Projected health and economic effects of a pan-tuberculosis treatment regimen: a modelling study.

BACKGROUND: A pan-tuberculosis regimen that could be initiated without knowledge of drug susceptibility has been proposed as an objective of tuberculosis regimen development. We modelled the health and economic benefits of such a regimen and analysed which of its features contribute most to impact and savings. METHODS: We constructed a mathematical model of tuberculosis treatment parameterised with data from the published literature specific to three countries with a high tuberculosis burden (India, the Philippines, and South Africa). Our model simulated cohorts of newly diagnosed tuberculosis patients, including drug susceptibility testing if performed, regimen assignment, discontinuation, adherence, costs, and resulting outcomes of durable cure (microbiological cure without relapse), need for retreatment, or death. We compared a pan-tuberculosis regimen meeting the WHO 2023 target regimen profile against the standard of care of separate rifampicin-susceptible and rifampicin-resistant regimens. We estimated incremental cures; averted deaths, secondary cases, and costs; and prices below which a pan-tuberculosis regimen would be cost saving. We also assessed scenarios intended to describe which mechanisms of benefit from a pan-tuberculosis regimen (including improved characteristics compared with the current rifampicin-susceptible and rifampicin-resistant regimens and improved regimen assignment and retention in care for patients with rifampicin-resistant tuberculosis) would be most impactful. Results are presented as a range of means across countries with the most extreme 95% uncertainty intervals (UIs) from the three UI ranges. FINDINGS: Compared with the standard of care, a pan-tuberculosis regimen could increase the proportion of patients durably cured after an initial treatment attempt from 69-71% (95% UI 57-80) to 75-76% (68-83), preventing 30-32% of the deaths (20-43) and 17-20% of the transmission (9-29) that occur after initial tuberculosis diagnosis. Considering savings to the health system and patients during and after the initial treatment attempt, the regimen could reduce non-drug costs by 32-42% (22-49) and would be cost saving at prices below US$170-340 (130-510). A rifamycin-containing regimen that otherwise met pan-tuberculosis targets yielded only slightly less impact, indicating that most of the benefits from a pan-tuberculosis regimen resulted from its improvements upon the rifampicin-susceptible standard of care. Eliminating non-adherence and treatment discontinuation, for example via a long-acting injectable regimen, increased health impact and savings. INTERPRETATION: In countries with a high tuberculosis burden, a shorter, highly efficacious, safe, and tolerable regimen to treat all tuberculosis could yield substantial health improvements and savings. FUNDING: Bill & Melinda Gates Foundation.

Potential of Pan-Tuberculosis Treatment to Drive Emergence of Novel Resistance.

New tuberculosis (TB) drugs with little existing antimicrobial resistance enable a pan-TB treatment regimen, intended for universal use without prior drug-susceptibility testing. However, widespread use of such a regimen could contribute to an increasing prevalence of antimicrobial resistance, potentially rendering the pan-TB regimen ineffective or driving clinically problematic patterns of resistance. We developed a model of multiple sequential TB patient cohorts to compare treatment outcomes between continued use of current standards of care (guided by rifampin-susceptibility testing) and a hypothetical pan-TB approach. A pan-TB regimen that met current target profiles was likely to initially outperform the standard of care; however, a rising prevalence of transmitted resistance to component drugs could make underperformance likely among subsequent cohorts. Although the pan-TB approach led to an increased prevalence of resistance to novel drugs, it was unlikely to cause accumulation of concurrent resistance to novel drugs and current first-line drugs.

Target regimen profiles for tuberculosis treatment.

Simpler, shorter, safer and more effective treatments for tuberculosis that are easily accessible to all people with tuberculosis are desperately needed. In 2016, the World Health Organization (WHO) developed target regimen profiles for the treatment of tuberculosis to make drug developers aware of both the important features of treatment regimens, and patient and programmatic needs at the country level. In view of recent ground-breaking advances in tuberculosis treatment, WHO has revised and updated these regimen profiles. We used a similar process as for the 2016 profiles, including a baseline treatment landscape analysis, an initial stakeholder survey, modelling studies estimating the impact and cost-effectiveness of novel tuberculosis treatment regimens, and an extensive stakeholder consultation. We developed target regimen profiles for the treatment of rifampicin-susceptible and rifampicin-resistant tuberculosis, as well as a pan-tuberculosis regimen that would be appropriate for patients with any type of tuberculosis. We describe the revised target regimen profile characteristics, with specific minimal and optimal targets to be met, rationale and justification, and aspects relevant to all target regimen profiles (drug susceptibility testing, adherence and forgiveness, treatment strategies, post-tuberculosis lung disease, and cost and access considerations). We discuss the trade-offs of proposed characteristics for decision-making at developmental or operational levels. We expect that, following these target regimen profile revisions, tuberculosis treatment developers will produce regimens that are quality-assured, affordable and widely available, and that meet the needs of affected populations.

