Systematic Review and Meta-Analysis of Doxycycline Efficacy for Rectal Lymphogranuloma Venereum in Men Who Have Sex with Men

Sexually Transmitted Infections in People with Human Immunodeficiency Virus

Sexually transmitted infections (STIs) are more commonly seen in patients with human immunodeficiency virus (PWH). Routine sexual history taking and appropriate multisite screening practices support prompt identification and treatment of patients, which in turn reduces morbidity and spread of STIs including HIV. Nucleic acid amplification testing has high accuracy for diagnosing many of the major STIs. Diagnosis of syphilis remains complex, requiring 2 stage serologic testing, along with provider awareness of the myriad symptoms that can be attributable to this disease. Prevention through mechanisms such as vaccines and postexposure prophylaxis hold promise to reduce the burden of STIs in PWH.

Effective Treatment of Lymphogranuloma Venereum With a 7-Day Course of Doxycycline

BACKGROUND

Lymphogranuloma venereum (LGV) remains endemic in the United Kingdom, primarily among gay, bisexual or other men who have sex with men (GBMSM). Current treatment guidelines recommend 21 days of doxycycline, but recent evidence suggests shorter antibiotic duration is as effective. We evaluated clinical outcomes in a cohort with LGV treated with 7 days of doxycycline.

METHODS

We reviewed case notes of all LGV cases at a South London sexual health service between November 2016 and September 2022, treated with only 7 days of doxycycline and anonymized data were collected from electronic patient records.

RESULTS

Fifty-two individuals with detected LGV-specific DNA were treated with 7 days of doxycycline 100 mg twice daily. All were GBMSM, median age of 35 years (range, 21-64 years), 21 (40%) were living with HIV, and 18 (35%) had concomitant sexually transmitted infections. Thirty-four (65%) were asymptomatic, whereas 18 (35%) reported symptoms: 7 (13%) urethral, 11 (21%) anorectal, and 2 (4%) other symptoms. Twenty-two (42%) were prescribed additional antimicrobials; however, none were active against Chlamydia trachomatis . All 52 underwent follow-up testing (range, 4-481 days). Chlamydia trachomatis was detected in one individual, but negative for LGV-specific DNA, and so considered to be a reinfection. All other cases were C. trachomatis -negative, indicating successful LGV eradication.

CONCLUSIONS

Our data support the approach of offering a 7-day doxycycline course routinely for asymptomatic or clinically mild C. trachomatis infections, and contacts of LGV infection, regardless of their LGV status. This may simplify patient management, reduce cost, and improve antimicrobial stewardship.

Proctitis: An Approach to the Symptomatic Patient

Proctitis is an inflammatory condition of the distal rectum that can be associated with common sexually transmitted infections (STIs), such as gonorrhea, chlamydia, and syphilis. For persons presenting with ulcerative findings on examination, in addition to syphilis, Mpox, lymphogranuloma venereum, and herpes simplex virus should be in the differential. Providers should also be aware that there are evolving data to support a role for Mycoplasma genitalium in proctitis. Performing a comprehensive history, clinical evaluation including anoscopy, and rectal nucleic amplification STI testing may be useful in identifying the cause of proctitis and targeting treatment.

Characteristics of rectal chlamydia among men who have sex with men in southern Taiwan, 2020-2022: An emerging threat of rectal lymphogranuloma venereum L2b

BACKGROUND

The prevalence of rectal chlamydia among men who have sex with men (MSM) without human deficiency virus infection (non-HIV) remains uncertain in Taiwan, and rectal lymphogranuloma venereum (LGV) among MSM has never been reported in the Far East.

MATERIAL AND METHODS

From January 2020 to April 2022, MSM coming for anonymous voluntary counseling and testing, for pre-exposure prophylaxis, and for antiretroviral therapy were enrolled. All participants submitted his fecal samples and completed a QR-code questionnaire. Medical records of those who took regular medical visits for HIV were recorded. Multiplex polymerase chain reaction (PCR) was performed for all fecal samples, and ompA gene sequencing was therefore performed for each Chlamydia-positive fecal sample.

