While pharma M&A action has slowed, it is not dead. After AstraZeneca ($AZN) last year agreed to pay $2.7 billion for ZS Pharma ($ZSPH) it stoked interest in new treatments for the blood disorder hyperkalemia, and Relypsa ($RLYP) has one already approved, Veltassa. That, Reuters says, has drawn buyout interest, leading the Redwood City, CA-based biotech to hire an investment bank to check out its offers. Relypsa isn't commenting but the news service says several companies that had bid on ZS, including Actelion, are eyeing Relypsa. More from FierceBiotech