Miltefosine is primarily used for the treatment of visceral and New World cutaneous leishmaniasis, and is undergoing clinical trials for this use in several countries.[11][12] This drug is now listed as a core medication for the treatment of leishmaniasis under the WHO Model List of Essential Medicines.[13] Several medical agents have some efficacy against visceral or cutaneous leishmaniasis, however, a 2005 survey concluded that miltefosine is the only effective oral treatment for both forms of leishmaniasis.[14]
Amoeba infections
Miltefosine has been used successfully in some cases of the very rare, but highly lethal, brain infection by the amoeba, Naegleria fowleri, acquired through water entering the nose during a plunge in contaminated water.[15] It has orphan drug status in the United States for acanthamoeba keratitis and primary amebic meningoencephalitis (PAM).[16][17]
Pregnancy and breastfeeding
Miltefosine is listed as pregnancy category D by the FDA. This means there is evidence-based adverse reaction data from investigational or marketing experience or studies in humans of harm to the human fetus.[18] Despite this evidence, the potential benefits of miltefosine may warrant use of the drug in pregnant women despite potential risks. A pregnancy test should be done prior to starting treatment. Effective birth control should be used while on miltefosine and 5 months after discontinuation of treatment. Its use during breast feeding is most likely unsafe.[3]
Contraindications
Miltefosine is contraindicated in individuals who have a hypersensitivity to this medication, pregnant women, and people who have the Sjögren-Larsson syndrome.[19] It is embryotoxic and fetotoxic in rats and rabbits, and teratogenic in rats but not in rabbits. It is therefore contraindicated for use during pregnancy, and contraception is required beyond the end of treatment in women of child-bearing age.[20]
Side effects
Common side effects from miltefosine treatment are nausea and vomiting, which occur in 60% of people. Other common side effects are dizziness, headache, and daytime sleepiness.[21]
Serious side effects include rash, diarrhea, and arthritis.[21] The side effects are more severe in women and young children. The overall effects are quite mild and easily reversed.[22]
Mechanism of action
Miltefosine primarily acts on Leishmania by affecting the species's promastigote and amastigote stages.[23] Miltefosine exerts its activity by interacting with lipids, inhibiting cytochrome c oxidase and causing apoptosis-like cell death.[24] This may affect membrane integrity and mitochondrial function of the parasite.[citation needed]
History
Cancer
While initially studied as a cancer medication, due to side effects it was never used for this purpose.[25]
In the same year as the discovery of the anticancer property, miltefosine was reported by S. L. Croft and his team at the London School of Hygiene and Tropical Medicine as having antileishmanial effect as well. The compound was effective against Leishmania donovaniamastigotes in cultured mouse peritoneal macrophages at a dose of 12.8 mg/kg/day in a five-day course.[33] However, priority was given to the development of the compound for cutaneous metastases of breast cancer. In 1992 a new research was reported in which the compound was highly effective in mouse against different life cycle stages of different Leishmania species, and in fact, more potent than the conventional sodium stibogluconate therapy by a factor of more than 600.[34] Results of the first clinical trial in humans were reported from Indian patients with chronic leishmaniasis with high degree of success and safety.[35] This promising development promulgated a unique public–private partnership collaboration between ASTA Medica (later Zentaris GmbH), the World Health Organization (WHO) Special Programme for Research and Training in Tropical Diseases, and the Government of India. Eventually, several successful Phase II and III trials led to the approval of miltefosine in 2002 as the first and only oral drug for leishmaniasis.[3]
Naegleria fowleri and Acanthamoeba
In 2013, the US Centers for Disease Control and Prevention recommended miltefosine for the treatment of free-living amoeba infections such as granulomatous amoebic encephalitis and primary amoebic meningoencephalitis, two fatal protozoal diseases.[36] Historically, only four survivors have been recorded out of 138 confirmed infections in North America. One American survived the infection in 1978 and one individual from Mexico in 2003. In 2013, two children survived and recovered from primary amoebic meningoencephalitis after treatment with miltefosine.[37][38] In 2016 after treatment that included miltefosine, another child became the fourth person in the United States to survive Naegleria fowleri infection.[39]
