ImmunoGen, Inc. (Nasdaq: IMGN), a biotechnology company that develops novel anticancer therapeutics using its Targeted Antibody Payload (TAP) ADC technology, today announced that the Company’s IMGN289 Investigational New Drug (IND) application has been accepted by the US FDA and is now active. This enables ImmunoGen to advance IMGN289 into human clinical testing, expected to start in 4Q2013. This is the third IND for a novel, wholly owned anticancer compound to be submitted by ImmunoGen and accepted by the FDA in the past two years. “We believe IMGN289 has the potential to be an important new therapy for many cancers, including squamous cell lung cancers and head and neck cancers, which have highly limited treatment options today,” commented Dr. Charles Morris, EVP and Chief Development Officer. “Based on its profile, we expect IMGN289 to be more active than existing EGFR-directed therapies against tumors with high EGFR expression and also to be effective for some tumor types where existing therapies have not demonstrated meaningful efficacy.” About IMGN289 IMGN289, an ADC, is a potential new treatment for lung, head and neck, and other EGFR-positive solid tumors. It is designed to bind to and kill cancer cells that highly express EGFR. IMGN289 contains an EGFR-targeting antibody developed by ImmunoGen that, in preclinical testing, demonstrated marked anticancer activity against EGFR-positive tumors responsive to EGFR inhibitors, with less skin toxicity than marketed antibodies to this target. 1 The Company’s potent DM1 cell-killing agent is attached to the antibody with ImmunoGen’s thioether linker. This design is also used in the approved product, Kadcyla ®. Both IMGN289 and Kadcyla target members of the ErbB family – EGFR (ErbB1) and HER2 (ErbB2), respectively – found on solid tumors that can act as driver oncoproteins. Against EGFR-positive tumors responsive to EGFR inhibitors, IMGN289’s antibody component alone demonstrated activity comparable to Erbitux ® in preclinical models. The complete ADC – with the DM1 component – provided superior activity. 1-3 Its DM1 component enables IMGN289 to kill EGFR-positive cancer cells by a second mechanism that is not dependent on the EGFR pathway – disruption of the function of cellular microtubules. Thus, IMGN289 would be expected to be active against EGFR-positive cancers that are not responsive to EGFR inhibitors. Preclinical results support this expectation: IMGN289 has been found to demonstrate activity superior to Erbitux and Tarceva ® against EGFR-independent and TKI-resistant cancer models, respectively. 1-3About the First-in-Human IMGN289 Clinical Trial IMGN289 will be evaluated in a multi-center, US Phase I trial designed to assess the safety, tolerability, pharmacokinetics, pharmacodynamics and anticancer activity of the compound in patients with non-small cell lung cancer (NSCLC), squamous cell carcinoma of the head and neck cancer (SCCHN), or other EGFR-positive solid tumors. Once its maximum tolerated dose is defined, the activity of IMGN289 will be evaluated in disease-specific patient cohorts. The ones planned include SCCHN, squamous cell NSCLC, and NSCLC resistant to EGFR inhibitors.