Des traitements de la tuberculose plus simples, plus courts, plus sûrs et plus efficaces, facilement accessibles à toutes les personnes atteintes de tuberculose, font cruellement défaut. En 2016, l'Organisation mondiale de la santé (OMS) a élaboré des profils de schéma thérapeutique cible pour le traitement de la tuberculose, afin de sensibiliser les concepteurs de médicaments aux caractéristiques importantes des schémas thérapeutiques et aux besoins des patients et des programmes au niveau national. Compte tenu des avancées récentes dans le traitement de la tuberculose, l'OMS a révisé et mis à jour ces profils de schéma thérapeutique. Nous avons appliqué un processus similaire à celui des profils de 2016, y compris une analyse de base des différentes possibilités thérapeutiques, une enquête initiale auprès des parties prenantes, des études de modélisation estimant l'impact et le rapport coût-efficacité des nouveaux schémas thérapeutiques pour la tuberculose, ainsi qu'une vaste consultation des parties prenantes. Nous avons élaboré des profils de schéma thérapeutique cible pour le traitement de la tuberculose sensible à la rifampicine ou résistant à la rifampicine, ainsi qu'un schéma multiforme qui conviendrait aux patients atteints de n'importe quel type de tuberculose. Nous décrivons les caractéristiques du profil révisé de schéma thérapeutique cible, avec les objectifs minimaux et optimaux spécifiques à atteindre, le raisonnement et les aspects pertinents pour tous les profils de schéma thérapeutique cible (tests de sensibilité aux médicaments, observance thérapeutique et manque d'observance («forgiveness¼), stratégies de traitement, maladie pulmonaire post-tuberculeuse et considérations de coût et d'accès). Nous discutons des compromis des caractéristiques proposées pour la prise de décisions au niveau du développement ou au niveau opérationnel. Nous espérons qu'à la suite de ces révisions du profil de schéma thérapeutique cible, les concepteurs de traitements antituberculeux produiront des schémas dont la qualité est assurée, qui sont abordables et largement disponibles et qui répondent aux besoins des populations touchées.

Se necesitan con urgencia tratamientos más sencillos, breves, seguros y eficaces contra la tuberculosis que sean fácilmente accesibles para todas las personas con tuberculosis. En 2016, la Organización Mundial de la Salud (OMS) elaboró perfiles objetivo de esquemas terapéuticos para el tratamiento de la tuberculosis con el fin de que los fabricantes de medicamentos conocieran tanto las características importantes de estos esquemas como las necesidades programáticas y de los pacientes en cada país. Teniendo en cuenta los recientes avances pioneros en el tratamiento de la tuberculosis, la OMS ha revisado y actualizado estos perfiles de esquemas terapéuticos. Se ha seguido un proceso similar al de los perfiles de 2016, que incluye un análisis de referencia del panorama terapéutico, una encuesta inicial a las partes interesadas, estudios de modelización para estimar el impacto y la rentabilidad de los nuevos esquemas terapéuticos para el tratamiento de la tuberculosis, y una amplia consulta a las partes interesadas. Se desarrollaron perfiles objetivo de esquemas terapéuticos para el tratamiento de la tuberculosis sensibles a la rifampicina y resistente a la rifampicina, así como un esquema farmacológico capaz de tratar todas las formas de tuberculosis que sería apropiado para pacientes con cualquier tipo de tuberculosis. Se describieron las características revisadas de los perfiles objetivo de los esquemas terapéuticos, con los objetivos mínimos y óptimos específicos que deben alcanzarse, los fundamentos y la justificación, y los aspectos relevantes para todos los perfiles objetivo de los esquemas terapéuticos (pruebas de sensibilidad a los fármacos, adherencia y olvido, estrategias de tratamiento, enfermedad pulmonar postuberculosa, y consideraciones de coste y acceso). Se discutieron las ventajas y desventajas de las características propuestas para la toma de decisiones a nivel de desarrollo u operativo. Se espera que, tras estas revisiones de los perfiles objetivo de los esquemas terapéuticos, las personas encargadas del desarrollo de tratamientos para la tuberculosis elaboren esquemas terapéuticos de calidad garantizada, asequibles y ampliamente disponibles, y que respondan a las necesidades de las poblaciones afectadas.

