Doxycycline for Chlamydia

Recruiting in Palo Alto (17 mi)

+12 other locations

Overseen by Julia Dombrowski, MD, MPH

Age: Any Age

Sex: Any

Travel: May Be Covered

Time Reimbursement: Varies

Trial Phase: Phase 4

Recruiting

Sponsor: National Institute of Allergy and Infectious Diseases (NIAID)

Must not be taking: Antibiotics, Retinoids, Barbiturates, others

Disqualifiers: Pelvic pain, Pregnancy, Allergy, others

No Placebo Group

Prior Safety Data

Approved in 5 Jurisdictions

Trial Summary

What is the purpose of this trial?

This is a Phase 4 blinded, randomized, active-controlled, non-inferiority trial. Persons of any gender identity will be eligible. Final evaluable population will include a minimum 596 individuals: 298 persons assigned female sex at birth (AFAB) with confirmed urogenital chlamydia (CT) and 298 persons assigned male at birth (AMAB) with confirmed rectal chlamydia (CT). Approximately 664 participants will be enrolled to achieve a minimum 596 participants who contribute primary outcome data. Randomization will be stratified by study site and sex at birth: 332 persons assigned female sex at birth (AFAB) and 332 persons assigned male sex at birth (AMAB). Participants will be randomized 1:1 to a 3-day regimen of doxycycline or a 7-day regimen of doxycycline. The study blind will be maintained by providing 7 days of identical pre-filled blister packs, one with 3 days of active treatment and 4 days of placebo, and the other with 7 days of active treatment. Participants will be asked to return 28 days after randomization (at day 29), at which time they will be re-tested for chlamydia (CT) using a laboratory-based chlamydia (CT) nucleic acid amplification test (NAAT).

Will I have to stop taking my current medications?

The trial does not specify if you must stop taking your current medications, but you cannot use certain antibiotics or medications that interfere with doxycycline during the study. If you are on any of these, you may need to stop them before joining the trial.

What data supports the effectiveness of the drug doxycycline for treating Chlamydia infections?

Research shows that doxycycline is highly effective in treating Chlamydia infections, with studies reporting a 100% bacteriological eradication rate and excellent clinical efficacy in patients with chlamydial infections. It is also well-tolerated by most patients. ^{1 2 3 4 5}

Is doxycycline safe for treating Chlamydia infections?

Doxycycline is generally considered safe for treating Chlamydia infections, with studies showing no side effects in some cases. However, it can cause gastrointestinal issues like abdominal pain, nausea, and vomiting, especially in certain formulations, but enteric-coated versions may reduce these reactions. ^{1 3 6 7 8}

How does the drug doxycycline differ from other treatments for Chlamydia?

Doxycycline is unique because it is highly effective in eradicating Chlamydia trachomatis, with a 100% cure rate in some studies, and it is generally well-tolerated without significant side effects. It is administered orally, typically at a dosage of 200 mg per day for two weeks, and has shown rapid symptom relief and pathogen eradication. ^{1 8 9 10 11}

Research Team

Christine Khosropour, PhD, MPH

Principal Investigator

University of Washington

Julia Dombrowski, MD, MPH

Principal Investigator

University of Washington

Eligibility Criteria

This trial is for individuals aged 16 or older with untreated chlamydia, willing to take a week-long drug regimen and abstain from unprotected sex during the study. Pregnant or breastfeeding individuals, those on certain medications, planning pregnancy, moving away soon, or with severe allergies to tetracyclines are excluded.

Inclusion Criteria

I have untreated chlamydia, confirmed by a test within the last 14 days.

Willing and able to understand and provide written informed consent before initiation of any study procedures

Willing and able to adhere to planned study procedures for all study visits

Exclusion Criteria

Known moderate to severe allergy to tetracyclines, excluding tetracycline-induced photosensitivity

I plan to take antibiotics that work against chlamydia during the study.

I experience lower abdominal or pelvic pain and may have pelvic inflammatory disease.

Trial Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants are randomized to receive either a 3-day or 7-day regimen of doxycycline

7 days

1 visit (in-person) for randomization

Follow-up

Participants are monitored for microbiologic cure and safety, with a re-test for chlamydia at Day 29

4 weeks

1 visit (in-person) at Day 29

Treatment Details

Interventions

• Doxycycline (Tetracycline Antibiotic)

Trial Overview The study compares two doxycycline treatment regimens for chlamydia: one group takes it for 3 days followed by a placebo for 4 days; the other takes it for a full week. Participants are randomly assigned to these groups and re-tested after four weeks using NAAT.

Participant Groups

Group I: Arm 3 Experimental Treatment 2 Interventions

100 mg of doxycycline orally administered twice daily for 3 and 4 days of placebo days to assigned male at birth (AMAB) participants \>/= 16 years old with confirmed rectal Chlamydia trachomatis (CT). N=166.

