DigiFab™ - a digoxin antidote
Product information: DigiFab is an antidote approved in the US to treat patients with life-threatening digoxin toxicity or overdose. Digoxin (also known as digitalis) is a drug used to treat congestive heart failure and to slow heart rate in some cardiac disturbances. It has a narrow therapeutic window, meaning it is easy to move from therapeutic levels to toxic levels as a result of overdose, slow elimination or interaction with other drugs. Digoxin toxicity can cause potentially life-threatening heart rhythm disturbances.
Protherics have acquired the intellectual property for the use of polyclonal ovine antibody fragments, such as DigiFab and GSK’s Digibind® for the treatment of severe pre-eclampsia and eclampsia, a life-threatening complication of pregnancy. Pre-eclampsia is characterised by high blood pressure and can lead to renal failure and seizures. It typically results in the early delivery of the baby, with potential developmental abnormalities and the possible death of the mother and/or baby. Currently there are no approved therapies available to treat pre-eclampsia and few products in development.
DigiFab is used in Sri Lanka for the treatment of Oleander poisoning after accidental or deliberate ingestion. Oleander is a plant commonly found in South-East Asia which contains digitalis-like substances.
Technology: Digoxin Immune Fabs (DIFs) (Ovine)
Mechanisms of action: DigiFab lowers the amount of digoxin in the blood which is capable of binding to its receptor and thereby reduces its cardio-toxic effects.
Incidence: 16 million digoxin prescriptions are written each year in the US and toxicity occurs in 26% to 29% of patients in 2006*. Pre-eclampsia is a life-threatening disorder occurring in 10% of pregnancies worldwide per year. By conservative estimates, pre-eclampsia and other hypertensive disorders of pregnancy are responsible for 76,000 deaths each year in the US. **
Market opportunity: For digoxin toxicity, US$30-35 million per annum globally**. The estimated potential market for the use of DIFs in severe pre-eclampsia is >US$1billion.
* American Association of Poison Control Centers data
** Protherics estimate
For further information see the
DigiFab fact sheet, the
Digixin Immune Fabs fact sheet or the
pre-eclampsia factsheet.
Important safety information: Adverse reactions that could occur with the use of DigiFab include exacerbation of low cardiac output states and congestive heart failure due to the withdrawal of inotropic effect of digitalis, hypokalemia due to reactivation of the sodium-potassium ATPase, rapid ventricular response in patients with atrial fibrillation due to withdrawal of the effects of digitalis on the atrioventricular node and rare allergic reactions.
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