Dalbavancin (DAL) is a lipoglycopeptide with bactericidal activity against a very wide range of Gram-positive microorganisms. It also has unique pharmacokinetic properties, namely a prolonged half-life (around 181 h), which allows a convenient weekly dosing regimen, and good diffusion in bone tissue. These features have led to off-label use of dalbavancin in the setting of bone and joint infection, including prosthetic joint infections (PJI). In this narrative review, we go over the pharmacokinetic and pharmacodynamic characteristics of DAL, along with published in vitro and in vivo experimental models evaluating its activity against biofilm-embedded bacteria. We also examine published experience of osteoarticular infection with special attention to DAL and PJI.

Background: The high effectiveness and safety of the two-drug (2DRs) strategy using dolutegravir (DTG) plus lamivudine (3TC) have led to international guidelines recommending their use for treatment-naive HIV patients. In virologically suppressed patients, de-escalating from 3DRs to DTG plus either rilpivirine (RPV) or 3TC has shown high rates of virological suppression. Objectives: This study aimed to compare the real-life data of two multicenter Spanish cohorts of PLWHIV treated with DTG plus 3TC (SPADE-3) or RPV (DORIPEX) as a switch strategy, not only in terms of virological suppression, safety, and durability but also in terms of immune restoration. The primary endpoint was the percentage of patients with virological suppression on DTG plus 3TC and DTG plus RPV at weeks 24 and 48. The secondary outcomes included the proportion of patients who experienced the protocol-defined loss of virological control by week 48; changes in immune status in terms of CD4+ and CD8+ T lymphocyte counts and the CD4+/CD8+ ratio; the rate, incidence, and reasons for discontinuation of treatment over the 48-week study period; and safety profiles at weeks 24 and 48. Methods: We conducted a retrospective, observational, multicenter study of 638 and 943 virologically suppressed HIV-1-infected patients in two cohorts who switched to 2DRs with DTG plus RPV or DTG plus 3TC. Results: The most frequent reasons for starting DTG-based 2DRs were treatment simplification/pill burden or drug decrease. The virological suppression rates were 96.9%, 97.4%, and 99.1% at weeks 24, 48, and 96, respectively. The proportion of patients with virological failure over the 48-week study period was 0.01%. Adverse drug reactions were uncommon. Patients treated with DTG+3TC increased CD4, CD8, and CD4/CD8 parameters at 24 and 48 weeks. Conclusions: We conclude that DTG-based 2DRs (combined with 3TC or RPV) in clinical practice were effective and safe as a switching strategy, with a low VF and high viral suppression rates. Both regimens were well tolerated, and ADR rates were low, including neurotoxicity and induced treatment discontinuations.

Background: Daily oral antiretroviral therapy (ART) has transformed HIV into a chronic, manageable condition, but it still poses psychological, logistical, and biological challenges. Long-acting injectable (LAI) cabotegravir plus rilpivirine provides an alternative for virologically suppressed individuals, reducing treatment fatigue, stigma, and daily dosing. While clinical trials have demonstrated efficacy and safety, real-world data remain limited. We assessed the effectiveness and safety of LAI cabotegravir plus rilpivirine in Spain. Methods: RELATIVITY is a 5-year, multicentre, ambispective, non-controlled cohort study. The primary endpoint was treatment effectiveness, defined as the proportion of patients discontinuing LAI therapy for any reason, including loss of virological suppression (HIV-RNA >50 copies/mL) during follow-up, regardless of formal failure criteria. Results: This interim analysis (cut-off: March 1, 2025) included 3203 patients from 58 Spanish hospitals; 57 were excluded due to detectable viral load at switch, leaving 3146 participants. Most were men (84.6%), with a median age of 45 years. Median time on ART before switching was 9.0 (5.0–15.0) years, and duration of viral suppression was 84.0 (36.0–132.0) months. Prior integrase inhibitor–based regimens were reported in 77.1%. Virological suppression was maintained in ≥96% through 23 months of follow-up. Overall, 6.4% (n = 199) discontinued, most frequently for injection-site reactions (n = 45), systemic adverse events (n = 29), or virological failure (n = 20). Conclusions: Interim results from the RELATIVITY cohort confirm high effectiveness and safety of LAI cabotegravir plus rilpivirine in Spanish clinical practice, consistent with randomized trial outcomes and real-world data. An extended follow-up will provide further insights.

Switching strategy with bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) has become a gold standard for people living with HIV (PLWH), achieving high efficacy and safety rates. However, data regarding immune status in long-term real-life cohorts of pretreated patients are needed. We performed a multicentre, non-controlled, retrospective study in virologically suppressed PLWH switching to B/F/TAF. We evaluated CD4⁺, CD8⁺ and CD4⁺/CD8⁺ ratio, efficacy and safety at weeks 48 and 96. The study comprised 1966 PLWH from 12 hospitals in Spain, of whom 80% were men, and the median age was 51.0 [42.0–57.0] years. The median time of HIV infection was 18.0 [10.0–27.0] years. No significant changes in CD4⁺, CD8⁺ T cells, or CD4⁺/CD8⁺ were observed after 96 weeks. Nevertheless, in women at weeks 48 and 96, we found a significant increase of CD4⁺ T cells and a significant decrease in CD8⁺ T cells. In patients ≥60 years at week 96, CD4 T cells significantly increased and CD8⁺ T cells significantly decreased at week 48. The on-treatment analysis revealed HIV-RNA <50 copies/mL in 95.6% (1700/1779) and 96.7% (1312/1356) of patients at weeks 48 and 96, respectively. The rates increased to 99.2% (1765/1779) and 99.7% (1352/1356) when considering HIV-RNA <200 copies/mL. No resistance mutations were detected in virologic failures. B/F/TAF discontinuations accounted for 10.2% (200). Simplification was the most common reason for discontinuation in 3.8% (74) of patients. In long-term virologically controlled PLWH, B/F/TAF achieved high efficacy rates and slightly improved immune status in women and individuals aged 60 and over after 48 and 96 of switching.

The in vivo selection of E157Q plus R263K has not been reported in patients treated with coformulated bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF). To the best of our knowledge, we hereby report the first case of high-grade INSTI resistance associated with the presence of these aminoacidic substitutions in a treatment-experienced HIV patient treated with BIC/FTC/TAF. Clinical case report and review of the literature. A heavily treatment-experienced patient was switched to BIC/FTC/TAF due to drug–drug interactions after being diagnosed with disseminated Mycobacterium avium-intracellulare disease. He had been treated before with raltegravir with poor adherence. No mutations in the integrase gene were detected 1 year after finishing treatment with raltegravir. Months after being switched to BIC/FTC/TAF, and again with poor adherence documented, virological failure (VF) was detected. The polymorphic substitution E157Q and the resistance mutation R263K in the integrase gene were detected, as well as M184V, among other mutations in the reverse transcriptase gene. The patient is currently being treated with dolutegravir q12h plus boosted darunavir along with directly observed treatment, and for the first time in 20 years, plasmatic viral load values are below 100 copies/mL. This case illustrates that the combination of E157Q and R263K plus M184V can be selected in vivo in a clinical scenario of poor adherence with BIC/FTC/TAF, although it is a very rare phenomenon. Previous VF with first-generation integrase strand transfer inhibitors (INSTIs) should be kept in mind when switching patients to second-generation INSTIs.