Antineoplastons are an experimental cancer therapy developed by S.R. Burzynski, MD, PhD. Chemically, antineoplastons are a mixture of amino acid derivatives, peptides, and amino acids found in human blood and urine.[1-4] The developer originally isolated antineoplastons from human blood and later found the same peptides in urine. Urine was subsequently used because it was less expensive and easier to obtain. Since 1980, antineoplastons have been synthesized from commercially available chemicals at the Burzynski Research Institute.[2,4]

According to the developer, antineoplastons are part of a biochemical surveillance system in the body and work as “molecular switches.” For the developer, cell differentiation is the key to cancer therapy. At the molecular level, abnormal cells that are potential cancer cells need to be “switched” to normal mode. Antineoplastons are the surveillance system that directs cancer cells into normal channels of differentiation. According to statements published by the developer, people with cancer lack this surveillance system because they do not have an adequate supply of antineoplastons.[1-3]

The notion of controlling tumor growth through a naturally occurring biochemical mechanism in the body that directs cancer cells into normal channels of differentiation is one of the theoretical foundations of antineoplaston therapy. In a complex organism like the body, cells are continuously differentiating. Groups of abnormal cells can arise under the influence of carcinogenic factors from outside or inside the body. The body must have a mechanism for dealing with these abnormal cells, or the organism will not live very long. The proposed components in the body that correct the differentiation problems of abnormal cells and send them into normal pathways have been given the name “antineoplastons.”[2]

The developer defines antineoplastons as “substances produced by the living organism that protect it against development of neoplastic growth by a nonimmunological process which does not significantly inhibit the growth of normal tissues.”[2]

The developer originally hypothesized the existence of antineoplastons by applying the cybernetic theory of information exchange in autonomous systems to the study of peptides in the blood.[2] The living cell is an autonomous cybernetic system connected to, and receiving, information from its environment through an energy pathway and an information pathway. It was postulated that a regulator within such a system would control the transfer of information and the expenditure of energy. Peptides were considered the information carriers in the body. Hypothesizing that peptides were the carriers of differentiation information to the cells, the developed began looking for peptides in the blood of cancer patients that might correct abnormal differentiation.[1-3,5]

To begin the search for antineoplastons, the developer used human blood, separating and removing the peptides found there. Later it was discovered that the same peptide fractions existed in human urine. Each peptide fraction was tested in vitro against various normal and neoplastic cell lines to gauge their effect on DNA synthesis and growth. The fractions that had little or no inhibitory effect on normal cells but a substantial inhibitory effect on neoplastic cell lines were separated into two classes: those that were effective against a specific cell line and those that were active against a broad array of neoplastic cell lines. Those with a broad spectrum of activity were grouped together and called “antineoplaston A.” Peptide fractions with specific antineoplastic activity were not investigated further.[2]

Antineoplaston A was further purified and yielded antineoplastons A1, A2, A3, A4, and A5. These mixtures of 7 to 13 peptides were patented in 1985.[6] In vitro tissue culture studies and in vivo toxicity studies in animal models were performed for antineoplastons A1 through A5. According to the developer, each individual fraction had a higher level of antitumor activity and lower toxicity level than antineoplaston A.[2]

Phase I trials of this antineoplaston group in patients with various advanced cancers showed A2 as contributing to the highest tumor response rate, so it was selected for further study.[2]

The active compound in A2 was found to be 3-phenylacetylamino-2,6-piperinedione, which was named antineoplaston A10.[7] From antineoplaston A10, three other compounds have been derived:

• AS2-5, which is phenylacetylglutamine (PAG).
• AS2-1, which is a 4:1 mixture of phenylacetic acid (PA) and PAG.
• A5, which is PA and an aromatic fatty acid.

Other antineoplastons (A3, A4, A10-1, AS5) were added to this group after further studies.[2-4]

There have been no independent analyses of which amino acids comprise the antineoplastons used in any of the reported studies.

Antineoplastons are administered by different methods. Antineoplaston A has been given intravenously, intramuscularly, rectally, topically, intrapleurally, and by bladder instillation.[8] Presently, antineoplastons A10, AS2-5, AS2-1, A2, A3, and A5 are given orally or by injection.[8-20]

Critical opposition to antineoplaston therapy and its developer have appeared in the published literature.[4] A basic criticism of the developer’s work is that although he has put forth a theory of peptides inducing cell differentiation, there is no published evidence that he has experimentally tested the hypothesis that information-bearing peptides could normalize cancer cells. Although some articles attempt to demonstrate that antineoplastons (specifically, antineoplaston A10) can bind to DNA at certain sites, this is an extrapolation from three-dimensional molecular models of DNA and A10 and does not demonstrate that this binding actually occurs.[21-23]

