Efficacy Threshold Research Articles

Regional results of the lead evaluation for defibrillation and reliability (LEADR) trial

Abstract Introduction ICD/CRT-D patients are living longer, and interest in reliable leads with targeted placement is growing. The Lead EvaluAtion for Defibrillation and Reliability (LEADR) trial was designed to assess the novel small-diameter, lumenless, catheter-delivered, defibrillation study lead. The study lead is based on the SelectSecure SureScan MRI Model 3830 lumenless pacing lead delivered by catheter that has a simplified durable construction with improved long-term reliability (97.2% 12-year RV lead survival). Purpose The LEADR trial assessed the efficacy and safety of the novel defibrillation lead. Methods The global LEADR Pivotal trial (NCT04863664) enrolled patients with ACC/AHA/ESC guideline-directed indications for de novo implant of a primary or secondary prevention ICD/CRT-D. The primary efficacy and safety endpoints were defibrillation success at implant and freedom from study lead-related major complications at 6-months, respectively. Results A total of 643 patients were successfully implanted (61.9±12.9 years, 26% female, 28.5±6.4 kg/m2 BMI, and 80.9% NYHA Class II) with the study lead placed in the desired RV location in 99.5%. The estimated freedom from study lead-related major complications was 97.1% at 6- and 12-months. Defibrillation testing was successful in 116/119 (97.5%) patients. The prespecified primary efficacy and safety thresholds (88% and 90%, respectively) were exceeded. There were zero study lead fractures and electrical measurements were stable through 12.7±4.8-month mean follow-up. Approximately 20% of patients were in Asia, 9% in Australia, 21% in Europe, and 50% in North America (Table). The estimated freedom from study lead-related major complications at 6- and 12-months per region were 96.2% in Asia, 100% in Australia, 96.4% in Europe, and 97.2% in North America (Figure), P=0.82 across regions. There were 19 study lead-related major complications (5 in Asia, 0 in Australia, 5 in Europe, 9 in North America), with the most common being lead dislodgement across regions. Defibrillation testing was successful in 116/119 patients with 33/33 in Asia, 32/32 in Australia, 7/8 in Europe, and 44/46 in North America, P=0.11 across regions. Among the 3 patients with unsuccessful testing, 2 (North America) remained in the study at physician discretion after successful conversion outside of protocol requirements, and 1 (Europe) was exited. Pacing capture threshold, pacing impedance, and R-wave amplitude were chronically stable across regions. Conclusion The LEADR Pivotal trial demonstrated the safety, efficacy, and reliability of the novel defibrillation lead, exceeding prespecified efficacy and safety thresholds. There were no notable differences in primary endpoints between regions. The trial has met its endpoints and ongoing follow-up will provide long-term performance. This trial demonstrated the ability to place the lead in targeted RV locations; a study of this lead for conduction system pacing is forthcoming.TableFigure

Complication rate across the minimally invasive surgical treatments (MISTs): where do we stand? A systematic review of the literature.

Over the past decade, the range of surgical options to benign prostatic obstruction (BPO) has expanded significantly with the advent of minimally invasive surgical therapies (MISTs). Nevertheless, the available evidence in the field is heterogeneous. Efficacy and safety thresholds are yet to be determined. To evaluate perioperative and long-term complications after MISTs - including Aquablation, steam injection (Rezūm), Transperineal laser ablation of the prostate (TPLA), implantation of a prostatic urethral lift (PUL) and temporary implantable nitinol device (iTIND) - in patients with lower urinary tract symptoms due to BPO. A systematic literature search was conducted in January 2024 using Medline (via PubMed), Embase (via Ovid), Scopus, and Web of Science. The search strategy used PICO criteria (Patients, Interventions, Comparisons, Outcomes) [1], focusing specifically on patients with BPH-associated LUTS who underwent MIST or other comparative treatments, aiming to assess both perioperative and long-term safety outcomes. Article selection was conducted in accordance with the PRISMA guidelines. The risk of bias and the quality of the articles included were assessed. A dedicated data extraction form was used to collect the data of interest. The initial electronic search identified 3660 records, of which 24 ultimately met the inclusion criteria and were included in the analysis. Overall, Aquablation was associated with a higher major complications rate of 14% (IQR 6-22), particularly in the case of patients with prostates <70 ml. PUL showed a higher early postoperative acute urinary retention rate (10.9%, IQR 9.2-12.3%), while 1.4% of patients treated with iTIND experienced major perioperative complications. Urinary tract infections were mostly reported in series assessing TPLA and Rezūm. The adoption of MISTs for LUTS due to BPH is associated with a varied spectrum of perioperative and long-term complications. Our findings showed an acceptable safety profile with specific complications dependent on the type of MIST performed, highlighting the importance of individualized patient selection and procedure-specific considerations.

