idelalisib: clinical use

Prescribing considerations

• Treatment should be supervised by a clinician experienced in anticancer therapy.
• Confirm the licensed disease context and review previous therapy, molecular findings and alternatives.
• Do not initiate with an ongoing systemic bacterial, fungal or viral infection.
• Reconcile all medicines for CYP3A and transporter interactions.
• Counsel patients to report infection, respiratory symptoms and diarrhoea promptly.

Contraindications and cautions

• Hypersensitivity to idelalisib or an excipient.
• Use caution with hepatic impairment, active hepatitis, previous inflammatory bowel disease or substantial immunosuppression.
• Safety and efficacy are not established in people younger than 18 years.

Monitoring

• Full blood count, particularly absolute neutrophil count.
• ALT, AST and bilirubin.
• Infection and CMV status in patients with previous CMV exposure.
• New respiratory symptoms, diarrhoea or colitis, rash, and neurological or behavioural change.

Clinical pharmacology

Idelalisib selectively inhibits the PI3K p110-delta catalytic subunit, suppressing Akt-pathway signalling and malignant B-cell proliferation, survival, homing and retention. It is metabolised mainly by aldehyde oxidase; its inactive primary metabolite strongly inhibits CYP3A.

Formulation and product differences

• The film-coated tablet contains sunset yellow FCF (E110), which may cause allergic reactions.
• The tablet should be swallowed whole and is essentially sodium-free.

Tablet

Route: Oral

Strengths: 100 mg, 150 mg