A multi-phase process will lead the molecule HPH116 to an approved drug.

In 2015, zinc ejectors show potent antiviral activity against a large spectrum of HIV-1 strains, without eliciting resistance. the sole of the librairy of molecules tested enough safe safe to be administrated to man remains HPH-116(azodicarbonamide)

 

Alternatively, due to their ability to inactivate HIV-1 efficiently without compromising viral surface antigens, they may have promise for use in
vaccine strategies (Arthur et al. 1998; Chertova et al. 1998, 2006).

This is highly regulated as it has to fulfil ICH/GMP, GLP, GCP rules by the authorities that evaluate the safety and efficacy of the product. Regulatory authorities have been consulted to ensure that the route to approval is clear and compliant with the highest standard of registration.


Despite substantial progress made over the past twenty years in the treatment of HIV disease and introduction of combinations of potent antiretroviral agent treatments (so called Highly Active Antiretroviral Therapy or HAART) leading to a clear reduction in the morbidity and mortality associated with HIV infection, the solution is not yet found and new challenge appears. Increasing resistance to available antiretroviral agents is one of these challenges. The other one is toxicity linked with long term use of existing drugs leading to a loss of compliance. It has also been noted that the prevalence of resistance to at least one class of antiretroviral therapy (ART) among treatment naïve HIV infected patients in the United States is increasing.

It was initially thought that transmitted drug-resistant HIV reverts rapidly to wild-type virus, given the usual absence of drug pressure, at least during the first years of infection.  However, recent data—the CATCH and the U.S.-based studies notwithstanding—suggest that transmitted drug-resistant HIV can remain the dominant population in peripheral blood for an extended period of time» claims Daniel R. Kuritzkes , MD at the Physicians' Research Network (PRN) meeting in May 2004. Clearly there is a pressing medical need for additional antiretroviral agents, with new mechanism of action, that are effective against resistant HIV isolates. The molecule Azodicarbonamide also called HPH116 (former ADA ) acts principally on the free circulating virus.

Its anti-HIV activity is due to its unique capacity to inactivate the nuclear capsid protein NCp7 of retroviruses. These particular domains called “zinc finger” are potentially non permissive to mutations.

What are HIV zinc finger proteins?

As all proteins “zinc finger” proteins are long chains of amino acids. The three-dimensional structures of some proteins sections is maintained through a zinc atom acting as a “magnet” that attracts certain types of amino acids, therefore called “zinc finger protein”.

Zinc Protein Inactivation?

Zinc finger proteins are multiple and they play important role in the normal cell metabolism. One of the principal activities of zinc protein is the modulation of the DNA and of gene expression. Zinc finger proteins facilitate also protein interactions. Clearly, to be useful a retroviral zinc finger inhibitor has to be selective. Pathogen proteins containing zinc finger motifs are potential drug target .They differ and are specifying for retroviruses .The retroviral zinc finger proteins are structurally different from the cellular zinc finger proteins. Azodicarbonamide inhibits the growth of retroviruses, including HIV, by ejection zinc ions from critical zinc finger viral proteins, with as consequence the inactivation of viral particles. The absence of replication of the inactivate virus renders mutations leading to drug resistance phenotypes very improbable if not impossible.

Selectivity

Published:

5/21/1998

Journal:

J Med Chem

Author(s):

Huang M, Maynard A, Turpin J A, Graham L, Janini G M, Covell D G, Rice W G

Institute:

Laboratory of Antiviral Drug Mechanisms, National Cancer Institute-Frederick Cancer Research and Development Center, SAIC Frederick, Frederick, Maryland 21702-1201, USA.

Abstract:

Agents that target the two highly conserved Zn fingers of the human immunodeficiency virus (HIV) nucleocapsid p7 (NCp7) protein are under development as antivirals. These agents covalently modify Zn-coordinating cysteine thiolates of the fingers, causing Zn ejection, loss of native protein structure and nucleic acid binding capacity, and disruption of virus replication. Concentrations of three antiviral agents that promoted in vitro Zn ejection from NCp7 and inhibited HIV replication did not impact the functions of cellular Zn finger proteins, including poly(ADP-ribose) polymerase and the Sp1 and GATA-1 transcription factors, nor did the compounds inhibit HeLa nuclear extract mediated transcription. Selectivity of interactions of these agents with NCp7 was supported by molecular modeling analysis which (1) identified a common saddle-shaped nucleophilic region on the surfaces of both NCp7 Zn fingers, (2) indicated a strong correspondence between computationally docked positions for the agents tested and overlap of frontier orbitals within the nucleophilic loci of the NCp7 Zn fingers, and (3) revealed selective steric exclusion of the agents from the core of the GATA-1 Zn finger. Further modeling analysis suggests that the thiolate of Cys49 in the carboxy-terminal finger is the site most susceptible to electrophilic attack. These data provide the first experimental evidence and rationale for antiviral agents that selectively target retroviral nucleocapsid protein Zn fingers.

