Shire nabbed FDA approval for its new long-acting ADHD drug, becoming the second drugmaker in two days to win a nod in that field.

Shire’s drug, Mydayis, has been a long time coming. Previously known as SHP465, was turned away by the FDA almost a decade ago and set aside at Shire for some time. The Dublin-based drugmaker pulled it off the shelf, however, and now the extended release medication—with the same active ingredient as Shire’s blockbuster Adderall—is set to hit the market in the third quarter of this year.

Shire sees Mydayis as a $500 million product by 2020, but some analysts aren’t as optimistic. Consensus estimates put the drug’s peak sales at $288 million by that year. But Shire believes its ADHD expertise could surprise those skeptical of its goals, Jefferies analyst David Steinberg said in a Wednesday note.

The FDA based its Mydayis approval on 16 clinical studies (yes, 16) that comprised more than 1,600 participants, including adolescents and adults, Shire said in a release. The med significantly improved symptoms as measured by two common assessment scales. Improvement on one of them, the Permanent Product Measure of Performance (PERMP), ramped up by two to four hours after dosing, and lasted up to 16 hours.

“Many of my patients living with ADHD are trying to manage symptoms that impact them in different settings—often across home life, school or work, and in social settings,” trial investigator Andrew Cutler said in a statement. “Patients have individual needs and may respond differently to treatments, so it is important for healthcare professionals to have multiple options.’

Mydayis is the latest med in Shire’s Adderall franchise. Adderall XR lasts for up to 12 hours, compared with Mydayis’ 16. With Adderall’s active ingredient available as a cheap generic, it could be tough to persuade increasingly picky payers to cover a new form simply for convenience’s sake.

But Steinberg said his firm is expecting $345 million in 2020 sales, with a peak at $425 million. Though his 2020 estimate falls lower than Shire’s, he noted that the new formula could appeal to adults, who make up about half of the ADHD market now—and represent the fastest-growing segment.

Shire management has higher expectations partly because it believes “Shire's market-leading salesforce and infrastructure [can] maximize Mydayis' potential,” Steinberg noted. “Given Shire's expertise in the area, we are inclined to agree with management, and note that every ADHD drug Shire launched has outperformed.”

Shire is the second to win a nod this week in ADHD. U.S. regulators greenlighted Neos Therapeutics' Cotempla, an extended-release tablet that disintegrates in the mouth, for patients ages 6 to 17. It’s the first methylphenidate drug that can boast both those features, and it joins Adzenys—a long-acting amphetamine in the same form—in that company’s portfolio.