Patents by Inventor Ravi V. J. Chari

Ravi V. J. Chari has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • METHOD OF TARGETING SPECIFIC CELL POPULATIONS USING CELL-BINDING AGENT MAYTANSINOID CONJUGATES LINKED VIA A NON-CLEAVABLE LINKER, SAID CONJUGATES AND METHODS OF MAKING SAID CONJUGATES
    Publication number: 20110281856
    Abstract: The present invention discloses a method for targeting maytansinoids to a selected cell population, the method comprising contacting a cell population or tissue suspected of containing the selected cell population with a cell-binding agent maytansinoid conjugate, wherein one or more maytansinoids is covalently linked to the cell-binding agent via a non-cleavable linker and the cell-binding agent binds to cells of the selected cell population.
    Type: Application
    Filed: July 8, 2011
    Publication date: November 17, 2011
    Applicant: IMMUNOGEN INC.
    Inventors: Ravi V. J. CHARI, Wayne WIDDISON
  • Prodrugs of CC-A1065 analogs
    Patent number: 8012978
    Abstract: The present invention provides prodrugs of analogs of the anti-tumor antibiotic CC-1065 having a cleavable protective group containing a sulfonic acid containing phenyl carbamate, in which the protecting group confers enhanced water solubility upon the prodrug, and in which the prodrug also has a moiety, such as a sulfide or a disulfide, that can conjugate to a cell binding reagent such as an antibody, and for the therapeutic use of such prodrug and conjugates, and for processes for preparing such prodrugs and conjugates.
    Type: Grant
    Filed: September 4, 2008
    Date of Patent: September 6, 2011
    Assignee: ImmunoGen, Inc.
    Inventors: Robert Zhao, Ravi V. J. Chari
  • Method of targeting specific cell populations using cell-binding agent maytansinoid conjugates linked via a non-cleavable linker, said conjugates and methods of making said conjugates
    Patent number: 7989598
    Abstract: The present invention discloses a method for targeting maytansinoids to a selected cell population, the method comprising contacting a cell population or tissue suspected of containing the selected cell population with a cell-binding agent maytansinoid conjugate, wherein one or more maytansinoids is covalently linked to the cell-binding agent via a non-cleavable linker and the cell-binding agent binds to cells of the selected cell population.
    Type: Grant
    Filed: October 29, 2007
    Date of Patent: August 2, 2011
    Assignee: Immunogen Inc.
    Inventors: Rita M. Steeves, Ravi V. J. Chari, Walter A. Blattler
  • CYTOTOXIC AGENTS COMPRISING NEW MAYTANSINOIDS
    Publication number: 20110158991
    Abstract: New thiol and disulfide-containing maytansinoids bearing a mono or di-alkyl substitution on the ?-carbon atom bearing the sulfur atom are disclosed. Also disclosed are methods for the synthesis of these new maytansinoids and methods for the linkage of these new maytansinoids to cell-binding agents. The maytansinoid-cell-binding agent conjugates are useful as therapeutic agents, which are delivered specifically to target cells and are cytotoxic. These conjugates display vastly improved therapeutic efficacy in animal tumor models compared to the previously described agents.
    Type: Application
    Filed: March 9, 2011
    Publication date: June 30, 2011
    Applicant: IMMUNOGEN INC.
    Inventors: Ravi V.J. CHARI, Wayne C. WIDDISON
  • Prodrugs of CC-1065 analogs
    Patent number: 7906545
    Abstract: Prodrugs of analogs of the anti-tumor antibiotic CC-1065 having a cleavable protective group such as a piperazino carbamate, a 4-piperidino-piperidino carbamate or a phosphate, in which the protecting group confers enhanced water solubility and stability upon the prodrug, and in which the prodrug also has a moiety, such as a disulfide, that can conjugate to a cell binding reagent such as an antibody. The therapeutic use of such prodrug conjugates is also described; such prodrugs of cytotoxic agents have therapeutic use because they can deliver cytotoxic prodrugs to a specific cell population for enzymatic conversion to cytoxic drugs in a targeted fashion.
    Type: Grant
    Filed: July 17, 2009
    Date of Patent: March 15, 2011
    Assignee: Immunogen Inc.
    Inventors: Robert Yongxin Zhao, Ravi V. J. Chari
  • PRODRUGS OF CC-1065 ANALOGS
    Publication number: 20110008373
    Abstract: Prodrugs of analogs of the anti-tumor antibiotic CC-1065 having a cleavable protective group such as a piperazino carbamate, a 4-piperidino-piperidino carbamate or a phosphate, in which the protecting group confers enhanced water solubility and stability upon the prodrug, and in which the prodrug also has a moiety, such as a disulfide, that can conjugate to a cell binding reagent such as an antibody. The therapeutic use of such prodrug conjugates is also described; such prodrugs of cytotoxic agents have therapeutic use because they can deliver cytotoxic prodrugs to a specific cell population for enzymatic conversion to cytoxic drugs in a targeted fashion.
    Type: Application
    Filed: September 20, 2010
    Publication date: January 13, 2011
    Applicant: IMMUNOGEN, INC.
