Nastech Pharmaceutical's

(NSTK)

shares rose after the company said it responded to regulators' concerns that its reformulated version of an osteoporosis nasal spray could cause allergic reactions.

According to a previous FDA review, a preservative in Nastech's version of the

Novartis

(NVS) - Get Report

branded drug Miacalcin could potentially interact with the treatment's active ingredient, causing an immune system reaction.

After receiving a letter regarding the FDA's concerns in July, Nastech said no allergic reactions were observed in any of the clinical trials it conducted on the drug. The company also said other nasal sprays on the market contain the preservative it used, called chlorobutanol.

During Nastech's development of the drug, the company says there were no cases of immediate hypersensitivity to the treatment. The Nastech drug was developed to be similar to Novartis' Miacalcin, but it doesn't use the drug giant's proprietary drug-delivery technology.

Shares of Nastech were up 10 cents to $15.26.