Group II: Arm 1 Experimental Treatment 2 Interventions

100 mg of doxycycline orally administered twice daily for 3 days and 4 days of placebo to assigned female at birth (AFAB) participants \>/= 16 years old with confirmed urogenital Chlamydia trachomatis (CT). N=166.

Group III: Arm 2 Active Control 1 Intervention

100 mg of doxycycline orally administered twice daily for 7 days to assigned female at birth (AFAB) participants \>/= 16 years old with confirmed urogenital Chlamydia trachomatis (CT). N=166.

Group IV: Arm 4 Active Control 1 Intervention

100 mg of doxycycline orally administered twice daily for 7 days to assigned male at birth (AMAB) participants \>/= 16 years old with confirmed rectal Chlamydia trachomatis (CT). N=166.

Doxycycline is already approved in Canada, Japan for the following indications:

Approved in Canada as Doxycycline for:

• Acne
• Bacterial infections
• Chlamydia
• Gonorrhea
• Lyme disease
• Malaria
• Pneumonia
• Rosacea
• Urinary tract infections

Approved in Japan as Doxycycline for:

• Acne
• Bacterial infections
• Chlamydia
• Gonorrhea
• Lyme disease
• Malaria
• Pneumonia
• Rosacea
• Urinary tract infections

Who Is Running the Clinical Trial?

National Institute of Allergy and Infectious Diseases (NIAID)

Lead Sponsor

Trials

3,361

Recruited

5,516,000+

Dr. Jeanne Marrazzo

National Institute of Allergy and Infectious Diseases (NIAID)

Chief Executive Officer since 2023

MD, MPH

Dr. H. Clifford Lane

National Institute of Allergy and Infectious Diseases (NIAID)

Chief Medical Officer

MD

Emory University

Lead Sponsor

Trials

1,735

Recruited

2,605,000+

Dr. R. Donald Harvey

Emory University

Chief Medical Officer

MD from Emory University School of Medicine

Dr. George Painter

Emory University

Chief Executive Officer since 2013

PhD in Synthetic Organic Chemistry from Emory University

Infectious Diseases Clinical Research Consortium

Collaborator

Trials

1

Recruited

660+

Findings from Research

Doxycycline (200 mg/day for 2 weeks) effectively eradicated Chlamydia trachomatis in 89% of patients by the 3rd day and maintained a 100% eradication rate by the 14th day, demonstrating its efficacy in treating nongonococcal urethritis.

The treatment was well-tolerated with no reported side effects, and a significant reduction in symptoms was observed, with 83% of patients symptom-free by the 7th day and 100% by the 14th day.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Clinical studies on doxycycline in the treatment of nongonococcal urethritis by Chlamydia trachomatis]. Ito, Y., Katoh, N., Takeda, A., et al.[2020]

In a study of 25 men with non-specific urethritis/adnexitis treated with 200 mg of doxycycline daily for 10 days, 67% of patients were cured and 25% showed improvement, indicating the efficacy of doxycycline in treating chronic infections.

Doxycycline achieved microbiological cure rates of 100% for chlamydial infections, 67% for mycoplasma, 80% for anaerobes, and 57% for aerobes, demonstrating its effectiveness against a range of pathogens, although one patient experienced side effects leading to treatment discontinuation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Doxycycline in the treatment of non-specific urethritis and/or prostatitis]. Hofstetter, A., Friesen, A.[2013]

Doxycycline (DOXY) was found to be clinically effective in treating chlamydial infections in 14 patients, with excellent efficacy observed in 12 evaluable patients after a treatment duration of 4 to 19 days.

No side effects related to doxycycline were reported, indicating a favorable safety profile for this antibiotic in the treatment of Chlamydia trachomatis infections.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[A clinical evaluation of doxycycline in the treatment of genitourinary infections caused by Chlamydia trachomatis]. Sumii, T., Ohnishi, Y., Mita, N., et al.[2016]

In a study of 211 patients, roxithromycin showed a high bacteriological eradication rate of 92.7% for chlamydial infections, comparable to doxycycline's 100%, indicating its effectiveness as a treatment option.

Roxithromycin was associated with fewer drug-related side effects (19%) compared to doxycycline (35%), suggesting it may be a better-tolerated alternative for patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Roxithromycin compared to doxycycline in the treatment of genital chlamydial infection and non-specific urethritis. Lidbrink, P., Bygdeman, S., Emtestam, L., et al.[2017]

In a study of 80 heterosexual men with chlamydial urethritis, both pivampicillin and doxycycline were found to be effective treatments, with doxycycline showing slightly better outcomes in terms of clinical failures and persistent infection rates.

