THE 20th European AIDS Clinical Society (EACS) Conference opened its doors in Paris, France, from 15th–18th October 2025, marking a landmark moment for the global HIV community. Gathering over 3,000 delegates from across the world and featuring a record number of more than 1,000 submitted abstracts, this year’s Conference reaffirmed the EACS’ role as a hub of scientific innovation, collaboration, and advocacy.
EACS President Miłosz Parcewski opened the ceremony by paying tribute to Paris as a historic centre of scientific progress and avant-garde thinking, an ideal host for a congress devoted to advancing HIV prevention, care, and research. He highlighted the Conference’s dynamic programme, which for the first time included a “Co-Chairs’ Choice” session showcasing cutting-edge, high-impact studies. The congress venue also featured several art exhibitions, among them the deeply moving ‘Dreams of Children in Ukraine’, which served as a poignant reminder of the human dimension behind global health challenges.
Parcewski reaffirmed the EACS’ enduring mission: to promote excellence in HIV care, research, and education across Europe, while standing firm for equity in access to healthcare. In a powerful address, he stated, “EACS stands against any form of aggression, war, and violation of human rights. We are deeply concerned by the ongoing wars and conflicts and their impact on HIV prevention and care. We stand by all communities, especially those most marginalised.”
EACS Co-Chair Bruno Spire, from the French National Institute of Health and Medical Research (INSERM), took the stage to reflect on France’s pivotal role in community-based HIV work, emphasising the essential partnerships with affected populations: transgender people, men who have sex with men, people who inject drugs, migrants, and sex workers. Yet, he warned, this progress is increasingly at risk. “Freedom of community-based activism is under threat,” he cautioned, pointing to rising conservatism, normalised transphobia and xenophobia, and shrinking public and international funding for HIV programmes. In this challenging environment, he called for renewed unity between science and activism: “Only by standing together can we push back against anti-science rhetoric, prejudice, and ignorance, and continue to advance public health.”
Co-Chair Karine Lacombe, Sorbonne Université, Paris, France, celebrated the extraordinary scientific journey since the discovery of HIV in Paris in 1983. In just over 3 decades, she noted, medical research has achieved what once seemed impossible: dramatically reducing new HIV infections and bringing the life expectancy of people living with HIV close to that of the general population. She highlighted that this 20th EACS Conference would spotlight the latest breakthroughs in prevention, diagnosis, and treatment, alongside renewed attention to the ethics of care, diversity, and inclusion.
The opening ceremony also welcomed Anne Hidalgo, Mayor of Paris, who reaffirmed the city’s deep commitment to the fight against HIV. It was in Paris, in 2014, that mayors from cities around the world launched the Fast-Track Cities initiative, committing to meeting the Joint United Nations Programme on HIV/AIDS (UNAIDS) 90-90-90 targets by 2020 and ending the AIDS epidemic by 2030. She reminded the audience that Paris, one of the European cities hit hardest by the epidemic, has long been a refuge for those seeking to live and love freely. “The fight against HIV,” Hidalgo declared, “is a fight against discrimination, for dignity, and for humanity.” With only 5 years remaining to fulfil the promise of ending the AIDS epidemic, she urged continued investment in science, defence of human rights, and unwavering solidarity.
The ceremony continued with a moving series of reflections from long-standing voices in the global HIV response, including leading physician and diplomat Michel Kazatchkine of the Geneva Graduate Institute in Switzerland; French militant and activist Eve Plenel; and Caroline Andoum, managing director of ‘Bamesso et Ses Amis’, Paris, France, a humanitarian association promoting sexual health across migrant populations in France and Africa.
Finally, the 2025 EACS Awards honoured two individuals whose sustained contributions have shaped the field: Ben Collins, a veteran activist and community organiser instrumental in strengthening EACS partnerships in Eastern Europe, and Jürgen Rockstroh of the University of Bonn, Germany, recognised as a visionary clinician-scientist and dedicated mentor.
With these inspiring words and recognitions, the 20th EACS Conference set the stage for 4 days of community dialogue and shared commitment to ending the HIV epidemic, upholding human rights, and ensuring that progress leaves no one behind.
