Preclinical development of CpG D35 for combined treatment of cutaneous leishmaniasis
Project Completed
Please click to see the final report.

Introduction and Background of the Project


Drugs for Neglected Diseases initiative (DNDi) and GeneDesign seeks to find a better treatment for cutaneous leishmaniasis (CL). About cutaneous Leishmaniasis: There are currently no satisfactory treatments for CL, a disease that affects about one million people worldwide each year. Unlike visceral leishmaniasis, CL is not fatal but causes devastating morbidity for the patient with scaring and social stigmatism particularly for children and women, which can mark their entire life. To address the unmet need in CL, DNDi and GeneDesign are working to develop a safe and efficacious, short duration, non-invasive treatments that are affordable and field-friendly.


Project objective

The aim of this project is to demonstrate the suitability of CpG D35 for progression to Phase I clinical trials. The objectives for this proposal are to: (1) Manufacture 200g of Active Pharmaceutical Ingredient (API) suitable for preclinical, stability, formulation development and phase I clinical trials; (2) Create a formulation design for preclinical safety studies and Phase I clinical trials; (3) Complete IND-enabling preclinical safety package (triggered by GO decision from in vivo efficacy study), and (4) Manufacture clinical supplies for a Phase I study.


Project design

Conventional chemotherapy of CL aims to kill most of the parasites thereby reducing the burden of infection. It is hypothesized that the host’s immune system is then able to control those parasites that remain. A novel approach to actively stimulate endogenous host response mechanisms and boost the host’s immune system to eliminate all parasites is to agonize the Toll 9 receptor pathway in turn stimulating the innate immune system to clear parasites from the body. Hence, combining chemotherapy and immune-stimulation offers an optimal regimen to rapidly clear the infection, stimulate lesion repair, and much improve CL patient care.


CpG D35 is a D-type CpG ODN TLR9 agonist optimized for use in man. It stimulates maturation and activation of plasmacytoid dendritic cells, and production of pro-inflammatory cytokines such as interferon-γ (IFN-γ) and IL-12, which are required for control of the Leishmania infection, but has little or no effect on B cells, thereby minimizing the undesired TH2 type response associated with most other CpGs tested for other conditions. In addition, CpG D35 has demonstrated excellent in vivo efficacy against CL parasites in preclinical studies in both rodents and primates.


Given these properties, we expect that CpG D35 in combination with chemotherapy is the best approach for patients with complicated CL diseases, i.e. patients with large or multiple lesions, patient who don’t respond to the standard treatment or who show relapses or patients with chronic lesions (>6 months, i.e. patients with lesions due to L. braziliensis and L. tropica) or patients with leishmania recidivans; all conditions for which the standard treatment has shown to have limited efficacy (<60% cure rate) or require multiple treatments.

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

Treatment Challenge: Currently, recommended treatment for CL are poorly justified and have sub-optimal effectiveness and have long depended on antiquated drugs that would be considered far too toxic for introduction under modern registration systems. DNDi and GeneDesign are working to develop a safe and efficacious, short duration, non-invasive treatments that are affordable and field-friendly.

What sort of innovation are you bringing in your project?

The purpose of treatment in CL is to increase the speed to complete cure, reduce scarring, and prevent relapse. One approach is to eliminate most organisms by chemotherapy, after which host immune mechanisms would control the remaining parasites. Another approach is to boost clearance by enhancing the immune mechanisms through immunotherapy. A combined approach offers the best opportunity for treatment, which if effective would reduce the chances of treatment failure, relapse, and drug resistance.

Role and Responsibility of Each Partner

The GeneDesign team will produce the active pharmaceutical ingredient (API), designing the formulation, prepare the study supplies and carrying out the quality control and stability testing.  GeneDesign has extensive project management experience in the field of CpG oligonucleotides.  Based on their accumulated LC-MS analysis technologies, they bring physical properties evaluation test suitable for toxicology and phase I/II clinical trials.


DNDi will be responsible for the overall project management, coordination, budgeting, reporting, and contracting with partners to meet the projected timelines. DNDi will also put in place the CpG D35 Advisory Committee comprised of senior representatives of DNDi, GeneDesign and relevant consultants which will convene at the beginning and conclusion of the in-vivo study.  DNDi will also submit an open source publication emanating from the R&D activities to enable the leishmaniasis research community to benefit from the knowledge generated from the R&D team.

Final Report

1. Project objective

CpG D35 is expected to improve cutaneous leishmaniasis (CL) patient care. Modulating the immune response with CpG oligonucleotides may improve the effectiveness of chemotherapies. Based on the final results of the preclinical in vivo efficacy study showing an improved outcome for CpG D35, either alone or in combination with pentavalent antimony (glucantime), this project aimed to demonstrate the suitability of CpG D35 for progression to Phase I clinical trials.


2. Project design

The project activities during this grant period were to; (1) manufacture Active Pharmaceutical Ingredient (API) suitable for preclinical, stability, formulation development and Phase I clinical trials; (2) develop a formulation for preclinical safety studies and Phase I clinical trials; (3) complete preclinical safety package, and (4) manufacture clinical supplies for a Phase I study.


3. Results, lessons learned

The following milestones have been achieved, resulting in successful progression to Phase I clinical trials.

(1) Completion of API manufacture

An initial 55g GLP batch was manufactured for non-clinical studies. A total of 145g of GMP API was also manufactured successfully for stability studies, formulation development and clinical manufacture. All API batches met GLP and GMP requirements.

(2) Formulation nomination

A trehalose-based formulation containing 15 mg/mL CpG D35 was selected for non-clinical and initial clinical studies, considering bracketing stability data on different concentrations (10 mg/mL and 50 mg/mL), physical characteristics (viscosity) and the ease of manufacture.

(3) Completion of preclinical safety package

・Genotoxicity assessment: CpG D35 did not show any potential for mutagenic or clastogenic activity, considering in vitro (Ames and human lymphocyte assays) and in vivo micronucleus tests.

・Assessment of systemic exposure after subcutaneous and intravenous administration route in non-rodent species: The comparative pharmacokinetic study has demonstrated plasma CpG D35 concentrations in blood after subcutaneous administration to be between 0.96 and 3.28% of the concentrations after intravenous administration.

・A dose range finding study in non-rodents: No clinical signs or organ toxicities have been observed at all three doses (2, 6 and 15.9 mg/kg) administrated by the subcutaneous route. Only local changes at the injection site such as odema were reported. The No Observed Adverse Effect Level (NOAEL) was 15.9 mg/kg.

・A 4-week GLP toxicology study in non-rodent species:

Preliminary results demonstrated that the compound is well tolerated at any of the three doses (2, 6 and 15.9 mg/kg) and the systemic exposure is dose proportional. No clinical signs or target organ toxicities. Local changes at the injection site such as odema were reported at all doses tested but are expected given the nature of CpG ODN D35 and are reversible. A No Observed Adverse Effect Level (NOAEL) of 15.9 mg/kg will be declared.

(4) Completion of clinical supply manufacture for a Phase I study

CpG D35 15 mg/mL solution and placebo were manufactured successfully and meet the release specifications. Clinical batches have been set down on a 3-year stability programme. A provisional shelf-life of 12 months at 2-8°C has been assigned based on earlier stability studies.