Seattle Genetics, Inc. has decided to discontinue development of SGN-15, a first-generation antibody-drug conjugate (ADC). The company has reported data from its phase II clinical trials of SGN-15 at the 11th World Conference on Lung Cancer being held in Barcelona, Spain.

According to the company release, its decision to discontinue development of SGN-15 was taken only to focus on advancing its other pipeline programs and second-generation ADC technology. Seattle Genetics currently has two product candidates in clinical trials, SGN-30 and SGN-40, as well as multiple preclinical programs, including two that are expected to enter clinical trials over the next twelve months, SGN-35 and SGN-33, and two that are IND candidates in 2007, SGN-70 and SGN-75.

The phase II studies presented at the World Conference on Lung Cancer were designed to assess the optimal dosing schedule of SGN-15 in combination with Taxotere, a chemotherapy treatment, in patients with non-small cell lung cancer (NSCLC). The data suggest that the administration of SGN-15 three days prior to Taxotere results in greater synergy and drug effect than when the combination is administered simultaneously.

"Our clinical data confirm what we observed in our preclinical studies, which indicated that dosing SGN-15 prior to Taxotere enhances the therapeutic effect of the combination as compared to concurrent administration," said Clay B. Siegall, president and CEO at Seattle Genetics. "However, given the strength and diversity of the other products in our pipeline, we have decided not to continue development of SGN-15 and instead will evaluate out-licensing opportunities for the programme," he added.

"This decision enables us to focus our resources and development activities on advancing the many other promising programs in our pipeline. We are particularly excited about our lead clinical programs, SGN-30 and SGN-40, as well as SGN-33, a humanized anti-CD33 antibody that we plan to move into clinical trials before the end of 2005," Dr. Siegall said adding, "In addition, we are making continued progress with our industry-leading second-generation ADC technology, which utilizes stable, enzyme-cleavable linkers to target highly potent auristatin derivatives to tumour cells. We employ this second-generation ADC technology in our SGN-35 and SGN-75 product candidates, as well as partner the technology with leading biotechnology and pharmaceutical companies such as Genentech, CuraGen, Bayer, MedImmune and, most recently, PSMA Development Company."