The Future of ImmunoGen - Care of Genentech

Includes: IMGN, RHHBY
by: Beta Delta

A preview of the future of ImmunoGen (NASDAQ:IMGN) began years ago when IMGN CEO Mitch Sayare had to beg the powers-that-be at Genentech (DNA) to try out ImmunoGen's ADC technology with HERCEPTIN, Genentech's flagship product for breast cancer. Sayare was loosely quoted as saying "I had to beg them to try it".

Genentech then proceeded not to return his calls for about six months. DNA finally called back and said "let's make a deal". Then Genentech called back again and said, "let's make another deal, a bigger deal."

That was a few years ago. Now we move to the present day. DNA announced data at the SABC in December 2007 on TRASTUZUMAB-MCC-DM1. The initial phase trial data didn't disappoint. 15 patients were dosed at MTD of 3.6mg/kg. 5 of the 15 patients dosed currently have had a PR (partial response) and 7 of 10 of those patients have SD (stable disease). That yields a response rate of 12 pts out of 15 dosed or 80%. How many chemo drugs get 80% RR? Few, if any, that I know of. Let me remind you that all of these patients had seen prior chemotherapy, in fact a median of three prior chemotherapy regimens. All suffered from incurable metastatic breast cancer, and all had been treated with and recently failed Herceptin prior to entry in this study.

What does this mean for ImmunoGen? It means Genentech believes that its franchise oncology product, HERCEPTIN, now has its successor, TRASTUZUMAB-DM1. Why am I so confident, you ask? First, you have to listen to what Genentech says, and then what they do.

Behind the scenes. First, Genentech laid out its production capabilities for TRASTUZUMAB-DM1 last fall, showing the world its hand. Genentech will move forward with this drug. Why so soon? When a drug works, you start planning ahead, and guess what? Genentech says it works.

Then, Roche (OTCQX:RHHBY), the majority owner of DNA, exercised its opt-in right to market trastuzumab-dm1, ex-US. In other words, Roche will market TRASTUZUMAB-DM1 worldwide, minus the US market. This is huge for ImmunoGen.

Currently, Genentech is running two trials with TRASTUZUMAB-DM1 - a weekly phase 1 dosing schedule and an every 3 week phase 2 dosing schedule. I fully expect DNA to eventually broaden this current phase 1 dose escalation trial into a full phase 2 trial. Compare the data between the two trials. Both trials will show remarkable, superior efficacy for past herceptin trial failures and will lead Genentech to determine its pivotal trial dose and begin this pivotal trial in 2009. Enrollment is both trials is going well and I expect both trials to complete enrollment before year end 2008. Comparative trial data studies are ongoing as we speak, so Genentech should be ready to proceed early in 2009.

So what lies next for the future of this partnership between ImmunoGen and Genentech? Well, Gennetech has the option to bring 3 new ADC drugs using IMGN technology into the clinic. The question is not IF they bring new drugs to clinic, but when?

Disclosure: Author has a long position in IMGN