Once-Weekly Oral HIV Regimen Maintains Suppression Through 96 Weeks
LATE-BREAKING findings presented at the 20th EACS Conference demonstrate that a once-weekly oral combination of islatravir (ISL) and lenacapavir (LEN) maintained durable virologic suppression and excellent safety through 96 weeks in adults living with HIV-1. The results, from an ongoing Phase 2 clinical trial, highlight the potential of ISL+LEN as the first complete, once-weekly, oral antiretroviral regimen.1
The randomised, open-label study enrolled virologically suppressed adults who were previously maintained on a daily fixed-dose combination of bictegravir/emtricitabine/tenofovir alafenamide. Participants were randomised 1:1 to either continue bictegravir/emtricitabine/tenofovir alafenamide or switch to oral ISL 2 mg plus LEN 300 mg once weekly. Those receiving ISL+LEN and completing the initial 48-week randomised phase were eligible to continue into a 48-week extension period, for a total of 96 weeks of treatment.
Of the 52 participants who began weekly ISL+LEN (median age: 40 years; 19.2% female), 47 entered the extension phase. Adherence remained exceptionally high, with a mean of 99.3% through 96 weeks. No participants experienced viral rebound (HIV-1 RNA ≥50 copies/mL) or developed treatment-emergent resistance to either study drug. Safety outcomes were favourable: 10 participants (19.2%) reported study drug-related adverse events, none of which were ≥Grade 3. Two participants (3.8%) discontinued the study due to adverse events considered unrelated to ISL+LEN.
Immunologic and metabolic parameters remained stable. Mean change in cluster of differentiation 4+ T cell count from baseline to Week 96 was –33 cells/µL (95% CI: -86–20), and mean lymphocyte count decreased modestly by -0.2×10³ /µL (95% CI: -0.3–-0.1). Median weight and BMI changes were negligible, with +0.1 kg and +0.04 kg/m² respectively.
The sustained efficacy, favourable safety profile, and excellent adherence observed through nearly 2 years of follow-up support ISL+LEN as a promising alternative to daily oral therapy. Two Phase 3 trials, ISLEND-1 and ISLEND-2, are now underway to further evaluate the once-weekly combination’s potential to simplify long-term HIV treatment.
Low Risk of Hepatitis B Virus Reactivation After Switching from Tenofovir
NEW data presented at the 20th EACS Conference provide reassuring evidence that hepatitis B virus (HBV) reactivation is rare among people with HIV who have previously been exposed to HBV and who switch from tenofovir-based to tenofovir-sparing antiretroviral therapy (ART). The findings, derived from the Swiss HIV Cohort Study, offer valuable guidance as clinicians increasingly consider non-tenofovir regimens for long-term HIV management.2
Up to 30% of people living with HIV carry antibodies against the hepatitis B core antigen, indicating prior HBV infection. While tenofovir effectively suppresses both HIV and HBV, concerns have arisen that discontinuing HBV-active drugs might trigger viral reactivation in those with past exposure. This study aimed to assess whether such risk is clinically meaningful in people who are hepatitis B surface antigen-negative but hepatitis B core antibody-positive (those with resolved or occult HBV infection).
Researchers included 380 participants who had switched to non-tenofovir ART. Participants were grouped based on whether their new regimen contained lamivudine or emtricitabine (XTC group) or excluded both agents (non-XTC group). All had plasma samples available from before and at least 1 year after stopping tenofovir. The presence of HBV DNA was measured using highly sensitive assays.
After a median follow-up of 1.3 years, detectable HBV DNA was found in 5.3% of participants in the non-XTC group, compared with 1.6% in the XTC group. Crucially, all detected viral loads remained below the quantification threshold, and the proportion of participants with elevated liver enzyme levels did not differ significantly between those with or without detectable HBV DNA.
Overall, only 3.4% of those switching to regimens without tenofovir showed evidence of HBV replication, none of which appeared clinically relevant. The study concludes that HBV reactivation in this population is uncommon and likely of minimal clinical consequence.
These findings support the safety of tenofovir-sparing ART strategies in individuals who are hepatitis B core antibody-positive, hepatitis B surface antigen-negative, and have HIV, providing important reassurance for both patients and clinicians as treatment paradigms evolve.
