ImmunoGen CEO Highlights Two New Souped-Up Antibodies Against Cancer

Xconomy Boston — 

ImmunoGen, in the eyes of Wall Street, is largely defined by one thing—its relationship with industry giant Genentech. That’s because Genentech uses ImmunoGen’s technology to help amp up the antibody trastuzumab (Herceptin) into a more potent breast cancer drug called T-DM1, which has shown significant promise in clinical trials.

Yet ImmunoGen chief executive Daniel Junius says there’s a lot more to the story. Today, his firm is hosting an analyst day in New York to emphasize some of the drugs that are wholly-owned by ImmunoGen—unlike T-DM1, in which Genentech will reap the lion’s share of the rewards. Junius gave me a preview yesterday of two so-called antibody-drug conjugates—which link targeted antibodies with toxins to make them more potent—that are 100-percent owned by ImmunoGen. Though these two molecules haven’t begun human testing, Junius made a good case for why they are important to his company and why they could prove valuable for the treatment of certain types of cancer.

Junius, who became CEO of ImmunoGen in 2009, wants his company to expand its own internal pipeline of compounds along with continuing its partnerships in which it shares rights to other products with drug giants such as Genentech (a unit of Swiss healthcare firm Roche) and Sanofi-Aventis. “We’re working very hard to be moving from a partner-based company—although that will still have a role—to being one that is much more focused on proprietary compounds,” he says.

This thinking makes sense given the impact of a recent regulatory setback for Genentech’s T-DM1 on ImmunoGen. The FDA handed Roche/Genentech a “refusal to file” letter in late August, essentially saying it wouldn’t accept the firm’s application for accelerated marketing approval of T-DM1 as a breast cancer treatment because of the agency’s opinion that the experimental treatment did not quality at this time for that faster-than-usual type of review. Some investors immediately fled from ImmunoGen’s stock, sending its shares down more than 35 percent on August 27, the day that Roche announced the “refuse to file” letter.

ImmunoGen’s stock has since recovered the value it lost on the day of the FDA letter, and Roche is still advancing T-DM1 through the third and final stage of clinical trials normally required for FDA approval. ImmunoGen also announced a partnership deal in October with Novartis that brought the firm $45 million in upfront cash and the opportunity for additional payments related to specific compounds within the collaboration. (ImmunoGen’s stock closed at $8.80 per share on Thursday, giving the company a market value of $598.7 million.)

The two compounds that the company plans to highlight today are called IMGN859 and IMGN529. Like T-DM1, these compounds combine the ability of antibodies to home in on tumor targets with the killer punch of an anti-cancer toxin. The firm uses linkers to keep the toxins bound to the antibody while it is in the bloodstream, limiting exposure to the anti-cancer agent on healthy tissues. ImmunoGen is reserving some of the details on its latest two compounds until a scientific meeting later this year.

Junius says that the compound called IMGN529 features an antibody with an affinity for an undisclosed target on non-Hodgkin’s lymphomas, a cancer of the white blood cells. In fact, the firm’s antibody alone—without any extra kick from an attached toxin—compared favorably in models of non-Hodgkin’s lymphoma with available antibody drugs such as Biogen Idec (NASDAQ:BIIB) and Genentech’s lucrative product, rituximab (Rituxan), according to Junius. Rituxan, first approved by the FDA in 1997, is a so-called “naked” antibody, which zeroes in on cancer cells, but which isn’t attached to a more potent toxin.

“We do think we have attributes with this [ImmunoGen] antibody that would potentially make it superior as a naked agent,” Junius says. And the company is boosting its compound’s cancer-killing ability further with its technology that links the toxin to the antibody.

ImmunoGen plans to file an Investigational New Drug (IND) application with FDA for permission to begin its first clinical trial of the compound by the middle of this year in patients with non-Hodgkin’s lymphoma, according to Junius. He declined to disclose the specific molecular target that the compound is supposed to home in on to treat lymphomas.

Dan Junius is CEO of ImmunoGen

Yet Junius did say that the target for the other compound, IMGN853, is a protein known as folate receptor 1 that is found in breast, lung, and ovarian tumors. One thing he highlighted was that the compound’s linker component not only keeps the antibody and the toxin intact in the circulation but also might play a role in preventing cancer cells from developing resistance to the treatment over time. The plan is to begin initial human testing of the compound next year in patients with a variety of tumor types, as is common in Phase I trials for cancer drugs.

While Junius is emphasizing the firm’s internal programs, Roche/Genentech’s T-DM1 is much further along in clinical development than ImmunoGen’s wholly-owned compounds. And Roche is now planning to apply for marketing approval of T-DM1 in the U.S. and Europe in mid-2012 for patients who have breast cancer that expresses HER2 gene and who have failed to respond to a previous therapy, according to ImmunoGen. The compound would provide ImmunoGen, which has no products on the market, its first major revenue from drug sales.

Yet the company’s analysts are quite familiar with the T-DM1 story by now, and already have sketched out how much money ImmunoGen stands to collect from royalties of T-DM1 sales around the world. Today, ImmunoGen wants to tell them about its younger prospects, which could generate a lot of money for ImmunoGen if they can prove over time they offer as much benefit to patients as T-DM1.