University of Dundee - Evaluation of P450 humanized mouse model (8HUM) as a tool to assess the impact of drug combinations on pharmacology (Europe)
Start : September 2020 | Status : Active
Alastair Kenneth - Kevin Sebastian Coquelin
The sponsor: University of Dundee
Foundation funding: The Foundation is providing £245,045 in support.
GSK’s contribution: GSK contribution will make a significant impact on the project. Mainly, related to GSK platform access and as well, scientific and technical expertise support. Main anticipated GSK contributions are highlighted below:
1. Murine Mycobacterium tuberculosis efficacy model and P3 facilities use to establish acute and chronic models of infection with the background of the 8HUM model.
2. Bioanalytical capabilities enabling to work with M tuberculosis infected samples
3. Access to different global databases related to DDI - University of Washington DIDB – The Drug Interaction Database (in vitro and in vivo datasets) - Pharmapendium Metabolizing Enzymes and Transporters module
4. In silico global predictive tools (Meteor, Metasite, ADMET predictor) as well as local models.
5. Modelling platforms and/or support (GastroPlus, Simcyp)
6. Scientific and technical expertise in DMPK, met ID, DDI and PBPK modelling.
Project Description: The aim of this project is to explore the utility of the proposed model (8HUM) for the early assessment of the impact of combinations on the pharmacology of treatments for major Global Health challenges like tuberculosis, visceral Leishmaniasis and Chagas disease. For this purpose, a set of compounds currently used in the clinic or in clinical phases to treat these diseases will be selected on the basis of the involvement of P450 enzymes in their disposition. These compounds will be characterised in the 8HUM mouse model, both by pharmacokinetic and metabolite profiling in vitro and in vivo. P450 expression levels will also be studied for comparison with human. In silico work will be performed by developing mechanistic models explaining the disposition of the drugs tested, and translation to the human will be assessed using available clinical data. Those compounds where the data obtained more closely reflects that observed in man will be selected for further pharmacological characterisation. In silico evaluation using the experimental data will be used to select drug doses for the in vivo efficacy studies. Finally, efficacy studies will be carried out using drug combinations of two agents. Blood samples will be analysed for drug concentration and metabolite profiling. Hepatic P450 expression will also be determined. The data generated will be integrated into an in silico model for human translation (using tools like GastroPlus from Simulation Plus or Simcyp from Certara), and compared with existing clinical data to interrogate the performance of the 8HUM model in terms of translational capacity.
Positive outcome from this project would provide a better translational animal disease model to assess drug combinations early in the development of treatments, making a significant impact in drug discovery cascades. These data, together with the use of in silico mechanistic PBPK-PD modelling, will allow improved prediction of the efficacy of new treatments in patients, with a significant impact on clinical trial design. The application of the 8HUM model could have wider application in drug discovery and development programmes out this current proposed project and could form the basis of further follow on collaborative investigative work eg. in drug safety evaluation.
Harvard T.H. Chan School of Public Health - Recapitulation of ATQ infection results using TCOL mosquitoes/parasites/facilities (America)
Start : September 2020 | Status : Active
Douglas Paton (PhD) (2nd scientist: TBD)
The sponsor: Harvard T.H. Chan School of Public Health
Foundation funding: The Foundation is providing £281,838 in support.
GSK’s contribution: This project will strongly benefit from the considerable expertise at GSK in medicinal chemistry and Plasmodium infections, including: 1) HPLC/MS facilities and expertise; 2) the availability of a large library of compounds with known antimalarial activity; 3) the vast experience in drug metabolism and pharmacokinetics studies; 4) the availability of fully functional insectary and mosquito infection facilities. These contributions will be critical to the success of this project and for the future implementation of our strategy in malaria settings.
Project Description: This project proposes a novel strategy for malaria control, based on exposing Anopheles mosquitoes to chemotherapeutics to kill malaria parasites during their sporogonic development (i.e. development within the mosquito vector). Even though human therapeutic drugs and conventional insecticide treated LLINs are routinely used in malaria control strategies, the combination of the two approaches is a radically novel concept. Importantly, ATQ is the primary component of malarone, a prophylactic drug used for travelers to malaria endemic countries. Protection of the efficacy of ATQ as a human therapeutic is of primary importance and as such ATQ may not be a suitable ingredient for a bed net or other mosquito-targeting antimalarial intervention. Thus, a crucial step in developing this concept is the identification of additional compounds with comparable – or superior – transmission blocking activity through tarsal contact. To accelerate discovery in this space it is essential to characterize the physicochemical properties necessary for compound uptake via the mosquito tarsi, as only limited data is available in Anopheles mosquitoes. Additionally, the identification of a diverse panel of compounds with different mode of action (MoA) is key to delay or prevent the emergence of parasite resistance by using combinations of drugs, thereby ensuring the long-term sustainability of this approach. Therefore, in this project we will 1) determine the key factors underlying chemical tarsal uptake to allow the in silico selection of a panel of antimalarial compounds with high probability of penetrating the mosquito cuticle, and 2) test these selected compounds for their ability to kill the mosquito stages of P. falciparum parasites in vivo.