RESULTS

Among 341 MSM during 2020-2022 in southern Taiwan, 21 (6.2%) had rectal chlamydia infection. Risk factors of rectal chlamydia included co-infection with rectal gonorrhea (adjusted odds ratio [AOR] 6.78, 95% confidence interval [CI] 1.44-31.91, P = 0.015) and multiple sexual partners (AOR 1.373, 95% CI 1.002-1.882, P = 0.048). Further ompA gene sequencing from 19 Chlamydia-positive fecal samples revealed that the prevalent genotypes or genovariants were Da (26.3%) and L2b (26.3%), followed by B (21.1%), J (14.3%), and G (9.5%). All cases of rectal LGV genovariant L2b presented as acute proctitis with diarrhea, anal pain, or discharge and were treated successfully with prolonged treatment of doxycycline.

CONCLUSIONS

Rectal gonorrhea and multiple sexual partners are risk factors for rectal chlamydia. Clinicians in Taiwan should be aware of the emerging threat of rectal LGV among MSM with acute proctitis.

Universal lymphogranuloma venereum (LGV) testing of rectal chlamydia in men who have sex with men and detection of asymptomatic LGV

BACKGROUND

Lymphogranuloma venereum (LGV) is caused by Chlamydia trachomatis serovars L1-L3. This study determined the positivity for LGV testing before and after introduction of universal LGV testing of positive rectal Chlamydia trachomatis samples in men who have sex with men (MSM).

METHODS

From March 2015 to February 2018, MSM with rectal C. trachomatis were not routinely tested for LGV at the Melbourne Sexual Health Centre unless they had HIV or symptoms of proctitis. From February 2018, universal testing for LGV of all positive rectal C. trachomatis specimens in men over the age of 25 years, regardless of symptoms was undertaken. LGV positivity was defined as the detection of LGV-associated C. trachomatis serovars.

RESULTS

There were 3429 and 4020 MSM who tested positive for rectal chlamydia in the selective and universal LGV-testing periods, respectively. Of the total 3027 assessable specimens in both periods, 97 (3.2%; 95% CI 2.6% to 3.9%) specimens tested positive for LGV. LGV positivity in the selective testing period was higher than in the universal testing period (6.6% (33/502) vs 2.5% (64/2525), p<0.001). The proportion of LGV cases that were asymptomatic increased from 15.2% (5/33) in the selective testing period to 34.4% (22/64) in the universal testing period (p=0.045). Of the 70 symptomatic LGV cases symptoms included rectal discharge (71.4%, n=45) and rectal pain (60.0%, n=42).

CONCLUSION

Universal LGV testing of all positive rectal chlamydia samples in MSM compared with selective testing led to the detection of asymptomatic rectal LGV, which constituted 34% of rectal LGV cases.

Chlamydia trachomatis anorectal infections by LGV (L1, L2 and L2b) and non-LGV serotypes in symptomatic patients in Buenos Aires, Argentina

BACKGROUND

Chlamydia trachomatis (CT) can infect the anorectum producing various signs and symptoms. There is scarce literature regarding the differences between LGV and non-LGV CT anorectal manifestations. We compare the clinical spectrum of LGV and non-LGV infections.

METHODS

Patients over 18 years with presumptive infectious anorectal symptoms were examined in two healthcare centres in Buenos Aires. The patients were studied and treated according to current sexually transmitted infection guidelines. Anorectal swabs were collected to detect and genotype CT.

RESULTS

A three-year-long study on 317 patients with anorectal symptoms showed 45.11% CT infection (85% LGV strains). Of 140 samples, 92 were sequenced: 80/119 LGV (L2b 45%, L1 32.5% and L2 22.5%) and 12/21 non-LGV. Older age and HIV+ status were significantly higher in the LGV group. Anal discharge, bleeding, severe proctitis and anal ulcers were more common in the LGV group. Multivariate logistic regression analysis revealed that HIV infection, anorectal bleeding and oro-anal sex are independent predictors of LGV infection.

CONCLUSIONS

In patients with anorectal symptoms, LGV serovars predominate over non-LGV ones. Clinical manifestations are not pathognomonic of a specific biovar. If genotyping is not available, having clinical predictors may help to presume an LGV infection and define length of treatment.

