Inavolisib: clinical use

Prescribing considerations

• Confirm an eligible PIK3CA mutation using a validated tumour or plasma assay.
• Treatment should be initiated by a clinician experienced in anticancer therapy.
• Optimise fasting glucose before treatment; diabetes was poorly represented in the pivotal study.
• Review renal and hepatic function, previous CDK4/6-inhibitor exposure, concomitant medicines and reproductive plans.
• Counsel about hyperglycaemia, hydration, stomatitis, diarrhoea and prompt symptom reporting.

Contraindications and cautions

• Hypersensitivity to inavolisib or any excipient.
• Rare hereditary galactose intolerance, total lactase deficiency or glucose-galactose malabsorption because the tablets contain lactose.
• Use particular caution with pre-existing diabetes or clinically significant renal impairment.
• Safety and efficacy have not been established in moderate or severe hepatic impairment.

Monitoring

• Check fasting glucose and HbA1c before treatment and regularly thereafter; consider home glucose monitoring for risk factors or hyperglycaemia.
• Increase glucose monitoring during infection, corticosteroid use or other circumstances that worsen glycaemic control; assess ketones when clinically indicated.
• Monitor for stomatitis, diarrhoea, dehydration, weight loss, cytopenias, electrolyte disturbance and raised liver enzymes.
• Assess treatment response and tolerability regularly.

Clinical pharmacology

Inavolisib selectively inhibits PI3K-alpha p110-alpha and promotes degradation of mutated p110-alpha. Oral bioavailability is approximately 76%; food has no clinically significant effect. Hydrolysis is the main metabolic pathway, and renal impairment increases systemic exposure.

Formulation and product differences

• Available as two strengths of film-coated tablet to support treatment modification.
• The lower-strength tablet is red and round; the higher-strength tablet is pink and oval.
• Both strengths contain lactose, are essentially sodium-free and must be swallowed intact.

Tablet

Route: Oral

Strengths: 3 mg, 9 mg