Prospect reports positive interim results from Phase II leukemia trial

The ongoing Phase II single-arm study of GCS-100 given intravenously as a single agent to relapsed chronic lymphocytic leukemia (CLL) patients is designed to evaluate the effects of GCS-100 on various markers of apoptosis and to assess clinical activity and safety.

Patients enrolled have had between one and two prior therapy regimens, which included chlorambucil, fludarabine, cyclophosphamide and rituximab in combination or as a single agent. Of the nine patients enrolled to date, six are evaluable for biological marker activity and five are evaluable for clinical activity.

The primary objective of the study is to evaluate the effect of GCS-100 on biomarkers of apoptosis in patients’s CLL cells. Caspases -8 and -9 were activated in the CLL cells from all six evaluable patients, as measured by western blot analysis. DNA fragmentation in patients’ CLL cells also was observed, strengthening the evidence that GCS-100 induces apoptosis.

The secondary objective of the study is to evaluate the effect of GCS-100 on peripheral blood leukocyte counts, which are aberrantly elevated in CLL patients. Of the five evaluable patients, two had significant reductions in leukocyte counts compared with baseline levels, including one with a 76% reduction and another with a 42% reduction and a reduction in lymph node size.

The promising interim results from this ongoing clinical trial indicate that single-agent GCS-100 induces apoptosis in patients’ CLL cells, reduces leukocyte count in some patients and is generally well tolerated.

GCS-100 targets galectin-3, a protein over-expressed in cancer cells that promotes their survival, proliferation and metastasis.