By the end of this 2-year project we will have greatly expanded our understanding of the mechanisms underpinning mosquito uptake of antimalarial compounds, the process crucial to our novel malaria transmission blocking strategy, and we will have identified new active ingredients that can be used in this strategy and will codify the path from lab development to end-user. Further studies will then focus on the developability of these compounds, on determining compound MoA when unknown, on testing the possible evolution of parasite resistance and how to counteract it, and on determining compound ability to interrupt ongoing sporogony in established mosquito infections. Combined, these goals represent the crucial first steps in a new technology with significant promise for the reduction of malaria transmission and the drive to eradicate this deadly disease.
Research and Development Agency of Aragon (ARAID) Foundation - Shortening and improving compliance to Buruli ulcer therapy- Four weeks daily triple betalactam (Europe)
Start : June 2020 | Status : Active
The sponsor: Research and Development Agency of Aragon (ARAID) Foundation
Foundation funding: The Foundation is providing £507,601 in support.
GSK’s contribution: GSK will provide in-kind scientific and statistical support in the development and delivery of the project; dependent on the needs identified by the investigators and the available GSK expertise.
Project Description: Buruli ulcer (BU) is a chronic debilitating skin and soft tissue mycobacterial infection that without treatment frequently progresses to massive ulceration. The greatest burden falls on children under the age of 15 years in sub-Saharan Africa. This neglected tropical disease generally affects poor communities in remote rural areas with limited access to health services. Although mortality is low, permanent disfigurement and disability are high, affecting up to 25% of the cases. Before 2004, surgical excision and skin grafting remained the mainstay of BU treatment until clinical evidence showed the effectiveness of rifampicin-streptomycin; however, serious adverse events associated to the injectable streptomycin and the lack of an efficacious oral treatment remained one of the main obstacles to decentralizing care in rural areas. Today, WHO recommends an 8-week full oral daily combination therapy of rifampicin-clarithromycin; however, access to medicines is difficult, and the need of hospitalization for treatment impacts household’s income and compromises patients’ adherence to the 8-weeks antibiotic course. A shortened, highly effective, all-oral regimen based on already approved drugs is urgently needed to improve care for this neglected tropical disease by reducing both duration of treatment and time to healing for all type of lesions after therapy completion; this would in addition reduce indirect costs and barriers to access therapy. Similar to Tuberculosis (TB), rifampicin is the cornerstone drug for BU therapy, showing a direct relation between dose increase and therapy efficacy due to its bactericidal and sterilizing activity. High-dose rifampicin studies suggested that BU treatment could be shortened if rifampicin dose was increased. However, this approach raises concerns due to high-dose rifampicin-related hepatotoxicity and public health implementation. It would be then desirable to maintain current dose and potentiate the activity of rifampicin avoiding its side effects. In addition, TB chemotherapy teaches us that combination therapy is critical for optimal cure outcomes and treatment shortening, suggesting that at least a three-drug regimen might be needed to improve and shorten BU treatment. In fact, synergistic partners could improve rifampicin efficacy without compromising tolerability and toxicity. Beta-lactams are one of the largest groups of antibiotics with an exceptional record of clinical safety. Recent studies from partners of this Clinical Study Protocol (CSP) provided evidence of their anti-mycobacterial clinical potential, opening a new avenue to optimize current BU therapy. We thus took advantage of knowledge gathered in TB Research and Development (R&D) repurposing programs and showed in in vitro preclinical studies that beta-lactams strongly increased the activity of rifampicin and clarithromycin against Mycobacterium ulcerans (Mul). We further confirmed these observations by time-kill kinetics. Among all beta-lactams, we focused on amoxicillin/clavulanate: oral, suitable for the treatment of children, pregnant women and adults and with a long track record of clinical pedigree. First launched in the UK in 1981, today it is clinically available in various formulations in over 150 countries around the world. The addition of amoxicillin/clavulanate to current WHO recommended therapy could contribute to treatment shortening in several ways:
- The median time to healing is directly proportional to the bacterial load in BU lesions at the beginning of therapy. Typically, healing occurs within 25 weeks from the start of treatment but for some BU patients this can take up to one year. One of the reasons for this slow healing could be a high initial bacterial load, since bacteria have been found in slowly healing lesions despite the recommended 8- week antibiotic therapy.