Nivolumab+AVD in Advanced-Stage Classic Hodgkin’s Lymphoma

BackgroundIncorporating brentuximab vedotin into the treatment of advanced-stage classic Hodgkin’s lymphoma improves outcomes in adult and pediatric patients. However, brentuximab vedotin increases the toxic effects of treatment in adults, more than half of pediatric patients who receive the drug undergo consolidative radiation, and relapse remains a challenge. Programmed death 1 blockade is effective in Hodgkin’s lymphoma, including in preliminary studies involving previously untreated patients.MethodsWe conducted a phase 3, multicenter, open-label, randomized trial involving patients at least 12 years of age with stage III or IV newly diagnosed Hodgkin’s lymphoma. Patients were randomly assigned to receive brentuximab vedotin with doxorubicin, vinblastine, and dacarbazine (BV+AVD) or nivolumab with doxorubicin, vinblastine, and dacarbazine (N+AVD). Prespecified patients could receive radiation therapy directed to residual metabolically active lesions. The primary end point was progression-free survival, defined as the time from randomization to the first observation of progressive disease or death from any cause.ResultsOf 994 patients who underwent randomization, 970 were included in the intention-to-treat population for efficacy analyses. At the second planned interim analysis, with a median follow-up of 12.1 months, the threshold for efficacy was crossed, indicating that N+AVD significantly improved progression-free survival as compared with BV+AVD (hazard ratio for disease progression or death, 0.48; 99% confidence interval [CI], 0.27 to 0.87; two-sided P=0.001). Owing to the short follow-up time, we repeated the analysis with longer follow-up; with a median follow-up of 2.1 years (range, 0 to 4.2 years), the 2-year progression-free survival was 92% (95% CI, 89 to 94) with N+AVD, as compared with 83% (95% CI, 79 to 86) with BV+AVD (hazard ratio for disease progression or death, 0.45; 95% CI, 0.30 to 0.65). Overall, 7 patients received radiation therapy. Immune-related adverse events were infrequent with nivolumab; brentuximab vedotin was associated with more treatment discontinuation.ConclusionsN+AVD resulted in longer progression-free survival than BV+AVD in adolescents and adults with stage III or IV advanced-stage classic Hodgkin’s lymphoma and had a better side-effect profile. (Funded by the National Cancer Institute of the National Institutes of Health and others; S1826 ClinicalTrials.gov number, NCT03907488.)

Exposure-Efficacy Analysis and Dopamine D2 Receptor Occupancy in Adults with Schizophrenia after Treatment with the Monthly Intramuscular Injectable Risperidone ISM.

Dopamine D2 receptor occupancy (D2RO) significantly influences the clinical effectiveness and safety of many antipsychotic drugs. Maintaining a D2RO range of 65%-80% provides the best antipsychotic effects while minimizing adverse reactions. Data from a Phase III trial were used to establish an exposure-response relationship for monthly intramuscular Risperidone ISM (75 and 100 mg) or placebo administered to adults with schizophrenia. Pharmacodynamic analysis was based on an Emax model for Positive and Negative Syndrome Scale (PANSS) developed in NONMEM. Plasma concentrations of the active moiety were derived using a previously developed population pharmacokinetic model, which was used for D2RO simulations in conjunction with a published Emax model. The optimal D2RO range (65%-80%) was reached for the median within hours following the first injection of both Risperidone ISM doses. At steady state, median D2RO for both doses remained above 65% throughout the 28-day dosing period and demonstrated lower variability than oral risperidone. PANSS response did not differ significantly between dose groups, most likely because active moiety concentrations had already reached the plateau of the concentration-response relationship. The pharmacokinetic/pharmacodynamic analysis showed a profound placebo effect (-11.7%), and an additional maximal drug effect (-6.6%) resulting in a total PANSS improvement over time of -18.3%. Pharmacokinetic/pharmacodynamic modeling quantified a PANSS improvement over time after Risperidone ISM administration. The response was not significantly different in either dose group, likely because D2RO was already above the proposed efficacy threshold (65%) within 1 h after the first Risperidone ISM injection and remained above this level following repeated administrations.

Pomalidomide for Epistaxis in Hereditary Hemorrhagic Telangiectasia

BackgroundHereditary hemorrhagic telangiectasia (HHT) is characterized by extensive telangiectasias and arteriovenous malformations. The primary clinical manifestation is epistaxis that results in iron-deficiency anemia and reduced health-related quality of life.MethodsWe conducted a randomized, placebo-controlled trial to evaluate the safety and efficacy of pomalidomide for the treatment of HHT. We randomly assigned patients, in a 2:1 ratio, to receive pomalidomide at a dose of 4 mg daily or matching placebo for 24 weeks. The primary outcome was the change from baseline through week 24 in the Epistaxis Severity Score (a validated bleeding score in HHT; range, 0 to 10, with higher scores indicating worse bleeding). A reduction of 0.71 points or more is considered clinically significant. A key secondary outcome was the HHT-specific quality-of-life score (range, 0 to 16, with higher scores indicating more limitations).ResultsThe trial was closed to enrollment in June 2023 after a planned interim analysis met a prespecified threshold for efficacy. A total of 144 patients underwent randomization; 95 patients were assigned to receive pomalidomide and 49 to receive placebo. The baseline mean (±SD) Epistaxis Severity Score was 5.0±1.5, a finding consistent with moderate-to-severe epistaxis. At 24 weeks, the mean difference between the pomalidomide group and the placebo group in the change from baseline in the Epistaxis Severity Score was −0.94 points (95% confidence interval [CI], −1.57 to −0.31; P=0.004). The mean difference in the changes in the HHT-specific quality-of-life score between the groups was −1.4 points (95% CI, −2.6 to −0.3). Adverse events that were more common in the pomalidomide group than in the placebo group included neutropenia, constipation, and rash.ConclusionsAmong patients with HHT, pomalidomide treatment resulted in a significant, clinically relevant reduction in epistaxis severity. No unexpected safety signals were identified. (Funded by the National Heart, Lung, and Blood Institute; PATH-HHT Clinicaltrials.gov number, NCT03910244).

