Zenapax (daclizumab)

On March 15, 2004 Protein Design Labs, Inc. reported results from the initial clinical study of the humanized antibody daclizumab in patients with chronic, persistent asthma whose disease was not well controlled with high doses of inhaled corticosteroid therapy. This Phase II randomized, double-blind, placebo-controlled clinical trial was conducted at 24 centers in the United States and treated a total of 114 patients. The primary endpoint, percent change in FEV1 from baseline to 12 weeks (day 84), met statistical significance (p=0.05). Secondary clinical endpoints also supported these findings. In the assessment of the primary endpoint, patients receiving daclizumab experienced a mean increase in FEV1 of 4.4% of baseline, compared to placebo patients who experienced a mean decrease of 1.5% (p=0.05). Other spirometric measures (FEV1/FVC, FEF25-75%) were consistent with these results. Patients receiving daclizumab also demonstrated a statistically significant increase in the time to asthma exacerbation requiring oral corticosteroid rescue (p=0.024). Peripheral eosinophil counts were significantly reduced in the daclizumab treatment group compared to the placebo group (p=0.04). Statistically significant (p less than or greater than 0.007) within-group changes in the daclizumab group revealed improvements from baseline in symptom diary scores, as well as morning and nighttime peak expiratory flow rates.

Zenapax is a humanized IgG1 antibody produced by recombinant DNA technology. It binds to a lymphocyte receptor known as the IL-2 receptor and impacts this cell’s role in the immune response. Zenapax is approved for the prevention of renal allograft rejection.

The estimated number of people reporting at least one asthma attack during the past 12 months in the United States is about 11.1 million or 40.7/1000 US population.

While the preliminary Phase II data looks intriguing, Biohorizon considers Zenapax to be at a relatively early stage in development. Injectable immunotherapies for asthma, at least in their current form, would likely be niche products, at best, in the asthma market. We have designated Zenapax as a Moderate Impact technology; we do not see any need for clients to plan for Zenapax’s diffusion in the near term.

Technology Details
Target Disease / Indication
Asthma

Technology Classification
Drug/Humanized Monoclonal Antibody

Body System
Respiratory System

Program Area
Medicine/Respirology

Regulatory Status
Phase II

BioHorizon Impact Score
50/100 – Moderate