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Roche, Immunogen ‘Guided Missile’ Targets Tumors (Update2)

By Rob Waters

Dec. 12 (Bloomberg) -- A “guided missile” combination drug called T-DM1 developed by Roche Holding AG and Immunogen Inc. shrank the tumors of one-third of the critically ill, advanced breast cancer patients in a study.

The therapy combines Roche’s Herceptin with a potent cancer-killing drug developed by Immunogen. Herceptin acts as a guidance system, using its ability to home in on cancer cells to deliver the cancer treatment directly to its target, said Ian Krop of the Dana-Farber Cancer Institute in Boston. The “T” in the name is trastuzumab, the chemical term for Herceptin.

T-DM1 would be the first product marketed by Waltham, Massachusetts-based Immunogen in its 28-year history. The two companies may seek regulatory approval next year, said Barbara Klencke, associate group director for clinical oncology at Genentech, the Roche unit that co-developed the drug. Herceptin generated $4.7 billion in sales last year.

The combination product is “an extremely big deal for Immunogen because it validates and proves their technology,” said Jason Kantor, an analyst for RBC Capital Markets in San Francisco, in a Dec. 8 telephone interview. ‘For Roche it’s important because it is a highly innovative follow-on product to one of their most successful franchises, and is the first of many drug conjugates Genentech has in development.”

‘Replace Herceptin’

The new therapy “has the potential to replace Herceptin” alone for patients whose breast cancer has spread and could also find use in treating gastric tumors, Kantor said. He predicted the drug could reach the market by the end of 2010.

Partial results from the trial, released by Immunogen in a Dec. 9 regulatory filing, boosted Immunogen 8.9 percent to $8.89 in Nasdaq stock market trading that day. They closed yesterday at $8.77. The biotechnology company’s shares have more than doubled this year. Roche, based in Basel, Switzerland, fell less than 1 percent to 168.5 Swiss francs in Zurich trading.

Immunogen, founded in 1981, has “had a few false starts” in past drug development efforts, said Chief Executive Officer Dan Junius in a telephone interview yesterday. The company has an accumulated deficit of $328 million over its 28-year history.

Immunogen will earn a “mid-single digit” percentage off the sales of T-DM1 and has received $13 million of a possible $44 million in milestone payments from Roche, Junius said.

Immunogen Technology

Immunogen developed the technology for linking drugs and antibodies like Herceptin and is testing T-DM1 and other combinations in different cancers with Roche and other companies, Junius said.

The study tested the drug in 110 women who’d had breast tumors for three years and whose cancer had moved outside their breasts. They had been treated with an average of seven different therapies including Herceptin, GlaxoSmithKline’s Tykerb and Roche’s Xeloda in an effort to stop or slow the cancer. Each intervention had failed.

The DM1 drug added to Herceptin was derived from an old chemotherapy drug called maytansine that was found to be too toxic for patients in clinical trials two decades ago, said Krop, the study leader. Because Herceptin homes on the cancer cells that express the protein HER2, it delivers and releases DM1 only to those cells.

‘Warhead’

“The warhead is the DM1,” said Krop, the study author, in an interview at the San Antonio symposium, where he presented his findings. “This approach gets the cytoxic drug to the cancer cells so it’s not floating around and causing other problems. Herceptin can still do all the things that Herceptin does” to prevent cancer cells from growing.

In one-third of the women, their tumors shrank by 30 percent or more. Another 12 percent had stable disease for at least six months though their tumors didn’t shrink by at least 30 percent.

The women went an average of 7.3 months without their condition worsening and had minimal side effects beyond those already seen with chemotherapy, Krop said.

The drug is being tested in larger trials comparing it with other anti-cancer drugs for patients with earlier stage breast cancer, Krop said. One ongoing Roche study is comparing T-DM1 with Herceptin and a chemotherapy drug as a first-line treatment, said Krysta Pellegrino, a Genentech spokeswoman.

To contact the reporter on this story: Rob Waters in San Francisco at [e-mail].