Majority of HIV Diagnoses Among Migrants Occur After Arrival
IMPORTANT research from the Swiss HIV Cohort Study (SHCS), presented at the 20th EACS Conference, reveals that most new HIV diagnoses among migrants in Switzerland occur after arrival in the country. The findings, spanning 15 years of data, reinforce the need for tailored HIV testing and prevention strategies to reach migrant populations at different stages of their migration journey.3
The analysis included 3,490 participants newly enrolled in the SHCS between 2010–2024, of whom 1,777 were Swiss nationals and 1,713 were migrants. Over time, the proportion of migrants among new enrollees steadily increased, reaching a median of 52% per year. Researchers classified participants as either Swiss nationals or migrants based on nationality and immigration information recorded in the SHCS, and examined whether HIV was diagnosed before or after migration.
Among migrants, 37.9% were diagnosed before migration, while 62.1% received their HIV diagnosis after arriving in Switzerland. Among those diagnosed post-migration, the main presumed mode of HIV acquisition was sex between men (43.1%), followed by heterosexual transmission among women (27.2%) and men (18.9%). Differences in immune status at diagnosis were observed: migrants diagnosed post-migration had significantly lower cluster of differentiation 4 counts compared with Swiss nationals, suggesting later diagnosis in this group.
The median time between immigration and HIV diagnosis varied by gender and mode of acquisition. Male heterosexuals experienced the longest delay (median: 6 years), followed by men who have sex with men (5 years) and female heterosexuals (2 years). This timing also differed according to region of origin, reflecting complex patterns of mobility, health-seeking behaviour, and access to testing.
These findings indicate that more than half of all HIV diagnoses among migrants in Switzerland occur after arrival, suggesting ongoing risk and transmission within the country. The study highlights the importance of strengthening culturally sensitive prevention, early testing, and linkage to care initiatives for migrant communities to ensure equitable HIV outcomes across populations.
Doxycycline Post-exposure Prophylaxis Reduces Chlamydia and Syphilis but Not Gonorrhoea in the Swiss HIV Cohort
AN INTERIM analysis presented at the 20th EACS Conference provides real-world evidence from the Swiss HIV Cohort Study on the effectiveness of doxycycline postexposure prophylaxis (DoxyPEP) and the 4-component meningococcal B vaccine (4CMenB) in preventing bacterial sexually transmitted infections (STI) among men who have sex with men (MSM) living with HIV.4
Although clinical trials have demonstrated strong protective effects of DoxyPEP against certain STIs, its performance in routine practice has been less well characterised, and data on 4CMenB’s cross-protection against gonorrhoea remain inconsistent.
The observational study enrolled 157 MSM at high behavioural risk, defined by sex without a condom with occasional partners and/or a recent history of bacterial STIs. Participants opted to use DoxyPEP and/or 4CMenB as off-label prevention strategies and were followed prospectively for a median of 253 days. STI incidence after study enrolment was compared with each individual’s prior 3-year history using adjusted mixed negative binomial regression models.
Overall, DoxyPEP use was associated with a marked reduction in bacterial STIs, with incidence dropping from 56.26 to 30.23 cases per 100 person-years (incidence rate ratio [IRR]: 0.53; p<0.005). The strongest effects were observed for chlamydia (IRR: 0.20; p<0.005) and syphilis (IRR: 0.30; p<0.01), aligning with previous trial data and reinforcing DoxyPEP’s role as an effective targeted prevention tool in high-risk populations.
However, neither DoxyPEP nor 4CMenB demonstrated protective effects against gonorrhoea. IRRs were non-significant for both DoxyPEP-only users (IRR: 0.97; p≥0.05) and those receiving both interventions (IRR: 1.09; p≥0.05), indicating no measurable benefit. These findings contribute to ongoing uncertainty around 4CMenB’s potential cross-protection and highlight the persistent challenge of preventing gonococcal infections amid rising antimicrobial resistance.
In summary, the interim results confirm that DoxyPEP substantially reduces chlamydia and syphilis infections in real-world practice among MSM living with HIV, while showing no impact on gonorrhoea. Likewise, 4CMenB offered no observable protection. Continued follow-up and larger datasets will be important for refining prevention strategies and understanding longer-term outcomes.
