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Doxycycline for Asymptomatic Anal LGV Infection in Patients with Asymptomatic Anal LGV Infection

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study is being done in people with asymptomatic anal lymphogranuloma venereum (LGV), which is an infection caused by a type of bacteria that can affect the anal area without causing clear symptoms. The treatment used in the study is doxycycline, taken by mouth as a 7-day course at 200 mg each day. The purpose of the study is to see how well this treatment clears the infection.

People in the study receive the tablet for 7 days and are then followed for about 4 weeks after treatment starts. During this time, anal samples are checked to see whether the infection is still present. The study also looks at the type of bacteria found, whether the infection comes back or was not fully cleared, and whether any signs of resistance to doxycycline are present. A diary is used to record how the medicine is taken, and any side effects are noted.

The study is focused on one disease, asymptomatic anal LGV infection, and one medicine, doxycycline monohydrate. It is a multicentre study, meaning it is carried out at more than one place.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Start of the trial

    At the start of the trial, you are included because you have asymptomatic anal LGV infection. LGV means lymphogranuloma venereum, a type of infection caused by Chlamydia trachomatis.

    Your treatment begins with doxycycline taken by mouth. The medicine is doxycycline monohydrate in 100 mg tablets.

  2. Step 2

    Treatment period

    You take 200 mg of doxycycline once daily for 7 days.

    This means you take two 100 mg tablets by mouth each day for the full 7-day treatment course.

  3. Step 3

    Recording of treatment use

    During the treatment period, you use a diary to record how well you take the medicine as instructed.

    This record is used to check adherence, which means whether you took the medicine as planned.

  4. Step 4

    Follow-up at 4 weeks after treatment start

    At 4 weeks after treatment initiation, you have a follow-up assessment.

    A sample from the anal area is collected again to check whether the infection is still present.

    The main result is called microbiological cure. This means the test on the anal sample is negative for LGV at 4 weeks after treatment started.

    The study also compares the sample from the start of the trial with the sample taken at 4 weeks to assess whether the infection has cleared, returned, or changed.

  5. Step 5

    Laboratory testing of samples

    The anal samples collected at the start of the trial and at 4 weeks are tested in the laboratory.

    The type of Chlamydia trachomatis present may be studied by checking a gene called ompA. This helps identify the strain, which is a specific form of the bacteria.

    The amount of bacteria is also measured at the start and at 4 weeks using a laboratory test that counts DNA copies per microliter.

    The study also checks for possible doxycycline resistance, which means whether the bacteria show signs of being less affected by the medicine.

  6. Step 6

    Safety monitoring

    Any adverse events are recorded during the trial. An adverse event is any unwanted health problem that happens during the study.

    Any serious adverse events are also recorded. These are more severe health problems that require special attention.

Who can join the trial?

10 criteria

  • Age 18 years or older.
  • Male sex at birth, meaning the person was registered as male when born.
  • Written informed consent signed before any study-related examination. This means the person agrees to take part in the study in writing, or a witness or legal representative signs if the person cannot write or cannot give consent.
  • A positive LGV test on an anal sample at screening, using a Nucleic Acid Amplification Test (NAAT), which is a laboratory test that looks for the genetic material of the germ.
  • Have already taken doxycycline for at least 2 days, which equals 400 mg total.
  • Have not taken more than 7 days of doxycycline at 200 mg per day.
  • Be included in the study within 12 days or less after the screening visit.
  • Have no anorectal symptoms, meaning no symptoms in the anus or rectum area, such as pain, discharge, bleeding, or discomfort.
  • Be available to take part in the study and attend follow-up visits for the 4 weeks required.
  • Be covered by a social security scheme, meaning they are registered in a health or social insurance system.

Who cannot join the trial?

8 criteria

  • Proctitis, which means inflammation of the rectum, the lower part of the bowel near the anus.
  • Use of any antibiotic with activity against chlamydia within the last 28 days before the screening visit. This includes fluoroquinolones, macrolides, lincosamides, streptogramins, ketolides, tetracyclines, and rifampicin.
  • Use of doxycycline post-exposure prophylaxis (Doxy-PEP), which means taking doxycycline after a possible exposure to lower the chance of infection.
  • Participation in another study that is testing an antibiotic for a sexually transmitted infection or for another type of infection.
  • Being under a legal protection measure, such as legal guardianship or curatorship, which means another person is legally responsible for decisions, or being unable to give informed consent.
  • Refusal to take part in the study.
  • Not understanding the study goals well enough to agree to participate.
  • Being detained by a court order or an administrative decision.
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Investigated drugs

Doxycycline is an antibiotic taken by mouth. In this trial, it is being tested as a short treatment to clear an anal infection caused by lymphogranuloma venereum (LGV) in people who do not have symptoms. The study is checking whether a 7-day course of doxycycline can remove the infection and lead to a microbiological cure four weeks after treatment starts.

What is already known about the treatment

Doxycycline monohydrate - Doxycycline monohydrate is an antibiotic taken by mouth as a tablet, and in this trial it is used as a 200 mg daily oral treatment. It is a well-known medicine in current medical practice and is widely described in medical literature, especially for treating certain bacterial infections. Its main uses include infections caused by susceptible bacteria, such as some sexually transmitted infections, respiratory infections, and skin infections. At the molecular level, it works by blocking the ability of bacteria to make proteins they need to grow and multiply, and it is classified as a tetracycline antibiotic.

Investigated diseases

Asymptomatic anal lymphogranuloma venereum infection - This is an infection of the anus and rectum caused by certain types of Chlamydia trachomatis. It can be present without symptoms, so the infection may not be noticed at first. Over time, it may remain silent or progress to local inflammation and irritation in the anal area.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-524978-42-00Estimated enrolment120 patientsSponsorCentre Hospitalier Universitaire De Bordeaux

sourced from the EU Clinical Trials Register and site verification

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