California stem cell agency Chairman Bob Klein has stepped down as president of the stem cell advocacy and lobbying group Americans for Cures, according to a spokesman for the California Institute for Regenerative Medicine.

The move came after my criticism of the advocacy group’s personal attack against Sen. Sheila Kuehl, sponsor of SB 1565. The bill would enact access and pricing provisions for manufacturers of CIRM funded drugs and treatments as well as ask the Little Hoover Commission to study the agency’s governance structure.

Don Gibbons, communications director for the California Institute for Regenerative Medicine, called this afternoon to tell me that Klein had stepped down from Americans for Cures. His phone call came after my posting the view today that holding both the state position and the advocacy position was untenable and the situation was a train wreck waiting to happen.

In fact, Gibbons said, Klein quit the presidency on Friday, but didn’t issue any public statement about it until he personally told Sen. Kuehl what he had done.

Friday both Klein and the co-executive directors of Americans for Cures apologized for the attack in an article posted on the Daily Kos and had the article taken down from the blog.

Gibbons said any formal statement about the resignation would have to come from Americans for Cures.  I’ve asked.