The firm's Staccato delivery system uses heat to quickly vaporise a drug to form a small particle aerosol which can then be inhaled by the patient. The drug is then quickly absorbed through the lungs into the bloodstream at a speed comparable to intravenous administration, and achieves peak plasma levels of the drug in less than five minutes - much faster than oral administration.
The device is comprised of a metal heating 'substrate' coated with a thin layer of a specific drug, and is activated simply by the patient putting the inhaler to their lips and taking a deep breath.
Within half a second of being activated, the drug is heated to a sufficient temperature to convert it from a solid form to a vapour. The drug then cools rapidly in the air, condensing to form pure drug aerosol particles which are inhaled by the patient.
The Staccato technology can deliver both water-soluble and non-water soluble compounds, and removes the need for excipients and additives, allowing delivery of unformulated drug. The company has so far screened around 400 compounds for their suitability with the Staccato system, ranging from psychotherapeutics and anti-emetics to analgesics and antihistamines - as well as smoking cessation products.
The company has developed two forms of the Staccato device, a disposable single dose version and multiple dose version. The single dose device consists of the metal element which is heated via a small battery, and can be loaded with up to 10 milligrams of drug compound. The device is small and easily portable, being around three inches in length, two inches in width and three quarters of an inch thick.
The multiple dose delivery version has a reusable controller combined with a disposable dose cartridge. The dose cartridge contains up to 25 metal substrates, each of which can be coated with a dose of up to 100 micrograms of drug compound. This device is only slightly larger - five inches in length, two and a half inches wide and one inch thick - and still very portable.
Alexza itself has four candidates currently in clinical trials: a prochlorperazine product for acute treatment of migraine, an alprazolam product for acute treatment of panic attacks and a loxapine product for acute treatment of agitation for patients with schizophrenia.
These three product candidates have been developed for use with the single dose delivery device, and the company's fourth candidate, based on fentanyl for treatment of acute pain, is for use with the multiple dose device.
In December 2006 the company announced promising results from a Phase I clinical study for the fentanyl product, showing that the Staccato device delivered doses of the drug that had comparable pharmacokinetics to intravenous administration.
New drug delivery methods are of key interest in the pharmaceutical industry, with inhalable delivery garnering particular interest of late - inhalable flu vaccines, measles vaccines and pain treatments as well as inhalable insulin have all emerged recently, as well as other novel forms of less invasive controlled release products, such as transdermal skin patches for the delivery of therapeutic drugs.