Novel Chemsex Patterns and Emerging HIV Prevention Needs
A RECENT study presented at the 20th EACS Conference has examined chemsex, the use of drugs to enhance or maintain sexual experiences, which is increasingly recognised as being linked to heightened risks of HIV and other sexually transmitted infections (STI).5
While ‘classic’ chemsex substances such as methamphetamine, ketamine, gamma-hydroxybutyrate/gamma-butyrolactone, and mephedrone have long been documented, newer synthetic cathinones and hallucinogens are now broadening the chemsex landscape across Europe.
The study surveyed 14,652 men who are HIV-negative and have sex with men and transgender individuals across 20 European countries to explore how these ‘novel’ substances relate to STI prevalence and engagement in HIV prevention, particularly pre-exposure prophylaxis (PrEP).
Using latent class analysis, researchers identified five patterns of sexualised substance use. One group, defined by the use of novel chemsex drugs, reported the highest rates of recent STIs, including syphilis, gonorrhoea, and chlamydia. Despite relatively high oral PrEP uptake within this group, adherence was often inconsistent, potentially diminishing the drug’s protective effect. Another group, involving younger individuals engaging in moderate chemsex, showed lower uptake of oral PrEP and similarly high rates of suboptimal adherence and discontinuation, indicating additional barriers to sustained prevention.
A notable finding was the strong interest in long-acting injectable PrEP (LAI-PrEP), especially among those using novel chemsex substances, suggesting that it may offer a practical alternative for people who struggle with daily pills. By contrast, those who did not use harder drugs showed the lowest interest in LAI-PrEP.
Overall, the study highlights that chemsex practices are evolving and that HIV prevention strategies must adapt accordingly. Expanding access to LAI-PrEP and developing tailored harm-reduction interventions could help address unmet prevention needs and reduce the elevated STI and HIV risks associated with novel chemsex use across Europe.
Comparable Quality of Life in Well-Treated People with HIV
A NEW 8-year longitudinal analysis from the AGEhIV cohort, presented at the 20th EACS Conference, provides reassuring evidence that ageing people with HIV (PWH) who are well treated and virally suppressed can experience health-related quality of life comparable to peers who are HIV-negative.6
While HIV has historically been associated with accelerated ageing and increased comorbidity burden, there has been uncertainty about whether this translates to measurable differences in long-term physical and mental wellbeing.
The study followed 522 PWH and 532 demographically matched controls enrolled between 2010–2012, the majority of whom were men who have sex with men. Participants completed the 36-Item Short Form (SF-36) questionnaire at multiple time points over a period of 8 years, generating physical (PCS) and mental (MCS) component scores. Analyses excluded individuals not on antiretroviral therapy or with detectable viraemia, ensuring that the cohort reflected contemporary standards of effective HIV care. Mixed-effects regression models adjusted for sociodemographic factors, comorbidities, and time-updated lifestyle behaviours.
Overall, trajectories in both PCS and MCS did not differ between PWH and controls, indicating parallel patterns of change in quality of life with ageing. Although PWH had slightly lower adjusted mean PCS scores (by about 2 points on a 100-point scale), and marginally lower MCS scores, these differences were small and of uncertain clinical significance. Importantly, no widening gap was observed over time, suggesting that effective HIV treatment and routine management of comorbidities largely mitigate health-related quality-of-life disparities.
These findings challenge assumptions that ageing with HIV necessarily entails accelerated physical or mental decline. Instead, the results reinforce that with sustained viral suppression and comprehensive care, middle-aged PWH can maintain levels of physical and mental wellbeing comparable to those of individuals who are HIV-negative over the long term.
The study provides valuable real- world evidence for clinicians counselling ageing patients with HIV and highlights the continued importance of early treatment, stable viral suppression, and proactive chronic disease management in supporting healthy ageing.
Switch to Doravirine Does Not Alter Metabolic Outcomes in HIV
RESULTS from the AIDS Clinical Trials Group A5391/DO-IT trial, presented at the 20th EACS Conference, revealed that switching from an integrase strand transfer inhibitor (INSTI) plus tenofovir alafenamide (TAF) regimen to doravirine (DOR)-based therapy, with or without tenofovir disoproxil fumarate (TDF), did not significantly affect weight, metabolic parameters, or body composition at 48 weeks among people with HIV and obesity.7
Weight gain associated with INSTI- and TAF-containing regimens has raised clinical concern, particularly for individuals who develop obesity or metabolic dysfunction during long-term antiretroviral therapy. The DO-IT study evaluated whether replacing INSTI+TAF with DOR, a non-nucleoside reverse transcriptase inhibitor, could improve metabolic outcomes while maintaining viral suppression.
