Aligning new interventions with developing country health systems: target product profiles, presentation, and clinical trial design

Involving patients in drug development for Neglected Tropical Diseases (NTDs): A qualitative study exploring and incorporating preferences of patients with cutaneous leishmaniasis into Target Product Profile development

BACKGROUND

Target Product Profiles (TPPs) are instrumental to help optimise the design and development of therapeutics, vaccines, and diagnostics - these products, in order to achieve the intended impact, should be aligned with users' preferences and needs. However, patients are rarely involved as key stakeholders in building a TPP.

METHODOLOGY

Thirty-three cutaneous leishmaniasis (CL) patients from Brazil, Colombia, and Austria, infected with New-World Leishmania species, were recruited using a maximum variation approach along geographic, sociodemographic and clinical criteria. Semi-structured interviews were conducted in the respective patient's mother tongue. Transcripts, translated into English, were analysed using a framework approach. We matched disease experiences, preferences, and expectations of CL patients to a TPP developed by DNDi (Drug for Neglected Diseases initiative) for CL treatment.

PRINCIPAL FINDINGS

Patients' preferences regarding treatments ranged from specific efficacy and safety endpoints to direct and significant indirect costs. Respondents expressed views about trade-offs between efficacy and experienced discomfort/adverse events caused by treatment. Reasons for non-compliance, such as adverse events or geographical and availability barriers, were discussed. Considerations related to accessibility and affordability were relevant from the patients' perspective.

CONCLUSIONS/SIGNIFICANCE

NTDs affect disadvantaged populations, often with little access to health systems. Engaging patients in designing adapted therapies could significantly contribute to the suitability of an intervention to a specific context and to compliance, by tailoring the product to the end-users' needs. This exploratory study identified preferences in a broad international patient spectrum. It provides methodological guidance on how patients can be meaningfully involved as stakeholders in the construction of a TPP of therapeutics for NTDs. CL is used as an exemplar, but the approach can be adapted for other NTDs.

Health policy making process in Cameroon: a case for the utilization of the Target Policy Profile

Background: Translating research findings into health policy often encounters numerous challenges in many African countries, including Cameroon. One of these challenges is the lack of standard tools and procedures to connect researchers to policy makers. A tool such as the Target Policy Profile (TPoP) can help to close this gap, since it is designed to optimize dialogue around the evidence needed to effect a change in policy. In this paper, we assessed the policy making process in Cameroon and suggest how the process can be optimized using the TPoP.   Methods: This study reports on qualitative data obtained from in-depth interviews of purposively selected individuals, and quantitative data extracted from strategic plans and reports of 17 vertical health programs in Cameroon. Results: The majority (10/17) of our respondents were males and had an average of 6.5 years’ experience in policy making in Cameroon. A relatively small number of interventions/policies (19) were introduced by the assessed programs between 2015-2020. An even smaller number (9) are planned for introduction in the upcoming years. Four major gaps were identified in the policy making process, including lack of standardized methods and tools, limited use of evidence, limited ownership of the process by the state, and limited evaluation of newly introduced policies/interventions. Our respondents considered the TPoP to be a useful tool, which can help improve policy development, implementation, and evaluation across their different programs. Conclusion: The TPoP can help address gaps identified in the health policy making process in Cameroon. Continued advocacy to help stakeholders understand its value proposition as well as training them on its use cases, may facilitate its adoption and use in Cameroon.

'It takes two to tango': Bridging the gap between country need and vaccine product innovation

Background

Despite a growing global commitment to universal health coverage, considerable vaccine coverage and uptake gaps persist in resource-constrained settings. One way of addressing the gaps is by ensuring product innovation is relevant and responsive to the needs of these contexts. Total Systems Effectiveness (TSE) framework has been developed to characterize preferred vaccine attributes from the perspective of country decision-makers to inform research and development (R&D) of products. A proof of concept pilot study took place in Thailand in 2018 to examine the feasibility and usefulness of the TSE approach using a rotavirus hypothetical test-case.

Methods

The excel-based model used multiple-criteria decision analysis (MCDA) to compare and evaluate five hypothetical rotavirus vaccine products. The model was populated with local data and products were ranked against decision criteria identified by Thai stakeholders. A one-way sensitivity analysis was performed to identify criteria that influenced vaccine ranking. Self-assessment forms were distributed to R&D stakeholders on the usability of the approach and were subsequently analysed.

Results

The model identified significant parameters that impacted on MCDA rankings. Self-assessment forms revealed that TSE was perceived as being able to encourage closer collaboration between country decision makers and vaccine developers.

Conclusions

The pilot study demonstrates that it is feasible to use an MCDA approach to elicit stakeholder preferences and determine influential parameters to help identify the preferred product characteristics for R&D from the perspective of country decision-makers. It found that TSE can help steer manufacturers to develop products that are better aligned with country need. Findings will guide further development of the TSE concept.

Ivermectin to reduce malaria transmission III. Considerations regarding regulatory and policy pathways

Vector control is a task previously relegated to products that (a) kill the mosquitoes directly at different stages (insecticides, larvicides, baited traps), or (b) avoid/reduce human-mosquito contact (bed nets, repellents, house screening), thereby reducing transmission. The potential community-based administration of the endectocide ivermectin with the intent to kill mosquitoes that bite humans, and thus reduce malaria transmission, offers a novel approach using a well-known drug, but additional steps are required to address technical, regulatory and policy gaps. The proposed community administration of this drug presents dual novel paradigms; first, indirect impact on the community rather than on individuals, and second, the use of a drug for vector control. In this paper, the main questions related to the regulatory and policy pathways for such an application are identified. Succinct answers are proposed for how the efficacy, safety, acceptability, cost-effectiveness and programmatic suitability could result in regulatory approval and ultimately policy recommendations on the use of ivermectin as a complementary vector control tool.

