Doxycycline for Sexually Transmitted Infections

Overseen By Colleen Kelley, MD, MPH

Age: 18 - 65

Sex: Any

Trial Phase: Phase 4

Sponsor: Emory University

Must not be taking: Immunomodulators, Steroids, Chemotherapy, others

Disqualifiers: Liver disease, Allergic reaction, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Prior Safety Data This treatment has passed at least one previous human trial

Approved in 5 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 3

Duration: 1 week

20 Participants Needed

Trial Summary

Will I have to stop taking my current medications?

The trial requires that you do not take doxycycline or other tetracycline-derived antibiotics during the study. Additionally, you cannot use certain medications like systemic immunomodulatory agents, high doses of steroids, chemotherapy, or experimental drugs within 90 days before joining the study.

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

Doxycycline has been shown to be effective in treating various sexually transmitted infections, such as Chlamydia trachomatis and gonorrhea, with high cure rates reported in studies. It is well-tolerated, has good tissue penetration, and can be taken orally, making it a convenient option for patients. ^{1 2 3 4 5}

Is doxycycline generally safe for humans?

Doxycycline is generally well tolerated in humans, but it can cause stomach upset, nausea, and diarrhea. New formulations have been developed to reduce these side effects. It is not recommended for children, pregnant women after the second trimester, and breastfeeding mothers due to potential risks. ^{6 7 8 9 10}

How does the drug doxycycline differ from other treatments for sexually transmitted infections?

Doxycycline is unique because it is a broad-spectrum antibiotic that can be taken orally once or twice daily, making it convenient for patients. Its high tissue penetration and long half-life make it effective against intracellular pathogens, which are common in sexually transmitted infections. Additionally, doxycycline is being explored for use as a preventive measure against STIs, which is not a standard approach for most antibiotics. ^{1 2 3 4 11}

What is the purpose of this trial?

The goal of this project is to collect data regarding the concentrations of doxycycline in mucosal tissues after daily dosing for 7 days in people assigned male sex at birth (AMAB) and assigned female sex at birth (AFAB) to inform future studies of doxycycline to protect against bacterial sexually transmitted infections (STIs).

Research Team

Colleen Kelley, MD, MPH

Principal Investigator

Emory University

Eligibility Criteria

This trial is for adults assigned male or female at birth, in good health, and willing to use condoms. It includes HIV positive individuals with undetectable viral loads and CD4 counts over 300. Pregnant individuals or those planning pregnancy are excluded, as well as anyone planning to take doxycycline outside the study.

Inclusion Criteria

I was assigned male or female at birth.

In good general health

Able to provide informed consent

Exclusion Criteria

I have a history of liver disease.

I haven't used strong immune system drugs, high-dose steroids, chemotherapy, radiation, or experimental treatments for cancer in the last 90 days.

Any other clinical condition or prior therapy that, in the opinion of the investigator, would make the patient unsuitable for the study or unable to comply with the study requirements

Timeline

Screening

Participants are screened for eligibility to participate in the trial

1 week

1 visit (in-person)

Treatment

Participants receive daily doses of 100mg doxycycline for 7 days

1 week

1 visit (in-person) for enrollment, 5 doses at home, 1 visit (in-person) for sample collection

Sample Collection

Rectal and vaginal swab samples collected 2 to 4 hours after the final dose; biopsy tissue collected 24 hours after the last dose

1 day

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

1 week

Treatment Details

Interventions

• Doxycycline

Trial Overview The study tests how daily doses of doxycycline concentrate in mucosal tissues over a week to prevent bacterial STIs. Participants will provide various biological samples and undergo biopsies to gather data.

Participant Groups

Group I: Doxycycline Experimental Treatment 1 Intervention

Study participants taking 7 consecutive, daily doses of 100mg of Doxycycline.

Doxycycline is already approved in United States, European Union, Canada, Japan for the following indications:

Approved in United States as Doxycycline for:

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

Approved in European Union as Doxycycline for:

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

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?

Emory University

Lead Sponsor

Trials

1,735

Recruited

2,605,000+

Centers for Disease Control and Prevention

Collaborator

Trials

902

Recruited

25,020,000+

Findings from Research

In a study of 50 uncomplicated male gonorrhea cases treated with doxycycline, the treatment showed an 88% success rate, with 44 out of 50 patients responding well to the therapy.