Population Pharmacokinetics and Pharmacodynamics of Dalbavancin and C-Reactive Protein in Patients with Staphylococcal Osteoarticular Infections.

Dalbavancin is increasingly used for the long-term treatment of chronic osteoarticular infections. A population pharmacokinetic/pharmacodynamic (PK/PD) analysis for assessing the relationship between dalbavancin exposure and C-reactive protein (C-RP) over time was conducted. Non-linear mixed-effect modeling was fitted to dalbavancin and C-RP concentrations. Monte Carlo simulations assessed the weekly percentage of C-RP reduction associated with different dosing regimens, starting from baseline to < 1mg/dL. A total of 45 patients were retrospectively included in the analysis. The PK of dalbavancin was described by a two-compartment model, and the PD of C-RP was described by an indirect turnover maximum inhibition model. The total dalbavancin concentration model estimate producing 50% of maximum C-RP production inhibition (IC50) was 0.70 mg/L. Monte Carlo simulations showed that in patients with staphylococcal osteoarticular infections targeting total dalbavancin concentrations at > 14.5 mg/L at any time point may achieve C-RP production inhibition over time in > 95% of patients. Based on this, the findings showed that a cumulative dose of 3000 mg administered in the first 3weeks may lead to a > 90% C-RP decrease versus baseline in approximately 5-6 weeks. In patients needing treatment prolongation, an additional 1500mg dose after this period may maintain C-RP concentrations < 1 mg/dL for other 3 weeks. A decrease in C-RP is related to dalbavancin exposure in osteoarticular infections. Targeting dalbavancin plasma concentrations above the efficacy threshold may be associated with effective treatment.

Cabozantinib plus ipilimumab/nivolumab in patients with previously treated advanced differentiated thyroid cancer.

This investigator-initiated phase II trial aimed to evaluate the efficacy of cabozantinib in combination with nivolumab and ipilimumab (CaboNivoIpi) in previously treated patients with radioactive iodine (RAI)-refractory differentiated thyroid cancer (DTC) (NCT03914300). Eligible patients with RAI-refractory DTC who progressed on 1 prior line of VEGFR-targeted therapy received a 2-week run-in of cabozantinib monotherapy followed by CaboNivoIpi for 4 cycles (cycle length = 6 weeks), followed by cabozantinib plus nivolumab (cycle length = 4 weeks) until disease progression. The primary endpoint was objective response rate (ORR) within the first 6 months of treatment. A Simon optimal 2-stage design allowed for an interim analysis after accrual of 10 evaluable patients. At least 5 responses were needed to proceed to stage 2. Among 11 patients enrolled, the median age was 69 years. Prior VEGFR-targeted therapies included lenvatinib, pazopanib, and sorafenib plus everolimus. Median follow-up was 7.9 months. Among 10 evaluable patients, ORR within the first 6 months of treatment was 10% (1 partial response). Median progression-free survival was 9 months [95% CI: 3.0, not reached] and median overall survival was 19.2 months [(95% CI: 4.6, not reached]. Grade 3/4 treatment-related adverse events (AEs) were noted in 55% (6/11) and grade 5 AEs in 18% (2/11) of patients. The most common treatment-related AE was hypertension. The study did not reach its prespecified efficacy threshold. CaboNivoIpi had low ORRs and a high rate of grade ≥3 treatment-related AEs. NCT03914300.

Performance improvement of reflective phosphor film via adjusting the thickness realizing bright and efficient laser lighting.

Phosphor-in-glass-film (PiG-F) has been extensively investigated, showing great potential for use in laser lighting technique. Thickness is apparently a key parameter for PiG-F, affecting the heat dissipation, absorption, and reabsorption, thus determining the luminous efficacy and luminescence saturation threshold (LST). Conventional studies suggest that thinner films often have lower thermal load than that of the thicker ones. Unexpectedly, we found that the Lu3Al5O12:Ce (LuAG:Ce)-based PiG-F with a moderate thickness (78 μm) yielded the optimal LST of 31.9 W (14.2 W·mm-2, rather than 28.0 W (12.3 W·mm-2) for the thinnest one (56 μm). This unexpected result was further verified by thermal simulations. With the high saturation threshold together with a high luminous efficacy (∼296 lm·W-1), an ultrahigh luminous flux of 7178 lm with a luminous exitance of 2930 lm·mm-2 was thus attained. We believe the new, to the best of our knowledge, findings in this study will substantially impact the design principles of phosphors for laser lighting.

Intra-individual Dose Escalation of Abiraterone According to Its Plasma Exposure in Patients with Progressive Metastatic Castration-Resistant Prostate Cancer: Results of the OPTIMABI Trial.

