Introduction and Background of the Project

Introduction

Herein, we answer a WHO call for new diagnostic tests to support the fight against onchocerciasis, a disease affecting 21 million people, with another 218 million people living at risk of contracting the disease. WHO has issued two Target Product Profiles (TPPs), to support mass-drug administration initiation and cessation, respectively. The most stringent TPP criterion is that the test must be extraordinarily specific (≥99.8%).
DDTD succeeded in developing a test composed of two novel antigens specific to Onchocerca volvulus, the causative disease pathogen. The CDC found the test to be 89.6% sensitive and 100% specific, meaning that our test meets the sensitivity and specificity requirements of both TPPs and, remarkably, its specificity is >99.8% even at the lower bound 95% CI. Given these outstanding data, USAID has committed funding to evaluate the test in the field on approximately 10,000 individuals in 2023. We have already produced 10’000 tests to support these first field evaluations.
Given these exciting results, the massive relevance for public health, and the big momentum already garnered with key players (TFGH, USAID, CDC, BMGF, WHO), our team is thankful and excited to have been awarded generous funding from GHIT-Fund and NIH to swiftly progress our test to manufacturing and commercialization.

Project objective

We propose a rapid diagnostic test (RDT) to detect exposure to Onchocerca volvulus, the pathogen responsible for onchocerciasis. Built in a biplex format, our test detects IgG4 antibodies specific for two O. volvulus antigens. Our RDT was shown by the CDC to be sensitive and specific enough to meet both WHO TPPs, with a specificity of >99.8% even at the lower bound 95% CI. GHIT and NIH funding will be used to generate the critical biological materials in ISO-13485 grade, and to transition test production from a low-throughput card-to-card format to a high-throughput, manufacturing-friendly reel-to-reel system, under ISO-13485 standards. Test performance will be validated in a laboratory setting by the CDC by leveraging a preexisting research collaboration agreement with DDTD under which the CDC will not receive any funds from GHIT. Finally, test performance will be assessed in regional laboratories of targeted onchocerciasis-endemic countries by the TFGH/USAID.
Objective 1: Generate critical reagents (antigens, positive control antibody, anti-IgG4 detector antibody).
Objective 2: Finalize RDT optimization (minimize inter-test variability, reduce time-to-result).
Objective 3: Re-validate the final RDT in a laboratory setting on large patient sample collections.
Objective 4: Transition test production from card-to-card system to reel-to-reel production line and demonstrate equivalent (or better) performance.
Objective 5: Produce 5 lots of 20’000 tests to be delivered to stakeholders.

Project design

Given the demand forecast of up to 1 million tests/year, it will be critical to
- ensure constant product quality by minimizing the variability between different production lots, compliant with ISO13485 standards. One key factor ensuring a reproducible product quality is to have access to a constant, reliable source of the biological components of the test, notably the two O. volvulus antigens. These will be produced by MBL under ISO13485- quality standards. MBL will also produce a positive control antibody raised against one of the antigens, and DDTD will subsequently generate a heat-stable formulation thereof. Finally, the detector anti-IgG4 antibody currently used in the assay will be discontinued by its manufacturer, and we wish to secure a proprietary alternative source with MBL.
- replace the current, low-throughput card-to-card production process with a high-throughput, manufacturing-friendly reel-to-reel process. Big Eye Diagnostics (BEDx) will establish a manufacturing process aimed at minimizing costs and maximizing speed, while ensuring robust lot-to-lot consistency. SOPs and QC protocols will be created and validated for a manufacturing context, and lot-to-lot reproducibility data will be recorded in our ISO13485-compliant quality management system. We will produce 5 lots at scales commensurate with production needs and determine the inter-lot agreement (kappa value). Importantly, each lot will be made with different batches of raw materials, to provide confidence that these will not impact the final product.
We will send the final candidate test to the CDC under a separate, GHIT-independent research agreement for advanced testing to ensure that sensitivity and specificity criteria defined in the TPPs are met. We will then organize a round-table meeting involving all key stakeholders (CDC/TFGH/USAID/NIH/BMGF/WHO/GHIT) with the goal to ensure alignment and accelerate the path towards a WHO recommendation to use the test for onchocerciasis elimination mapping and, depending on the test’s exact performance profile, for potential additional clinical applications.

