GlaxoSmithKline’s respiratory blockbuster Advair may have once been a top target for generics, but now Novartis is backing out of its copycat program—and paying a hefty price. It's not just a blow to the Swiss drugmaker, but a word of caution for other would-be copycats. Along with fourth-quarter results, Novartis’ Sandoz business disclosed it’s discontinuing its Advair generic program after a 2018 rejection from the FDA and a “recent review of data read-outs,” the company said in its annual report. Following the review, "we no longer see pathway to launch in the next 18 months," a spokesman said. Novartis is forfeiting more than potential future sales. It's taking a $442 million charge, writing off the costs of the development work and other related investments. That hit Sandoz's overall profit for the year, which fell 53% at constant currencies. The generics outfit reported operating income of $551 million in 2019, and Novartis said the decline came from “higher impairments of intangible assets and property, plant and equipment” related to the generic Advair discontinuation, plus an ongoing restructuring. In the fourth quarter, Sandoz posted a $195 million operating loss. After accepting Novartis' Advair copycat application in 2017, the FDA rejected the program in February 2018 and requested more data. At the time, Novartis said it would work with the agency to make the generic available as soon as possible. RELATED: Bad news for Novartis, good for GlaxoSmithKline: Sandoz' Advair copy stiff-armed at FDA That's all changed now, of course. But Novartis isn't the only company to get burned by its Advair struggles. In Mylan's third-quarter results, the company disclosed inventory write-offs due to its copycat's later-than-expected FDA nod. Mylan’s copycat won its green light early last year only after numerous slip-ups of its own, and now, the market opportunity isn’t what it once was. Even before Mylan launched its generic, GSK had been heavily discounting its brand to win payer contracts and keep share in the competitive brand race. It reported declining sales over the years, but it's still clinging to 36% of the market, even in the face of generic competition, a recent SVB Leerink analyst report states. Its authorized generic claimed 16%. During an interview early last year, GSK chief strategy officer David Redfern told FiercePharma the Advair market in the U.S. was worth about £1.2 billion annually, down from about £3.5 billion at peak. “You can only lose it once,” he said at the time. At that point, generic entry was a “non-issue” for GSK investors. RELATED: Mylan finally crosses the finish line with long-awaited generic of GlaxoSmithKline's Advair Mylan's results bear out some of those dynamics. On a November conference call, Mylan President Rajiv Malik said the copycat crossed the 30% market share threshold "despite the very aggressive share retention strategy taken by the brand." Overall, sales for the copycat will be "a bit short of original expectations" due to GSK's moves to keep market share, CFO Ken Parks added. Upon Mylan's approval, analysts predicted the generic could generate $170 million to $250 million in 2019 sales. As of the third quarter, the company hadn't published Wixela Inhub sales. Aside from Mylan, partners Hikma and Vectura are seeking an FDA nod but suffered a rejection back in March 2018 as the agency requested another study. In November, they completed their FDA response and resubmitted their application.