Specifically, 12.5% of patients treated with pivampicillin experienced treatment failure compared to 5.1% for doxycycline, although the differences were not statistically significant, indicating that both medications are viable options for treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Pivampicillin versus doxycycline in the treatment of chlamydial urethritis in men. Lassus, AB., Virrankoski, T., Reitamo, SJ., et al.[2013]

Doxycycline (Doxy-PEP) has been shown to effectively prevent bacterial sexually transmissible infections (STIs) like chlamydia, gonorrhoea, and syphilis in men who have sex with men with a history of multiple STIs.

Concerns remain regarding potential adverse effects of Doxy-PEP, including the risk of developing antimicrobial resistance and disrupting the microbiome, which clinicians need to discuss with patients considering this preventive treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Interim position statement on doxycycline post-exposure prophylaxis (Doxy-PEP) for the prevention of bacterial sexually transmissible infections in Australia and Aotearoa New Zealand - the Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine (ASHM). Cornelisse, VJ., Ong, JJ., Ryder, N., et al.[2023]

In a study of 367 patients with Chlamydia trachomatis infections, both doxycycline (100 mg) and spiramycin (1 g) were found to be highly effective, with cure rates of 100% for doxycycline and 98% for spiramycin, indicating that both treatments are viable options.

Spiramycin was associated with a higher incidence of dysethesias in female patients, although these side effects resolved after treatment, suggesting that while effective, further research is needed to explore its safety profile, especially in shorter treatment durations and during pregnancy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparison of spiramycin and doxycycline for treatment of Chlamydia trachomatis genital infections. Dylewski, J., Clecner, B., Dubois, J., et al.[2021]

A systematic evaluation of Chlamydia trachomatis serovars D through K showed that all tested serovars have similar susceptibility to various antibiotics, including levofloxacin, erythromycin, doxycycline, clarithromycin, and azithromycin.

This study confirms previous findings that C. trachomatis exhibits homogeneous susceptibility patterns to these antimicrobial agents, suggesting consistent treatment options across different serovars.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

In vitro activities of several antimicrobial agents against recently isolated and genotyped Chlamydia trachomatis urogenital serovars D through K. Donati, M., Di Francesco, A., D'Antuono, A., et al.[2021]

In a study involving 30 calves with respiratory Chlamydia psittaci infection, the combination therapy of doxycycline and rifampicin did not show a significant advantage over doxycycline alone in terms of disease severity or resolution time.

All treatment groups, including untreated controls, ultimately cleared the infection within 2 weeks, indicating that while doxycycline is the standard treatment, the addition of rifampicin did not enhance efficacy in this model.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Evaluation of antimicrobial treatment in a bovine model of acute Chlamydia psittaci infection: tetracycline versus tetracycline plus rifampicin. Prohl, A., Lohr, M., Ostermann, C., et al.[2015]

References

1. Japan pubmed.ncbi.nlm.nih.gov

[Clinical studies on doxycycline in the treatment of nongonococcal urethritis by Chlamydia trachomatis]. [2020]

2. Germany pubmed.ncbi.nlm.nih.gov

[Doxycycline in the treatment of non-specific urethritis and/or prostatitis]. [2013]

3. Japan pubmed.ncbi.nlm.nih.gov

[A clinical evaluation of doxycycline in the treatment of genitourinary infections caused by Chlamydia trachomatis]. [2016]

4. England pubmed.ncbi.nlm.nih.gov

Roxithromycin compared to doxycycline in the treatment of genital chlamydial infection and non-specific urethritis. [2017]

5. United States pubmed.ncbi.nlm.nih.gov

Pivampicillin versus doxycycline in the treatment of chlamydial urethritis in men. [2013]

6. New Zealand pubmed.ncbi.nlm.nih.gov

Enteric Coating Reduces Upper Gastrointestinal Adverse Reactions to Doxycycline. [2018]

7. Australia pubmed.ncbi.nlm.nih.gov

Interim position statement on doxycycline post-exposure prophylaxis (Doxy-PEP) for the prevention of bacterial sexually transmissible infections in Australia and Aotearoa New Zealand - the Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine (ASHM). [2023]

8. United States pubmed.ncbi.nlm.nih.gov

Comparison of spiramycin and doxycycline for treatment of Chlamydia trachomatis genital infections. [2021]

9. United States pubmed.ncbi.nlm.nih.gov

In vitro activities of doxycycline and enrofloxacin against European Chlamydia psittaci strains from turkeys. [2022]

10. United States pubmed.ncbi.nlm.nih.gov

In vitro activities of several antimicrobial agents against recently isolated and genotyped Chlamydia trachomatis urogenital serovars D through K. [2021]

11. United States pubmed.ncbi.nlm.nih.gov

Evaluation of antimicrobial treatment in a bovine model of acute Chlamydia psittaci infection: tetracycline versus tetracycline plus rifampicin. [2015]