Sexually Transmitted Infections Treatment Guidelines, 2021

These guidelines for the treatment of persons who have or are at risk for sexually transmitted infections (STIs) were updated by CDC after consultation with professionals knowledgeable in the field of STIs who met in Atlanta, Georgia, June 11-14, 2019. The information in this report updates the 2015 guidelines. These guidelines discuss 1) updated recommendations for treatment of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis; 2) addition of metronidazole to the recommended treatment regimen for pelvic inflammatory disease; 3) alternative treatment options for bacterial vaginosis; 4) management of Mycoplasma genitalium; 5) human papillomavirus vaccine recommendations and counseling messages; 6) expanded risk factors for syphilis testing among pregnant women; 7) one-time testing for hepatitis C infection; 8) evaluation of men who have sex with men after sexual assault; and 9) two-step testing for serologic diagnosis of genital herpes simplex virus. Physicians and other health care providers can use these guidelines to assist in prevention and treatment of STIs.

Azithromycin or Doxycycline for Asymptomatic Rectal Chlamydia trachomatis

BACKGROUND

Rectal chlamydia is a common bacterial sexually transmissible infection among men who have sex with men. Data from randomized, controlled trials are needed to guide treatment.

METHODS

In this double-blind trial conducted at five sexual health clinics in Australia, we randomly assigned men who have sex with men and who had asymptomatic rectal chlamydia to receive doxycycline (100 mg twice daily for 7 days) or azithromycin (1-g single dose). Asymptomatic chlamydia was selected as the trial focus because more than 85% of men with rectal chlamydia infection are asymptomatic, and clinical guidelines recommend a longer treatment course for symptomatic infection. The primary outcome was a negative nucleic acid amplification test for rectal chlamydia (microbiologic cure) at 4 weeks.

RESULTS

From August 2016 through August 2019, we enrolled 625 men (314 in the doxycycline group and 311 in the azithromycin group). Primary outcome data were available for 290 men (92.4%) in the doxycycline group and 297 (95.5%) in the azithromycin group. In the modified intention-to-treat population, a microbiologic cure occurred in 281 of 290 men (96.9%; 95% confidence interval [CI], 94.9 to 98.9) in the doxycycline group and in 227 of 297 (76.4%; 95% CI, 73.8 to 79.1) in the azithromycin group, for an adjusted risk difference of 19.9 percentage points (95% CI, 14.6 to 25.3; P<0.001). Adverse events that included nausea, diarrhea, and vomiting were reported in 98 men (33.8%) in the doxycycline group and in 134 (45.1%) in the azithromycin group (risk difference, -11.3 percentage points; 95% CI, -19.5 to -3.2).

CONCLUSIONS

A 7-day course of doxycycline was superior to single-dose azithromycin in the treatment of rectal chlamydia infection among men who have sex with men. (Funded by the National Health and Medical Research Council; RTS Australian New Zealand Clinical Trials Registry number, ACTRN12614001125617.).

Lymphogranuloma venereum as a cause of persistent perianal ulcers

Lymphogranuloma venereum (LGV) has been increasingly reported, and many clinicians are familiar with it as a cause of proctocolitis or inguinal adenopathy. On the other hand, LGV is less commonly considered as a cause of isolated genital ulcerative disease in comparison to other etiologies such as syphilis or herpes simplex. We report a case of persistent perianal ulcerations due to LGV in an HIV-positive patient, confirmed by nucleic acid amplification testing.

Effective treatment of Lymphogranuloma venereum proctitis with Azithromycin

BACKGROUND

Lymphogranuloma venereum (LGV) is a sexually transmitted infection caused by Chlamydia trachomatis (CT) serovars L1, L2, and L3 and is endemic among men who have sex with men (MSM) in Europe. We evaluated weekly oral Azithromycin 1 g for 3 weeks as a treatment for LGV proctitis.

METHODS

This is an open clinical trial with convenience allocation according to treating physician preferences. Adults with clinical proctitis received a single dose of 1 g of intramuscular ceftriaxone and were subsequently allocated to receive (i) Doxycycline 100 mg twice daily for 21 days (Doxycycline-group) or, (ii) Azithromycin 1 g orally once weekly for 3 weeks (Azithromycin-group). LGV-cure, (primary endpoint) was defined as resolution of symptoms at week 6 (clinical cure, LGV-CC), with an additional supporting negative rectal PCR at week 4 (microbiological cure; LGV-MC), if available.