    Inventors: Robert Yongxin ZHAO, Ravi V.J. CHARI
  • CONJUGATION METHODS
    Publication number: 20110003969
    Abstract: This invention describes a method of conjugating a cell binding agent such as an antibody with an effector group (e.g., a cytotoxic agent) or a reporter group (e.g., a radionuclide), whereby the reporter or effector group is first reacted with a bifunctional linker and the mixture is then used without purification for the conjugation reaction with the cell binding agent. The method described in this invention is advantageous for preparation of stably-linked conjugates of cell binding agents, such as antibodies with effector or reporter groups.
    Type: Application
    Filed: June 3, 2010
    Publication date: January 6, 2011
    Applicant: Immunogen Inc.
    Inventors: Brenda A. Kellogg, Rajeeva Singh, Ravi V. J. Chari
  • LEPTOMYCIN DERIVATIVES
    Publication number: 20110002947
    Abstract: Leptomycin derivatives having a moiety, such as a sulfide or a disulfide, that can conjugate to a cell binding reagent such as an antibody are disclosed. The therapeutic use of such leptomycin derivative conjugates is also described; such conjugates have therapeutic use because they can deliver cytotoxic leptomycin derivatives to a specific cell population in a targeted fashion.
    Type: Application
    Filed: September 14, 2010
    Publication date: January 6, 2011
    Applicant: SANOFI-AVENTIS
    Inventors: Hervé BOUCHARD, Alain COMMERCON, Ravi V.J. CHARI
  • CYTOTOXIC AGENTS COMPRISING NEW TOMAYMYCIN DERIVATIVES AND THEIR THERAPEUTIC USE
    Publication number: 20100316656
    Abstract: The invention relates to novel tomaymicine derivatives comprising a linker. It also relates to the conjugate molecules that comprise one or more of said tomaymicine derivatives covalently linked to a cell binding agent through a linking group that is present on the linker of the tomaymycin derivative. It also relates to the preparation of the tomaymicine derivatives and of the conjugate molecules.
    Type: Application
    Filed: January 19, 2010
    Publication date: December 16, 2010
    Applicant: sanofi-aventis
    Inventors: Hervé Bouchard, Ravi V.J. Chari, Alain Commercon, Yonghong Deng, Laurence Gauzy
  • Cytotoxic agents comprising new maytansinoids
    Patent number: 7851432
    Abstract: New thiol and disulfide-containing maytansinoids bearing a mono or di-alkyl substitution on the ?-carbon atom bearing the sulfur atom are disclosed. Also disclosed are methods for the synthesis of these new maytansinoids and methods for the linkage of these new maytansinoids to cell-binding agents. The maytansinoid-cell-binding agent conjugates are useful as therapeutic agents, which are delivered specifically to target cells and are cytotoxic. These conjugates display vastly improved therapeutic efficacy in animal tumor models compared to the previously described agents.
    Type: Grant
    Filed: July 16, 2007
    Date of Patent: December 14, 2010
    Assignee: Immunogen Inc.
    Inventors: Ravi V. J. Chari, Wayne C. Widdison
  • Leptomycin derivatives
    Patent number: 7816543
    Abstract: Leptomycin derivatives having a moiety, such as a sulfide or a disulfide, that can conjugate to a cell binding reagent such as an antibody are disclosed. The therapeutic use of such leptomycin derivative conjugates is also described; such conjugates have therapeutic use because they can deliver cytotoxic leptomycin derivatives to a specific cell population in a targeted fashion.
    Type: Grant
    Filed: November 24, 2008
    Date of Patent: October 19, 2010
    Assignee: Sanofi-Aventis
    Inventors: Herve Bouchard, Alain Commercon, Ravi V. J. Chari
  • POTENT CONJUGATES AND HYDROPHILIC LINKERS
    Publication number: 20100129314
    Abstract: Linkers for binding drugs to cell binding agents are modified to hydrophilic linkers by incorporating a polyethylene glycol spacer. The potency or the efficacy of the cell-binding agent-drug conjugates is surprisingly enhanced several folds in a variety of cancer cell types, including those expressing a low number of antigens on the cell surface or cancer cells that are resistant to treatment. A method for preparing maytansinoids bearing a thioether moiety and a reactive group which allows the maytansinoid to be linked to a cell-binding agent in essentially a single step is also provided.
    Type: Application
    Filed: October 6, 2009
    Publication date: May 27, 2010
    Applicant: Immunogen Inc.
    Inventors: Rajeeva Singh, Yelena Kovtun, Sharon D. Wilhelm, Ravi V.J. Chari
  • POTENT CELL-BINDING AGENT DRUG CONJUGATES
    Publication number: 20100092495
    Abstract: The present invention relates to the use of about 2 to about 8 drug molecules, for example, maytansinoid, per cell binding agent, such as an antibody, and maximal efficacy as compared to a drug load of lesser or higher number of drugs linked to such a cell binding agent.
    Type: Application
    Filed: October 6, 2009
    Publication date: April 15, 2010
    Applicant: IMMUNOGEN INC.
