Irish drug developer secures orphan status for cancer therapy

Priothera looking to improve survival rates of patients with acute myeloid leukaemia

An Irish company looking for cures for blood-related cancers has secured orphan status form US regulators for its lead treatment candidate, Mocravimod.

Priothera said the Food and Drug Administration had granted the orphan drug designation to Mocravimod as a treatment “to improve outcome following hematopoietic [blood-forming] stem cell transplantation in hematologic malignancies”.

Haematologic malignancies are cancers, such as leukaemia, lymphoma and multiple myeloma. The FDA said Priothera’s drug aimed to increase leukaemia patients long-term prospects of survival.

The FDA grants orphan drug status to treatments for rare diseases affecting fewer than 200,000 patients in the US.


The benefits for drug companies is that medicines with such a designation are generally able to charge more therapy if it gains market approval. They also get extended protection from copycats – seven years market exclusivity following approval against five years for other drugs.

Financial support through tax credits for some clinical trials and exemption from FDA fees that can run into million of dollars are also available.

Priothera’s Mocravimod is a drug taken orally that activates cell receptors to trigger part of the body’s immune response against acute myeloid leukaemia (AML).

AML is a cancer that features rapid growth of abnormal white blood cells which accumulate in the bone marrow and hamper production of normal blood cells. It is seen as the most common acute leukaemia affecting adults.

Mocravimod is currently being developed as a treatment to improve the prospects of acute myeloid leukaemia patients who undergo stem cell therapy with blood cells from a healthy donor.

The stem cell therapy, known as allogeneic HSCT, is the only therapy promising the potential of a cure for acute myeloid leukaemia patients but, at present, it is seen as having unacceptably high rates of mortality and illness.

Priothera was set up in 2020 specifically to search for cures for haemotaligical malignancies – cancers of the blood, the bone marrow and lymph nodes. Three of its top executives were involved with inflammatory disease company, Inflazome, which was sold in 2020 to Swiss group Roche for an initial €380 million months before Priothera was founded.

Irish life sciences venture capital group Fountain Healthcare Partners led a €30 million fundraising for Priothera back in 2020.

Dominic Coyle

Dominic Coyle

Dominic Coyle is Deputy Business Editor of The Irish Times