SANOFI’s asthma and eczema drug Dupixent met all targets in a trial to treat “smoker’s lung,” giving a major boost to the French drugmaker’s growth prospects, but also underscoring a heavy reliance on its bestseller.

In a late stage trial Dupixent, jointly developed with Regeneron, led to a 30% reduction in moderate or severe acute exacerbations of chronic obstructive pulmonary disease (COPD), a potentially deadly disease marked by progressive lung function decline.

Sanofi and partner Regeneron said in a statement on Thursday that the Phase 3 trial with 939 current or former smokers as participants also showed improvements in lung function, quality of life and COPD respiratory symptoms.

Sanofi previously forecast that Dupixent would generate up to 13 billion euros ($14.2 billion) in sales in its best year as it seeks to widen its use across several inflammatory conditions.

Investors had expected even more on average, partly on hopes that the injection will also qualify as a COPD treatment, a common disease that the company has so far excluded from its sales target.

Sanofi did not provide an immediate update on its estimate.

“The safety results were generally consistent with the known safety profile of Dupixent in its approved indications,” the companies said, adding that full efficacy and safety results would be presented later.

Overall rates of adverse events were 77% for Dupixent and 76% for placebo.

The companies on Tuesday announced that the European Commission (EC) had approved Dupixent in the European Union to treat severe atopic dermatitis in children aged 6 months to 5 years old who are candidates for systemic therapy.

Dupixent was also approved by the EC to treat eosinophilic esophagitis, which is a condition that damages the esophagus, in January. — Reuters