How can your partnership (project) address global health challenges?

WHO needs new, highly sensitive and ultra-specific rapid diagnostic tests to support its endeavors to eliminate onchocerciasis, a disease also known as river blindness, which is fought by mass drug administration. WHO critically needs new diagnostic tests to support decisions to start and stop MDA programs and published in 2021 the corresponding TPPs. This is the strongest indication the WHO can give regarding the urgency to develop such a test.

Building on funding by the Task Force for Global Health (TFGH) and USAID, DDTD succeeded in developing an RDT composed of two O. volvulus antigens that are arranged as two distinct test lines on the assay strip. In an independent evaluation, the CDC found the test to be 89.6% sensitive and 100% specific. Remarkably, the specificity is >99.8% even at the lower bound 95%-CI. This means that our test meets the sensitivity and specificity requirements at least of the Mapping TPP, and likely as well those of the MDA-stopping TPP. Given this, USAID has already committed funding to evaluate the test in the field on approximately 10,000 individuals. The study is being conducted this year by local Ministries of Health, with support from TFGH and CDC.

Given these exciting results, the massive relevance for public health, and the big momentum already garnered among key stakeholders, there is now a common sense of urgency that the test be swiftly progressed to large-scale manufacturing and to more extensive field trials. GHIT funding, in conjunction with a recent and generous NIH grant, will enable our team to achieve this goal.

Thus, we respectfully submit that our new test will address an unmet need of great significance to global health by contributing to the elimination of onchocerciasis, a disease with 21 million active cases and 218 million at-risk individuals.

What sort of innovation are you bringing in your project?

Lateral Flow Immunoassays (LFIAs) per se are not novel, but they represent a tried-and-true technology in the field of rapid diagnostic test development, particularly well adapted to field work in low-resource settings, which is why they are WHO’s preferred assay format. Our innovative contributions in the field of LFIAs have allowed us to deliver best-in-class tests for several other indications, including lymphatic filariasis and Buruli ulcer. The relevant innovative contributions for this project are:

- Use of a novel O. volvulus biomarker recently discovered at NIH (confidential), which is placed alongside a second, well-known O. volvulus biomarker in a novel biplex assay format.

- Use of novel plasmonic nanoparticles for optical detection, which improve test sensitivity by a factor of 2-10 (depending on the assay) compared to classical 40nm colloidal gold particles.

- Proprietary test strip architecture (confidential) allowing to build the assay strip in such a way that, upon addition of chase buffer, the sample reaches the test line first, and only then the nanoparticles are released, which leads to an increase in sensitivity.

- Proprietary cassette design (confidential).

Role and Responsibility of Each Partner

- Drugs & Diagnostics for Tropical Diseases (DDTD) is the Designated Development Partner and, as such, will provide management of the overall project and the Collaboration Partners. DDTD will also coordinate and ensure timely execution of the project and provide governance in terms of progress and finance reporting to the GHIT Fund. Furthermore, DDTD will be responsible for a smooth technology transfer to BEDx. All experimental procedures, as well as chemical, biochemical, biophysical, and clinical data generated during the project will be captured by DDTD in a separate database under ISO-13845 standards.

- Medical & Biological Laboratories Co., Ltd. (MBL) will be responsible for producing two Onchocerca volvulus antigens, one positive control antibody raised against one of these antigens, and a new anti-IgG4 detector antibody. Antigens and antibodies will first be produced in smaller amounts in R&D grade quality, followed by production of larger batches in ISO13485 grade quality.

- The Centers for Disease Control and Prevention (CDC), more specifically, Dr. Kim Won in the Division of Parasitic Diseases and Malaria, will be responsible for independent and unbiased laboratory-based assessment of the performance (sensitivity and specificity), of the rapid diagnostic tests produced by DDTD and BEDx. The assessment will be performed using the CDC plasma and sera collections. Thereby, CDC and DDTD will be able to leverage a separate Research Collaboration Agreement put in place in early 2022, hence the CDC will not receive any funds under this GHIT grant.

- Big Eye Diagnostics, Inc. (BEDx) will be in charge of developing robust high-throughput manufacturing standard operating procedures (SOPs) and stringent quality control (QC) protocols, which will be validated by producing 5 lots of 10’000 to 40’000 final RDT devices.