Our increasing body of preclinical research further demonstrates the power of our ADC technology to effectively target tumor cells, deliver potent drug payloads and induce antitumor activity at well-tolerated doses, said Clay B. Siegall, Ph.D., President and Chief Executive Officer at Seattle Genetics. SGN-35 is in late-stage clinical trials, including an ongoing pivotal trial for Hodgkin lymphoma. We are positioning our next ADC product candidate, SGN-75, for an investigational new drug submission in the second half of 2009 for the treatment of both hematologic malignancies and solid tumors.

SGN-35 Program

SGN-35 is an ADC utilizing Seattle Genetics' proprietary technology comprising an anti-CD30 monoclonal antibody attached to the synthetic, highly potent drug monomethyl auristatin E (MMAE) through an enzyme-cleavable linker system. The linker is designed to be stable in the bloodstream but to release the drug payload under specific conditions once inside target cells, thereby sparing non-target cells many of the toxic effects of traditional chemotherapy.

Preclinical data were presented at AACR showing superior antitumor activity of SGN-35 in Hodgkin lymphoma compared to administration of several non-targeted drugs, including vinorelbine, vinblastine and unconjugated MMAE. Due to the targeting ability of SGN-35, concentrations of MMAE within tumors were up to 30-fold higher than the non-targeted drugs. Further, MMAE tumor concentrations were 1000 fold greater than MMAE blood concentrations following dosing with SGN-35. These data demonstrate that SGN-35 effectively targets and releases its cell-killing payload, MMAE, within CD30-positive tumors. The results provide a basis for understanding the profound antitumor activity of SGN-35 at well tolerated doses in clinical trials (Abstract #3234).

SGN-35 is in an ongoing pivotal clinical trial for relapsed or refractory Hodgkin lymphoma and a planned phase II trial for systemic anaplastic large cell lymphoma. The company intends to report additional phase I clinical data with SGN-35 during an oral presentation at the American Society of Clinical Oncology annual meeting to be held May 29 to June 2, 2009.

SGN-75 Program

SGN-75 is an ADC comprising an anti-CD70 monoclonal antibody attached to the synthetic, highly potent drug monomethyl auristatin F (MMAF). Data presented at AACR demonstrate CD70 expression on a variety of solid tumors, including pancreatic, larynx/pharynx, ovarian, skin, lung and colon cancer. This presentation adds to data previously reported by Seattle Genetics on CD70 expression in multiple hematologic malignancies, renal cancer and glioblastoma. SGN-75 was also shown to induce potent antitumor activity in models of pancreatic and ovarian cancer, underscoring its therapeutic potential in a range of carcinomas (Abstract #4652).

seattlegenetics