Other criticism focuses on the form of antineoplastons. Although the active fraction, antineoplaston A10, is insoluble in aqueous solutions, the developer has stated that it is present in body fluids.[4]

Antineoplastons AS2-5 and AS2-1 are derived from A10. Antineoplaston AS2-5 is PAG, and AS2-1 is a 4:1 mixture of PA and PAG. Because it is a strong acid, PA would exhibit cytotoxicity in vitro if in high enough concentration and not neutralized.[4]

The active component of antineoplaston A10 is 3-phenylacetylamino-2,6-piperidinedione. Reagents necessary for the synthesis of this antineoplaston compound are readily available internationally from any chemical supply company.[24] The developer retains patents on antineoplaston compounds and their use when administered pharmaceutically to inhibit the growth of neoplastic cells.[6,25]

To conduct clinical drug research in the United States, researchers must file an Investigational New Drug (IND) application with the U.S. Food and Drug Administration (FDA). The FDA’s IND process is confidential, and the existence of an IND application can be disclosed only by an applicant.

There are currently several active clinical trials sponsored and administered by the developer of antineoplastons. Information on these trials can be accessed through the NCI Web site. None of these trials are randomized controlled trials.

Although several possible mechanisms of action and theories about the activity of antineoplastons have been proposed, specifically for antineoplaston A10, none of the theories has been conclusively demonstrated.

One theoretical mechanism of action proposes that antineoplaston A10 is specifically capable of intercalating with DNA at specific base pairs and thereby might interfere with carcinogens binding to the DNA helix. This interweaving of A10 into the DNA helix may be capable of interfering with DNA replication, transcription, or translation.[21,23] The theory is based on the manipulation of molecular models of DNA and A10; however, no published evidence of the creation of this actual molecule or evidence of the properties ascribed to it exists in the medical literature.

Another theoretical mechanism of action is based on the structural similarities of antineoplaston A10 to other experimental anticancer drugs such as carmustine and 5-cinnamoyl-6-aminouracil. A10 has been proposed to bind to chromatin and therefore relate to other anticancer drugs such as doxorubicin that interact directly with DNA.[21,26,27]

At the cellular level, two other mechanisms of action have been proposed to explain inhibition of tumor growth. One theory involves the activity of PAG, a component of some antineoplastons. PAG appears to compete with glutamine for access to the glutamine membrane transporter and may inhibit the incorporation of glutamine into the proteins of neoplastic cells. Because glutamine is essential for the cell cycle transition from G1 to S phase where DNA replication occurs, antineoplastons may arrest cell cycle progression and stop cell division.[28] Another theory proposes that phenylacetic acid, also a component of several antineoplastons, inhibits methylation of nucleic acids in cancer cells. The hypomethylation of DNA in cancer cells may lead to terminal differentiation and prevention of tumor growth or progression.[28]

References

1. Burzynski SR: Antineoplastons: biochemical defense against cancer. Physiol Chem Phys 8 (3): 275-9, 1976.  [PUBMED Abstract]
   
   
2. Burzynski SR: Antineoplastons: history of the research (I). Drugs Exp Clin Res 12 (Suppl 1): 1-9, 1986.  [PUBMED Abstract]
   
   
3. Burzynski SR: Potential of antineoplastons in diseases of old age. Drugs Aging 7 (3): 157-67, 1995.  [PUBMED Abstract]
   
   
4. Green S: 'Antineoplastons'. An unproved cancer therapy. JAMA 267 (21): 2924-8, 1992.  [PUBMED Abstract]
   
   
5. Burzynski SR: The present state of antineoplaston research (1). Integr Cancer Ther 3 (1): 47-58, 2004.  [PUBMED Abstract]
   
   
6. Burzynski SR: Purified Antineoplaston Fractions and Methods of Treating Neoplastic Disease. US Patent 4558057. December 10, 1985. Washington, DC: US Patent and Trademark Office, 1985. Available online. Last accessed October 16, 2007. 
   
   
7. Revelle LK, D'Avignon DA, Wilson JA: 3-[(Phenylacetyl)amino]-2,6-piperidinedione hydrolysis studies with improved synthesis and characterization of hydrolysates. J Pharm Sci 85 (10): 1049-52, 1996.  [PUBMED Abstract]
   
   
8. Burzynski SR, Stolzmann Z, Szopa B, et al.: Antineoplaston A in cancer therapy. (I). Physiol Chem Phys 9 (6): 485-500, 1977.  [PUBMED Abstract]
   
   
9. Tsuda H, Hara H, Eriguchi N, et al.: Toxicological study on antineoplastons A-10 and AS2-1 in cancer patients. Kurume Med J 42 (4): 241-9, 1995.  [PUBMED Abstract]
   
