Aimmune Prices Upsized $160M IPO, Climbs Higher in Debut

Xconomy San Francisco — 

Aimmune Therapeutics is capping a year of positive news with a larger-than-expected initial public offering.

The company raised $160 million late Wednesday by selling 10 million shares at $16 each, pricing at the top of its projected $14 to $16 per share range and selling about 1.7 million more shares than it had anticipated. Aimmune started trading on the Nasdaq Thursday morning under the ticker symbol AIMT and climbed higher: It opened at $17.50, and shares changed hands at $24.50 apiece around 1 p.m. ET.

Brisbane, CA-based Aimmune is using the funds to pay for the Phase 3 testing of its lead drug candidate, a pharmaceutical-grade oral therapy for peanut allergies called AR101. The company also plans to use the IPO cash to develop similar treatments for two other unnamed food allergies, according to regulatory filings.

Aimmune set the stage for its IPO when it released positive Phase 2 data June 7. The company’s treatment exposed peanut-allergic patients to a specially formulated peanut protein, and in its trial, the company increased the amount of drug patients were exposed to over a 20-week period. The company was attempting to prove it could desensitize the patients to large amounts of peanut protein. The patients responded to the treatment regimen, tolerating the increased exposure, according to the results.

Later in June, the FDA gave the treatment a breakthrough drug designation for children 4 to 17 years old with peanut allergies. The breakthrough tag helps speed up the review process.

Aimmune, formerly known as Allergen Research Corp., received an $80 million Series B round in March led by Foresite Capital, the San Francisco-based healthcare investment firm founded by Jim Tananbaum in 2011. Those funds are also being used for the Phase 3 trial.

“Their data is spectacular,” Christine Aylward, a managing director of Foresite, said in July when Foresite also closed a new $450 million investment fund. “It’s not as simple as it sounds to make a pharmaceutical-grade peanut protein, if you want to have a product that’s used by the masses.”

At the time of Foresite’s investment, the company said it would also use the money to start early stage trials on milk and egg allergies. Aimmune has since refrained from specifically naming any new allergy it will target.

Aimmune filed paperwork for an IPO the same day it released the Phase 2 data. In addition to the $160 million raised in the IPO, the company may gain about $24 million more if its underwriters exercise the option to buy almost 1.5 million additional shares.

Aimmune raised an additional $17 million in 2013, two years after it was founded. Longitude Capital led the round and Food Allergy Research & Education, a nonprofit focused on food allergies, also participated.

Longitude was the company’s largest shareholder before the offering, holding 523.2 percent of the business. Foresite held 12.3 percent, while Aisling Capital had 7.14 percent of the holdingss. The food allergy nonprofit had about 8.4 percent of the company.

Stephen Dilly is the company’s chairman and CEO. A pharmaceutical and biotech executive since the 1980s, Dilly most recently ran Carlsbad, CA-based PhotoThera, a company with a laser therapy used to treat acute ischemic stroke that liquidated in 2013. He also was CEO of APT Pharmaceuticals from 2006 to 2011.