The treatment regimen involved a total of 400 mg of doxycycline administered intravenously over three days, and side effects were minimal, indicating a favorable safety profile.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Doxycycline in the Treatment :uncomplicated Gonorrohea. Wadhwa, SL., Marquis, L.[2019]

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]

A systematic review of 7 studies involving oral tetracycline-class antibiotics, including doxycycline, indicated that these antibiotics can increase resistance to tetracyclines in normal flora, particularly in subgingival, gastrointestinal, and upper respiratory tract bacteria.

While some studies showed a transient increase in non-tetracycline resistance, the overall impact on non-tetracycline AMR was minimal, suggesting that the use of doxycycline for STI prophylaxis may require careful monitoring of antimicrobial resistance in commensal bacteria.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A systematic review of the impacts of oral tetracycline class antibiotics on antimicrobial resistance in normal human flora. Truong, R., Tang, V., Grennan, T., et al.[2022]

Doxycycline is a well-established, broad-spectrum antibiotic that is effective against various bacterial infections, including sexually transmitted infections (STIs), and is particularly beneficial due to its high tissue diffusion and long half-life, allowing for convenient oral dosing.

With the rise of antibiotic resistance in first-line STI treatments, doxycycline is being reconsidered as a safe and effective option for managing STIs, especially in populations at higher risk, such as men who have sex with men (MSM) and those living with HIV.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Doxycycline in the management of sexually transmitted infections. Peyriere, H., Makinson, A., Marchandin, H., et al.[2019]

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]

In a study involving 111 healthy volunteers, enteric-coated doxycycline hyclate pellets in capsules were found to cause significantly fewer gastrointestinal adverse reactions compared to doxycycline monohydrate tablets, with only 43% of participants reporting side effects versus 66% for monohydrate.

The new formulation demonstrated improved tolerability, particularly reducing incidents of abdominal pain, nausea, and vomiting, making it a safer option for patients requiring doxycycline therapy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Enteric Coating Reduces Upper Gastrointestinal Adverse Reactions to Doxycycline. Järvinen, A., Nykänen, S., Paasiniemi, L., et al.[2018]

Doxycycline is effective against a wide range of bacterial infections and is particularly notable for its safety profile, as it does not require dosage adjustments in patients with renal failure.

It is well tolerated with common side effects like stomach upset and nausea, but new formulations are available to minimize these issues; however, it is contraindicated in children and pregnant or breastfeeding women.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Doxycycline]. Aupee, O., Almeras, D., Le Garlantezec, P., 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]

Doxycycline is an effective antibiotic for treating various infections, particularly respiratory tract diseases like pneumonia, as demonstrated in a study involving 49 patients.

The drug shows good safety and compatibility, especially in children, and achieves effective serum levels when administered at a dose of 4 mg/kg in two injections.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Clinical and pharmacokinetic researches of doxycyclin vibravenös in childhood (author's transl)]. Weingärtner, L., Straube, D., Baum, W., et al.[2013]

Doxycycline hyclate (DH) has a favorable safety profile, especially in its delayed-release form (Doryx), compared to the standard powder form (Vibramycin), making it a safer option for treating conditions like acne and rosacea.

Despite historical safety concerns associated with tetracyclines, including gastrointestinal issues and effects on tooth development, subantimicrobial dosing of DH has shown to be effective and safe for acne treatment, supporting its continued use in dermatology.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The use and safety of doxycycline hyclate and other second-generation tetracyclines. Sloan, B., Scheinfeld, N.[2022]

Doxycycline has been shown to lower the risk of sexually transmitted diseases (STDs), making it a potentially effective preventive treatment.

Concerns exist regarding the possibility that widespread use of doxycycline could lead to increased drug resistance, which may undermine its effectiveness in treating infections in the future.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Antibiotic after sex could help curb infections. Cohen, J.[2022]

References

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

Doxycycline in the Treatment :uncomplicated Gonorrohea. [2019]

2. Japan pubmed.ncbi.nlm.nih.gov

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

3. England pubmed.ncbi.nlm.nih.gov

A systematic review of the impacts of oral tetracycline class antibiotics on antimicrobial resistance in normal human flora. [2022]

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

Doxycycline in the management of sexually transmitted infections. [2019]

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

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

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

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

7. France pubmed.ncbi.nlm.nih.gov

[Doxycycline]. [2013]

8. 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]

9. Germany pubmed.ncbi.nlm.nih.gov

[Clinical and pharmacokinetic researches of doxycyclin vibravenös in childhood (author's transl)]. [2013]

10. England pubmed.ncbi.nlm.nih.gov

The use and safety of doxycycline hyclate and other second-generation tetracyclines. [2022]

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

Antibiotic after sex could help curb infections. [2022]