Trough abiraterone concentration (ABI Cmin) of 8.4 ng/mL has been identified as an appropriate efficacy threshold in patients treated for metastatic castration-resistant prostate cancer (mCRPC). The aim of the phase II OPTIMABI study was to evaluate the efficacy of pharmacokinetics (PK)-guided dose escalation of abiraterone acetate (AA) in underexposed patients with mCRPC with early tumour progression. This multicentre, non-randomised study consisted of two sequential steps. In step 1, all patients started treatment with 1000 mg of AA once daily. Abiraterone Cmin was measured 22-26 h after the last dose intake each month during the first 12 weeks of treatment. In step 2, underexposed patients (Cmin < 8.4 ng/mL) with tumour progression within the first 6 months of treatment were enrolled and received AA 1000 mg twice daily. The primary endpoint was the rate of non-progression at 12 weeks after the dose doubling. During step 1, adherence to ABI treatment was assessed using the Girerd self-reported questionnaire. A post-hoc analysis of pharmacokinetic (PK) data was conducted using Bayesian estimation of Cmin from samples collected outside the sampling guidelines (22-26 h). In the intention-to-treat analysis (ITT), 81 patients were included in step 1. In all, 21 (26%) patients were underexposed in step 1, and 8 of them (38%) experienced tumour progression within the first 6 months. A total of 71 patients (88%) completed the Girerd self-reported questionnaire. Of the patients, 62% had a score of 0, and 38% had a score of 1 or 2 (minimal compliance failure), without a significant difference in mean ABI Cmin in the two groups. Four patients were enrolled in step 2, and all reached the exposure target (Cmin > 8.4 ng/mL) after doubling the dose, but none met the primary endpoint. In the post-hoc analysis of PK data, 32 patients (39%) were underexposed, and ABI Cmin was independently associated with worse progression-free survival [hazard ratio (HR) 2.50, 95% confidence interval (CI) 1.07-5.81; p = 0.03], in contrast to the ITT analysis. The ITT and per-protocol analyses showed no statistical association between ABI underexposure and an increased risk of early tumour progression in patients with mCRPC, while the Bayesian estimator showed an association. However, other strategies than dose escalation at the time of progression need to be evaluated. Treatment adherence appeared to be uniformly good in the present study. Finally, the use of a Bayesian approach to recover samples collected outside the predefined blood collection time window could benefit the conduct of clinical trials based on drug monitoring. OPTIMABI trial is registered as National Clinical Trial number NCT03458247, with the EudraCT number 2017-000560-15).

Efficacy thresholds and target populations for antiviral COVID-19 treatments to save lives and costs: a modelling study

In 2023 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was declared endemic, yet hospital admissions have persisted and risen within populations at high and moderate risk of developing severe disease, which include those of older age, and those with co-morbidities. Antiviral treatments, currently only available for high-risk individuals, play an important role in preventing severe disease and hospitalisation within this subpopulation. Here, we further explore the public health and economic benefits of extending target populations for treatment, and assess efficacy thresholds for a treatment strategy to be cost-saving. We adapted an individual-based transmission model of SARS-CoV-2, OpenCOVID, which was calibrated and validated to 2020-2023 Swiss, European, and Northern Hemisphere epidemiological data. We used the model to estimate hospitalisations and overall costs for preventatively treating three risk groups for a full range of treatment efficacies and coverages with, besides vaccination and hospital treatments, no other interventions in place. We further calculated efficacy thresholds for strategies to be cost-saving. A global sensitivity analysis was conducted to test the sensitivity of all outcomes for a wide range of treatment properties, emerging variant properties, and vaccination coverages. In a high vaccination coverage setting, we found that a high efficacy antiviral treatment given to all those at high-risk could reduce hospitalisations by up to 40%. When expanding treatment coverage to also include all those at moderate-risk, an additional 50% of hospitalisations could be averted. Targeting both high-risk and moderate-risk groups was found to be cost-saving for a treatment efficacy greater than ∼40%. This threshold was found to be robust regardless of vaccination coverage and emerging variant properties, but highly sensitive to treatment costs. For a sufficiently efficacious antiviral treatment, expanding the target population to include both high-risk and moderate-risk groups should be considered. Equitable treatment costs are found crucial in achieving the best possible public health and health economic outcomes. Botnar Research Centre for Child Health (DZX2165 to MAP), the Swiss National Science Foundation Professorship of MAP (P00P3_203450) and Swiss National Science Foundation NFP 78 Covid-19 2020 (4079P0_198428 to MAP).

Real-world evidence demonstrates an appropriate atrial fibrillation population for hybrid convergent approach versus stand-alone cryoballoon ablation: A long-term safety and efficacy study.

A hybrid convergent approach (endocardial and epicardial ablation) demonstrated superior effectiveness in a recent randomized study for long-standing persistent atrial fibrillation (LSPAF). Yet, there is a lack of real-world, long-term evidence as to which patients are best candidates for a hybrid convergent approach compared to standard endocardial cryoballoon pulmonary vein isolation (CB PVI). This single-center, retrospective analysis spanning from 2010 to 2015 compared two distinctly different atrial fibrillation (AF) cohorts; one treated with stand-alone cryoablation and one treated with a hybrid convergent approach. Baseline characteristics described candidates for each approach. The following criteria were utilized to determine CB PVI candidacy: (1) paroxysmal AF (PAF) (stage 3A) with failed class I/III antiarrhythmic drug (AAD) or (2) persistent/LSPAF (stage 3B/3C/3D) with failed class I/III AAD unwilling to undergo hybrid procedure. Selection criteria for the hybrid procedure included: (1) PAF refractory to both class I/III AAD and prior CB PVI (stage 3D) or (2) persistent/LSPAF (stage 3B/3C/3D) with failed class I/III AAD agreeable to hybrid procedure. Prior sternotomy was excluded. Serial electrocardiograms and continuous monitoring evaluated primary efficacy outcome of time-to-first recurrence of atrial arrhythmia after a 90-day blanking period. Secondary outcomes were procedure-related complications and AAD use (at discharge, 12, and 36 months). Kaplan-Meier methods evaluated arrhythmia recurrence. Of 276 patients, 197 (64.2 ± 10.6 years old; 66.5% male; 74.1% 3A-PAF; 18.3% 3B/3D-persistent AF; 1.0% 3C-LSPAF; 6.6% undetermined) underwent CB PVI and 79 (61.4 ± 8.1 years old; 83.5% male; 41.8% 3D-PAF; 45.5% 3B/3D-persistent AF; 12.7% 3C/3D-LSPAF) underwent hybrid procedure. Arrhythmia freedom through 36 months was 55.2% for CB PVI and 50.4% for hybrid (p = .32). Class I AAD utilization at discharge occurred in 38 (19.3%) patients in the CB PVI group and 5 (6.3%) patients in the hybrid group (p = .01). CB PVI class I AAD utilization at 12 months occurred in 14 (9.0) patients versus 0 patients for hybrid convergent (p = .004). Patients with one or more adverse event were as follows: two (1.0%) in the CB PVI group (both transient phrenic nerve palsy) and three (3.7%) in the hybrid group (two with significant bleeding and one with wound infection) (p = .14). This study demonstrated that patients with more complex forms of AF (3D-PAF or 3B/3C/3D-persistent/LSPAF) could be well managed with a convergent approach. In a real-world evaluation, outcomes match safety and efficacy thresholds achieved for patients with earlier, less complex AF etiologies treated by CB PVI alone.

