Investment

Details

Immune therapy to prevent VL complications
  • RFP Year
    2018
  • Awarded Amount
    $558,315
  • Disease
    NTD (Leishmaniasis)
  • Intervention
    Vaccine
  • Development Stage
    Preclinical Development
  • Collaboration Partners
    University of Tokyo, International Center for Diarrheal Disease Research Bangladesh, Infectious Disease Research Institute

Introduction and Background of the Project

Introduction

Caused by L. donovani infection, visceral leishmaniasis (VL; Kala-azar) is endemic in large areas of the Indian subcontinent. Primary symptoms include splenomegaly, weight loss and anemia  and VL has the highest mortality rate among neglected tropical diseases. Improved treatment regimen are being sought to reduce toxicity and drug resistance. Resistance to antimonials has resulted in their replacement with Amphotericin B, paromomycin and miltefosine. Treatment failure occurs in 3-30% of treated cases in VL endemic populations and can be as high as 50-60% for patients co-infected with HIV. Extended observation periods are required to detect relapse and progression to post-Kala azar dermal leishmaniasis (PKDL).

 

Project objective

Intervention in VL patients at greatest risk of treatment failure, relapse or subsequent development of PKDL is critical for effective disease management. Our published data has identified vaccine candidates that are effective as a prophylaxis in advanced animal models. In this proposal we will build upon this data to determine the candidate antigen best suited for use in the Indian subcontinent (Bangladesh) and use a long term preclinical model of L. donovani infection to develop immune/chemotherapeutic approaches to prevent complications of VL.

 

Project design

To develop an effective therapeutic vaccine for VL, selection of good antigen(s) and adjuvant is important. Besides, the vaccine, when used a component of the immune/chemotherapeutics, is not supposed to compromise the effect of chemotherapy. Therefore, this project will comprise three major activities; 1) Patient-instructed selection of vaccine antigen for prevention of PKDL, 2) Evaluation of compatibility of vaccines with Ambisome treatment, 3) Evaluation of efficacy of immune therapy in long term VL model. Based on the success in these activities, all the partners will start preparation for clinical trial of the therapeutic vaccine in combination with AmBisome.

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

VL is endemic in large areas of the tropics, subtropics and the Mediterranean Basin. VL in East Africa and the Indian subcontinent is caused by L. donovani infection. Elimination programs have reduced active VL case numbers in the past few years, but eradication is impeded by: individuals who are asymptomatically infected with L. donovani; the increase of relapsed VL cases, and; the development of PKDL. Recurrence of VL occurs in 3.7% of treated patients within 24 months after treatment, while PKDL occurs in >50% of VL patients in East Africa and 10-20% in the Indian sub-continent within months of completing treatment. Despite being considered a research priority, validated strategies to prevent relapse or PKDL development are lacking. In addition, the use of a single drug (AmBisome) for treatment presents risk of developing resistance. This proposal aims to develop an immune/chemotherapeutic regimen to provide short and long-term protection against the complications, and potential transmission, of L. donovani infection.

What sort of innovation are you bringing in your project?

Novel treatment regimen involving chemoimmunotherapy to reduce or prevent typical post-treatment sequelae of VL.

Role and Responsibility of Each Partner

icddr,b researchers will address patient-instructed selection of vaccine antigen for prevention of PKDL, which will guarantee the wide coverage by the vaccine of people having distinct immunological background. IDRI scientists will determine compatibility of vaccines with Ambisome treatment by evaluating the antigen-specific CD4 T cell responses induced by immunization and determine the impact of AmBisome on these. University of Tokyo scientists will address the efficacy of immune therapy in long term VL model by evaluating the impact of chemo-immunotherapeutic regimen on various pathologies induced by long-term L. donovani infection.