- Despite antibiotic efficacy, the most common treatment complication of BU patients in Africa is paradoxical reaction, a phenomenon observed following an initial period of clinical improvement characterized by worsening of existing lesion(s) and occurrence of new ones during or after antibiotic therapy due to unspecific immune responses. Importantly, fast bacterial clearance reduces the rate of paradoxical responses. Due to its rapid bactericidal activity, amoxicillin/clavulanate would be extremely effective at targeting extracellular bacteria; thus, reducing initial bacterial burden, paradoxical responses, local levels of the immune-suppressive mycolactone toxin, and allowing recovery of the host immune response to clear remaining bacteria.
- What is more, in vitro studies have demonstrated the sterilizing activity of synergistic combinations of beta-lactams and rifampicin, these could target the remaining persistent populations having a positive impact in treatment and healing periods.
In this study, we propose the combination of amoxicillin/clavulanate with current oral BU therapy, rifampicin and clarithromycin as a new anti-BU treatment with the potential of treatment shortening and readily implementation in the field.
Research and Development Agency of Aragon (ARAID) Foundation - Designing optimal regimes for tuberculosis therapy using one-step high content dynamic in vitro kill kinetic assay linked to hollow fiber studies (Europe)
Start : June 2020 | Status : Active
The scientists: Maria Pilar Arenaz (2nd scientist: TBD)
The sponsor: Research and Development Agency of Aragon (ARAID) Foundation
Foundation funding: The Foundation is providing £174,142 in support.
GSK’s contribution: GSK R&D contribution has been, so far, critical for the successful development of the former TC256 project, leading to this current proposal. We envision GSK R&D contribution to this new project as a continuation of current scientific and operational support that can be structured within several main activities:
- Access to compounds and screening infrastructure: the microplate reader EnVision is critical to meet the throughput requirements of the project in a timely manner.
- Mass spectroscopy analytical capacity to characterize the medium degradation kinetics of drugs used in the OPTIKA screening and drug concentrations in the different hollow fiber compartments.
- Data analysis and modeling support to integrate PD (in vitro activity) and PK (drug degradation) drug’s parameters.
- Data analysis and modeling support to integrate data generated under this project proposal with currently available preclinical and clinical data and to develop a machine learning/AI model to predict up to 4-way drug interactions.
- Capacity to perform murine in vivo models of Mtb infection to evaluate drug combinations.
Project Description: Recent years have seen a resurgence of new drug-like chemical entities with anti-ycobacterial activity, a number of which progressing into clinical trials. Understanding how to develop these compounds into therapeutically effective multi-drug regimens remains, however, an unresolved question. Traditional efforts to identify new potential drug combinations involve empirical phenotypic screening for in vitro synergies at the microbiological level. This is typically done by checkerboard assays (CBA) able to interrogate 2-way drug interactions but with limited power to identify 3-way or higher order drug interactions. A new technology called DiaMOND (diagonal measurement of n-way drug interactions) has overcome this limitation by reducing the number of interactions that require testing and vastly simplified the ability to identify favourable combinations of 3, 4 or even higher number of drugs. However, both CBA and DiaMOND remain inherently rooted in the use of the Fractional Inhibitory Concentration Index (FICI), a measurement of growth inhibition, as the metric of drug activity, rather than bacterial killing, which remains unmeasured. In addition, any synergistic combinations identified by FICI-based readouts require secondary validation by time kill assays (TKA) that significantly, and in some cases prohibitively, increase the complexity and duration of combination testing. TKAs are the most valuable assay in static in vitro pharmacokinetic (PK) and harmacodynamics (PD) studies and rely on Colony Forming Unit (CFU) enumeration at different time points (instead of a fixed time point as in the case of CBA or DiaMOND). TKAs are also the basis of mathematical modelling of antimicrobial drug action; however, TKA throughput in Mtb is typically limited to the working capacity of the technical operator, ca. 30 samples; this limited throughput capacity creates a barrier when it comes to validate 3 or higher n-way interactions. During the course of project TC256, we developed a new methodology named OPTIKA (Optimized Time Kill Assays, described below) that increased the capacity of traditional TKAs by more than 30-fold. OPTIKA allows facile high throughput interrogation of n-way drug interactions that are also dynamic and include direct measures of cidality. In doing so, we can now more rapidly and rigorously identify new potential triple drug interactions by coupling OPTIKA to in vivo studies and dynamic PKPD models using the Hollow Fibre System for Tuberculosis. The goal of this project is thus to provide robust preclinical evidence to suggest new therapeutic regimen options for TB treatment.
