FDA has approved the first generic of GlaxoSmithKline‘s (NYSE:GSK) blockbuster Advair respiratory drug, this one by Mylan (NSDQ:MYL), six months after rejecting Mylan’s application.

Canonsburg, PA-based Mylan’s shares jumped 7% to $30.82 at market close after yesterday’s late-afternoon announcement, and were trading at $30.96 mid-morning today. GSK’s stock dipped 2% to$38.70 on the news late yesterday, but had more than recovered by noon today, reaching $39.23.

Mylan won approval to market its generic inhaler, Wixela Inhub, in three strengths: fluticasone propionate 100 mcg/ salmeterol 50 mcg, fluticasone propionate 250 mcg/ salmeterol 50 mcg and fluticasone propionate 500 mcg/ salmeterol 50 mcg. The drug is intended for inhalation twice daily in asthma patients aged four years and older and for maintenance treatment of COPD.

In June 2018, FDA denied Mylan’s application for what the company said were “minor deficiencies.”

Advair brings GSK $3 billion in annual sales, and a number of companies are looking to take a bite out of that market. But until now, all of those competitors have received setbacks from the FDA. For example, the U.S. regulatory agency denied Novartis’ application for an Advair generic in February 2017.

“Today’s approval of the first generic drug product for one of the most commonly prescribed asthma and COPD inhalers in the U.S. is part of our longstanding commitment to advance access to lower cost, high-quality generic alternatives,” said Janet Woodcock, M.D., director of the FDA’s Center for Drug Evaluation and Research, in a prepared statement. “People living with asthma and COPD know too well the critical importance of having access to the treatment they need to feel better. Today’s approval will bring more competition to the market which will ultimately benefit the patients who rely on this drug.”

“We have seen the announcement by the FDA regarding the approval of a generic copy of fluticasone propionate and salmeterol inhalation powder,” GSK said in a prepared statement. “We’ve anticipated and planned for the possible introduction of generic competition to Advair Diskus in the U.S for some time.”

FDA issued a draft product-specific guidance for proposed generic drug versions of  Advair Diskus in 2013. The guidance provided bioequivalence recommendations as well as formulation and device considerations.

The research and development program for Wixela Inhub compared all strengths of treatment to Advair Diskus in order to meet the FDA requirements of therapeutic equivalence for a substitutable generic, according to Mylan. In the 28-day, randomized, double-blind, placebo-controlled, parallel group study of 1,128 adult asthma patients conducted to evaluate the local (lung) bioequivalence of Wixela Inhub 100 mcg/50 mcg and Advair 100 mcg/50 mcg, the two treatments produced equivalent efficacy. Both treatments were safe and well-tolerated with lower numbers of withdrawals due to asthma compared to the placebo group. The study included both new and current Advair users.

“This milestone represents the culmination of an extensive research and development program and Mylan’s more than $700 million of investment,” Mylan CEO Heather Bresch said in a prepared statement. “We’re proud of our Wixela Inhub team, who worked tirelessly and in close collaboration with the FDA to bring this important medicine to market.”

More than 26 million people in the U.S. are known to have asthma, including about seven million children. COPD is a progressive lung disease that makes it hard to breathe and may become worse over time.