First Clinical Data Presented with IMGN853, ImmunoGen, Inc.'s Potential New Therapy for Ovarian and Other Cancers

First Clinical Data Presented with IMGN853, ImmunoGen, Inc.'s Potential New Therapy for Ovarian and Other Cancers

  • First clinical findings presented with ImmunoGen's folate receptor α (FRα)-targeting antibody-drug conjugate (ADC), IMGN853.
  • Preliminary evidence of activity seen in dose-finding portion of trial.

--(BUSINESS WIRE)--  (Nasdaq: IMGN), a biotechnology company that develops anticancer therapeutics using its Targeted Antibody Payload (TAP) ADC technology, today announced the presentation of the first clinical data with the Company's IMGN853 product candidate. The data are from the ongoing dose-finding portion of a Phase I clinical assessment of the compound, which is a potential treatment for many ovarian, endometrial, and non-small cell lung cancers, as well as other FRα-overexpressing cancers. The data are being presented (abstract #2573) at the  (ASCO) annual meeting taking place in 

First Data from Dose-Finding Assessment

The dose-finding portion of this Phase I clinical trial is designed to establish the maximum tolerated dose of IMGN853 and to define its dose-limiting toxicity (DLT). Patients with any type of cancer known to overexpress IMGN853's FRα target are eligible for enrollment in this phase of the trial. Once the maximum tolerated dose is established, IMGN853 will be evaluated in patients with specific types of FRα-overexpressing cancers, with prescreening to ensure tumor levels of FRα-overexpression meet defined criteria.

At the time of data cutoff for presentation, 18 patients had received IMGN853 at doses ranging from 0.15 to 7.0 mg/kg. DLT, seen at 7.0 mg/kg, was reversible blurred vision with epithelial corneal changes. The patients assigned to this dose were reduced to 5.0 mg/kg, the second highest dose evaluated. Additional new patients are being treated with 5.0 mg/kg to further assess that dose.

While this assessment is designed to evaluate the safety of IMGN853 and establish its maximum tolerated dose, evidence of clinical activity is also identified. Activity started to be seen when dose levels reached 3.3 mg/kg and included:

  • A patient with serous epithelial ovarian cancer assigned to treatment with IMGN853 at 3.3 mg/kg had a confirmed CA-125 response — a pronounced, sustained reduction in CA-125 levels — and stable disease lasting 18 weeks. This patient previously had received 12 other treatment regimens.
  • A patient with serous endometrial cancer achieved a partial response (PR), awaiting confirmation, after four cycles of treatment with IMGN853; she also had a marked decrease in CA-125 levels. This patient previously had received two platinum-based regimens that included paclitaxel. She was assigned to treatment with IMGN853 at the 5.0 mg/kg dose level and continues on therapy.
  • A patient with platinum-resistant, transitional cell ovarian cancer achieved a PR, awaiting confirmation, after two cycles of treatment with IMGN853. She also had a pronounced decrease in her CA-125 levels. She was assigned to receive IMGN853 at 7.0 mg/kg, experienced a DLT, and remains on study at 5.0 mg/kg.

All three of these patients had cancer that scored strongly positive1 for IMGN853's FRα target, as determined by well-established immunohistochemistry (IHC) assessment.

"We are highly encouraged by these initial clinical findings with IMGN853," commented Dr. , Executive Vice President and Chief Development Officer. "Preliminary evidence of activity has been seen in the dose-finding portion of this trial. We look forward to completing this part of the trial and beginning evaluation of IMGN853 in disease-specific patient populations."

ImmunoGen expects to begin the disease-specific, dose-expansion phase of this trial later this year. In that phase, IMGN853 will be evaluated in patients who have been prescreened for specific levels of FRα-overexpression and have either: (1) platinum-resistant ovarian cancer treated with three or fewer prior regimens; (2) relapsed/refractory ovarian cancer treated with less strictly defined prior therapies; or (3) adenocarcinoma non-small cell lung cancer. Addition of a cohort to assess IMGN853 for endometrial cancer is now also planned.

About IMGN853

IMGN853 is a FRα-targeting ADC wholly owned by ImmunoGen. It comprises three components developed by Company scientists: a humanized FRα-binding antibody, which serves to target the compound to FRα-expressing cancer cells; DM4, a potent cell-killing agent; and an engineered linker, which serves to keep the DM4 attached to the antibody en route to the cancer cells and also — once inside a cancer cell — helps counter the multi-drug resistance that can make previously treated cancers harder to kill.

IMGN853 is in Phase I testing for the treatment of FRα-overexpressing cancers, which include many ovarian, endometrial and adenocarcinoma non-small cell lung cancers.

About Ovarian, Endometrial, and Adenocarcinoma Non-Small Cell Lung Cancers

Each year, there are approximately 22,000 new cases of ovarian cancer diagnosed in the US and more than 14,000 women die from the disease.2Epithelial ovarian cancer accounts for approximately 85% to 90% of all cases of ovarian cancer.3

An estimated 48,500 cases of endometrial cancers will be diagnosed in the US in 2013 and approximately 8,000 women will die from the disease.4

Each year, approximately 228,000 patients in the US are diagnosed with lung cancer and approximately 160,000 die from the disease.2 About 40% of lung cancers are the adenocarcinoma subtype of non-small cell lung cancer.5


 develops targeted anticancer therapeutics. The Company's TAP technology uses a tumor-targeting monoclonal antibody to deliver one of ImmunoGen's highly potent cancer cell-killing agents specifically to tumor cells. Ten TAP compounds are now in the clinic, of which three are wholly owned by the Company. The most advanced compound using ImmunoGen's TAP technology, Kadcyla™, has been approved for marketing in the US and , and is undergoing regulatory review in the  and . Kadcyla is being commercialized in the US by, a member of the Roche Group. More information about ImmunoGen can be found at

Kadcyla™ is a trademark of .

1Target expression rated 3 on scale of 0-3. IHC method described in Carrigan et al., AACR 2011, abstract #3617.
2  (2013), Cancer Facts & Figures.
3  (2013), Ovarian Cancer Detailed Guide.
4  (2013), Endometrial (Uterine) Cancer Detailed Guide.
5  (2013),  (Non-Small Cell) Detailed Guide.

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 products, including IMGN853, including risks related to preclinical and clinical studies, 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  and other reports filed with the.