IMM Lisboa - Generation, characterization and in vivo evaluation of a novel live malaria vaccine (Europe)
Start : December 2019 | Status : Active
The scientists: Patricia dos Santos
The sponsor: Instituto de Medicina Molecular Lisboa
Foundation funding: The Foundation is providing £147,121 in support.
GSK’s contribution: GSK contribution to the project will include providing the humanized mouse models to be employed in the project, as well as the technical expertise, equipment and reagents to assess the parasite’s ability to infect and develop in human and mouse red blood cells. This project will synergize with ongoing efforts of the GSK-DDW group, as the liver stage of Plasmodium infection has been considered a strategy priority of the unit. A follow up of the successful open Lab TC111 is planned for 1Q19 in order to transfer and implement an optimized pseudo liver-mouse model.
Project Description: Malaria remains the most prevalent parasitic disease for which a vaccine is still not available. So far, whole-sporozoite (Wsp) vaccines have shown most success among current candidates. The applicant’s lab has defined and established the proof-of-concept of a novel approach to Wsp malaria vaccination, based on the use of non-pathogenic rodent malaria parasites, genetically engineered to express antigens of their human-infective counterparts. PbVac, a Plasmodium berghei (Pb) parasite that expresses the P. falciparum (Pf) circumsporozoite protein is the first member of this new class of vaccine candidates. PbVac has demonstrated high safety profile and significant immunizing efficacy in recent phase I/IIa clinical trials. Stemming from these encouraging results, we now propose to generate and evaluate a new transgenic Pb parasite with enhanced immunogenicity and efficacy against Pf infection. To this end, we will engineer a Pb parasite line that expresses multiple antigens of the human-infective Pf parasite, we will characterize the expression of the inserted transgenes, and we will define its infectivity both in the mosquito vector and in the mammalian host. In order to ensure the safety and regulatory compliance of the newly generated Pb-based immunization agent, we will make use of GSK-DDW’s blood-humanized (BH) mouse model to pre-clinically assess lack of infection of human (Hu) red blood cells (RBC) by these parasites. This is a pivotal step in the definition of the parasite’s safety profile and a crucial requirement for the regulatory approval of its clinical use.
University of Dundee - Design of novel inhibitors of Shigella LpxC (Europe)
Start : October 2019 | Status : Active
The scientists: Joel McMillan
The sponsor: University of Dundee
Foundation funding: The Foundation is providing £293,009 in support.
GSK’s contribution: GSK has developed both extra-cellular assays for Shigella and also intracellular assays, both in Caco2 cells and macrophages (THP1 cells). These assays will be used to assay compounds for whole cell activity. In addition, GSK has the possibility to run most promising hits in a panel of enteric bacteria (E.g. Salmonella, E. coli, Campylobacter) including drug-sensitive and MDR organisms. For key compounds, screening against a panel fo Gram-negative and Gram-positive bacteria. GSK has already identified LpxC inhibitors with activity against Shigella, and they can provide this expertise. The in-kind contributions from GSK will also be involve in the characterization of promising hits (in vitro profiling). In the medium term, further evaluations of these types will guide a medicinal chemistry effort for hit-to-lead development.
Project Description: Shigellosis is a major cause of diarrhea in Low and Middle Income Countries and is responsible for hundreds of thousands of deaths each year. Drug resistance is a major problem and there is a need for new drugs with novel modes of action to tackle this terrible disease. Furthermore, the complex array of Shigella species and serotypes may make vaccine development challenging. The aim of this project is to develop novel inhibitors of LpxC as potential agents for the treatment of shigellosis. A recent screen carried out in GSK against whole cell bacteria has validated this as a drug target in Shigella. LpxC is a zinc metalloprotein responsible for de-acetylation of an advanced precursor to Lipid A. A number of different organizations have worked on LpxC inhibitors; the majority of disclosed inhibitors of LpxC are based on hydroxamic acid analogues, which suffer from poor pharmacokinetics and toxicity issues. No hydroxamate based LpxC inhibitor has reached the clinic. Our aim is to use a structure-based approach to find non-hydroxamate-based inhibitors of Shigella LpxC. To achieve this, we will screen with a series of Zn binders, identified from the literature and protein data bank (pdb). We aim to explore a wide range of zinc binding groups. We wil also explore the possibility to use benzoxaboroles as new Zn binders (exploiting the ability of zinc to activate a water molecule to generate active Zn binders as reported in DDU recent publication: PNAS, 2018, vol. 115,no. 38, 9616–9621). As well as finding non-hydroxamate Zn binders, we also aim to exploit the relatively weakly explored UDP-binding region of the enzyme, which should allow us to develop novel scaffolds. We will screen using our fragment library. There is a lot of structural information from the literature and the pdb we could then utilize to guide optimization. Final goal for this proposal is to find a non-hydroxamate zinc binding motif for LpxC and to carry out a fragment-based optimization to find inhibitors that are active in a cellular model.