Economic implications of novel regimens for tuberculosis treatment in three high-burden countries: a modelling analysis.

BACKGROUND: With numerous trials investigating novel drug combinations to treat tuberculosis, we aimed to evaluate the extent to which future improvements in tuberculosis treatment regimens could offset potential increases in drug costs. METHODS: In this modelling analysis, we used an ingredients-based approach to estimate prices at which novel regimens for rifampin-susceptible and rifampin-resistant tuberculosis treatment would be cost-neutral or cost-effective compared with standards of care in India, the Philippines, and South Africa. We modelled regimens meeting targets set in the WHO's 2023 Target Regimen Profiles (TRPs). Our decision-analytical model tracked cohorts of adults initiating rifampin-susceptible or rifampin-resistant tuberculosis treatment, simulating their health outcomes and costs accumulated during and following treatment under standard-of-care and novel regimen scenarios. Price thresholds included short-term cost-neutrality (considering only savings accrued during treatment), medium-term cost-neutrality (additionally considering savings from averted retreatments and secondary cases), and cost-effectiveness (incorporating willingness-to-pay for improved health outcomes). FINDINGS: Total medium-term costs per person treated using standard-of-care regimens were estimated at US$450 (95% uncertainty interval 310-630) in India, $560 (350-860) in the Philippines, and $730 (530-1090) in South Africa for rifampin-susceptible tuberculosis (current drug costs $46) and $2100 (1590-2810) in India, $2610 (2090-3280) in the Philippines, and $3790 (3090-4630) in South Africa for rifampin-resistant tuberculosis (current drug costs $432). A rifampin-susceptible tuberculosis regimen meeting the optimal targets defined in the TRPs could be cost-neutral in the short term at drug costs of $140 (90-210) per full course in India, $230 (130-380) in the Philippines, and $280 (180-460) in South Africa. For rifampin-resistant tuberculosis, short-term cost-neutral thresholds were higher with $930 (720-1230) in India, $1180 (980-1430) in the Philippines, and $1480 (1230-1780) in South Africa. Medium-term cost-neutral prices were approximately $50-100 higher than short-term cost-neutral prices for rifampin-susceptible tuberculosis and $250-550 higher for rifampin-resistant tuberculosis. Health system cost-neutral prices that excluded patient-borne costs were 45-70% lower (rifampin-susceptible regimens) and 15-50% lower (rifampin-resistant regimens) than the cost-neutral prices that included patient costs. Cost-effective prices were substantially higher. Shorter duration was the most important driver of medium-term savings with novel regimens, followed by ease of adherence. INTERPRETATION: Improved tuberculosis regimens, particularly shorter regimens or those that facilitate better adherence, could reduce overall costs, potentially offsetting higher prices. FUNDING: WHO.

Forecasting the effect of HIV-targeted interventions on the age distribution of people with HIV in Kenya.

OBJECTIVES: To provide accurate forecasts of the age distribution of people with HIV (PWH) in Kenya from 2025 to 2040. DESIGN: Development of a compartmental model of HIV in Kenya, calibrated to historical estimates of HIV epidemiology. METHODS: We forecasted changes in population size and age distribution of new HIV infections and PWH under the status quo and under scale-up of HIV services. RESULTS: Without scale-up, new HIV infections were forecasted to fall from 34 000 (28 000-41 000) in 2,025 to 29 000 (15 000-57 000) in 2,040; the percentage of new infections occurring among persons over 30 increased from 33% (20-50%) to 40% (24-62%). The median age of PWH increased from 39 years (38-40) in 2025 to 43 years (39-46) in 2040, and the percentage of PWH over age 50 increased from 26% (23-29%) to 34% (26-43%). Under the full intervention scenario, new infections were forecasted to fall to 6,000 (3,000-12 000) in 2,040. The percentage of new infections occurring in people over age 30 increased to 52% (34-71%) in 2,040, and there was an additional shift in the age structure of PWH [forecasted median age of 46 (43-48) and 40% (33-47%) over age 50]. CONCLUSION: PWH in Kenya are forecasted to age over the next 15 years; improvements to the HIV care continuum are expected to contribute to the growing proportion of older PWH.

