Premenopausal Estrogen Levels Linked to Higher Death Rate Among Women Receiving Chemotherapy for Advanced NSCLC

Cell Therapeutics, Inc (CTI) announced that data presented at the 2007 Annual Meeting of the American Society for Clinical Oncology (ASCO), held in Chicago on June 1-5, provides independent supportive data validating the potential survival benefit of paclitaxel poliglumex (Xyotax) over standard chemotherapy in the treatment of advanced non-small-cell lung cancer (NSCLC) in women whose estrogen levels are in the normal range for premenopausal women.

"We now have independent confirmation from large prospective cooperative group studies that normal premenopausal estrogen levels are associated with a poorer response to standard chemotherapy for advanced NSCLC," said James A. Bianco, MD, president and CEO of CTI. "This is the first time that this biomarker has been shown to have a strong negative correlation with survival in lung cancer and underscores the relevance of the significant survival advantage we observed with Xyotax in this subset of women in our STELLAR trials. We believe our confirmatory gender-specific first-line trial (PGT307) qualifies for inclusion in the FDA's recently announced Critical Path Initiative as the first such study to explore the role of a negative risk factor—estrogen—and its potential positive metabolic interaction with a biologically enhanced chemotherapeutic, Xyotax."

The STELLAR trials (Selective Targeting for Efficacy in Lung cancer Lower Adverse Reactions), conducted by CTI, were among the largest randomized, phase III trials for either first- or second-line performance status 2 NSCLC, treating more than 1,700 patients.

Free Estradiol Levels in Men With NSCLC

In another STELLAR analysis, reported in an ASCO poster presentation, Helen Ross, MD, a thoracic oncologist in Portland, Oregon, presented data that show free estradiol (E2) levels in serum are prognostic in men as well as women with NSCLC. A retrospective analysis of estradiol levels from male participants in STELLAR 3 and 4 was conducted using stored serum samples. The analysis showed that men with higher levels of free E2 have shorter survival, consistent with the shorter survival noted in premenopausal women, compared to older women.

"Retrospective analyses of several datasets now show a consistent detrimental effect of estrogen on NSCLC survival in women and in men," said Dr. Ross. "Prospective trials with laboratory correlative studies will help define ways to exploit steroid hormone pathways in NSCLC treatment design using drugs like Xyotax to overcome negative estrogen effects on outcome, particularly in women."

Toxicity and Survival by Sex in NSCLC Patients

Kathy Albain, MD, professor of medicine and director of the thoracic oncology and breast clinical research programs at Cardinal Bernardin Cancer Center, Maywood, Illiniois, presented a CTI-sponsored retrospective analysis of data from Southwest Oncology Group (SWOG) trials that showed younger women, under 60 years old, with advanced NSCLC have shorter survival than older women. As part of her presentation, she included information about estrogen levels in female patients on first-line phase III Xyotax trials (STELLAR 3, STELLAR 4, and PIONEER) that showed estrogen levels, rather than age, are a determinant factor for survival. Her analysis demonstrated that age had no effect on survival if patients with comparable estradiol values were considered.

"We believe this confirmatory data shows women with higher estrogen levels have worse survival, irrespective of age," said Jack W. Singer, MD, chief medical officer at CTI. "We look forward to advancing our upcoming phase III trial, PGT307, to prove enhanced efficacy for Xyotax in this high-risk patient group."