Its latest clinical results in hand, Seattle Genetics Inc. said it would continue one program, drop one outright and move forward with the most promising phases of another.
The Bothell, Wash.-based firm moved its SGN-30 candidate into a Phase I/II study to treat Hodgkin's disease, anaplastic large-cell lymphoma or certain other lymphomas. For its SGN-15 program, it plans to continue a dose-escalation study in non-small-cell lung cancer, wait on interim results from a prostate cancer study and drop its breast cancer indication. The company is eliminating its SGN-10 program altogether.
"Strategically we are going in the right direction," President and Chief Scientific Officer Clay Siegall said. "It's certainly not a dramatic shift at all, but certainly more of a minor shift in our strategy to give us more opportunity on the other molecules that we feel have higher priority."
Data from the recently completed single-dose study with SGN-30 demonstrated that the monoclonal antibody that targets and kills CD30-expressing hematologic malignancies was safe to administer over a range of doses, but also showed evidence of antitumor activity in some patients with only a single dose. The Phase I/II, multidose study is being conducted at 10 U.S. sites.
"We would like to be able to accrue all the patients and complete the study in 18 to 24 months," Siegall said.
Seattle Genetics also is upbeat, given encouraging results from a Phase II lung cancer study of up to 60 patients receiving either the combination of SGN-15 and the chemotherapeutic agent Taxotere (docetaxel, from Aventis SA, of Frankfurt, Germany) or Taxotere alone. The company said the SGN-15 regimen has been well tolerated, leading to an intra-patient dose escalation of the compound.
The original dose level of about 200 mg/m2, based on the maximum dose used in the SGN-15 and Taxotere combination study in breast cancer, was found to be very well tolerated in non-small-cell lung cancer.
"We were encouraged by our data in which patients were given 200 mg/m2," Siegall said. "We feel we have a great opportunity to get even better data by escalating SGN-15 to its maximum tolerated dose in lung cancer, which we're trying to determine."
Still up in the air is the Phase II prostate cancer study of SGN-15. Seattle Genetics said an interim analysis would include data from patients who have already been treated and those recently enrolled. The randomized trial is designed to treat more than 120 patients.
"We have sufficient patients to do the analysis, but they have to complete their cycles of study," Siegall said, adding that he expects the company to report its complete data set at June's American Society of Clinical Oncology meeting in Chicago. "We need to see data that shows that SGN-15 is substantially better than Taxotere alone, and with a very good safety profile."
Seattle Genetics said it expects to report data from lung and prostate cancer studies in the first half of next year, as well as data from ovarian cancer studies using the same candidate. Launched in September, the ovarian cancer trial is studying SGN-15 in combination with Gemzar (gemcitabine, from Eli Lilly and Co., of Indianapolis).
But Seattle Genetics will not pursue SGN-15 in combination with Taxotere for patients with breast cancer, based on a Phase II trial.
"While there were responses in the study, and it was a very interesting data set, we felt that our data in the other diseases with SGN-15 would give us a higher likelihood for a clear registrational pathway," Siegall said. "Our data set was interesting, but we are trying to prioritize the indications in which we're testing SGN-15."
He said company strategy has long included plans to test the compound in multiple indications, then continue with the most promising while concluding the others.
Seattle Genetics also is dropping its clinical investigation of SGN-10 after completing accrual in a single-agent trial and discontinuing accrual of a trial in combination with Taxotere. The company said results of both studies, designed to evaluate the product in various solid tumors, including breast, colon and pancreatic cancer, did not meet corporate objectives.
"We have investigated SGN-10 for a number of years in some very interesting trials and pursued it vigorously in the past," Siegall said. "But we have reached a point where strategically it was no longer on the top of our priority list. We just have other product candidates whose data we're more excited about and have a higher likelihood of success."
But the dropped programs far from signal a slowdown in development at Seattle Genetics, which features a number of preclinical candidates deeper in its pipeline.
SGN-35, an antibody-drug conjugate, is being developed to treat hematologic malignancies. SGN-35 also may have utility in treating immunologic diseases such as multiple sclerosis and lupus, the company said. SGN-14 is a genetically engineered monoclonal antibody that targets CD40, a receptor expressed on hematologic malignancies such as multiple myeloma. In preclinical models, SGN-14 has been shown to have potent antitumor activity without a cytotoxic payload. SGN-17/19 is the lead product candidate from Seattle Genetics' antibody-directed enzyme prodrug therapy platform, and is targeted to a receptor that is expressed in metastatic melanoma.
Siegall said the company would in the next year seek partners for its candidates and technology, specifically its antibody-drug conjugate technology.
The company's third-quarter net loss attributable to common stockholders was $5.1 million, or 17 cents per share. Siegall said the company had about $49.3 million in cash, equivalents and short- and long-term investments as of Sept. 30.
"This gives us well over two years of funding, without other revenue through partnering dollars," Siegall said. "We are comfortable with our financial position, and we want to use our capital and resources to focus on the highest priorities we have for the largest chance of success."
Its stock (NASDAQ:SGEN) fell 9 cents Thursday to close at $2.96.