FINDINGS

One hundred and twenty-five individuals with LGV clinical proctitis were included. All were MSM and 96% were HIV-positive. Eighty-two were in the Azithromycin-group and 43 in the Doxycycline-group. LGV-cure on a modified intention-to-treat analysis (primary endpoint), occurred in 80 of 82 (98%) in the Azithromycin-group versus 41 of 43 (95%) in Doxycycline-group [treatment difference (95% CI) 2.2% (-3.2; 13.2)]. LGV-MC occurred in 70 of 72 (97%) vs 15 of 15 (100%) in Azithromycin-group and Doxycycline-group, respectively [treatment difference (95% CI) -2.8% (-9.6; 17.7)]. Adverse events were similar in both treatment groups.

INTERPRETATION

Our findings support extended azithromycin dosing as an alternative treatment option for symptomatic LGV proctitis and provides the rationale for future randomized trials.

Chlamydia trachomatis: when the virulence-associated genome backbone imports a prevalence-associated major antigen signature

Chlamydia trachomatis is the most prevalent sexually transmitted bacterium worldwide and the causative agent of trachoma. Its strains are classified according to their ompA genotypes, which are strongly linked to differential tissue tropism and disease outcomes [ocular disease, urogenital disease and lymphogranuloma venereum (LGV)]. While the genome-based species phylogenetic tree presents four main clades correlating with tropism/prevalence, namely ocular, LGV, urogenital T1 (more prevalent genotypes) and urogenital T2 (less prevalent genotypes), inter-clade exchange of ompA is considered a rare phenomenon probably mediating marked tropism alterations. An LGV epidemic, associated with the clonal expansion of the L2b genotype, has emerged in the last few decades, raising concerns particularly due to its atypical clinical presentation (ulcerative proctitis) and circulation among men who have sex with men (MSM). Here, we report an LGV outbreak, mostly affecting human immunodeficiency virus-positive MSM engaging in high-risk sexual practices, caused by an L2b strain with a rather unique non-LGV ompA signature that precluded the laboratory notification of this outbreak as LGV. C. trachomatis whole-genome capture and sequencing directly from clinical samples was applied to deeply characterize the genomic backbone of this novel LGV outbreak-causing clone. It revealed a chimeric genome structure due to the genetic transfer of ompA and four neighbouring genes from a serovar D/Da strain, likely possessing the genomic backbone associated with the more prevalent urogenital genotypes (T1 clade), to an LGV (L2b) strain. The hybrid L2b/D-Da strain presents the adhesin and immunodominant antigen MOMP (major outer membrane protein) (encoded by ompA) with an epitope repertoire typical of non-invasive genital strains, while keeping the genome-dispersed virulence fingerprint of a classical LGV strain. As previously reported for inter-clade ompA exchange among non-LGV clades, this novel C. trachomatis genomic mosaic involving a contemporary epidemiologically and clinically relevant LGV strain may have implications on its transmission, tissue tropism and pathogenic capabilities. The emergence of variants with epidemic and pathogenic potential highlights the need for more focused surveillance strategies to capture C. trachomatis evolution in action.

Lymphoganuloma venereum in the Western world, 15 years after its re-emergence: new perspectives and research priorities

PURPOSE OF REVIEW

Lymphogranuloma venereum (LGV) is a serious sexually transmitted infection caused by Chlamydia trachomatis. If left untreated LGV can cause irreversible late sequelae. LGV is endemic among a high-risk population of men who have sex with men (MSM), and largely reported in Western metropoles.

RECENT FINDINGS

Although the majority of LGV patients are HIV positive, in recent years the proportion of HIV-negative MSM with LGV is rising. This could indicate a shift toward lower risk populations. Apart from a few European countries, no proper LGV surveillance efforts have been implemented so far. Moreover, a considerable proportion of the infections are asymptomatic. As a result, the true magnitude of the LGV epidemic is underestimated.Depending on the stage and location of infection, LGV manifests in a variety of clinical presentations. Among MSM, anorectal infections are overreported as opposed to genital LGV infections in a ratio of 15 to 1, respectively. Therefore, other modes of transmission apart from anal sex are here discussed.

SUMMARY

To improve surveillance, cheaper and more practical screening methods are needed. Moreover, randomized clinical trials are needed to evaluate more simple treatment modalities as opposed to the currently recommended 3-week course of doxycycline.

Lymphogranuloma venereum (LGV) in men who have sex with men (MSM): a re-emerging problem, Malta, 2018

From 1 January to 30 June 2018, 11 cases of Lymphogranuloma venereum (LGV; all preserved samples (n = 4) genovar L2b) were identified at the Genitourinary Clinic (GUC), Mater Dei Hospital, Msida, Malta. All cases were diagnosed in men who have sex with men (MSM); six participated in three group-sex parties. Here, we describe the outbreak and risk factors associated with LGV diagnoses in MSM in Malta in 2018.