Products :

Link: http://www.ncbi.nlm.nih.gov/

Zinc Finger Inactivation

14% of current antiretrovirals (ARV) drugs become ineffective against HIV largely due to the emergence of drug resistant viral mutants and intolerance to side effects. HIV-1,HIV-2 and retroviruses contains proteins known as CCHC zinc fingers in their nucleocapsid . These zinc fingers are highly conserved throughout nearly all retroviruses (except spumaviruses) including viruses responsible for leukaemia and paresthesia in human being. The zinc fingers contains sequences of 14 amino acids with four invariant residues, Cys(X) 2Cys(X)4His(X)4Cys, essential in viral infectivity. Mutations in the CCHC zinc fingers render retroviruses (HIV) non-infectious.

The invariant nature of the retroviral zinc fingers and the requirement of both fingers would make the development of drug resistant viral mutants unlikely. HIV-1 CCHC zinc fingers exhibit a susceptibility to attack by certain types of compounds. Compounds with this activity are useful for developing new types of anti-retroviral
drugs called “zinc finger inhibitor” currently in development. Azodicarbonamide (ADA) is the only known zinc finger inhibitor currently involved in clinical trials.

Azodicarbonamide inhibits HIV-1 replication by targeting the nucleocapsid protein.

Nat Med. 1997 Mar;3(3):341-5.
Rice WG; Turpin JA; Huang M; Clanton D; Buckheit RW Jr; Covell DG; Wallqvist A; McDonnell NB; DeGuzman RN; Summers MF; Zalkow L; Bader JP; Haugwitz RD; Sausville EA; Laboratory of Antiviral Drug Mechanisms, National Cancer; Institute-Frederick Cancer Research and Development Center, SAIC; Frederick, Maryland 21702, USA.

Abstract: “ Nucleocapsid p7 (NCp7) proteins of human immunodeficiency virus type 1 (HIV-1) contain two zinc binding domains of the sequence Cys-(X)2-Cys-(X)4-His-(X)4-Cys (CCHC). The spacing pattern and metal-chelating residues (3 Cys, 1 His) of these nucleocapsid CCHC zinc fingers are highly conserved among retroviruses. These CCHC domains are required during both the early and late phases of retroviral replication, making them attractive targets for antiviral agents. Toward that end, we have identified a number of antiviral chemotypes that electrophilically attack the sulphur atoms of the zinc-coordinating cysteine residues of the domains. Such nucleocapsid inhibitors were directly virucidal by preventing the initiation of reverse transcription and blocked formation of infectious virus from cells through modification of CCHC domains within Gag precursors. Herein we report that Azodicarbonamide ( ADA ) represents a new compound that inhibits HIV-1 and a broad range of retroviruses by targeting the nucleocapsid CCHC domains. Vandevelde et al. also recently disclosed that ADA inhibits HIV-1 infection via an unidentified mechanism and that ADA was introduced into Phase I/II clinical trials in Europe for advanced AIDS. These studies distinguish ADA as the first known nucleocapsid inhibitor to progress to human trials and provide a lead compound for drug optimization.”

ADA reacts with the CCHC zinc fingers and removes the zinc ions cause a change in the conformation and charge of the nucleocapsid protein, which can be detected as a change in its electrophoretic mobility using capillary zone electrophoresis (CZE).

Reactive orientation between ADA lowest unoccupied molecular orbital (LUMO) and C-terminal Zn finger highest occupied molecular orbital (HOMO), localized at S49.

Nearly the most Potent on its target

From: Proc. Natl. Acad. Sci. USA Vol. 95, pp. 11578–11583, September 1998 Biochemistry. Maynard et al 

Compliant GMP micronized ADA

H-PHAR SA is the ONLY Company having a pharmaceutical grade miconized ADA GMP Compliant (HPH116) The synthesis route avoids any semicarbazide and heavy metal intermediate.

The micronization of the product (patented) leads to a better bioavailability and standardization of the active product.

Efficacy

Safe Dose Established for New Anti-HIV Drug, Setting Stage for Larger TrialReuters Health Information Services (www.reutershealth.com) ( 01/31/01 ). Preliminary data from a phase I/II trial of Azodicarbonamide (ADA) indicates that the HIV-1 zinc finger inhibitor is generally safe and could be beneficial to some AIDS patients who are experiencing virologic failure, when used in combination with standard antiviral therapies. Researchers from the Ludwig-Maximilians-Universitat in Germany report in the January 5th issue of AIDS (2001; 15:33 -45) that most of the 15 subjects tolerated ADA well and that toxicity was dependent upon the dosage. The tests indicated that ADA increased the percentage of CD4 cells and the CD4/CD8 ratio and decreased plasma RNA viral load levels in comparison to baseline data.

Major ADA advantages are:

new mode of action
absence of viral resistance
viral load reduction
CD 4 + T lymphocytes increase
minor side effects
 
 
 
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