(Reuters) – Aimmune Therapeutics Inc said on Monday 80% of patients being treated with its drug Palforzia were successfully desensitized to peanut proteins after two years of daily dosing, sending its shares up 6%.

Palforzia, approved in late January and priced at $890 per month, is designed to reduce sensitivity to peanuts by exposing patients to refined version of peanut flour over time.

The current data, from a two-year follow-on study, suggests that for at least the first two years of treatment, daily dosing is the optimal approach for patients, the company said.

Palforzia received approval based on data from a pivotal trial where patients who received the drug for six months showed greater tolerance to peanut protein, compared to placebo.

Aimmune in March warned of a slow launch of the peanut allergy therapy, as its marketing plans take a hit from U.S. authorities’ recommendation of social distancing to contain the spread of the coronavirus.

Palforzia approval came with a host of restrictions, including requiring initial doses of the treatment to be administered under the supervision of allergists.