Joshua Brumm, chief operating and chief financial officer of Kaleido Biosciences (NASDAQ: KLDO) since last year, will step down on Oct. 11. Lexington, MA-based Kaleido said that Brumm is leaving to become president and CEO of an undisclosed biotechnology company. Richard Scalzo, Kaleido’s corporate controller, has been appointed principal accounting officer and will assume some of Brumm’s responsibilities. The microbiome drug developer plans to start a search for a successor to Brumm, who has agreed to advise the company until the end of this year. Kaleido went public in February, raising $75 million to finance Phase 2 tests of lead compound KB195, an experimental treatment for hyperammonemia.