DEER PARK, Ill., May 19, 2026
Eton Pharmaceuticals announced a new agreement with Knight Therapeutics to acquire exclusive U.S. commercialization rights to IMPAVIDO® (miltefosine), the first and only FDA-approved oral therapy for visceral, cutaneous, and mucosal leishmaniasis caused by specific Leishmania species. The agreement further strengthens Eton’s growing rare disease portfolio and expands the company’s presence in specialized infectious disease markets where treatment options remain limited. Under the agreement, Eton will assume exclusive U.S. commercialization rights beginning September 26, 2026.
IMPAVIDO is approved for adults and adolescents aged 12 years and older weighing at least 30 kilograms and is indicated for the treatment of several serious forms of leishmaniasis, a rare parasitic disease transmitted through infected sand flies. The disease can cause severe skin lesions, mucosal destruction involving the mouth and throat, or life-threatening systemic infection affecting internal organs such as the liver and spleen. Although relatively rare in the United States, global travel, migration, and military deployment continue to increase awareness and diagnosis of the disease within specialized infectious disease centers.
IMPAVIDO Adds FDA-Approved Oral Therapy to Eton’s Rare Disease Portfolio
The acquisition gives Eton access to a commercially established orphan drug that has been available in the U.S. market since 2016. IMPAVIDO remains the only FDA-approved oral treatment option for multiple forms of leishmaniasis, providing a convenient alternative to more complex injectable therapies often associated with hospitalization or extended administration schedules.
According to Eton CEO Sean Brynjelsen, the therapy aligns closely with the company’s orphan-drug commercialization strategy focused on highly specialized patient populations requiring high-touch patient support and targeted distribution models. The company stated that the transaction complements its expanding portfolio of rare disease products while broadening its capabilities across infectious and tropical disease treatment markets.
Leishmaniasis remains a significant global health concern, particularly in tropical and subtropical regions. The disease is caused by protozoan parasites of the Leishmania genus and can manifest in several forms. Cutaneous leishmaniasis typically causes ulcerative skin sores, while mucosal leishmaniasis can lead to destructive lesions affecting the nose, mouth, and throat. The most severe form, visceral leishmaniasis, affects internal organs and can become fatal if left untreated. Healthcare experts consider access to effective oral treatment options particularly important in regions where healthcare infrastructure and infusion-based therapies may be difficult to access.
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Eton Continues Expansion Across Specialized Orphan Drug Markets
The IMPAVIDO agreement represents another strategic step in Eton’s broader effort to build a diversified portfolio of niche rare disease therapies. The company currently markets multiple orphan-focused products across endocrinology, metabolic disorders, and pediatric rare diseases, while continuing to advance additional late-stage pipeline programs.
Eton emphasized that the addition of IMPAVIDO supports its ongoing strategy of acquiring and commercializing differentiated rare disease therapies with established clinical value and limited market competition. By leveraging its specialized commercial infrastructure, the company aims to improve treatment access and patient support services for individuals living with complex rare conditions.
The therapy also carries important safety considerations. IMPAVIDO includes a boxed warning regarding serious pregnancy-related risks, including fetal harm and birth defects, and requires pregnancy testing before treatment initiation in women who may become pregnant. Common side effects associated with the therapy include nausea, vomiting, diarrhea, abdominal pain, dizziness, liver function abnormalities, and kidney-related laboratory changes.
Industry analysts note that the agreement strengthens Eton’s positioning within the growing orphan drug market, where pharmaceutical companies continue to prioritize highly specialized therapies addressing significant unmet medical needs. The transaction also demonstrates continued interest in rare infectious diseases that often receive limited commercial focus despite substantial clinical burden in vulnerable patient populations.
Source: Eton Pharmaceuticals, press release
