Substance UseT-REXNCT07505875
Pre-implementation Study to Develop Trans-tailored Services for Transgender Persons in Relation to chemsEX
An observational study of Substance Use and HIV Prevention, run by Institute of HIV Research and Innovation Foundation, Thailand at 1 site in Thailand.
Trial summary
The study is a pre-implementation cross-sectional study exploring chemsex behaviors among transgender persons and gathering perspectives from multiple stakeholders to inform the development of transgender-tailored harm reduction services. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Substance Use, HIV Prevention, Sexually Transmitted Infections (STIs)
- What is being tested?
- Understanding of chemsex patterns, impacts, and service needs among transgender persons
- Type of treatment
- Lifestyle or therapy programme
- How many people
- 50 participants
- Where
- 1 siteThailand
- Study dates
- 1 May 2024to 1 May 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
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 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: G1: Transgender chemsex users * Transgender women or transgender men * Current or former chemsex users G2: Family / partners * Family members, friends, or partners of transgender persons * Never engaged in chemsex * Able to communicate in Thai G3: Stakeholders * Healthcare providers, policymakers, law enforcement, counselors, community leaders * Involved in chemsex-related care/policy * Able to communicate in Thai
Who may be able to join
- Age ≥18 years
- Able to communicate in Thai
- Provide informed consent
Who cannot join
- Unable to participate in in-depth interview (IDI) (online or onsite)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Thailand1 site, 1 recruiting
- Recruiting
Tangerine Clinic, Institute of HIV Research and Innovation
Pathum Wan, Bangkok, 10330
Nittaya Phanuphak, MD.,Ph.D., +66 2 1605371, nittaya.p@ihri.org
Jakkrapatara Boonruang, MD, +66 2 1605371, jakkrapatara.b@ihri.org
About this study
The study is a pre-implementation cross-sectional study exploring chemsex behaviors among transgender persons and gathering perspectives from multiple stakeholders to inform the development of transgender-tailored harm reduction services.
Read the detailed description
This study is designed under the EPIS framework (Exploration and Preparation phases) to better understand chemsex use among transgender populations in Thailand.
The study aims to:
- Explore reasons and patterns of chemsex use
- Assess positive and negative impacts (physical, sexual, mental, and socio-legal)
- Identify key components, barriers, and facilitators for developing transgender-tailored chemsex services
Data will be collected using a mixed-methods approach, including:
- In-depth interviews (IDIs)
- Self-administered questionnaires Participants include transgender chemsex users, their family/partners, and stakeholders such as healthcare providers and policymakers.
- Being tested
- Understanding of chemsex patterns, impacts, and service needs among transgender persons
- Keywords
- Chemsex, Harm reduction
- Medical subject headings
- Substance-Related Disorders, Sexually Transmitted Diseases, Chemsex, Harm Reduction
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Understanding of chemsex patterns, impacts, and service needs among transgender personsBehavioural
: During study period (single visit within ~12 months study duration)
| Study group | Role | What they receive |
|---|---|---|
| Transgender Chemsex Users | Transgender women and transgender men who are current or former chemsex users. Participants will take part in semi-structured in-depth interviews (IDIs) exploring chemsex behaviors, patterns of use, perceived impacts, and needs for transgender-tailored harm reduction services. Receives: Behavioral: Understanding of chemsex patterns, impacts, and service needs among transgender persons | |
| Family Members, Friends, or Partners | Family members, friends, or partners of transgender persons who have not engaged in chemsex. Participants will provide perspectives on the social, behavioral, and relational impacts of chemsex and support needs. Receives: Behavioral: Understanding of chemsex patterns, impacts, and service needs among transgender persons | |
| Stakeholders | Stakeholders including healthcare providers, policy makers, law enforcement officers, counselors, public health professionals, and community leaders involved in care, policy, or regulation related to chemsex. Participants will be interviewed to identify system-level facilitators and barriers to implementation of services. Receives: Behavioral: Understanding of chemsex patterns, impacts, and service needs among transgender persons |
What is being measured
The primary outcome is the main question the study is designed to answer.
Key themes on chemsex behaviors and service needs
Qualitative themes identified from semi-structured in-depth interviews, including:
- Reasons for engaging in chemsex
- Patterns of substance use
- Perceived positive and negative impacts
- Harm reduction practices
- Needs for transgender-tailored services Themes will be identified using thematic analysis.
