Alexza Completes Target Enrollment in AZ-104 Phase 2a Clinical Trial in Migrain...( Initial Results Expected...),Health

Initial Results Expected to be Reported in Q1 2008

PALO ALTO, Calif., Dec. 18 /PRNewswire-FirstCall/ -- Alexza Pharmaceuticals, Inc. (Nasdaq: ALXA) announced today that it has completed its target patient enrollment in its Phase 2a proof-of-concept clinical trial with AZ-104 (Staccato(R) loxapine) in patients with migraine headache. AZ-104 is a lower dose version of AZ-004, which is being developed to treat acute agitation in patients with schizophrenia or bipolar disorder. AZ-004 and AZ-104 are being developed through Symphony Allegro, a development collaboration formed between Alexza and Symphony Capital in 2006.

The Phase 2a clinical trial was an in-clinic, multi-center, randomized, double-blind, single-administration, placebo-controlled study in approximately 160 migraine patients with or without aura. Three doses of AZ-104 (1.25, 2.5 and 5 mg) were evaluated against placebo in the clinical trial. Using the IHS (International Headache Society) 4-point rating scale, the primary efficacy endpoint was pain-relief response at 2 hours post-administration. Secondary efficacy endpoints for the trial included additional pain response assessments and other symptom assessments at various time points. Safety evaluations were made throughout the clinical trial period.

"Loxapine's mechanism of action is unique. It acts as an antagonist at D2 dopamine receptors and also acts as an antagonist at 5-HT2 serotonergic receptors. This dual mechanism of pharmacological action makes AZ-104 an interesting product candidate to study in this proof-of-concept clinical trial in patients with migraine," said James V. Cassella, PhD, Senior Vice President, Research and Development at Alexza and chairman of the Symphony Allegro Develop
'/>"/>