2019 European guideline on the management of lymphogranuloma venereum

New or important issues in this updated version of the 2013 European guideline on the management of lymphogranuloma venereum (LGV): EPIDEMIOLOGY: Lymphogranuloma venereum continues to be endemic among European men who have sex with men (MSM) since 2003. Lymphogranuloma venereum infections in heterosexuals are extremely rare in Europe, and there is no evidence of transmission of LGV in the European heterosexual population.

AETIOLOGY AND TRANSMISSION

Chlamydia trachomatis serovars/genovars L2b and L2 are the causative strains in the majority of cases in Europe.

CLINICAL FEATURES

Among MSM, about 25% of the anorectal LGV infections are asymptomatic. Genital infections among MSM are rare; the ratio of genital vs. anorectal LGV infections is 1 in 15.

DIAGNOSIS

To diagnose LGV, a sample tested C. trachomatis positive with a commercial nucleic acid amplification test (NAAT) platform should be confirmed with an LGV discriminatory NAAT.

TREATMENT

Doxycycline 100 mg twice a day orally for 21 days is the recommended treatment for LGV. This same treatment is recommended also in asymptomatic patients and contacts of LGV patients. If another regimen is used, a test of cure (TOC) must be performed.

Observed Treatment Responses to Short-Course Doxycycline Therapy for Rectal Lymphogranuloma Venereum in Men Who Have Sex With Men

BACKGROUND

Lymphogranuloma venereum (LGV) has reestablished itself as an endemic sexually transmitted infection in the United Kingdom and elsewhere in Europe and North America over the last decade. Current guidelines suggest treatment with 21 days of doxycycline; however, the evidence base for LGV treatment including its duration is very limited.

METHODS

We conducted a retrospective review in 2 central London genitourinary medicine clinics of men who have sex with men (MSM) with LGV in whom less than 21 days of doxycycline was used initially.

RESULTS

Sixty MSM were treated initially with less than 21 days of doxycycline, of whom 50 (83%) were prescribed a 7-day course. Fifty percent of patients were asymptomatic, with the rest having rectal or other symptoms. Fifty-nine (97%) of 60 had a negative test of cure for LGV at a median of 31 days (7-200 days). Reinfection as opposed to treatment failure was considered likely in the patient testing positive. A second test of cure at a median of 139 days later (37-638 days) was completed in 30 patients, of whom 28 (93%) were negative for LGV.

CONCLUSIONS

Seven to 14 days of doxycycline is effective in most cases of LGV with negative TOCs in 59 of 60 patients. These data suggest that 7 days of doxycycline is effective in achieving cure of rectal LGV in most MSM. There is a case for a randomized controlled trial of LGV treatment including a 7-day regimen of doxycycline.

Doxycycline in the management of sexually transmitted infections

Doxycycline is a second-generation tetracycline, available worldwide for half a century. It is an inexpensive broad-spectrum antimicrobial agent largely used in the management of several bacterial infections, particularly involving intracellular pathogens, as well as in the treatment of acne or for the prophylaxis of malaria. Physicochemical characteristics of doxycycline (liposolubility) allow a high diffusion in the tissues and organs. It has high bioavailability and a long elimination half-life allowing oral administration of one or two daily doses. Over the last decade, the prevalence of bacterial sexually transmitted infections (STIs) (syphilis, chlamydiosis, gonorrhoea and Mycoplasma genitalium infections) has increased in most countries, mainly in MSM, many of whom are infected with HIV. In light of increasing prevalence of resistance towards first-line regimens of some STI agents and recently updated recommendations for STI management, doxycycline appears to be an attractive option compared with other available antibiotics for the treatment of some STIs due to its efficacy, good tolerability and oral administration. More recently, indications for doxycycline in STI prophylaxis have been evaluated. Considering the renewed interest of doxycycline in STI management, this review aims to update the pharmacology of, efficacy of, safety of and resistance to doxycycline in this context of use.