Measured: At interview (single time point)
Barriers and facilitators to implementation of transgender-tailored chemsex services
Barriers and facilitators to implementation identified using the Consolidated Framework for Implementation Research (CFIR) domains based on stakeholder and participant interviews.
Measured: At interview (single time point)
Chemsex-related behavioral and demographic characteristics
Descriptive characteristics of participants, including demographic data, substance use patterns, and behavioral risk factors collected via questionnaire.
Measured: At interview (single time point)
HIV-related stigma score
HIV-related stigma will be assessed using the HIV Stigma Scale (HSS). The HSS is a validated instrument measuring multiple domains of stigma, including personalized stigma, disclosure concerns, negative self-image, and concerns with public attitudes.
The total score ranges from 40 to 160, with higher scores indicating greater levels of HIV-related stigma (worse outcome)
Score (range: 40-160)
Measured: Baseline, Month 3, Month 6
Transgender-related stigma score
Transgender-related stigma will be measured using the Transgender Identity Survey (TIS) (or instrument used in the protocol). This scale assesses experiences of stigma, discrimination, and internalized transphobia.
Unit of Measure:
Score (range: 20-100)
Measured: Baseline, Month 3, Month 6
PrEP adherence (self-reported adherence score)
Self-reported adherence will be measured using a standardized adherence questionnaire assessing the number of doses taken over the past 30 days.
Scores range from 0 to 100%, with higher percentages indicating better adherence (better outcome).
In addition, adherence will be objectively assessed using tenofovir diphosphate (TFV-DP) concentrations in dried blood spots.
Unit of Measure:
Percentage (%) Drug concentration (fmol/punch)
Measured: Baseline, Month 3, Month 6
Intervention acceptability score
Description:
Acceptability will be assessed using the System Usability Scale (SUS). The SUS is a 10-item questionnaire with scores ranging from 0 to 100, with higher scores indicating better usability and acceptability (better outcome).
Score (range: 0-100)
Measured: Month 3
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Apr 2026
- Study start1 May 2024
- Primary completion1 Dec 2026 (estimated)
- Study completion1 May 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Substance UseStudies 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
- Observational
- Observational model
- Other
- Time perspective
- Cross-sectional
- Enrolment
- 50 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Institute of HIV Research and Innovation Foundation, Thailand
- Sponsor type
- University, hospital or other
- Collaborators
- amfAR, The Foundation for AIDS Research
- Responsible party
- Sponsor
- Investigators
- Nittaya Phanuphak, MD,PhD., Principal investigator, Institute of HIV Research and Innovation (IHRI)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07505875
- Sponsor's protocol ID
- IHRI028
- Acronym
- T-REX
- Status last verified
- Mar 2026
- First submitted
- 22 Mar 2026
- Last updated
- 6 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pre-implementation Study to Develop Trans-tailored Services for Transgender Persons in Relation to chemsEX
- ClinicalTrials.gov ID
- NCT07505875
- Acronym / sponsor ID
- T-REX / IHRI028
- Keywords
- Chemsex, Harm reduction
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 50 participants (estimated)
- Lead sponsor
- Institute of HIV Research and Innovation Foundation, ThailandUniversity, hospital or other
- Collaborators
- amfAR, The Foundation for AIDS Research
- Study start
- 1 May 2024 (actual)
- Primary completion
- 1 Dec 2026 (estimated)
- Study completion
- 1 May 2027 (estimated)
- First posted
- 1 Apr 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The study is a pre-implementation cross-sectional study exploring chemsex behaviors among transgender persons and gathering perspectives from multiple stakeholders to inform the development of transgender-tailored harm reduction services.
Detailed description
This study is designed under the EPIS framework (Exploration and Preparation phases) to better understand chemsex use among transgender populations in Thailand.
The study aims to:
- Explore reasons and patterns of chemsex use
- Assess positive and negative impacts (physical, sexual, mental, and socio-legal)
- Identify key components, barriers, and facilitators for developing transgender-tailored chemsex services
Data will be collected using a mixed-methods approach, including:
- In-depth interviews (IDIs)
- Self-administered questionnaires Participants include transgender chemsex users, their family/partners, and stakeholders such as healthcare providers and policymakers.
