Pharma, R&D

Seattle Genetics grabs Immunomedics’ tumor drug in $2B deal, shooting for a quick OK

Clay Siegall, Seattle Genetics

You can count Seattle Genetics as the new flag carrier for Immunomedics’ solid tumor drug IMMU-132. The biotech is paying $300 million to claim global rights on the drug, committing up to $1.7 billion more in milestones.

That milestone money should get rolling soon. Seattle Genetics will now take the lead on a Phase III study for metastatic triple negative breast cancer. And once the BLA is filed, it’s obligated to pay over the first of its milestone money as Seattle Genetics looks to vault to an approval as early as late 2017.

“In just over three years, we have brought IMMU-132 through clinical developments in multiple indications, and have advanced the TNBC indication to a potential accelerated approval and launch by late 2017 or early 2018, which could make IMMU-132 available to patients dealing with a highly malignant form of breast cancer,” noted Morris Plains, NJ-based Immunomedics CEO Cynthia L. Sullivan.

Seattle Genetics $SGEN investors drove the stock down 6%, while Immunomedics $IMMU saw their shares rise only 7%.

IMMU-132 (sacituzumab govitecan) fits squarely in Seattle Genetics’ comfort zone. It is an armed antibody that contains SN-38, the active metabolite of irinotecan, designed for precise delivery to avoid off-target toxicity.

The deal — with a $250 million in an upfront and an additional $50 million for additional ex-US rights — falls just days after Sullivan and her crew touted the latest update on the drug and its plans to seek an accelerated approval. At a recent review, the company said:

(P)atients experienced two complete and 23 partial responses, while an additional three patients with initial partial responses are awaiting confirmation. Overall, 81% of patients treated with IMMU-132 showed tumor shrinkage from baseline measurements. The clinical benefit rate (complete and partial remissions, and patients with stable disease) at six months or later computed to 44%. The median duration of response for those with objective responses was almost 11 months. It was emphasized that these are interim results, since 20 patients are continuing treatment; a final outcome must await analysis of all patients enrolled.

Analysts though, have fretted about this drug in the recent past, including worries about the manufacturing process, which Seattle Genetics is likely to tackle quickly.

After TNBC, Seattle Genetics plans to go after new indications as it follows up on Phase II studies in urothelial cancer, small-cell lung cancer and non-small-cell lung cancer. And Seattle Genetics CEO Clay Siegall says the late-stage tumor drug will fit neatly in its pipeline of antibody drug conjugates. He said:

This program would complement our rich pipeline of late- and early-stage programs, potentially allowing us to bring a new therapy for triple-negative breast cancer to patients in need. We have successfully demonstrated our expertise in the development, manufacturing and commercialization of ADCs in oncology, and we look forward to working with Immunomedics to advance this program.

In addition to the cash and milestones, Seattle Genetics is also buying into Immunomedics, paying $14.7 million for shares at a slight premium and reserving the right to buy more later at the same price. Seattle Genetics has the right to make up to a $57 million equity investment for up to a 9.9% stake in Immunomedics.

Right after the deal was announced, Immunomedics said it would postpone its annual meeting as its investors took time to absorb the implications of the pact.

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VP Oncology Biology
Skyhawk Therapeutics Waltham, MA
Director Process Development
Elektroki Boston, MA
Director Process Development
Elektroki Boston, MA
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Recursion Pharmaceuticals Salt Lake City, UT

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