UPDATE 2-Bayer, J&J say FDA wants more data on Xarelto

* Gets so-called "complete response letter"

* No new clinical or non-clinical studies needed

* Confident questions raised can be promptly addressed

* J&J shares down 0.3 percent

(Adds company comment, analyst comment, J&J shares)

FRANKFURT, May 28 (Reuters) - Bayer BAYG.DE and Johnson & Johnson (JNJ.N: Quote, Profile, Research) said on Thursday the U.S. Food and Drug Administration declined to approve their experimental blood thinning pill Xarelto, asking for more information.

In a so-called "complete response letter" the FDA has, however, not requested that any new clinical or non-clinical studies be conducted to evaluate the drug -- known scientifically as rivaroxaban -- the companies added.

"Together with our development partner, we are evaluating the letter and we will promptly address the FDA's questions," Bayer said, declining to specify what type of information was requested.

The drug is already approved in Europe to prevent blood clots after major orthopaedic surgery, and the two companies are also seeking clearance for the potential blockbuster in the United States, its largest market.