WHITEHOUSE STATION, N.J. -- Drugmaker Merck & Co. says federal regulators are reviewing its application to sell a new type of treatment for grass pollen allergy that gradually reduces allergy symptoms over time, rather than just temporarily relieving the sneezing and itching.

The treatment, a tablet that dissolves under the tongue, could become the first alternative available in the U.S. to getting a long series of uncomfortable allergy shots. Both methods work by gradually desensitizing the patient's immune system to the substance triggering the allergic reaction.

Merck's immunotherapy, still unnamed, would be taken daily throughout allergy season for three years.

The company, which is based in Whitehouse Station, N.J., also recently applied to the Food and Drug Administration for approval to sell an immunotherapy tablet for ragweed pollen.