ImmunoGen Stops Lung Cancer Trial, Shares Fall 20%.

ImmunoGen’s (IMGN) gave up most of this year’s gains when the company announced that it was stopping a phase 2 clinical trial of IMGN901 in small-cell lung cancer due to infection risk and an apparent lack of efficacy. The company still has 10 compounds in development and separately announced the first in-human clinical trial for IMGN289.

ImmunoGen develops cancer therapeutics using its antibody-drug conjugate (ADC) technology. ADCs are a new class of highly potent biopharmaceutical drugs designed as a targeted therapy for the treatment of cancer. Compared with traditional chemotherapeutic agents, ADCs target and attack specifically cancer cells, leaving healthy cells unaffected – leading to fewer side effects and better efficacy.

IMGN901 is the most advanced drug in the company’s internal pipeline. The study looked at progression-free survival in small-cell lung cancer by adding IMGN901 to an existing regimen of etoposide/carboplatin (E/C). The trial’s independent data monitoring committee (DMC) made the recommendation based on a lack of evidence showing meaningful improvement in progression-free survival as well as a possible higher risk of infection/infection-related death as a complication for patients receiving IMGN901.

IMGN will look at the study findings to date to determine next steps with the compound. However, as recently as two-weeks ago on its earnings conference call, management was still optimistic, citing plans to complete the IMGN901 patient enrollment process and move to next-step decisions by mid-2014.

Separately, the company announced the start of the first in-human clinical trials for its IMGN289 compound. MGN289 will be evaluated in a multi-center, Phase I trial in patients with non-small cell lung cancer (NSCLC), squamous cell carcinoma of the head and neck (SCCHN), or other EGFR-positive solid tumors. The first trial will focus on quantifying a maximum tolerated dose.

ImmunoGen has 11 products in development internally and seven other ADC technology compounds in trials through partnerships. While some continue to look to Kadcyla, the company’s approved ADC for HER2+ breast cancer, as validation of this technology, there seems to be more and more evidence that the underlying “linkers” at ImmunoGen aren’t holding up in the body, causing the toxicity issues seen repeatedly. If this is the case – that ImmunoGen’s technology is inherently flawed – the company may be in real trouble without a major revamp.