In this RCT, USA participants with HIV, obesity (BMI >30 kg/m²), and stable viral suppression on INSTI+TAF regimens were assigned to switch to DOR+TAF/emtricitabine (FTC), DOR+TDF/FTC, or to continue their existing therapy. Linear regression models adjusted for sex, race, and baseline values were used to compare 48-week changes in fasting lipids, insulin resistance (measured by homeostatic model assessment for insulin resistance [HOMA-IR]), and body composition by dual-energy X-ray absorptiometry. Participants using lipid-lowering or insulin therapies were excluded from the relevant analyses.
Among 145 participants initiating or maintaining study treatment, the median age was 49 years, with a median BMI of 34.9 kg/m² and a median HOMA-IR of 6.2, indicating substantial insulin resistance. Nearly half of participants (49%) were female, 53% were Black, and 18% were Hispanic/Latino.
No significant differences were observed between DOR-based and INSTI-based regimens for triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or HOMA-IR. Similarly, changes in total fat, trunk fat, and lean mass were comparable across groups. At 48 weeks, the estimated difference in total fat mass change versus INSTI+TAF/FTC was +3.43 percentage points (p=0.13) for DOR+TAF/FTC and –0.09 points (p=0.97) for DOR+TDF/FTC. Differences for trunk fat and lean mass were also non-significant.
These findings indicate that switching to DOR-based regimens does not meaningfully improve lipid profiles, insulin resistance, or adiposity in people with HIV and obesity. Additional interventions beyond antiretroviral modification are needed to address metabolic complications in this population.
Injectable HIV Therapy Failure Linked to Drug Resistance
RECENT findings presented at the 20th EACS Conference revealed that virological failure on long-acting injectable cabotegravir (CAB)/rilpivirine (RPV) remains uncommon, but often leads to the emergence of drug resistance. This resistance may restrict future treatment options for people living with HIV.8
Researchers conducted a literature review up to January 2025 and identified 56 cases of virological failure. Resistance data were available for 46 individuals. Overall, 15/40 (37.5%) people experiencing failure showed suboptimal drug concentrations for either CAB or RPV. The most frequently detected resistance mutations were E148R/K/S (34.1%; 15/44) and N155H/S (22.7%; 10/44) in the integrase gene. Mutations in the reverse transcriptase gene included E138A/K/T (47.7%; 21/44), Y181C (11.4%; 5/44), and K101E/P (25.0%; 11/44).
Resistance testing showed that 59% (26/44) had integrase inhibitor resistance and 81% (36/44) had non-nucleoside reverse transcriptase inhibitor resistance. In addition, 54% (25/46) carried resistance to both CAB and RPV. Rates were highest in individuals with HIV-1 subtype A. Resistance was detected in 92.3% (12/13) for CAB and 100% (14/14) for RPV, compared with 46.7% (14/30) and 75.9% (22/29) for non-A subtypes. These resistance mutations not only reduce the future effectiveness of CAB/RPV, but also limit options for other integrase (dolutegravir or bictegravir: 39% of cases) and non-nucleoside reverse transcriptase inhibitor drugs (etravirine: 32%; doravirine: 23%).
Researchers emphasised that real-world use of long-acting CAB/RPV requires vigilant monitoring. While most individuals maintained viral suppression, those with failure and resistance needed individualised rescue regimens. Selection of future drug options must consider observed resistance mutations and patient subtype. This highlights the importance of timely intervention and personalised follow-up. These findings reinforce the need to balance novel delivery approaches with careful management to sustain long-term HIV control.
Long-Acting Cabotegravir Pre-exposure Prophylaxis Shows Good Safety
LATE-BREAKING findings presented at the 20th EACS Conference highlight the real-world tolerability and safety profile of long-acting cabotegravir (CAB-LA) for HIV pre-exposure prophylaxis (PrEP) in Italy.9
From December 2024–April 2025, 310 adults at hospital HIV prevention clinics in Milan and Rome, Italy, began CAB-LA PrEP. Of these, 255 received a second dose (98.8% on time) and 74 reached a third dose (100% on time). Pain at the injection site was the most frequent side effect, affecting 74.5% after the first dose and 58.1% after the second. Mean pain lasted 4.26 days after dose one and 3.7 days after dose two, with a mean severity score of 4.73 and 2.67 (out of 10) for the first and second doses, respectively.
