CTN 313: The DaDHS Trial
A randomized, placebo-controlled trial of oral doxycycline for the prevention of syphilis in HIV-positive men who have sex with men (MSM)
About the Study
With the success of PrEP in HIV prevention among gay, bisexual, and other men who have sex with men (gbMSM), CTN 313 is seeking to determine whether the use of doxycycline is a feasible option for syphilis PrEP in this population. Doxycycline is an antibiotic that has been commercially available since the 1960s, and is often used to prevent malaria and treat skin conditions such as acne.
One previous pilot study has shown some promise for the use of doxycycline as syphilis PrEP; however, with the rising rate of syphilis and disproportionate impact on gbMSM living with HIV, there is an urgent need to conduct further studies to examine this question. CTN 313 (The DaDHS Trial) is a pilot, randomized placebo-controlled trial to determine the feasibility and tolerability of using daily doxycycline as syphilis PrEP in gbMSM living with HIV.
Background
Up to 75% of early syphilis infections occur in gbMSM and infection rates in gbMSM living with HIV are higher than those not living with HIV. Syphilis can have a significant impact on HIV management, as syphilis may increase HIV viral load levels in those who are virologically suppressed. Genital ulcers, which form in the early stages of syphilis infection, increase the risk of HIV transmission and acquisition.
Study Approach
CTN 313 is a prospective, double-blind, randomized, controlled multi-centre pilot trial of daily doxycycline versus placebo for the prevention of syphilis among gbMSM living with HIV. The participants, who will be recruited from clinical sites in Vancouver and Toronto, will receive either daily doxycycline or placebo for 48 weeks. During this time, they will attend visits every three months to complete questionnaires on items such as syphilis PrEP acceptability, drug adherence, sexual risk behaviours, and self-reported STIs. Participants will also attend a visit at week 60 to check for any infections that may have not yet been diagnosed at week 48.
Participant safety will be assessed through clinical observation and monitoring of routine hematology and biochemistry, and the study will undergo quarterly reviews by an external study monitor, as part of the safety monitoring plan.
Eligibility Requirements
Required
- Males, ≥ 18 years of age at baseline
- Self-reported gbMSM status
- Self-reported condomless anal sex with a man within the last six months
- Laboratory documentation of HIV-1 infection
- Prior diagnosis of early/infectious syphilis within preceding 36 months
- Able to provide informed consent
Not Allowed
- Known allergy or intolerance to doxycycline or tetracyclines
- A known diagnosis of myasthenia gravis
- Use of medications that could lower doxycycline levels, including barbiturates, phenytoin and carbamazepine
- Use of isotretinoin
- Any individual capable of getting pregnant
Investigators
Here’s who is leading this study.
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Email ctninfo@ctnplus.ca.
Participating Sites
BCCDC Provincial STI clinic (West 12th Clinic)
- 655 West 12th Avenue, Vancouver, BC V5Z 4R4
Bute Street Clinic
- 1128 Hornby Street, Vancouver, BC V6Z 2L4
Positive Care Clinic (PCC) at St. Michael’s Hospital
- 4th Floor, St. Michael’s Hospital, 30 Bond Street, Toronto, ON M5B 1W8
- Site Investigator
-
12345 Street Name,
City Name, BC V3M 9J3
- Contact Person
- contact@email.com
- 1 (604) 555-9999
- Site Investigator
-
12345 Street Name,
City Name, BC V3M 9J3
- Contact Person
- contact@email.com
- 1 (604) 555-9999
- Site Investigator
-
12345 Street Name,
City Name, BC V3M 9J3
- Contact Person
- contact@email.com
- 1 (604) 555-9999
- Site Investigator
-
12345 Street Name,
City Name, BC V3M 9J3
- Contact Person
- contact@email.com
- 1 (604) 555-9999
- Site Investigator
-
12345 Street Name,
City Name, BC V3M 9J3
- Contact Person
- contact@email.com
- 1 (604) 555-9999
- Site Investigator
-
12345 Street Name,
City Name, BC V3M 9J3
- Contact Person
- contact@email.com
- 1 (604) 555-9999
- Site Investigator
-
12345 Street Name,
City Name, BC V3M 9J3
- Contact Person
- contact@email.com
- 1 (604) 555-9999
- Site Investigator
-
12345 Street Name,
City Name, BC V3M 9J3
- Contact Person
- contact@email.com
- 1 (604) 555-9999
- Site Investigator
-
12345 Street Name,
City Name, BC V3M 9J3
- Contact Person
- contact@email.com
- 1 (604) 555-9999