Leishmaniasis/kala azar

Largely unknown in the developed world, leishmaniasis  - known as Kala-azar in Asia - is a parasitic disease that affects over 12 million people worldwide.  Approximately half a million new cases are reported to occur each year although it's thought that only up to a third of all new cases actually get reported. 

Fatal if left untreated, the disease persists today in poor, remote, and sometimes politically unstable areas, where there is limited health care and patients have little access to preventive measures and affordable drugs. A significant proportion of clinical cases occur in children. Treatment of leishmaniasis has been hampered by inadequate drugs, high prices and slow progress on research and development into new cures.

The parasitic protozoa Leishmania is transmitted by flies and causes three different forms of the disease of which visceral leishmaniasis (VL) is the most severe. VL is characterized by prolonged fever, enlarged spleen and liver, substantial weight loss, progressive anemia, and can be complicated by co-infection with other infectious diseases such as HIV or malaria.

 

Challenges for Treating Leishmaniasis

The most common treatment for visceral leishmaniasis was developed  in the 1930s using derivatives of antimony. Sodium stibogluconate (SSG) is injected over 30 days. SSG is still effective in many regions. But resistance to the drug is a growing problem - especially in India, where as many as 65% of patients are resistant.

The drawbacks include the length of treatment, the toxicity of the drugs, painful administration and cost.  A generic version of SSG is being manufactured in India at a considerably reduced price (around US$20 compared with US$270 for the brand name product) but it is not yet widely registered in Africa.

In addition the drugs may not work effectively in patients who are co-infected with other diseases such as HIV.

Combination therapy is the way forward

Amphotericin B can be used to treat visceral leishmaniasis but is complicated to administer (15 prolonged infusions on alternate days) and can be toxic for the kidneys. A liposomal form of amphotericin B called Ambisome is much better tolerated and is very efficient. Its high price remains a challenge despite recent price cuts.

Miltefosine is the only oral drug available to treat visceral leishmaniasis. Given for 28 days, it was shown to be effective in India but its efficacy in East African countries is poorly documented. 

Paromomycin given for 21 days was shown to be safe and efficient in India. However, paromomycin appears to be less efficient in East Africa in ongoing studies coordinated by the DNDi.

Combined therapy is the way forward. The combination of antimonials-paromomycin, successfully used by MSF in Sudan, is being formally evaluated by the DNDi in East African countries. Studies on combinations Ambisome-miltefosine, Ambisome-paromomycin and miltefosine-paromomycin are being started in India and are planned in East Africa.

MSF and Leishmaniasis

 Since 1988, MSF has treated more than 80 000 patients with leishmaniasis principally in East African countries, including Sudan, Ethiopia, Kenya, Somalia and Uganda. MSF has validated and introduced rapid diagnostic tests (rK39 antigen-based dipsticks), that can be used in remote settings, providing much greater access to patients.  Antimonials are used as first-line treatment in most MSF programmes except in Sudan and in India. Cheaper, safer and more practical drugs are needed to improve patients' access for this forgotten disease.

MSF continues to call for:

  • Lower prices for existing drugs
  • Acceleration of the registration of anti-leishmanial drugs in East African countries including generic SSG and Ambisome
  • Increased use of Ambisome and combination therapies.

Read Leishmaniasis/Kala-azar Fact Sheet