Laboratory Processes for Confirmation of Lymphogranuloma Venereum Infection During a 2015 Investigation of a Cluster of Cases in the United States

In September 2015, the Centers for Disease Control and Prevention were notified of a suspected outbreak investigation of lymphogranuloma venereum (LGV) cases by the Michigan Department of Health and Human Services. The Centers for Disease Control and Prevention offered support with a laboratory-developed polymerase chain reaction test for LGV. This note describes the laboratory workflow and procedures used for the laboratory confirmation of LGV infection.

Asymptomatic lymphogranuloma venereum among Nigerian men who have sex with men

OBJECTIVES

Recent outbreaks of anorectal lymphogranuloma venereum (LGV) among men who have sex with men (MSM) have been characterised by proctocolitis requiring extended antibiotic treatment compared with infections caused by other serovars of Chlamydia trachomatis (CT). We describe the prevalence and clinical features of LGV among Nigerian MSM diagnosed with anorectal CT.

METHODS

MSM were recruited for this observational cohort in Lagos, Nigeria, using respondent-driven sampling and screened for HIV and bacterial STIs every three months for up to 18 months. Nucleic acid amplification tests for CT were performed on rectal swab specimens. Prevalent and incident cases of anorectal CT underwent additional testing to identify LGV using novel real-time PCR assays specific for the L-serovars of CT.

RESULTS

From April 2014 to July 2016, 420 MSM underwent testing for rectal STIs, of whom 66 (15.7%) had prevalent anorectal CT. Among those without prevalent disease, 68 developed incident infections during 208 person-years of follow-up. Of 134 prevalent and incident cases of anorectal CT, 7 (5.2%) were identified as LGV. None of the seven participants with LGV reported any symptoms. Two of the participants with LGV were simultaneously coinfected with rectal gonorrhoea. HIV coinfection was common among participants with both LGV (n=5, 71%) and non-LGV (n=98, 77%) serovars of CT (P=0.66).

CONCLUSIONS

Anorectal LGV was uncommon but present among Nigerian MSM in this study. Consistent screening for L-serovars of CT, or presumptive treatment for LGV in cases with a high suspicion for this diagnosis, could potentially improve patient outcomes and decrease transmission.

Treatment Outcomes for Rectal Lymphogranuloma Venereum in Men Who Have Sex with Men Using Doxycycline, Azithromycin, or Both: A Review of Clinical Cases

BACKGROUND

Treatment for rectal lymphogranuloma venereum where doxycycline 100 mg twice daily for 21 days was used-either alone or together with azithromycin 1 g single dose-resulted in microbiological cure of 97%. These data support doxycycline 100 mg twice daily for 21 days as the preferred treatment for rectal lymphogranuloma venereum.

Treatment efficacy of azithromycin 1 g single dose versus doxycycline 100 mg twice daily for 7 days for the treatment of rectal chlamydia among men who have sex with men - a double-blind randomised controlled trial protocol

BACKGROUND

Rectal infection with Chlamydia trachomatis is one of the most common bacterial sexually transmissible infections among men who have sex with men (MSM) with diagnosis rates continuing to rise. Current treatment guidelines recommend either azithromycin 1 g single dose or doxycycline 100 mg twice daily for 7 days. However, there are increasing concerns about treatment failure with azithromycin. We are conducting the first randomised controlled trial (RCT) to compare treatment efficacy of azithromycin versus doxycycline for the treatment of rectal chlamydia in MSM.

METHODS/DESIGN

The Rectal Treatment Study will recruit 700 MSM attending Australian sexual health clinics for the treatment of rectal chlamydia. Participants will be asked to provide rectal swabs and will be randomised to either azithromycin 1 g single dose or doxycycline 100 mg twice daily for 7 days. Participants will be asked to complete questionnaires about adverse drug reactions, sexual behaviour and drug adherence via short message service and online survey. The primary outcome is the treatment efficacy as determined by a negative chlamydia nucleic acid amplification test at 4 weeks post treatment. Secondary outcomes will utilise whole genome sequencing and mRNA assay to differentiate between treatment failure, reinfection or false positive results.

DISCUSSION

Rectal chlamydia is an increasing public health concern as use of pre-exposure prophylaxis against HIV becomes commonplace. Optimal, evidence-based treatment is critical to halting ongoing transmission. This study will provide the first RCT evidence comparing azithromycin and doxycycline for the treatment of rectal chlamydia. The results of this trial will establish which treatment is more efficacious and inform international management guidelines.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12614001125617.