University Hospital Tübingen - Microbiome restoration therapeutics for environmental enteric dysfunction (EED) and associated stunted childhood growth
Start : November 2019 | Status : Active
The scientists: Nermin Akduman
The sponsor: University Hospital Tübingen
Foundation funding: The Foundation is providing £215,576 in support.
GSK’s contribution: The project would immensely benefit from the exceptional setting of the Tres Cantos Open Lab Foundation, allowing access to topnotch expertise in screening and drug development and connections to a network of experts in the EED field. Furthermore, an ‘Open Lab’ collaboration would offer a unique opportunity to conduct a pioneering and innovative study on microbiome modulating therapeutics with broader impact, as the presence of members of the oral microbiome at distant body sites is not restricted to EED alone but also typical for other inflammatory diseases including colorectal cancer and rheumatoid arthritis.
Project Description: Environmental enteric dysfunction (EED) is a poorly understood inflammatory syndrome characterized by reduced absorptive capacity and barrier function in the small intestine. It is widespread among children in low-income countries and impairs child growth and development (stunting). Although various infectious agents have been suggested to cause EED, recent evidence supports the idea that a “decompartmentalization” of intrinsic throat microbes towards the small intestine combined with a depletion of beneficial butyrate-producing microbes sustains inflammatory conditions. Effective treatment strategies such as microbiome modulation to revert this imbalance are still missing. The overarching goal of this study is to identify lead compounds, drugs or drug/food combinations that modulate the gastrointestinal microbiome in stunted children towards a healthy microbial community. To this end, we propose screening for inhibitors of EED-related taxa from the oropharynx and for growth enhancers of protective microbes. This endeavor will profit from both, GSK’s compound libraries, expertise and screening platforms as well as from our recently established anaerobic high-throughput platform that is perfectly geared towards the needs of fastidious EED-related microbes. Promising candidates/combinations will be followed up in vitro with EED-mimetic microbial communities and in vivo using EED gnotobiotic mouse models. Successful microbiome modulators have tremendous potential to resolve EED’s inflammatory conditions with crucial impact on growth and development of young children around the world.
University of South Florida (USF), WRAIR and NIH - Antimalarial drug discovery targeting pre-erythrocytic stages of Plasmodium falciparum (America)
Start : September 2019 | Status : Active
The scientists: Ana Lisa Valenciano
The sponsor: University of South Florida (USF), WRAIR and NIH
Foundation funding: The Foundation is providing £394,606 in support.
GSK’s contribution: GSK to share access to all generated data and provide access/use of compounds identified from the screen for further evaluation beyond the scope of this proposal. The Tres Cantos unit will provide in kind assay consumables and resources equivalent to two full-time personnel who will assist with gametocyte production, mosquito rearing and infections, dissections, imaging, data analysis, and support.
Project Description: This project offers a major advance in antimalarial drug discovery by targeting pre-erythrocytic stages to block malaria infection. We have developed an innovative P. falciparum in vitro liver assay to evaluate drug toxicity and inhibitory efficacy of critical early phase of malaria infection in human hepatocytes. Consequently, this project can efficiently evaluate drug inhibition of the complete liver stage of the malaria life cycle. Central to this new screening strategy is a G384 microplate culture system using primary human hepatocytes (PHHs)(1) with modified P. falciparum sporozoite isolation procedures (2, 3). To enhance identification of the best lead compounds we will use quantitative functional assays of sporozoite entry into and egress from human hepatocytes along with transmission-blocking assays for mosquito infections. In developing our assays, we identified key microenvironmental triggers of infectivity that downstream can be used to elucidate target specificity and mechanisms of action. Altogether we provide a comprehensive new screening strategy for antimalaria drugs to block infection.
University of California - Hit-to-Lead Development of the Kalihinol Scaffold for Malaria Treatment (America)
Start : June 2019 | Status : Active
The scientists: Ramakrishna Kankanala - Milandip Karak
The sponsor: University of California
Foundation funding: The Foundation is providing £197,190 in support.