Costing RTS,S introduction in Burkina Faso, Ghana, Kenya, Senegal, Tanzania, and Uganda: A generalizable approach drawing on publicly available data

Recent results from the phase 3 trial of RTS,S/AS01 malaria vaccine show that the vaccine induced partial protection against clinical malaria in infants and children; given the high burden of the disease it is currently considered for use in malaria endemic countries. To inform adoption decisions the paper proposes a generalizable methodology to estimate the cost of vaccine introduction using routinely collected and publicly available data from the cMYP, UNICEF, and WHO-CHOICE. Costing is carried out around a set of generic activities, assumptions, and inputs for delivery of immunization services adapted to a given country and deployment modality to capture among other factors the structure of the EPI program, distribution model, geography, and demographics particular to the setting. The methodology is applied to estimate the cost of RTS,S introduction in Burkina Faso, Ghana, Kenya, Senegal, Tanzania, and Uganda. At an assumed vaccine price of $5 per dose and given our assumptions on coverage and deployment strategy, we estimate total economic program costs for a 6–9 months cohort within $23.11–$28.28 per fully vaccinated child across the 6 countries. Net of procurement, costs at country level are substantial; for instance in Tanzania these could add as much as $4.2 million per year or an additional $2.4 per infant depending on the level of spare capacity in the system. Differences in cost of vaccine introduction across countries are primarily driven by differences in cost of labour. Overall estimates generated with the methodology result in costs within the ranges reported for other new vaccines introduced in SSA and capture multiple sources of heterogeneity in costs across countries. Further validation with data from field trials will support use of the methodology while also serving as a validation for cMYP and WHO-CHOICE as resources for costing health interventions in the region.

Development of malaria transmission-blocking vaccines: from concept to product

Despite decades of effort battling against malaria, the disease is still a major cause of morbidity and mortality. Transmission-blocking vaccines (TBVs) that target sexual stage parasite development could be an integral part of measures for malaria elimination. In the 1950s, Huff et al. first demonstrated the induction of transmission-blocking immunity in chickens by repeated immunizations with Plasmodium gallinaceum-infected red blood cells. Since then, significant progress has been made in identification of parasite antigens responsible for transmission-blocking activity. Recombinant technologies accelerated evaluation of these antigens as vaccine candidates, and it is possible to induce effective transmission-blocking immunity in humans both by natural infection and now by immunization with recombinant vaccines. This chapter reviews the efforts to produce TBVs, summarizes the current status and advances and discusses the remaining challenges and approaches.

Development of a transmission-blocking malaria vaccine: progress, challenges, and the path forward

New interventions are needed to reduce morbidity and mortality associated with malaria, as well as to accelerate elimination and eventual eradication. Interventions that can break the cycle of parasite transmission, and prevent its reintroduction, will be of particular importance in achieving the eradication goal. In this regard, vaccines that interrupt malaria transmission (VIMT) have been highlighted as an important intervention, including transmission-blocking vaccines that prevent human-to-mosquito transmission by targeting the sexual, sporogonic, or mosquito stages of the parasite (SSM-VIMT). While the significant potential of this vaccine approach has been appreciated for decades, the development and licensure pathways for vaccines that target transmission and the incidence of infection, as opposed to prevention of clinical malaria disease, remain ill-defined. This article describes the progress made in critical areas since 2010, highlights key challenges that remain, and outlines important next steps to maximize the potential for SSM-VIMTs to contribute to the broader malaria elimination and eradication objectives.

Malaria vaccine R&D in the Decade of Vaccines: breakthroughs, challenges and opportunities

While recent progress has been made in reducing malaria mortality with other interventions, vaccines are still urgently needed to further reduce the incidence of clinical disease, including during pregnancy, and to provide "herd protection" by blocking parasite transmission. The most clinically advanced candidate, RTS,S, is presently undergoing Phase 3 evaluation in young African children across 13 clinical sites in eight African countries. In the 12-month period following vaccination, RTS,S conferred approximately 50% protection from clinical Plasmodium falciparum disease in children aged 5-17 months, and approximately 30% protection in children aged 6-12 weeks when administered in conjunction with Expanded Program for Immunization (EPI) vaccines. The development of more highly efficacious vaccines to prevent clinical disease caused by both P. falciparum and Plasmodium vivax, as well as vaccines to support elimination efforts by inducing immunity that blocks malaria parasite transmission, are priorities. Some key barriers to malaria vaccine development include: a paucity of well-characterized target immunogens and an absence of clear correlates of protection to enable vaccine development targeting all stages of the P. falciparum and P. vivax lifecycles; a limited number of safe and effective delivery systems, including adjuvants, that induce potent, long-lived protective immunity, be it by antibody, CD4+, and/or CD8+ T cell responses; and, for vaccines designed to provide "herd protection" by targeting sexual stage and/or mosquito antigens, the lack of a clear clinical and regulatory pathway to licensure using non-traditional endpoints. Recommendations to overcome these, and other key challenges, are suggested in this document.