Study design
- Observational model
- Other
- Time perspective
- Cross-sectional
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Transgender Chemsex Users | – | Behavioral: Understanding of chemsex patterns, impacts, and service needs among transgender personsTransgender women and transgender men who are current or former chemsex users. Participants will take part in semi-structured in-depth interviews (IDIs) exploring chemsex behaviors, patterns of use, perceived impacts, and needs for transgender-tailored harm reduction services. |
| Family Members, Friends, or Partners | – | Behavioral: Understanding of chemsex patterns, impacts, and service needs among transgender personsFamily members, friends, or partners of transgender persons who have not engaged in chemsex. Participants will provide perspectives on the social, behavioral, and relational impacts of chemsex and support needs. |
| Stakeholders | – | Behavioral: Understanding of chemsex patterns, impacts, and service needs among transgender personsStakeholders including healthcare providers, policy makers, law enforcement officers, counselors, public health professionals, and community leaders involved in care, policy, or regulation related to chemsex. Participants will be interviewed to identify system-level facilitators and barriers to implementation of services. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- G1: Transgender chemsex users * Transgender women or transgender men * Current or former chemsex users G2: Family / partners * Family members, friends, or partners of transgender persons * Never engaged in chemsex * Able to communicate in Thai G3: Stakeholders * Healthcare providers, policymakers, law enforcement, counselors, community leaders * Involved in chemsex-related care/policy * Able to communicate in Thai
Key inclusion criteria (3 listed)
- Age ≥18 years
- Able to communicate in Thai
- Provide informed consent
Key exclusion criteria (1 listed)
- Unable to participate in in-depth interview (IDI) (online or onsite)
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 |
|---|---|---|
| Understanding of chemsex patterns, impacts, and service needs among transgender persons: During study period (single visit within ~12 months study duration) | Behavioural | Family Members, Friends, or Partners, Stakeholders, Transgender Chemsex Users |
Primary outcome
Key themes on chemsex behaviors and service needs
Time frame: At interview (single time point)
Qualitative themes identified from semi-structured in-depth interviews, including: * Reasons for engaging in chemsex * Patterns of substance use * Perceived positive and negative impacts * Harm reduction practices * Needs for transgender-tailored services Themes will be identified using thematic analysis.
Barriers and facilitators to implementation of transgender-tailored chemsex services
Time frame: At interview (single time point)
Barriers and facilitators to implementation identified using the Consolidated Framework for Implementation Research (CFIR) domains based on stakeholder and participant interviews.
Chemsex-related behavioral and demographic characteristics
Time frame: At interview (single time point)
Descriptive characteristics of participants, including demographic data, substance use patterns, and behavioral risk factors collected via questionnaire.
HIV-related stigma score
Time frame: Baseline, Month 3, Month 6
HIV-related stigma will be assessed using the HIV Stigma Scale (HSS). The HSS is a validated instrument measuring multiple domains of stigma, including personalized stigma, disclosure concerns, negative self-image, and concerns with public attitudes. The total score ranges from 40 to 160, with higher scores indicating greater levels of HIV-related stigma (worse outcome) Score (range: 40-160)
Transgender-related stigma score
Time frame: Baseline, Month 3, Month 6
Transgender-related stigma will be measured using the Transgender Identity Survey (TIS) (or instrument used in the protocol). This scale assesses experiences of stigma, discrimination, and internalized transphobia. Unit of Measure: Score (range: 20-100)
PrEP adherence (self-reported adherence score)
Time frame: Baseline, Month 3, Month 6
Self-reported adherence will be measured using a standardized adherence questionnaire assessing the number of doses taken over the past 30 days. Scores range from 0 to 100%, with higher percentages indicating better adherence (better outcome). In addition, adherence will be objectively assessed using tenofovir diphosphate (TFV-DP) concentrations in dried blood spots. Unit of Measure: Percentage (%) Drug concentration (fmol/punch)
Intervention acceptability score
Time frame: Month 3
Description: Acceptability will be assessed using the System Usability Scale (SUS). The SUS is a 10-item questionnaire with scores ranging from 0 to 100, with higher scores indicating better usability and acceptability (better outcome). Score (range: 0-100)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Apr 2026.
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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.
Nittaya Phanuphak, MD,PhD. principal investigator
Institute of HIV Research and Innovation (IHRI)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Substance Use and HIV Prevention, run by Institute of HIV Research and Innovation Foundation, Thailand at 1 site in Thailand.
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 3 inclusion and 1 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: looking for participants now, as of the sponsor's last update on 6 Apr 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 Thailand. 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.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Nittaya Phanuphak, MD,PhD. (6681 825 3544, nittaya.p@ihri.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Key themes on chemsex behaviors and service needs (time frame: At interview (single time point)). The study lists 7 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 6 Apr 2026.