Injection site nodules were reported in 22% of patients after the first dose and 13.5% after the second. Fever occurred in five patients after the first dose and two after the second. Four participants discontinued CAB-LA, three because of injection site pain and one due to entering a monogamous relationship. Two cases of gluteal phlegmon resolved with oral antibiotics without interrupting treatment. No HIV seroconversions were observed during a median 78-day follow-up.
Preliminary real-world experience shows that CAB-LA PrEP is well-tolerated and highly acceptable, with most local reactions diminishing after the first dose. Discontinuation for adverse events was rare. No new HIV infections were recorded in the cohort, supporting CAB-LA as a promising option for PrEP.
Lenacapavir Shows Promise for Sustained HIV Prevention
PRESENTED at the 20th EACS Conference, this analysis highlights the importance of persistence in pre-exposure prophylaxis (PrEP), as consistent use is central to preventing HIV.10
The PURPOSE 2 study compared twice-yearly subcutaneous lenacapavir with daily oral emtricitabine/tenofovir disoproxil fumarate (F/TDF) among cisgender gay, bisexual, and other men who have sex with men, as well as gender-diverse individuals. Lenacapavir had already shown superior efficacy in preventing HIV, and this analysis sought to understand whether its injectable delivery also supports better long-term persistence.
Participants were randomised to receive either twice-yearly lenacapavir injections or to take daily oral F/TDF. Persistence with PrEP was assessed after 1 year. For those receiving injections, persistence required an on-time Week 26 injection and an on- time follow-up visit at Week 52. For the F/TDF group, persistence was defined as maintaining dried blood spot levels consistent with taking at least four pills per week across four time points throughout the year.
Across PURPOSE 2, 66.2% of participants remained persistent with injections at 1 year, including both lenacapavir and placebo groups. In the randomly selected subgroup with dried blood spot samples, 61.2% of those receiving lenacapavir were persistent, compared with only 37.3% of those taking oral F/TDF. Notably, 68.6% of participants receiving placebo injections in the F/TDF arm also persisted, suggesting that the injection schedule itself may support routine adherence.
These findings indicate that twice-yearly injectable PrEP may help overcome challenges associated with maintaining consistent oral dosing, particularly for those who struggle with daily medication. The ongoing PURPOSE 5 study is now examining whether lenacapavir can similarly support improved PrEP persistence in real-world settings in the UK and France, which may further inform national HIV prevention strategies.
Prostate Cancer in People with HIV
FINDINGS presented at the 20th EACS Conference suggests that people living with HIV present with prostate cancer (PC) approximately a decade earlier, with more than a quarter of patients having metastatic disease at the time of diagnosis. These data emphasise the importance of tailored screening and treatment strategies in this population.11
PC is the most common malignancy in males living with HIV, but data on tumour stage at diagnosis and course of localised disease are limited. Researchers in Germany used a standardised questionnaire to collect data on HIV-related parameters, PC characteristics, and details of oncological and antiretroviral therapy from 16 HIV centres. They applied multivariable logistic discrete hazard models, adjusted for age at diagnosis, time since PC diagnosis, and CDC stage of HIV infection, to assess the impact of treatment strategies on overall survival (OS) and progression-free survival in patients with localised PC.
A total of 161 patients were included in the study (median age at PC diagnosis: 61 years). Of those with available staging data, 26% (31/118) had metastatic disease at presentation, and among those with localised PC, 29% were considered intermediate-risk and 59% high-risk for progression, based on the D’Amico classification. Over a 15-year period, there was no difference in progression-free survival between treatment strategies; however, researchers found a significant association between treatment modality and OS, after adjustment for age and CDC stage, with the lowest OS in patients receiving radiotherapy.
The team concluded that, compared to the German cancer registry, people living with HIV presented with PC earlier and with advanced disease, highlighting the need for appropriate screening and treatment strategies.
