A poll surveying 74 dermatologists about Sanofi and Regeneron’s dupilumab and conducted on behalf of Leerink Partners was enough to prompt the investment firm to increase its sales expectations for the experimental atopic dermatitis drug by $1.5 billion.

Leerink analyst Seamus Fernandez said in a research note that the firm now projects that the injectable biologic could earn $3.5 billion in sales by 2026. He wrote that Sanofi and Regeneron could see an additional $500 million in sales if the drug is also approved for resistant asthma, another indication the drug manufacturers are exploring.

Atopic dermatitis is a severe form of eczema. The National Eczema Association said that the itching associated with all forms of eczema can be so extreme that patients sometimes scratch until they bleed.

Physicians told Leerink they were likely to prescribe the medication for adults with moderate to severe atopic dermatitis. Current treatments include antihistamines, steroids and Xolair, which is indicated for chronic idiopathic urticaria and asthma. It is co-marketed by Novartis and Roche subsidiary Genentech.

Poll results indicated that current treatment options do not adequately manage the skin condition for between 35% and 45% of moderate to severe patients and that doctors are interested in more options. About 80% of the surveyed doctors told Leerink they were interested in using the medication. This included doctors who were aware of the pipeline treatment before the poll and some who were not aware of the drug.

Fernandez said he anticipates little competition for the new drug, which could be appropriate for 700,000 to 800,000 patients. Using the plaque-psoriasis market as a benchmark because of its similar size, Leerink estimated that a year of treatment would be priced between $15,000 and $20,000.

Dupilumab is part of a larger Sanofi-Regeneron collaboration that includes the experimental cholesterol drug Praluent (alirocumab) and sarilumab, an experimental rheumatoid arthritis medication.

Sanofi is expected to file dupilumab with the FDA for atopic dermatitis by the fourth quarter of 2016.