clinically significant.
  • Male subject has a QT interval corrected using Fridericia's formula (QTcF) >450 ms or female subject has a QTcF >470 ms at screening or Day -1.
  • In the opinion of the investigator, the subject is not suitable for entry into the study.

Trial locations and contacts

1 site in 1 country.

United States1 site

  • PPD Phase I Clinic

    Austin, Texas, 78744

Other trials in United States

About this study

Official title: A Post-Marketing Open-Label, 5 Period Crossover, Drug-Drug Interaction Study of Orally Adminstered TPOXX When Co-administered With 4 Different Phosphate Binders in Healthy Subjects

An open-label, drug-drug interaction study with TPOXX and phosphate binders.

Read the detailed description

A postmarketing open-label, 5 period crossover, drug-drug interaction study of orally administered TPOXX when coadministered with 4 different phosphate binders in healthy adult subjects.

Conditions
Smallpox
Being tested
Tecovirimat, sevelamer carbonate oral tablet, sucroferric oxyhydroxide chewable tablet, calcium acetate oral tablet, Lanthanum Carbonate Chewable Tablet
Medical subject headings
Smallpox

What participants receive

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

  • TecovirimatDrug

    Also called TPOXX

    oral antiviral

  • sevelamer carbonate oral tabletDrug

    Also called Renvela

    phosphate binder

  • sucroferric oxyhydroxide chewable tabletDrug

    Also called Velphoro

    phosphate binder

  • calcium acetate oral tabletDrug

    Also called PhosLo

    phosphate binder

  • Lanthanum Carbonate Chewable TabletDrug

    Also called Fosrenol

    phosphate binder

Study groups in NCT04485039
Study groupRoleWhat they receive
TPOXX: oral antiviralOtherSingle oral dose of TPOXX 600 mg
Receives: Drug: Tecovirimat
TPOXX: oral antiviral and sevelamer carbonateOtherSingle oral dose of TPOXX 600 mg co-administered with single oral dose of 1600 mg sevelamer carbonate
Receives: Drug: Tecovirimat; Drug: sevelamer carbonate oral tablet
TPOXX: oral antiviral and sucroferric oxyhydroxideOtherSingle oral dose of TPOXX 600 mg co-administered with single oral dose of 500 mg sucroferric oxyhydroxide chewable tablet
Receives: Drug: Tecovirimat; Drug: sucroferric oxyhydroxide chewable tablet
TPOXX: oral antiviral and calcium acetateOtherSingle oral dose of TPOXX 600 mg co-administered with a single oral dose of 1334 mg calcium acetate
Receives: Drug: Tecovirimat; Drug: calcium acetate oral tablet
TPOXX: oral antiviral and lanthanum carbonateOtherSingle oral dose of TPOXX 600 mg co-administered with a single oral dose of 500 mg lanthanum carbonate chewable tablet
Receives: Drug: Tecovirimat; Drug: Lanthanum Carbonate Chewable Tablet

What is being measured

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

  1. AUC0-inf

    Area under the plasma concentration of vs. time curve (AUC) of TPOXX from 0 extrapolated to infinity

    Measured: Day 3

  2. Cmax

    Cmax - maximum observed plasma concentration of TPOXX

    Measured: Day 3

Secondary outcomes (1)

  1. Adverse Events

    Number of participants with adverse events when TPOXX is coadministered with phosphate binders

    Measured: 59 days

Timeline

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

  1. First posted24 Jul 2020
  2. Study start8 Jun 2022
  3. Primary completion15 Dec 2022
  4. Study completion23 Apr 2023

Resources

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 4
Primary purpose
Other
Allocation
Randomised
Intervention model
Crossover
Model description
5 period crossover
Masking
None (open label)
Enrolment
44 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04485039
Sponsor's protocol ID
SIGA-246-023
Other IDs
HHSO100201800019C
Status last verified
Dec 2024
First submitted
11 May 2020
Last updated
11 Sep 2026
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Phase 4 study testing Tecovirimat, sevelamer carbonate oral tablet and sucroferric oxyhydroxide chewable tablet in people with Smallpox, run by SIGA Technologies at 1 site 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 6 inclusion and 52 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 1 site 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. 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 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.

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 9 Oct 2024). 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?

AUC0-inf (time frame: Day 3). The study lists 2 primary outcomes in all. 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 NCT04485039.

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.

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