GSK’s contribution:The in-kind contributions from GSK will involve the characterization of simplified kalihinol analogues for their efficacy, safety, pharmacodynamics, and pharmacokinetics properties, initially to ensure that this series of compounds is as promising as our initial data suggest. In the medium term, further evaluations of these types will guide a medicinal chemistry effort for hit-to-lead development.
Project Description: The ultimate goal of this collaborative research program is to identify antimalarial clinical candidates among analogues of the kalihinol family of isocyanoterpenes (Figure 1), an understudied class of natural products with potent activity against Plasmodium falciparum, the causative agent of the deadliest form of human malaria. Preliminary data generated in our laboratories support the premise of this research that the kalihinols could be developed as novel antimalarial agents. Our data demonstrate that (i) kalihinol natural products have potent activity against blood stages of both drug-sensitive and drug-resistant P. falciparum strains with IC50 values in the low nanomolar range; (ii) the synthetic route to these compounds has been simplified producing analogues that retain potent antimalarial activity, and there is a chemical plan in place for further synthetic simplification; (iii) the compounds have good HepG2 inhibition data and no major in silico safety alerts, and; (iv) they may exert their antimalarial activity through a novel mode of action. Building upon this body of data, we propose to delve deeply into the structure-activity relationship of these compounds, characterize their in vitro and in vivo efficacy and safety, and unravel their mode of action.
University of Zaragoza- TB antivirulence therapeutics: small molecule inhibitors against M. tuberculosis replication and persistence pathways as novel alternatives to classic antibiotics. (Europe)
Start : March 2019 | Status : Active
The scientists: Stefan Prior - Irene Pérez
The sponsor: University of Zaragoza
Foundation funding: The Foundation is providing £174,268 in support.
GSK’s contribution:The in-kind contributions from GSK will involve:
- HTS using the GSK chemical library
- Cytotoxicity, solubility, stability, …assays to define the value of identified compounds
- Chemistry support for SAR and compound selection
- Proteomics approaches
- In vivo activity in a mouse model of TB virulence
Project Description: Multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB have alarmingly spread worldwide and make treatment difficult or even impossible. In addition, the one third of the human population latently infected with TB (LTBI) constitutes an enormous reservoir. Antivirulence therapies with small molecules that sabotage bacterial survival in the host may have advantages over traditional antibiotics because it targets factors required for pathogenesis, potentially reducing selection for resistance and limiting collateral damage to the resident microbiota (1, 2).
Our project proposes a novel approach to disarm M. tuberculosis (Mtb), focused on searching antivirulence therapies against transcription factor PhoP as a paradigm regulon essential for Mtb virulence (3, 4). Recently, a small molecule inhibiting a transcription factor has been described to revert antibiotic resistance (5). We propose the construction of a reporter Mtb strain by placing strongly PhoP-regulated promoters (4) upstream GFP which will allow the screening of the complete GSK compound collection. Loss of GFP fluorescence upon treatment, indicative of selective virulence inhibition, can be easily monitored by high-throughput screening. Potential synergies between inhibitors, or between inhibitors and current anti-TB drugs will be assayed. We will confirm whether these compounds are active in macrophage and mouse models of TB and we also plan to assay the selected compounds against representative isolates of Mtb Complex lineages, which reflect the current genetic diversity of TB worldwide.
University of Cambridge - High throughput small molecule screen for drugs that alter the shape of Campylobacter jejuni (Europe)
Start : June 2020 | Status : Active
The scientists: Sophia Katherine Berry
The sponsor: University of Cambridge
Foundation funding: The Foundation is providing £143,040 in support
GSK’s contribution: GSK will contribute with high throughput screening expertise to miniaturize the assay. GSK will provide compounds for screening and access to Shigella animal models as well as drug discovery expertise to assess the potential of this approach to deliver a drug for patients.
Project Description: The world faces a major infectious disease challenge that is being made worse by antimicrobial resistance. We need new therapeutic modalities that overcome resistance and that do not affect the natural gastrointestinal flora, which is proven to be essential for gastrointestinal health. We contend that cell shape may be a targetable Achilles heel for enteric bacterial pathogens and has not yet been fully exploited for drug discovery applications. There is evidence that cell shape can affect the virulence of pathogens (e.g. Campylobacter spp. and Salmonella spp.). Through this Open Lab project, this characteristic will be exploited for high-throughput screens against Shigella spp. and other enteric bacteria.