TRIUMPH: phase II trial of rucaparib monotherapy in patients with metastatic hormone-sensitive prostate cancer harboring germline homologous recombination repair gene mutations.

The activity of PARP inhibitors (PARPi) in patients with homologous recombination repair (HRR) mutations and metastatic castration-resistant prostate cancer has been established. We hypothesized that the benefit of PARPi can be maintained in the absence of androgen deprivation therapy (ADT) in an HRR-mutated population. We report the results of a phase II clinical trial of rucaparib monotherapy in patients with metastatic hormone-sensitive prostate cancer (mHSPC). This was a multi-center, single-arm phase II trial (NCT03413995) for patients with asymptomatic, mHSPC. Patients were required to have a pathogenic germline mutation in an HRR gene for eligibility. All patients received rucaparib 600 mg by mouth twice daily, without androgen deprivation. The primary endpoint was a confirmed PSA50 response rate. Twelve patients were enrolled, 7 with a BRCA1/2 mutation and 5 with a CHEK2 mutation. The confirmed PSA50 response rate to rucaparib was 41.7% (N = 5/12, 95% CI: 15.2-72.3%, one-sided P = .81 against the 50% null), which did not meet the pre-specified efficacy boundary to enroll additional patients. In patients with measurable disease, the objective response rate was 60% (N = 3/5), all with a BRCA2 mutation. The median radiographic progression-free survival on rucaparib was estimated at 12.0 months (95% CI: 8.0-NR months). The majority of adverse events were grade ≤2, and expected. Rucaparib can induce clinical responses in a biomarker-selected metastatic prostate cancer population without concurrent ADT. However, the pre-specified efficacy threshold was not met, and enrolment was truncated. Although durable responses were observed in a subset of patients, further study of PARPi treatment without ADT in mHSPC is unlikely to change clinical practice.

Insufficient duration of insecticidal efficacy of Yahe® insecticide-treated nets in Papua New Guinea

BackgroundInsecticide-treated nets (ITNs) are the backbone of anti-malarial vector control in Papua New Guinea (PNG). Over recent years the quality and performance of ITNs delivered to PNG decreased, which has likely contributed to the stagnation in the malaria control effort in the country. The present study reports results from the first 24 months of a durability study with the ITN product Yahe LN® in PNG.MethodsThe durability study was conducted in four villages on the northern coast of PNG, in an area with high malaria parasite transmission, following WHO-recommended methodology adapted to the local scenario. A cohort of n = 500 individually identifiable Yahe® ITNs was distributed by the PNG National Malaria Control Programme from October to December 2021. Insecticidal efficacy of the ITNs was tested using cone bioassays with fully pyrethroid susceptible Anopheles farauti colony mosquitoes at baseline and at 6 months intervals, alongside evaluation of physical integrity and the proportion of ITNs lost to follow-up. A questionnaire was used to collect information on ITN end user behaviour, such as the frequency of use and washing. The observations from the durability study were augmented with simulated laboratory wash assays.ResultsGradual uptake and replacement of previous campaign nets by the communities was observed, such that at 6 months 45% of all newly distributed nets were in use in their designated households. Insecticidal efficacy of the Yahe® nets, expressed as the percent 24 h mortality in cone bioassays decreased from 91 to 45% within the first 6 months of distribution, even though > 90% of study nets had never been washed. Insecticidal efficacy decreased further to < 20% after 24 months. ITNs accumulated physical damage (holes) at a rate similar to previous studies, and 35% were classified as ‘too torn’ by proportional hole index after 24 months. ITNs were lost to follow-up such that 61% of cohort nets were still present after 24 months. Laboratory wash assays indicated a rapid reduction in insecticidal performance with each consecutive wash such that average 24 h mortality was below 20% after 10 washes.ConclusionYahe® ITNs are not performing as per label claim in an area with fully pyrethroid susceptible vectors, and should be investigated more comprehensively and in other settings for compliance with currently recommended durability and efficacy thresholds. The mass distribution of low quality ITN products with variable performance is one of the major ongoing challenges for global malaria control in the last decade.

