Possible Anti-Leukemia Activity in Liposomal Grb-2 Trial

Bio-Path Holdings, Inc. has completed treatment of the first dosage cohort in the company’s Phase I clinical trial of BP-100-1.01 (Liposomal Grb-2), a systemic treatment for blood cancers including acute myeloid leukemia (AML), chronic myelogenous leukemia (CML), acute lymphoblastic leukemia (ALL) and myelodysplastic syndrome (MDS).

The trial is being conducted at the MD Anderson Cancer Center. The drug was well tolerated with no treatment-related serious adverse events reported and data suggests some possible anti-leukemia activity.

Bio-Path’s drug delivery technology involves microscopic-sized liposome particles that distribute nucleic acid drugs systemically and safely throughout the human body, via simple intravenous infusion. The delivery technology can be applied both to double stranded (siRNA) and single stranded (antisense) nucleic acid compounds.

The adaptor protein Growth Receptor Bound protein-2 (Grb-2) is utilized by oncogenic tyrosine kinases to induce cancer progression. Suppressing the function or expression of Grb2 should interrupt its vital signaling function and have a therapeutic application in cancer. BP-100.1.01 is a neutral-charge, liposome-incorporated antisense drug substance designed to inhibit Grb-2 expression.

A total of 14 patients were enrolled in the first cohort of the study. All patients had failed prior therapies. Of the 14 patients, one patient withdrew prior to treatment and 13 were treated. Of the treated patients, six were evaluable and seven failed to complete a full 28-day cycle because of disease progression. Liposomal Grb-2 is systemically delivered by intravenous injection. Patients received a dose of 5 mg/m2 twice a week for four weeks, for a total of eight doses.

Preliminary results suggest that Liposomal Grb-2, at a dose of 5 mg/m2 is well tolerated. In addition, there is already a suggestion of possible anti-leukemia activity, even at the low starting dose used in the first cohort. Of the six evaluable patients, lab parameters for blasts and bone marrow demonstrated possible anti-leukemia activity.

Two patients had transient improvement and/or stable disease and received a total of five cycles each, representing five months on treatment with the drug. In addition, two patients had transient improvement on leukemia cutis lesions.

In addition to the six evaluable patients, a patient with CML blast phase who had failed all available TKI (tyrosine kinase inhibitor) and other experimental options showed a significant reduction in blasts from 81% to 4%. The patient discontinued study treatment due to progression of disease into the central nervous system.

“The suggestion of possible anti-leukemia activity, in particular, was an unexpected and very positive result, especially because of the low dose used in the cohort,” says Peter Nielsen, president and chief executive officer of Bio-Path.

Release Date: August 11, 2011
Source:Bio-Path Holdings, Inc.