Harvard T.H. Chan School of Public (America) - Understanding the development of drug resistance in liver stages of Plasmodium falciparum
Start: TBD | Status: Set up
Openlab fellow/s: TBD
The sponsor: Harvard T.H. Chan School of Public
Foundation funding: The Foundation is providing £225,312 in support.
GSK’s contribution: GSK´s in-kind contribution to the project will include access to the GSK-Tres Cantos animal facilities providing the malaria animal models to be employed in the project, as well as the technical expertise, equipment, and reagents (bioimaging, flow cytometry, qPCR) to assess the parasite´s ability to infect and develop in liver cells.
The insectary unit available in Tres Cantos will also be critical for providing all the sporozoites needed for the project.
GSK-Tres Cantos has a wide experience in parasitology and development of animal models for drug discovery purposes in which they have focused mainly in the translation of PK-PD predictions from animals to humans.
Project Description: Despite a remarkable recent reduction in the global burden of malaria, there remains an urgent need for novel anti-malarial drug treatments. Chemoprophylaxis remains the mainstay for malaria prevention, but its efficacy is compromised by non-adherence to medication. A safe and effective long-acting intramuscular (LAI) drug-dosing preparation would provide a promising approach to deliver a new medicine vision for malaria control and eradication.
A significant gap not yet addressed by drug discovery scientists is the understanding of the evolution and impact of drug resistance in liver stages of Plasmodium. Liver-stage parasites are an important reservoir of infection, but because there are far fewer of them compared to blood stage parasites it makes the development of drug resistance at this stage less likely but still possible.
This project will provide insights regarding the development of drug resistance in liver stages and will evaluate the impact of pre-existing resistance for dose prediction of new drug classes targeting bc1 in the context of chemoprophylaxis.
The long-term goal of this project is to understand basic molecular mechanisms of drug resistance in the different stages of protozoan parasites with the aim of applying the best preventive and therapeutic interventions against infection.
University of Oxford (Europe) - Studies on Nucleophilic Cysteine Enzymes Involved in Bacterial Cell Wall Biosynthesis- iCASE
Start: TBD | Status: Set up
Openlab fellow/s: Mariska de Munnik
The sponsor: Oxford University
Foundation funding: The Foundation is providing £27,350 in support (co-funded by the iCASE doctoral training programme).
GSK’s contribution: The origination of this project has benefitted greatly through the collaboration with GSK R&D to date (previous Openlab project) and continued collaboration throughout the iCASE studentship will continue to progress the work. In particular, this will involve the expertise of GSK scientists who provide their scientific input through regular meetings. This expertise includes their extensive background in β-lactams for tuberculosis along with more general expertise in Hit-to-Lead activities.
In addition, experimental input will be provided through MIC determination of M. tuberculosis with compounds of interest. A large portion of inhibition studies will be performed with compounds originated from the GSK database or related commercially obtained compounds.
Furthermore, as part of the iCASE studentship, an internship will be performed at the GSK site (COVID-19 permitting). This internship is proposed to last for 6 months. This internship will be of particular value, as it would enable us to perform cutting edge cellular imaging assays which cannot be performed in Oxford for safety and technical reasons. Benefits would include access to GSK facilities and the trained ability to work in a biosafety level III environment, and the access to GSK expertise in advanced cellular assay techniques. The results will provide insight into the modes of action, selectivity and cidality of inhibitors and will be used to guide future optimization work.
Project Description: As part of a previous Tres Cantos Open Lab project “Structural biology and assays enabling β-lactams that target Mycobacterium tuberculosis” (TC241), a high-throughput screening (HTS) campaign for LdtMt2 has been performed by Manja de Munnik in collaboration with staff at GSK Tres Cantos. This involved the development of a fluorogenic assay, utilizing a thiol-reactive fluorogenic probe which reacts with the active-site cysteine to release a fluorescent signal, therefore providing us with a “nonclassical” inhibition assay, which would allow us to assess the impact of inhibitors on the availability of the catalytic site.19 A library of approximately 10.000 compounds was designed by combining a variety of structurally diverse compounds from β-lactam database, cysteine protease inhibitors database, serine protease inhibitors database and a database consisting of substructures with known cysteine binding warheads from literature. This led to the identification of 733 active compounds. In order to select compounds that are BlaC resistant, these compounds were subjected to a fluorogenic assay with BlaC was used as counter screen. Based on the potency and structural diversity, 52 analogues were selected for follow-up experiments.
This project aims to open up opportunities to design, synthesise and characterise a series of compounds based on the obtained results, which will hopefully lead to the identification of highly active and highly selective non beta-lactam inhibitors of LdtMt2 and potentially other Ldts. These will be characterised in detail including by crystallography. This would help us to gain insight into the function Ldts play in bacterial survival and antibacterial resistance and their efficacy as drug targets. Specifically, this will help us analyse the potential of LdtMt2 as a drug target for novel tuberculosis therapy, as well as open the way to new types of inhibitors for the enzyme.