Correlation between imatinib trough concentration and efficacy in patients with advanced GIST with different genotypes.

e23515 Background: Imatinib (IM) has significantly enhanced the prognosis of patients (pts) with advanced gastrointestinal stromal tumors (GISTs). The clinical outcomes may correlate with IM exposure. However, the efficacy threshold, particularly based on different primary KIT mutant, remains undefined. This study aimed to establish the efficacy threshold of IM plasma trough concentration (Cmin) at steady-state in Chinese pts with advanced GIST, additionally to define subgroup thresholds based on various primary KIT mutations. Methods: This was a single-center, prospective, observational cohort study. Pts with histologically confirmed recurrent/metastatic GIST who received regular IM treatment and had undergone at least two measurements of steady-state IM Cmin were enrolled from Jul 2017 to Jun 2022. Clinical outcomes including objective response rate (ORR), survival, and IM Cmin were assessed. Results: A total of 168 pts with a median age of 52y were enrolled. The primary lesion locations comprised stomach, small intestine, rectum and others. Metastatic lesions were found in the liver, peritoneum, both liver and peritoneum and others. Median sum of longest diameter of target lesions was 10.7cm. Of 168 pts, 117 (69.6%) harbored KIT 11, 27 (16.1%) harbored KIT 9, 5 (3.0%) harbored PDGFRA, and 9 (5.4%) were KIT/PDGFRA wild type. During IM response period, 104 pts combined with surgical treatment (surgery or interventional therapy). After a median follow-up duration was 50.6m (range, 16.3–189.8), 72 pts had disease progression and 20 died. Estimated median progression-free survival (mPFS) for all patients was 79.4m (95%CI 55.7–103.1). The median overall survival was not reached. A Cmin threshold of ≥738ng/ml defined by log-rank test was associated with longer PFS for the whole population (P = 0.002) irrespective of other clinical characteristics. Pts with an IM Cmin below 738ng/ml exhibited a shorter mPFS (25.3m, 95%CI 41.9–97.1) compared to those surpassing this threshold (96.7m, 95%CI 65.8–127.6). The ORR for the whole population was 73.0% (CR 2.2%, PR 70.8%), with no significant difference observed between pts with IM Cmin below and above 738ng/ml. For pts with KIT 11 and KIT 9 mutations, the efficacy thresholds for IM Cmin were ≥680ng/ml and ≥1877ng/ml, respectively. Multivariate Cox regression analysis revealed that IM Cmin ≥738ng/ml, primary gastric origin, liver-only metastasis, sum of target lesions diameter ≤5cm, KIT 11 mutation, and combined with surgical treatment were favorable prognostic factors. Conclusions: IM exposure significantly correlates with clinical benefits in advanced GISTs, with an IM Cmin above 738ng/ml associated with a longer PFS in Chinese population. Considering different primary KIT mutant, a threshold of 680 ng/ml could be considered for efficacy in KIT 11 mutations, while a higher Cmin of 1877 ng/ml was necessary for KIT 9 mutation.

Pembrolizumab for advanced urothelial carcinoma: exploratory ctDNA biomarker analyses of the KEYNOTE-361 phase 3 trial

Circulating tumor DNA (ctDNA) is emerging as a potential biomarker in early-stage urothelial cancer, but its utility in metastatic disease remains unknown. In the phase 3 KEYNOTE-361 study, pembrolizumab with and without chemotherapy was compared with chemotherapy alone in patients with metastatic urothelial cancer. The study did not meet prespecified efficacy thresholds for statistical significance. To identify potential biomarkers of response, we retrospectively evaluated the association of pre- and posttreatment ctDNA with clinical outcomes in a subset of patients who received pembrolizumab (n = 130) or chemotherapy (n = 130) in KEYNOTE-361. Baseline ctDNA was associated with best overall response (BOR; P = 0.009), progression-free survival (P < 0.001) and overall survival (OS; P < 0.001) for pembrolizumab but not for chemotherapy (all; P > 0.05). Chemotherapy induced larger ctDNA decreases from baseline to treatment cycle 2 than pembrolizumab; however, change with pembrolizumab (n = 87) was more associated with BOR (P = 4.39 × 10−5) and OS (P = 7.07 × 10−5) than chemotherapy (n = 102; BOR: P = 1.01 × 10−4; OS: P = 0.018). Tumor tissue-informed versions of ctDNA change metrics were most associated with clinical outcomes but did not show a statistically significant independent value for explaining OS beyond radiographic change by RECIST v.1.1 when jointly modeled (pembrolizumab P = 0.364; chemotherapy P = 0.823). These results suggest distinct patterns in early ctDNA changes with immunotherapy and chemotherapy and differences in their association with long-term outcomes, which provide preliminary insights into the utility of liquid biopsies for treatment monitoring in metastatic urothelial cancer. Clinical trial registration: NCT02853305.

Standard atezolizumab leads to severe overexposure in real-world patients with lung cancer: How far could we go in extending dosing intervals and saving money?

