A Phase 3 interventional study of Tecovirimat and Placebo in Monkeypox, sponsored by Marina Klein. Suspended at 3 sites in Canada. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-03-04.
Sponsored by Marina Klein · Phase 3, Interventional, and Treatment
PLATINUM-CAN is a parallel collaborative trial linked with the sister trial PLATINUM led by Oxford University. PLATINUM-CAN is a multi-centre, randomized, placebo-controlled trial of Tecovirimat in non-hospitalized patients with presumptive or PCR confirmed monkeypox infection. The study will provide evidence on the efficacy and safety of Tecovirimat for laboratory-confirmed monkeypox in outpatients with monkeypox infection and determine the feasibility of conducting interventional monkeypox trials in Canada.
In order to generate needed therapeutic efficacy evidence rapidly, international collaboration is essential. PLATINUM-CAN is a parallel collaborative trial linked with the sister trial PLATINUM led by Oxford University. Given the rapidly evolving epidemic and important differences in healthcare contexts and public health systems between countries that could impact the number of cases and access to diagnosis and treatment, a Canadian study is warranted to assess the feasibility and acceptability of conducting large scale interventional monkeypox trials in Canada. Such a focused trial also allows for the opportunity to explore a number of secondary objectives that can address concerns raised during consultation with Canadian community members (e.g., resolution of pain, quality of life) and validate use of self-assessed primary outcomes using blinded photography assessment.
The trial is pragmatic and minimizes number of visits, tests performed and contacts with the healthcare system through use of self-assessment diaries and self-testing. Lesion and/or throat swabs taken as part of standard care will be sent for detection of monkeypox virus DNA by PCR to local public health/provincial laboratories for initial screening (using panorthopox DNA testing) and confirmation with monkeypox specific PCR either locally or by National Microbiology Laboratory. The protocol allows for a broad range of patients to be enrolled. The trial has been designed so that it can accommodate patients who may be assessed in a variety of medical settings (e.g., hospital emergency rooms, outpatient HIV and infectious diseases clinics, community sexual health clinics, primary care, or through public health services). Similarly, we will ensure our trial design is able to contribute to global efforts such as the core protocol for the evaluation of treatments for human monkeypox (led by the Institut National de Recherche Biomédicale (INRB)/ANRS/NIAID in collaboration with WHO) and the AIDS Clinical Trials Group (ACTG) STOMP protocol.
As a feasibility study, PLATINUM CAN is underpowered for evaluating a primary endpoint of time to active lesion resolution. To achieve full study power, results will be combined with the sister study, PLATINUM-UK (n=500), being conducted at Oxford University, UK of similar design using a pre-planned individual patient meta-analysis. In addition to feasibility outcomes, the trial will evaluate the correlation between the time to active and complete resolution of lesions between self-report and blinded photographic validation from an adjudication committee, in consenting participants.
72 studies on the registry are indexed under Mpox, Monkeypox; 30 are open to participants now.
This study's planned enrollment of 120 is below the median of 305 across 36 interventional studies indexed under Mpox, Monkeypox.
Browse Mpox, Monkeypox studies →Marina Klein is the lead sponsor of 2 studies on the registry; none are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Laboratory-confirmed or presumptive monkeypox infection:
Laboratory-confirmed monkeypox infection is defined as determined by PCR, culture, or antigen test obtained from a sample collected from blood, oropharynx, anal or skin lesion within 4 days of randomization OR
Presumptive diagnosis:
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Tecovirimat (TPOXX®) Capsules, 200 mg (as tecovirimat monohydrate) administered as 600 mg (three 200 mg capsules) taken twice daily orally, every 12 hours, within 30 minutes after a full meal of moderate or high fat (approximately 25 g of fat) for 14 days
Drug: Tecovirimat
Identical placebo supplied by SIGA Technologies Inc.
Drug: Placebo
600 mg po BID
Also known as: TPOXX
identical placebo 600 mg po BID
Time to active lesion resolution
Time (days) to active lesion resolution, defined as the first day on which all skin lesions are scabbed or desquamated (and mucosal lesions healed).
Time frame: Up to 28 days after randomization
Feasibility and acceptability of conducting a pragmatic phase 3 interventional trial for outpatients with Monkeypox in Canada
Number of eligible patients per month and proportion randomized
Time frame: 4 months
Time to complete lesion resolution
Time (days) to complete lesion resolution, defined as the first day on which all lesions are completely resolved (all scabs dropped off and intact skin remains underneath, mucosal lesions healed)
Time frame: Up to 28 days after randomization
Time to negative throat swab viral culture
Defined as time to consistently negative culture for monkeypox virus on throat swab
Time frame: Days 7, 14, 21, and 28
Time to negative skin or mucosa swab viral culture
Defined as time to consistently negative culture for monkeypox virus on swab of most recent active skin or mucosa
Time frame: Days 7, 14, 21, and 28
Secondary feasibility outcomes
the proportion who adhere to at least 85% of daily questionnaires and self-sampling, and the proportion of participants who are able to complete all protocol procedures
Time frame: 4 months
Clinical status
The ordinal scale is a) all lesions completely resolved (all scabs dropped off and intact skin remains underneath, mucosal lesions healed), b) all active lesions resolved (all lesions scabbed or desquamated, mucosal lesions healed), c) active lesions persist but no new lesions, d) new active lesions.
Time frame: day 7, 14, 21 and 28
Throat swab monkeypox DNA levels
Change from baseline in monkeypox virus DNA concentration in throat swabs
Time frame: day 7, 14, 21 and 28
Hospitalization rates
Number (%) of patients admitted to hospital for a complication of monkeypox, overall and by type
Time frame: study duration
Time to sustained absence of use of analgesia
defined as time to consistently reporting no use of analgesia
Time frame: Up to 28 days post randomization
Assessment of safety
1. Number (%) of patients suffering serious adverse events (overall and by type) up to 28 days of randomization 2. Number (%) of patients suffering adverse events of special interest (overall and by type) up to 28 days of randomization 3. Number (%) of patients suffering death, overall and by cause
Time frame: Duration of study
Time to resolution of pain
Time to resolution of pain using an assessment for proctitis (rectal) and/or lesional pain comparing tecovirimat relative to placebo
Time frame: 28 days
Rate of improvement in overall quality of well-being
Change in EuroQol- 5 Dimension (EQ-5D) Quality Of Life scale
Time frame: 28 days
Validation of self reported time to active lesion resolution
Correlation between the time to active and complete resolution of lesions, in consenting participants, between self-report and blinded photographic validation from an adjudication committee
Time frame: 28 days
This study is suspended, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Tecovirimat
Marina Klein