Society and culture
Availability
Since 2017 Miltefosine is commercially available in the United States through Profounda.[40] Previously one could only get it from the CDC for emergency use under an expanded access IND protocol for treatment of free-living amoeba (FLA) infections: primary amoebic meningoencephalitis caused by Naegleria fowleri and granulomatous amoebic encephalitis caused by Balamuthia mandrillaris and Acanthamoeba species.[37] Miltefosine is almost exclusively produced by Profounda, a private pharmaceutical company.[41]
Miltefosine is being investigated by researchers interested in finding treatments for infections which have become resistant to existing drugs. Animal and in vitro studies suggest it may have broad anti-protozoal and anti-fungal properties:
A 2006 in vitro study found that miltefosine is effective against metronidazole-resistant variants of Trichomonas vaginalis, a sexually transmitted protozoal disease.[46]
An in vitro test in 2006 showed that miltefosine is effective against the deadly protozoan pathogens, Naegleria fowleri, Balamuthia mandrillaris, and Acanthamoeba.[48] However, later in vitro and animal model experiments showed that it is not as potent as other drugs, such as chlorpromazine[49] and diminazene aceturate (Berenil).[50]
In 2013, there were reports of failure of miltefosine in the treatment of leishmaniasis.[51][52] Although drug resistance was suspected, studies in 2014 reported that miltefosine is not so effective in children, most probably related to a lack of drug exposure in children.[53] Moverover, males appeared to have a higher probability of relapse as well.[54]
Miltefosine targets HIV infected macrophages, which play a role in vivo as long-lived HIV-1 reservoirs. The HIV protein Tat activates pro-survival PI3K/Akt pathway in primary human macrophages. Miltefosine acts by inhibiting the PI3K/Akt pathway, thus removing the infected macrophages from circulation, without affecting healthy cells.[56][57] It significantly reduces replication of HIV-1 in cocultures of human dendritic cells (DCs) and CD4+ T cells, which is due to a rapid secretion of soluble factors and is associated with induction of type-I interferon (IFN) in the human cells.[58]
^World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
^World Health Organization (2021). World Health Organization model list of essential medicines: 22nd list (2021). Geneva: World Health Organization. hdl:10665/345533. WHO/MHP/HPS/EML/2021.02.
^Sindermann H, Engel J (December 2006). "Development of miltefosine as an oral treatment for leishmaniasis". Transactions of the Royal Society of Tropical Medicine and Hygiene. 100 (Suppl 1): S17–S20. doi:10.1016/j.trstmh.2006.02.010. PMID16730362.
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^Fleer EA, Unger C, Kim DJ, Eibl H (November 1987). "Metabolism of ether phospholipids and analogs in neoplastic cells". Lipids. 22 (11): 856–861. doi:10.1007/bf02535544. PMID3444378. S2CID4055850.
^Berger MR, Petru E, Schmähl D (1987). "Therapeutic ratio of mono or combination bacterial lipopolysaccharide therapy in methylnitrosourea-induced rat mammary carcinoma". Journal of Cancer Research and Clinical Oncology. 113 (5): 437–445. doi:10.1007/bf00390037. PMID3624299. S2CID21064546.
^Hilgard P, Stekar J, Voegeli R, Engel J, Schumacher W, Eibl H, et al. (September 1988). "Characterization of the antitumor activity of hexadecylphosphocholine (D 18506)". European Journal of Cancer & Clinical Oncology. 24 (9): 1457–1461. doi:10.1016/0277-5379(88)90336-7. PMID3141197.
^Croft SL, Neal RA, Pendergast W, Chan JH (August 1987). "The activity of alkyl phosphorylcholines and related derivatives against Leishmania donovani". Biochemical Pharmacology. 36 (16): 2633–2636. doi:10.1016/0006-2952(87)90543-0. PMID3606662.
^Ahmad AF, Heaselgrave W, Andrew PW, Kilvington S (2013). "The in vitro efficacy of antimicrobial agents against the pathogenic free-living amoeba Balamuthia mandrillaris". The Journal of Eukaryotic Microbiology. 60 (5): 539–543. doi:10.1111/jeu.12062. PMID23869955. S2CID12941376.
^Vila TV, Ishida K, de Souza W, Prousis K, Calogeropoulou T, Rozental S (January 2013). "Effect of alkylphospholipids on Candida albicans biofilm formation and maturation". The Journal of Antimicrobial Chemotherapy. 68 (1): 113–125. doi:10.1093/jac/dks353. PMID22995097.