3085 Background: Immune checkpoint inhibitors are given as fixed doses, which may lead to drug exposure exceeding the plasma concentrations required for target engagement. If confirmed, this could pave the way for de-escalating treatments without compromising efficacy while reducing drug-costs. Methods: We monitored plasma concentrations of Atezolizumab in 40 real-world patients. A final set of 33 patients with SCLC or NSCLC were available for full PK/PD analysis. Individual PK parameters were derived using a population pharmacokinetics approach. Individual PK parameters allowed to simulate the full concentration-time profiles and to further simulate for each patient the time to reach the target threshold after the first dose of Atezolizumab. In addition, efficacy (RECIST criteria) and immune-related adverse events, (IRAEs, CTCAE grading) were monitored and statistical analysis was performed to search for possible exposure-response relationships. Results: Overall Response Rate was 55% and no severe IRAEs were observed. All patients had Cmin levels significantly above the target threshold on the first cycle of Atezolizumab. The mean Cmax after the first dose on cycle 1 was 426.1 µg/ml and the mean Cmin was 68.5 µg/ml, i.e. 11-time higher than the target threshold associated with target engagement (i.e., 6 µg/ml). The mean AUC at the first cycle was 4763 µg.d/ml. Exposure metrics and PK parameters at baseline and simulated prior RECIST evaluation were tested together with other covariates (i.e. age, sex, smoking, NLR, number of metastatic sites, line of treatment) as possible predictive markers of response or toxicity. None of the parameters related to Atezolizumab pharmacokinetics or exposure levels were associated with efficacy or toxicity, most likely because all patients had plasma levels well above pharmacologically active concentrations. First-line therapy was associated with better response on univariate analysis, but this effect was lost on multivariate analysis. Further simulations based on time required to fall below the efficacy threshold suggest that dosing intervals could be extended from Q7W to Q19W (mean: Q12W). Considering the annual budget for Atezolizumab at our institution, further simulations showed that the annual drug cost could thus be reduced from 2.5 M€ to 0.6 M€ while ensuring that all patients remain above active concentrations. Conclusions: Our study demonstrates in a real-world setting that standard Atezolizumab given as 1200 mg Q3W infusion leads to severe overexposure of the drug. This strong overexposure was not associated with more severe treatment-related toxicities. Finally, our study suggests that PK-guided dosing with Atezolizumab could help customizing the dosing interval while maintaining efficacious trough levels and that Q12W could be an alternate scheduling leading to significant cut in drug costs.

A phase I/II study of talazoparib and axitinib in patients with advanced clear cell renal cell carcinoma.

4541 Background: Targeting the VEGF pathway is a backbone therapeutic for patients with advanced clear cell renal cell carcinoma (ccRCC). Tumor and tissue hypoxia may also lead to DNA repair suppression and PARPs are key regulators of DNA damage and genomic maintenance which interact with HIF proteins. Pairing a potent VEGFR TKI with a selective PARP inhibitor (PARPi) may lead to improved outcomes in ccRCC patients. Methods: This was a phase I/II, investigator-initiated, single-center, open-label study (NCT04337970) of talazoparib plus axitinib in previously treated ccRCC patients. In the phase Ib dose escalation, patients must have been previously treated with a PD-1/PD-L1 inhibitor with no maximum lines of prior therapy, and those in dose expansion were required to have prior treatment with a PD-1/PD-L1 inhibitor and prior VEGFR TKI, with a maximum of 2 prior lines of therapy. Patients received escalating doses of talazoparib (0.5 mg, 0.75 mg and 1 mg daily) with axitinib (5 mg twice daily) in a 3+3 design, with primary endpoint of safety and tolerability. After establishing the recommended phase II dose (RP2D), a dose expansion cohort enrolled patients in a Simon two-stage design with a primary endpoint of objective response (ORR), and secondary endpoints including progression-free survival (PFS). Results: From 2020-2023, 23 ccRCC patients were enrolled and treated on study. In the dose escalation, 15 patients enrolled across all 3 dose levels and there were 2 observed DLTS (1 in dose levels 2 and 3). Both DLTs was due to a lack of minimum exposure to study drugs during cycle 1 due to treatment-related toxicities. The maximum tolerated dose and RP2D established was 1 mg talazoparib daily with axitinib 5 mg twice daily. In the phase II dose expansion portion, an additional 9 patients were enrolled to evaluate preliminary efficacy. In total, 13/14 patients treated at the RP2D discontinued therapy due to progressive disease. The objective response rate (ORR) was 7% (90% CI 0, 30), with 1 patient achieving a partial response and 12 patients achieving stable disease (86%). With a median follow-up of 13.2 months (R: 6.6 -29), the median PFS was 6.1 months (95% CI 3.5, 8.4) and median overall survival (OS) was 27 months (95% CI 12- NE). Across the study, 13 (56%) patients had at least one treatment-emergent AE of grade 3+, and 9 (39%) patients had at least one treatment-related AE of grade 3+. Most common grade 3+ AEs included diarrhea, nausea, and anemia. Conclusions: This is the first clinical study evaluating combination PARPi and VEGFR TKI in metastatic ccRCC patients. This study established the RP2D and MTD of combination talazoparib and axitinib and demonstrated a tolerable safety profile across all dose escalation cohorts. The study did not meet the pre-defined efficacy threshold for further enrollment per Simon stage two design. Exploratory efforts to evaluate this treatment approach with tissue biomarker data remain ongoing. Clinical trial information: NCT04337970 .