    Inventor: Ravi V. J. CHARI
  • Cytotoxic agents comprising new taxanes
    Patent number: 7667054
    Abstract: The invention relates to novel cytotoxic agents comprising taxanes and their therapeutic use as a result of delivering the taxanes to a specific cell population in a targeted fashion by chemically linking the taxane to a cell binding agent.
    Type: Grant
    Filed: December 6, 2005
    Date of Patent: February 23, 2010
    Assignee: Aventis Pharma S.A.
    Inventors: Michael L. Miller, Ravi V. J. Chari, Erkan Baloglu, Alain Commercon
  • Prodrugs of CC-1065 analogs
    Patent number: 7655661
    Abstract: Prodrugs of analogs of the anti-tumor antibiotic CC-1065 having a cleavable protective group such as a piperazino carbamate, a 4-piperidino-piperidino carbamate or a phosphate, in which the protecting group confers enhanced water solubility and stability upon the prodrug, and in which the prodrug also has a moiety, such as a disulfide, that can conjugate to a cell binding reagent such as an antibody. The therapeutic use of such prodrug conjugates is also described; such prodrugs of cytotoxic agents have therapeutic use because they can deliver cytotoxic prodrugs to a specific cell population for enzymatic conversion to cytotoxic drugs in a targeted fashion.
    Type: Grant
    Filed: June 23, 2008
    Date of Patent: February 2, 2010
    Assignee: ImmunoGen Inc.
    Inventors: Robert Yongxin Zhao, Ravi V. J. Chari
  • Prodrugs of CC-1065 analogs
    Patent number: 7655660
    Abstract: Prodrugs of analogs of the anti-tumor antibiotic CC-1065 having a cleavable protective group such as a piperazino carbamate, a 4-piperidino-piperidino carbamate or a phosphate, in which the protecting group confers enhanced water solubility and stability upon the prodrug, and in which the prodrug also has a moiety, such as a disulfide, that can conjugate to a cell binding reagent such as an antibody. The therapeutic use of such prodrug conjugates is also described; such prodrugs of cytotoxic agents have therapeutic use because they can deliver cytotoxic prodrugs to a specific cell population for enzymatic conversion to cytoxic drugs in a targeted fashion.
    Type: Grant
    Filed: January 5, 2007
    Date of Patent: February 2, 2010
    Assignee: Immunogen Inc.
    Inventors: Robert Yongxin Zhao, Ravi V. J. Chari
  • PRODRUGS OF CC-1065 ANALOGS
    Publication number: 20090281158
    Abstract: Prodrugs of analogs of the anti-tumor antibiotic CC-1065 having a cleavable protective group such as a piperazino carbamate, a 4-piperidino-piperidino carbamate or a phosphate, in which the protecting group confers enhanced water solubility and stability upon the prodrug, and in which the prodrug also has a moiety, such as a disulfide, that can conjugate to a cell binding reagent such as an antibody. The therapeutic use of such prodrug conjugates is also described; such prodrugs of cytotoxic agents have therapeutic use because they can deliver cytotoxic prodrugs to a specific cell population for enzymatic conversion to cytoxic drugs in a targeted fashion.
    Type: Application
    Filed: July 17, 2009
    Publication date: November 12, 2009
    Applicant: IMMUNOGEN, INC.
    Inventors: ROBERT YONGXIN ZHAO, Ravi V.J. Chari
  • CROSS-LINKERS AND THEIR USES
    Publication number: 20090274713
    Abstract: Charged or pro-charged cross-linking moieties and conjugates of cell binding agents and drugs comprising the charged or pro-charged cross-linking moieties and method of making the same.
    Type: Application
    Filed: April 30, 2009
    Publication date: November 5, 2009
    Applicant: IMMUNOGEN INC.
    Inventors: Ravi V. J. CHARI, Robert Yongxin Zhao, Yelena Kovtun, Rajeeva Singh, Wayne Charles Widdison
  • Compositions and methods for treating cancer using immunoconjugates and chemotherapeutic agents
    Patent number: 7601354
    Abstract: The present invention is based on the discovery that the administration of at least one immunoconjugate and at least one chemotherapeutic agent provides an unexpectedly superior treatment for cancer. The present invention is directed to compositions comprising at least one immunoconjugate and at least one chemotherapeutic agent and to methods of treating cancer using at least one immunoconjugate and at least one chemotherapeutic agent. The present invention also provides methods of modulating the growth of selected cell populations, such as cancer cells, by administering a therapeutically effective amount of at least one chemotherapeutic agent and at least one immunoconjugate.
    Type: Grant
    Filed: June 15, 2006
    Date of Patent: October 13, 2009
    Assignee: Immunogen Inc.
    Inventor: Ravi V. J. Chari
  • Cytotoxic agents comprising new C-2 modified taxanes
    Patent number: 7598290
    Abstract: The invention relates to taxanes and to novel cytotoxic agents comprising taxanes and their therapeutic use as a result of delivering the taxanes to a specific cell population in a targeted fashion by chemically linking the taxane to a cell binding agent.
    Type: Grant
    Filed: February 27, 2007
    Date of Patent: October 6, 2009
    Assignee: Immunogen, Inc.
    Inventors: Michael L. Miller, Ravi V. J. Chari, Erkan Baloglu