COSAMIDE

What it is

COSAMIDE is a non-steroidal anti-androgen that binds to androgen receptors without activating gene expression, thus inhibiting the androgen stimulus. COSAMIDE tablets contain 50 mg bicalutamide. This inhibition impairs the growth and encourages apoptosis in androgen-dependent tumour cells and regression of prostatic tumours.

Approved indications

— Treatment of advanced prostate cancer in combination with LHRH agonist therapy.

Dosing overview

The recommended dose for adult males including the elderly is one tablet (50 mg) once a day. Treatment with COSAMIDE should be started at the same time as treatment with a LHRH agonist. No dosage adjustment is necessary for patients with renal impairment. No dosage adjustment is necessary for patients with mild hepatic impairment, although increased accumulation may occur in patients with moderate to severe hepatic impairment, in which cases a lower or less frequent dose may be considered.

Key safety warnings

In patients with metastatic prostate cancer, treatment with bicalutamide monotherapy has been associated with reduced survival compared to castration, and COSAMIDE should therefore not be used without concomitant LHRH agonist therapy in these patients. Rare cases of death or hospitalisation due to severe liver injury have been observed with COSAMIDE therapy, which should be discontinued if at any time a patient develops jaundice or if serum ALT rises above two times the upper limit of normal. COSAMIDE is extensively metabolised in the liver, and its elimination may be slower in subjects with severe hepatic impairment, which could lead to increased accumulation; therefore, COSAMIDE should be used with caution in patients with moderate to severe hepatic impairment. Potentiation of coumarin anticoagulant effects have been reported in patients receiving concomitant COSAMIDE therapy, which may result in increased Prothrombin Time (PT) and International Normalised Ratio (INR), with some cases associated with risk of bleeding; close monitoring of PT/INR is advised and anticoagulant dose adjustment should be considered. Androgen deprivation therapy may prolong QT/QTc interval, and prescribers should consider whether the benefits of androgen deprivation therapy outweigh the potential risks in patients with congenital long QT syndrome, congestive heart failure, frequent electrolyte abnormalities and in patients taking drugs known to prolong the QT interval; electrolyte imbalances should be corrected and periodic monitoring of electrocardiograms and electrolytes should be considered.

Contraindications

COSAMIDE is contraindicated in females and children. COSAMIDE is contraindicated in patients with known hypersensitivity to bicalutamide or any other constituents of the formulation. Co-administration of terfenadine, astemizole or cisapride with COSAMIDE is contraindicated.

Regulatory history

COSAMIDE bicalutamide 50 mg tablets were first listed on the Australian Register of Therapeutic Goods (ARTG 135219) on 7 November 2007. A film-coated tablet blister pack formulation (ARTG 162829) was subsequently listed on 23 July 2010.