Final analysis of a phase II trial of daratumumab, carfilzomib, lenalidomide, and dexamethasone in newly diagnosed multiple myeloma without transplant

We evaluated the efficacy and safety of 24 cycles of Dara in combination with carfilzomib (K), lenalidomide (R), and dexamethasone (d) without autologous stem cell transplant (ASCT) in newly diagnosed multiple myeloma (NDMM) irrespective of ASCT eligibility in a single-arm, phase II study. The primary endpoint was the rate of stringent complete response (sCR) and/or measurable residual disease (MRD) < 10−5 by next-generation sequencing (NGS) at the end of cycle 8 (C8). MRD was also assessed on peripheral blood samples using both the EXENT® system and liquid chromatography–mass spectrometry (LC–MS). Forty-two patients entered the treatment phase; forty were evaluable for the primary endpoint. The rate of sCR and/or MRD < 10−5 following C8 was 30/40 (75%), meeting the statistical threshold for efficacy. The 10−6 MRD negative rate improved with treatment beyond C8. Agreement between EXENT® and NGS was high and increased over time; agreement between LC-MS and NGS was lower. The estimated 3-year progression-free survival progression-free survival was 85%, and 3-year overall survival was 95%. Upper respiratory infections occurred in 67% (7% grade 3–4). There were no treatment-related deaths. Extended frontline Dara-KRd induced a high rate of sCR and/or MRD negativity; the rate and depth of MRD negativity improved beyond C8.

Establishing adherence-concentration-efficacy thresholds of TDF-FTC pre-exposure prophylaxis for HIV prevention in African women: a protocol for the Women TDF-FTC Benchmark Study.

Oral pre-exposure prophylaxis (PrEP) using co-formulated emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF) is a potent HIV prevention method for men and women, with its efficacy highly dependent on adherence. A pivotal HIV efficacy study combined with a directly observed pharmacological study defined the thresholds for HIV protection in men who have sex with men (MSM), which are the keys to PrEP promotion and development of new PrEP agents. For African women at risk for HIV and belonging to a priority group considered due to disproportionately high incident HIV infections, the variable adherence in PrEP clinical trials and the limited pharmacologic data have resulted in a lack of clarity about the PrEP adherence required for HIV protection. We propose a study to quantify the adherence-concentration-efficacy thresholds of TDF/FTC PrEP among African cisgender women to inform decisions about optimal PrEP dosing and adherence for HIV protection. We randomized 45 low-risk HIV-uninfected African women, aged 18-30 years old, to directly observe the TDF/FTC PrEP of two, four, or seven doses per week for 8 weeks. A complementary age-matched pregnant women cohort at high risk of HIV, who will receive seven doses per week, was recruited (N = 15) with the primary aim of establishing benchmark concentrations in dried blood spots and peripheral blood mononuclear cells. Plasma, whole blood (WB), urine, hair, vaginal fluid, and vaginal tissue (non-pregnant women only) were archived for future testing. Drug concentrations were measured using methods validated for each biological matrix. Pharmacokinetic models were fitted to drug concentrations to quantify concentration-adherence thresholds. To define the drug concentrations associated with HIV protection, we applied the newly defined thresholds from the primary pharmacologic trial to the subset of women randomized to TDF/FTC or TDF in the Partners PrEP Study with the drug concentration assessed in plasma and WB samples. Multiple imputation was used to construct a data set with drug concentrations at each visit when an HIV test was performed for the entire cohort, replicating the work for MSM. The proposed study generated the first African women-specific TDF-PrEP adherence-concentration-efficacy thresholds essential for guiding the accurate interpretation of TDF/FTC PrEP programs and clinical trials of novel HIV prevention products using TDF/FTC as an active control. ClinicalTrials.gov, identifier (NCT05057858).

First report of ivermectin resistance in cyathostomins (small strongyles) of horses in Argentina

In Argentina, as in the rest of the world, cyathostomins are the most common nematodes parasitizing horses. Control is based almost exclusively on the administration of benzimidazoles, pyrimidines, and macrocyclic lactones. However, intensive use of these drugs is resulting in the development of anthelmintic resistance (AR). For example, AR to benzimidazoles is currently distributed throughout Argentina, while incipient AR to pyrimidines (pyrantel embonate) is appearing in areas where this drug is used. Macrocyclic lactones and especially ivermectin, are by far the most used drugs by the vast majority of equine premises in the country. Although ivermectin has been used since 1982, its efficacy against equine strongylid parasites has remained very high until the present. In this study we report for the first time, the presence of a cyathostomin population with resistance to ivermectin in adult horses belonging to an equine premise located in central Argentina. Fecal egg count reduction tests (FECRT) were performed following the most recent guidelines of the World Association for the Advancement of Veterinary Parasitology (WAAVP) for the diagnosis of anthelmintic resistance (research protocol) and resistance was considered when the Upper 90% Credible Interval fell below the expected efficacy threshold of 99.9%. Calculations were carried out using two different online calculation interfaces suggested by WAAVP. For the 14-day post-treatment interval, ivermectin efficacy was 79.5% (90% Credible Interval: 68.1–88.8) and 79.3% (74.2–83.6.3%) with the two methods, respectively. At 19 days post treatment, fecal egg count reductions were 68.6% (50.5–83.1) and 68.4% (61.9–74.1), respectively. At both intervals, this cyathostomin population fullfilled the criteria for AR. These findings suggest dispersion of ivermectin resistant cyathostomins in Argentina. Given the widespread use of macrocyclic lactones, it is important that veterinarians and the equine industry promote a more selective and evidence-based use of these drugs and establish routine monitoring to determine anthelmintic field efficacy to detect treatment failures as early as possible and avoid potential health problems as well as further spread of resistant genes.