Sanger Institute - A chemogenomic overexpression screen to identify malaria liver stage targets (Europe)
Start : May 2019 | Status : Active
The scientists: Cindy Smidt & Riaz Shaik
The sponsor: Sanger Institute
Foundation funding: The Foundation is providing £181,975 in support.
GSK’s contribution: At early stages of the project GSK will provide significant input in shortlisting compounds for target identification and provide panels of compounds, as well as collaboratively prioritising targets of interest to be included in the screening panel of PACs. GSK will as well perform chemical re-synthesis of compounds if required. Later they will provide chemo-informatics expertise for data analysis. Targets for validation will be jointly decided. At a late stage of the project, targets with potential for cellular or recombinant enzyme screening will be selected. If compounds have the appropriate characteristics (solubility, DMPK properties, etc) validation work in mouse models will be done at Tres Cantos.
Project Description: There is a widely recognised need for antimalarial drugs that target liver stages (1) but the paucity of suitable liver stage culture systems for human Plasmodium species has so far limited their development. Screening systems are now improving, and cellular screens have identified compounds that selectively kill this parasite stage, with the expectation that such compounds would have prophylactic potential. However, current screening assays have limited throughput. Identifying targets would allow target-based screens in a high-throughput format and explore millions of compounds. Because of the culture systems target ID cannot be achieved through conventional resistance selection approaches used so successfully with blood stage targets (2). In addition, the inefficiency (in the case of P. falciparum) or impossibility (in the case of P. vivax) of experimental genetics has so far prevented rational, target-led approaches to develop liver-active compounds. The strategy we propose here will therefore be potentially paradigm shifting, since it enables systematic screens for targets of liver-specific compounds for the first time.
Genome-scale chemical-genetic interaction screens have successfully identified small molecule targets in libraries of diploid yeast (3-4) that carry heterozygous loss-of-function mutations in individual genes, sensitising their carriers to inhibitors of the same target or pathway. For malaria parasites, which are haploid, we here present evidence that chemical-genetic interaction screening can be used to identify targets not only at the blood stage but also in liver stages. Working with P. berghei, a parasite species that is uniquely suited to study liver stage biology in vitro, we have generated tools and methods to increase expression of parasite genes in a controlled and selective manner by introducing extra copies of the part of the genome that encodes them. We have created a library of Plasmodium artificial chromosomes (PACs) that can be transfected efficiently in pools during blood stages and are faithfully inherited through mosquito and liver stages. Our preliminary data show that treating cultured liver stages reproducibly shifts the relative abundance of individual PACs in accordance with known modes of action and modes of resistance, associating targets with compounds in an unbiased manner.
Using this approach, we have defined the parameters for successful chemogenomic screening in liver stages. We propose here to apply the system to screen 24 liver-active compounds against 625 high priority targets. We will then work with GSK to select and follow up on the most interesting new targets by more detailed validation, cellular/recombinant protein assay development and target-based screens, which will be used to discover new chemical series for future development.
University of Dundee (Europe) - Development of a Drug Discovery Platform Targeting Salmonella Typhimurium Persister Cells
Start: TBD | Status: Set up
Openlab fellow/s: TBD
The sponsor: University of Dundee
Foundation funding: The Foundation is providing £204,292 in support.
GSK’s contribution: This project will benefit tremendously from GSK’s extensive HTS capabilities and expertise, in particular with respect to intra-macrophage assays as well as persister experience in the fields of TB and Chagas, and also from access to its compound collection.
Project Description: Non-growing persister bacteria are antibiotic tolerant and contribute to treatment failure and acquisition of antibiotic resistance in multiple infection contexts, including invasive non-typhoidal Salmonellosis (iNTS). iNTS kills approximately 50,000 people per year in sub-Saharan Africa, disproportionately affecting children. Despite this, persister biology remains poorly understood, and most drug discovery screening platforms seek compounds that inhibit growth without assessing impacts on non-growing persisters.
This project will develop a novel screening cascade that focuses on compounds capable of killing the persisters that survive conventional antibiotics. As a proof of concept, we will screen key sets of compounds and deploy a series of secondary screens on a subset of identified hits. This will allow us both to optimise the cascade and identify compounds for further development. Additionally, we will develop persister-specific assays to use as secondary screens, leading to new insights in persister biology with potentially broad applications to other infectious diseases.