Omalizumab Shows Promise as Rescue Therapy in Status Asthmaticus

Omalizumab rescue therapy produced rapid results in a patient with refractory status asthmaticus, according to a case report published by the Annals of Internal Medicine.

The 41-year-old patient had a history of asthma and pollen allergy and had developed severe dyspnea, despite usage of a short-acting β2-agonist inhaler several times daily for several weeks. During mechanical ventilation, an arterial blood gas analysis revealed severe hypercapnic respiratory failure (partial pressure of oxygen, 267 mm Hg; partial pressure of carbon dioxide, 118 mm Hg; and pH, 6.95). Pneumothorax and obstruction from a foreign body or mucus were ruled out after bronchoscopy and chest radiography.

The patient was administered intravenous prednisone 1000 mg, nebulized salbutamol-ipratropium bromide, subcutaneous terbutaline, intravenous theophylline, and sedation that included intravenous ketamine for status asthmaticus. Low tidal volumes of approximately 1.0 to 1.5 mL/kg of body weight at a positive end-expiratory pressure of 5 cm H₂O with a peak inspiratory pressure of 36 cm H₂O persisted for the next hour. The hypercapnia rapidly improved with single-needle venovenous extracorporeal membrane oxygenation.

Total immunoglobulin E (IgE) levels were elevated at 584 IU/mL and eosinophil levels were suppressed at <0.01×10⁹ cells/L. Therapy was continued with nebulized salbutamol-ipratropium bromide (0.5 mg salbutamol and 2.5 mg ipratropium bromide) 6 times daily, intravenous theophylline monitored by drug level measurement, 1 mg/d subcutaneous terbutaline, and 150 mg/h intravenous ketamine. Mechanical ventilation remained difficult after 2 mg/kg/d intravenous prednisolone, 2 mg/d nebulized budesonide, 10 mg/d oral montelukast, 2 g intravenous magnesium over 20 minutes and then adjusted for serum magnesium levels, isoflurane via the Anaesthetic Conserving Device anesthetic delivery system (Sedana Medical) with an end-tidal concentration of 0.5%, and intermittent muscle relaxation with intravenous rocuronium.

In response to total IgE levels that increased to 780 IU/mL and blood eosinophil levels that remained undetectable on day 7, tracheostomy was performed. On day 8, 600 mg subcutaneous omalizumab was administered according to body weight and total blood IgE. The patient’s ventilation began to improve and extracorporeal membrane oxygenation was discontinued on day 10. Five weeks after the initial event, the patient was discharged to inpatient rehabilitation, and returned home 4 weeks later, once the dosage of oral prednisone was tapered to discontinuation.

The patient experienced no further attacks while receiving a high dose of inhaled corticosteroid along with a long-acting β2-agonist and biweekly subcutaneous omalizumab. Lung function tests were normal and the patient returned to work. The results of this case report suggest that clinicians should consider targeted biologic therapies guided by IgE and eosinophil levels when maximal treatment with standard options is inadequate.

Disclosures: Multiple authors declare associations with the pharmaceutical industry. Please see original reference for a full list of disclosures.

Reference

Milger K, Schroeder I, Behr J, Meis T, Wulffen WV, Kneidinger N. Omalizumab rescue therapy for refractory status asthmaticus [published online November 20, 2018]. Ann Intern Med. doi:10.7326/L18-0359