Laetrile is synthesized from amygdalin by hydrolysis. Laetrile (patented 1961) is a simpler semisynthetic derivative of amygdalin. The controversial cancer treatment laetrile was at one point lettered as vitamin B. The side effects of laetrile treatment are the symptoms of cyanide poisoning. This mechanism was subsequently abandoned as he later claimed Laetrile was instead a vitamin. Amygdalin (sometimes called "laetrile") is a toxic glycoside. Krebs, Jr. would ultimately work closely with his father in promoting Laetrile and pangamic acid. In a 1977 controlled, blinded trial, laetrile showed no more activity than placebo. Over the years, the NHF has promoted a range of alternative cancer therapies, including laetrile. Subsequently, laetrile was tested on 14 tumor systems without evidence of effectiveness. More than twenty states passed laws making the use of Laetrile legal. The first wave was the legalization by 27 states of laetrile in the late 1970s. The use of laetrile led to a number of deaths.