Merck & Co and ALK-Abello's ragweed allergy pill Ragwitek is a giant leap closer to US market entry after an FDA advisory panel backed its approval.

The Allergenic Products Advisory Committee of the US Food and Drug Administration (FDA) has voted that the available data support the efficacy and safety of the drug, a sublingual allergy immunotherapy tablet to which Merck holds North American rights.  

According to reports, the panel voted six to two (with one abstention) that data support the drug's efficacy, and eight to 0 (also with one abstention) in favour of its safety.

The FDA is assessing Ragwitek for the treatment of ragweed pollen induced allergic rhinitis, with or without conjunctivitis, in adults 18 to 65 years of age, and a decision is expected during the first half of this year.  

Analysts are expecting the drug to generate peak sales of around $300 million, although Reuters reports that Morningstar analyst Damien Conover believes they could hit $1 billion if enough patients favour the pill over the alternative option of injections.

Last month the FDA panel also backed approval of the firms' grass allergy pollen pill Grastek, which is already marketed in Europe as Grazax.