Antineoplastons are a group of naturally occurring peptide fractions, which were observed by Stanislaw Burzynski, MD, PhD in the late 1970s to be absent in the urine of cancer patients. It was hypothesized that these substances may have anti-tumor properties. In the 1980s, Burzynski identified chemical structures for several of these antineoplastons, and developed a process to prepare them synthetically. Antineoplaston A10, identified as 3-phenylacetylamino-2,6-piperidinedione, was the first to be synthesized. The use of antineoplastons in the treatment of various cancer types has been studied in the laboratory and in animals, and in limited preliminary human research. In 1991, the Cancer Therapy Evaluation Program of the National Cancer Institute (NCI) examined records of seven patients with brain tumors treated at the Burzynski Clinic in Texas. Based on their findings, the NCI sponsored a brain tumor clinical trial. However, due to difficulty recruiting patients, and a disagreement over study design, this research was canceled. The results in nine patients included prior to cancellation were reported, but were not conclusive. In 1997, Dr. Burzynski had legal troubles for permitting antineoplastons to be shipped out of Texas. There is a lack of sufficient evidence from randomized, controlled trials in support of antineoplastons as a cancer treatment, and antineoplastons are not FDA approved therapies. Antineoplastons are not widely available in the United States, and safety and efficacy are not proven. Multiple studies of antineoplastons in various cancers have been sponsored by the Burzynski Research Institute. In recent years, antineoplastons have also been suggested as treatment for other conditions such as Parkinson's disease, sickle cell anemia, and thalassemia.