Colistimethate sodium and tobramycin dry powders for inhalation for treating pseudomonas lung infection in cystic fibrosis

Colistimethate sodium DPI (Colobreathe, Essential Pharma) is a formulation of colistimethate sodium supplied as hard capsules for use with an inhaler. It belongs to the polymixin class of antibacterials and works by disrupting the structure of the bacterial cell membrane, leading to bacterial death. It is active against aerobic gram-negative organisms including P. aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae. Colistimethate sodium DPI is indicated for the management of chronic pulmonary infections caused by P. aeruginosa in patients with cystic fibrosis aged 6 years and older.

The summary of product characteristics lists the following adverse reactions for colistimethate sodium DPI: respiratory disorders (such as dyspnoea, cough and wheezing), ear and labyrinth disorders, thoracic and gastrointestinal disorders, musculoskeletal, connective tissue and bone disorders, general disorders and administration site conditions, and renal and urinary disorders. For full details of adverse reactions and contraindications, see the summary of product characteristics.

The recommended dosage for colistimethate sodium DPI is 1 capsule (approximately equal to 125 mg of colistimethate sodium) to be inhaled twice daily using the 'Turbospin' inhaler device (PH&T Pharma) which is a breath-activated, reusable dry powder inhaler. The price for a 28-day pack including 1 Turbospin inhaler is £968 (excluding VAT; price provided by the manufacturer). The list price cost for 56 days of treatment is therefore £1936 excluding VAT. Costs may vary in different settings because of negotiated procurement discounts. The manufacturer of colistimethate sodium DPI has agreed a patient access scheme with the Department of Health which makes colistimethate sodium DPI available with a discount applied to all invoices. The size of the discount is commercial in confidence (see section 5.4). The Department of Health considered that this patient access scheme does not constitute an excessive administrative burden on the NHS.

Tobramycin DPI (TOBI Podhaler, Viatris) is a formulation of tobramycin supplied as hard capsules for use with an inhaler. It is an aminoglycoside antibiotic that acts primarily by disrupting protein synthesis leading to altered cell membrane permeability, progressive disruption of the cell envelope and eventual cell death. Tobramycin inhibits protein synthesis of many gram-negative bacteria and it is active against P. aeruginosa. Tobramycin DPI is indicated for the suppressive treatment of chronic pulmonary infection caused by P. aeruginosa in adults and children aged 6 years and older with cystic fibrosis.

The summary of product characteristics lists the following adverse reactions for tobramycin DPI: respiratory, thoracic and mediastinal disorders (such as dyspnoea, productive cough and wheezing), ear and labyrinth disorders, vascular disorders, gastrointestinal disorders, skin and subcutaneous tissue disorders, musculoskeletal, connective tissue and bone disorders, general disorders, and administration site conditions. For full details of adverse reactions and contraindications, see the summary of product characteristics.

The recommended dosage for tobramycin DPI is 112 mg tobramycin (4×28-mg capsules), administered twice daily for 28 days using the Podhaler device in alternating cycles of 28 days on treatment followed by 28 days off treatment. The price for a pack of 56×28-mg capsules and 1 Podhaler device is £447.50 (excluding VAT; 'British national formulary' [BNF] edition 64). The list price cost for 56 days of treatment is therefore £1790 excluding VAT. Costs may vary in different settings because of negotiated procurement discounts. The manufacturer of tobramycin DPI (Novartis) has agreed a patient access scheme with the Department of Health which makes tobramycin DPI available with a discount applied to all invoices. The size of the discount is commercial in confidence (see section 5.3). The Department of Health considered that this patient access scheme does not constitute an excessive administrative burden on the NHS.