ImmunoGen : Announces Initiation of Clinical Testing of First-in-Class IMGN779 for Acute Myeloid Leukemia

• Novel CD33-targeting product candidate is the first antibody-drug conjugate (ADC) to employ an IGN, a new type of cancer-killing agent.
• Phase 1 study in acute myeloid leukemia (AML) is designed to efficiently inform the IMGN779 development pathway.

WALTHAM, Mass.--(BUSINESS WIRE)-- ImmunoGen, Inc. (Nasdaq: IMGN), a biotechnology company that develops targeted anticancer therapeutics using its extensive ADC technology portfolio, today announced the start of clinical testing of the Company's IMGN779 product candidate for the treatment of AML, a CD33-positive cancer.

IMGN779 contains a CD33-targeting antibody - enabling it to bind to AML cells - with a powerful cancer-killing agent attached to kill them. IMGN779 is the first ADC to utilize one of ImmunoGen's new family of indolino-benzodiazepine cancer-killing agents, which the Company calls IGNs. DNA-alkylating IGNs have been designed to be ultra-potent, yet provide the tolerability necessary for ongoing retreatment.

'There is substantial need for new therapies for AML and considerable appeal to an ADC approach,' said Ravi Chari, Ph.D., VP of Chemistry and Biochemistry. 'A key challenge has been achieving the potency needed for clinical benefit with the tolerability required for continued patient retreatment. We developed our DNA-alkylating IGNs to meet these dual needs and believe this innovative new class can further extend the types of cancers that can be effectively treated with ADC therapeutics.'

The IMGN779 Phase 1 trial in CD33-positive AML will assess two alternative dosing schedules - weekly and biweekly administration - concurrently in its dose-finding stage. The selected dose and schedule will then be used in the two planned expansion cohorts: one assessing IMGN779 in patients with AML in first relapse and one assessing it in patients with relapsed/refractory AML.

'IMGN779 has the potential to make an important difference for patients with AML,' said Anna Berkenblit, MD, VP and Chief Medical Officer. 'This Phase 1 trial has been designed to efficiently inform the development pathway for IMGN779 by assessing alternative dosing schedules concurrently and then evaluating the selected schedule in specific under-served patient populations.'

About Acute Myeloid Leukemia (AML)

AML is a cancer of the bone marrow cells that produce white blood cells. It causes the marrow to increasingly generate abnormal immature white blood cells (blasts) that do not mature into effective infection-fighting cells. The blasts quickly fill the bone marrow, impacting the production of normal platelets and red blood cells. The resulting deficiencies in normal blood cells leaves the patient vulnerable to infections, bleeding problems and anemia.

It is estimated that, in the US alone, 20,000 patients will be diagnosed with AML this year and 10,000 patients will die from the disease. CD33 is expressed in virtually all cases of AML.

About IMGN779

IMGN779 comprises a CD33-targeting antibody with a potent DNA-alkylating agent, the IGN DGN462, attached. The antibody serves to target the ADC to the CD33-positive AML cells which DGN462 can then kill. IMGN779 is wholly owned by ImmunoGen.

About IGNs

IGNs are a new class of cancer-killing agent developed by ImmunoGen for use in ADCs. Ultra-potent, these DNA-alkylating indolino-benzodiazepines are expected to extend the types of cancers able to be effectively treated with ADC therapies beyond those addressable with ImmunoGen's well-established tubulin-acting agents. Such cancers can include ones insensitive to tubulin-acting agents and/or with reduced antigen expression.

About ImmunoGen, Inc.

ImmunoGen is a clinical-stage biotechnology company that develops targeted anticancer therapeutics using its proprietary ADC technology. The Company has four wholly owned clinical-stage ADCs. The lead, mirvetuximab soravtansine, is in Phase 2 testing for the treatment of folate receptor α-positive ovarian cancer. ImmunoGen's ADC technology is used in Roche's marketed product, Kadcyla, and in agents in development by partners Amgen, Bayer, Biotest, CytomX, Lilly, Novartis, Sanofi and Takeda. More information about the Company can be found at www.immunogen.com.

American Cancer Society (2016), Leukemia - Acute Myeloid (Myelogenous) Detailed Guide.

ImmunoGen Forward-Looking Statement

This press release includes forward-looking statements. For these statements, ImmunoGen claims the protection of the safe harbor for forward-looking statements provided by the Private Securities Litigation Reform Act of 1995. It should be noted that there are risks and uncertainties related to the development of novel anticancer agents, including IMGN779 and IGNs, including risks related to clinical studies and regulatory processes, their timings and results. A review of these risks can be found in ImmunoGen's Annual Report on Form 10-K for the fiscal year ended June 30, 2015 and other reports filed with the Securities and Exchange Commission.

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For Investors:
ImmunoGen, Inc.Carol Hausner, 781-895-0600
info@immunogen.com
or
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michael@scientpr.com

Source: ImmunoGen, Inc.

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