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one of these, dacetuzumab, after it failed in a mid-stage clinical trial of 224 patients with diffuse large B-cell lymphoma. Another naked antibody from Seattle Genetics, SGN-33, is in a mid-stage trial for patients with acute myeloid leukemia. Results from that trial are expected before the end of June.
“Expectations [for SGN-33] are very low given the tough nature of the disease and lack of convincing earlier-stage data,” said JP Morgan analyst Cory Kasimov in a note to clients last month.
Siegall doesn’t want to go quite so far as to declare naked antibodies dead, noting that Seattle Genetics hasn’t decided what to do yet with dacetuzumab, and it doesn’t yet have the data from SGN-33.
“If you are talking about the future, I’d say yes, it’s unlikely that we’ll move another naked antibody into the clinic,” Siegall says.
To that end, Siegall noted he has high hopes for a second antibody-drug conjugate in the clinical pipeline, known as SGN-75. There’s a “high likelihood” the drug will generate clinical trial results in 2010, Siegall says. Plus, Seattle Genetics is looking to introduce a third member of the antibody-drug conjugate class into clinical trials this year.
All told, between Seattle Genetics’ internally developed antibody-drug conjugates and those from its partners, “I would bet that by the end of 2011, there will be close to 10 antibody drug conjugates in clinical trials,” Siegall says.
But Seattle Genetics has more than just antibody-drug conjugates in mind when it talks about making antibodies more potent. The company has also developed another technique, which it calls sugar-engineered antibody technology (SEA).