Shares in Mylan (NSDQ:MYL) dropped -3% to $40.46 apiece today after the FDA rejected its Abbreviated New Drug Application for the generic version of GlaxoSmithKline‘s (NYSE:GSK) Advair Diskus.

The Canonsburg, Penn.-based company said it is “in the process of reviewing this response and will provide an update on its application as soon as practicable once it has completed its review and discussed the FDA’s feedback with the agency.”

GSK’s Advair Diskus inhaler features a combination of a corticosteroid, fluticasone, and a beta2-adrenergic bronchodilator used to treat asthma, chronic bronchitis and COPD.

Rumors that Mylan could be considering a possible takeover bid for collaboration partner Pulmatrix sent the Lexington, Mass.-based company’s shares up more than 8% today.

In 2015, the 2 companies inked an ex-U.S. development deal for PUR0200, Pulmatrix’s investigational bronchodilator for the treatment of chronic obstructive pulmonary disease. Mylan had an option on the rights to the COPD candidate, but reportedly did not exercise it.

Earlier this month, Abbott (NYSE:ABT) divested 60% of its remaining stake in Mylan, according to regulatory filings, disposing of 44 million shares at $41.60 apiece. The trade was valued at $1.7 billion.

In 2014, Mylan bought Abbott’s generics business outside the U.S. in a deal that rang in at nearly $5.3 billion. The deal allowed Canonsburg, Penn.-based Mylan to cut its tax bill by moving its tax address outside the U.S., and Abbott received an ownership stake of 21% with 105 million shares of the company.

In the year following the initial deal, Abbott sold off 1/3 of the stock, reducing its stake in Mylan to 15%.