   
10. Burzynski SR: Toxicology studies on antineoplaston AS2-5 injections in cancer patients. Drugs Exp Clin Res 12 (Suppl 1): 17-24, 1986.  [PUBMED Abstract]
    
    
11. Burzynski SR, Burzynski B, Mohabbat MO: Toxicology studies on antineoplaston AS2-1 injections in cancer patients. Drugs Exp Clin Res 12 (Suppl 1): 25-35, 1986.  [PUBMED Abstract]
    
    
12. Burzynski SR, Kubove E: Toxicology studies on antineoplaston A10 injections in cancer patients. Drugs Exp Clin Res 12 (Suppl 1): 47-55, 1986.  [PUBMED Abstract]
    
    
13. Burzynski SR, Kubove E, Burzynski B: Treatment of hormonally refractory cancer of the prostate with antineoplaston AS2-1. Drugs Exp Clin Res 16 (7): 361-9, 1990.  [PUBMED Abstract]
    
    
14. Burzynski SR, Kubove E, Burzynski B: Phase I clinical studies of antineoplaston A5 injections. Drugs Exp Clin Res 13 (Suppl 1): 37-43, 1987.  [PUBMED Abstract]
    
    
15. Burzynski SR, Kubove E: Phase I clinical studies of antineoplaston A3 injections. Drugs Exp Clin Res 13 (Suppl 1): 17-29, 1987.  [PUBMED Abstract]
    
    
16. Burzynski SR, Kubove E: Initial clinical study with antineoplaston A2 injections in cancer patients with five years' follow-up. Drugs Exp Clin Res 13 (Suppl 1): 1-11, 1987.  [PUBMED Abstract]
    
    
17. Sugita Y, Tsuda H, Maruiwa H, et al.: The effect of Antineoplaston, a new antitumor agent on malignant brain tumors. Kurume Med J 42 (3): 133-40, 1995.  [PUBMED Abstract]
    
    
18. Tsuda H, Sata M, Kumabe T, et al.: Quick response of advanced cancer to chemoradiation therapy with antineoplastons. Oncol Rep 5 (3): 597-600, 1998 May-Jun.  [PUBMED Abstract]
    
    
19. Kumabe T, Tsuda H, Uchida M, et al.: Antineoplaston treatment for advanced hepatocellular carcinoma. Oncol Rep 5 (6): 1363-7, 1998 Nov-Dec.  [PUBMED Abstract]
    
    
20. Buckner JC, Malkin MG, Reed E, et al.: Phase II study of antineoplastons A10 (NSC 648539) and AS2-1 (NSC 620261) in patients with recurrent glioma. Mayo Clin Proc 74 (2): 137-45, 1999.  [PUBMED Abstract]
    
    
21. Lehner AF, Burzynski SR, Hendry LB: 3-Phenylacetylamino-2,6-piperidinedione, a naturally-occurring peptide analogue with apparent antineoplastic activity, may bind to DNA. Drugs Exp Clin Res 12 (Suppl 1): 57-72, 1986.  [PUBMED Abstract]
    
    
22. Hendry LB, Muldoon TG, Burzynski SR, et al.: Stereochemical modelling studies of the interaction of antineoplaston A10 with DNA. Drugs Exp Clin Res 13 (Suppl 1): 77-81, 1987.  [PUBMED Abstract]
    
    
23. Michalska D: Theoretical investigations on the structure and potential binding sites of antineoplaston A10 and experimental findings. Drugs Exp Clin Res 16 (7): 343-9, 1990.  [PUBMED Abstract]
    
    
24. Choi BG, Seo HK, Chung BH, et al.: Synthesis of Mannich bases of antineoplaston A10 and their antitumor activity. Arch Pharm Res 17 (6): 467-9, 1994.  [PUBMED Abstract]
    
    
25. Burzynski SR: Purified Antineoplaston Fractions and Methods of Treating Neoplastic Disease. US Patent 4559325. December 17, 1985. Washington, DC: US Patent and Trademark Office, 1985. Available online. Last accessed October 16, 2007. 
    
    
26. Wood JC, Copland JA, Muldoon TG, et al.: 3-phenylacetylamino-2,6-piperidinedione inhibition of rat Nb2 lymphoma cell mitogenesis. Proc Soc Exp Biol Med 197 (4): 404-8, 1991.  [PUBMED Abstract]
    
    
27. Tsuda H: Inhibitory effect of antineoplaston A-10 on breast cancer transplanted to athymic mice and human hepatocellular carcinoma cell lines. The members of Antineoplaston Study Group. Kurume Med J 37 (2): 97-104, 1990.  [PUBMED Abstract]
    
    
28. Sołtysiak-Pawłuczuk D, Burzyński SR: Cellular accumulation of antineoplaston AS21 in human hepatoma cells. Cancer Lett 88 (1): 107-12, 1995.  [PUBMED Abstract]
    
    

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