Seattle and Genmab Sign Antibody-Drug Conjugate Agreement in Cancer

Seattle retains option to codevelop resulting candidates at end of Phase I development.

Genmab has signed a second antibody-drug conjugate (ADC) research collaboration with Seattle Genetics. The new agreement gives the Danish firm rights to use Seattle’s ADC technology in combination with a preclinical antibody candidate, HuMax-CD74, which targets CD74 expressed on a range of hematological and solid cancer cells.

Under terms of the new deal Genmab will be responsible for research, manufacturing, preclinical development, and Phase I clinical evaluation of ADCs under the collaboration. Seattle will receive an up-front payment and funding for research support provided to Genmab. Seattle in addition has the right to exercise a co-development and co-commercialization option for any resulting ADC products at the end of Phase I clinical development. If the firm does opt into an ADC program it will make a payment to Genmab and the firms will then share all future costs and profits on a 50:50 basis. If Seattle decides not to opt in to any ADC products, it will receive a payment from Genmab and additional milestones and mid-single-digit royalties on future worldwide net product sales.

Seattle and Genmab signed their initial ADC collaboration in December 2010. Under terms of this deal Genmab is using Seattle’s ADC technology in combination with its own HuMax-TF antibody that targets the tumor-expressed tissue factor (TF) antigen.

Seattle’s ADC technology is designed to target monoclonal antibody-drug conjugates specifically to tumor cells. The platform uses synthetic cytotoxic auristatins and stable linker systems that attach auristatin to the antibody. The linker systems are designed to be stable in the bloodstream and only release the cell-killing agent once inside targeted cancer cells.

Seattle’s own lead, registrational-stage candidate, brentuximab vedotin (SGN-35), is being developed in partnership with Millennium. The CD30-targeting ADC was submitted to FDA for approval in February as a treatment for both relapsed or refractory Hodgkin lymphoma, and relapsed or refractory systemic anaplastic large cell lymphoma. A Phase III trial is separately evaluating brentuximab vedotin for the prevention of post-transplant Hodgkin lymphoma relapse. The ADC is also being assessed in a Phase II study for the retreatment of Hodgkin lymphoma and systemic anaplastic large cell lymphoma, and Phase I trials as front-line therapy for both cancers, in combination with chemotherapy. Under terms of the deal with Millennium Seattle retains full commercialization rights to brentuximab vedotin in the U.S. and Canada, while its partner has exclusive rights to commercialize the product in all other countries. Seattle says Millennium plans a first half 2011 marketing authorization submission to the European regulators.

Seattle’s early clinical-stage pipeline includes ADC candidates against renal cell carcinoma, pancreatic and prostate cancers, and CD19+ hematologic malignancies, together with engineered monoclonal antibodies targeting non-Hodgkin lymphoma, multiple myeloma, and autoimmune diseases.