It's been less than 8 months since the company formerly known as Actavis agreed to swallow Allergan ($AGN), taking a $66 billion plunge into branded sales and pledging to run its branded and generics businesses as "one culture, one company."

But it took just a few weeks to undo those plans, as lucky bidder Teva ($TEVA) found out with Monday's $40.5 billion deal for the drugmaker's generic offerings.

"If you had asked me three weeks ago if this business was for sale, I would have said 'absolutely not,'" CEO Brent Saunders told CNBC's "Squawk Box" Monday. "But they came to us with a compelling offer."

Speedy dealmaking has become a hallmark for Saunders, who helped orchestrate then-Actavis' brand-focused buys of Forest Labs and Allergan--each of which came together in less than two weeks. And this time, he said, the right choice was just as clear.

"When you think about it, we weren't going to be a consolidator of the generic business. We've always said that. We weren't going to be a buyer of future generics. We were going to be a buyer of brands," Saunders said, as quoted byCNBC. "Teva is a natural consolidator. This is their legacy. They're very good at it. They have global scale."

But that's quite a different tune than the company was singing earlier this year. In a January interview with FiercePharma, Saunders touted the benefits of running branded and generics businesses under one roof.

"We spend half the time talking about how to go after other programs and the other half of the time on how to defend our own programs," he said. "To have that unique perspective of being able to play offense and defense at the same time adds tremendous value." And bringing a generics-minded focus on service levels and supply chain to branded drugs also "keeps us sharper and crisper," he added.

Since then, though, the company has turned its attention more and more toward its branded sales, taking up the Allergan moniker to put emphasis on its new identity. And as it bids its generics unit goodbye, it'll be sharpening that branded focus on its newly minted core therapeutic areas, Saunders said--urology and women's health among them.

Importantly, selling off its generics will also help the company pare down its debt. Allergan should be essentially debt-free by the time the deal closes, Saunders said, an event Teva and Allergan expect for next year's Q1.