Active case-finding of tuberculosis compared with symptom-driven standard of care: a modelling analysis.

BACKGROUND: In settings with large case detection gaps, active case-finding (ACF) may play a critical role in the uberculosis (TB) response. However, ACF is resource intensive, and its effectiveness depends on whether people detected with TB through ACF might otherwise spontaneously resolve or be diagnosed through routine care. We analysed the potential effectiveness of ACF for TB relative to the counterfactual scenario of routine care alone. METHODS: We constructed a Markov simulation model of TB natural history, diagnosis, symptoms, ACF and treatment, using a hypothetical reference setting using data from South East Asian countries. We calibrated the model to empirical data using Bayesian methods, and simulated potential 5-year outcomes with an 'aspirational' ACF intervention (reflecting maximum possible effectiveness) compared with the standard-of-care outcomes. RESULTS: Under the standard of care, 51% (95% credible interval, CrI: 31%, 75%) of people with prevalent TB at baseline were estimated to be diagnosed and linked to care over 5 years. With aspirational ACF, this increased to 88% (95% CrI: 84%, 94%). Most of this difference represented people who were diagnosed and treated through ACF but experienced spontaneous resolution under standard-of-care. Aspirational ACF was projected to reduce the average duration of TB disease by 12 months (95% CrI: 6%, 18%) and TB-associated disability-adjusted life-years by 71% (95% CrI: 67%, 76%). CONCLUSION: These data illustrate the importance of considering outcomes in a counterfactual standard of care scenario, as well as trade-offs between overdiagnosis and averted morbidity through earlier diagnosis-not just for TB, but for any disease in which population-based screening is recommended.

Accuracy of C-Reactive Protein for Tuberculosis Detection in General-Population Screening and Ambulatory-Care Triage in Uganda.

Rationale: C-reactive protein (CRP) has demonstrated utility as a point-of-care triage test for tuberculosis (TB) in clinical settings, particularly among people with human immunodeficiency virus (HIV), but its performance for general-population TB screening is not well characterized. Objective: To assess the accuracy of CRP for detecting pulmonary TB disease among individuals undergoing community-based screening or presenting for evaluation of TB symptoms in Kampala, Uganda. Methods: We pooled data from two case-control studies conducted between May 2018 and December 2022 among adolescents and adults (⩾15 yr) in Kampala, Uganda. We conducted community-based screening for TB, regardless of symptoms. We enrolled people with Xpert MTB/RIF Ultra-positive (including trace) sputum results and a sample of people with Ultra-negative results. We also enrolled symptomatic patients diagnosed with TB and controls with negative TB evaluations from ambulatory care settings. Participants underwent further evaluation, including sputum culture, CRP, and HIV testing. We assessed the accuracy of CRP alone or with symptom screening against a bacteriologic reference standard. Our primary analysis evaluated the sensitivity and specificity of CRP at a cutoff of 5 mg/L. Diagnostic performance was summarized by calculating the area under the receiver operating curve (AUC). Results: In the community setting (n = 544), CRP ⩾ 5 mg/L had a sensitivity of 55.3% (95% confidence interval, 47.0-63.4%) and specificity of 84.7% (79.7-88.8%) for confirmed TB; AUC was 0.75 (0.70-0.79). Screening for CRP ⩾ 5 mg/L or positive symptoms increased sensitivity to 92.0% (86.4-95.8%) at the expense of specificity (57.1% [50.8-63.2%]). In the ambulatory care setting (n = 944), sensitivity of CRP ⩾ 5 mg/L was 86.7% (81.8-90.7%), specificity was 68.6% (64.8-72.2%), and AUC (0.84 [0.81-0.87]) did not differ significantly by HIV status. CRP ⩾ 5 mg/L was >90% sensitive among individuals with a medium or high semiquantitative Xpert result in both settings. Conclusions: Although CRP did not meet World Health Organization (WHO) TB screening benchmarks in the community, it demonstrated high specificity, and sensitivity was high among individuals with high sputum bacillary burden who are likely to be most infectious. In ambulatory care, estimated sensitivity and specificity were each within 4 percentage points of WHO benchmarks, with no meaningful difference in performance by HIV status.