A buying spree may be underway at troubled Southern California biotech giant Amgen Inc., the Los Angeles Times reports.

After a difficult year during which sales of its key products fell in light of safety concerns, the company Monday acquired a privately held California company for $420 million in cash.

Ilypsa Inc. of Santa Clara doesn’t yet have any drugs on the market, but its major candidate has shown promise in chronic kidney disease patients on dialysis, a growing and lucrative market.

Many analysts say the deal could be the first of many acquisitions for the Thousand Oaks-based biotech giant, which is seeing sales of its top-selling drugs fall dramatically amid increased scrutiny by regulators and researchers in recent months.

“They have no other choice but to buy new drugs right now, plain and simple,” WBB Securities biotech analyst Steve Brozak said.

Several high-profile studies have raised questions about the safety of two of Amgen’s top-selling drugs, Aranesp and its shorter-acting cousin Epogen, which treat anemia in more than a million cancer and dialysis patients a year. The drugs accounted for nearly half the company’s revenue last year and 60% of its profit.

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