By Grant Zeng, CFA
On June 3, 2013 at the ASCO meeting, Galena Biopharma (GALE) provided product pipeline update. The Company is making progresses in three clinical programs.
NeuVax Continues to Demonstrate Durable Response Rates
At the ASCO meeting, GALE presented a poster entitled: "Biomarker Correlation to Clinical Response in Phase I/II Trials of the Adjuvant Breast Cancer Vaccine, NeuVax (nelipepimut-S or E75)".
The poster presentation examined the relationship between in vitro immunologic response (IR) and clinical recurrence (CR) after five years of follow-up in patients with breast cancer. The study looked at the levels of E75 specific T-cells as measured by the dimer assay and correlated the IR with clinical benefit, or lack of recurrence. The dimer assay is a way of counting E75-specific killer T cells that are induced by the NeuVax vaccine. The vaccine was administered in the adjuvant setting to prevent recurrence in breast cancer patients rendered disease-free following standard-of-care therapy. Evaluable patients (n=187) combined both the SN-33 (node-positive) and SN-34 (node negative) patients from the Phase I/II NeuVax trials. In the study, the majority of the recurrences occur in women that had lower absolute levels of NeuVax-specific T cells or more modest increases in their NeuVax-specific T cells.
The study concluded that in completed Phase I/II trials of NeuVax, patients who exhibit robust in vitro IR have lower recurrence rates. This finding suggests that nelipepimut-specific CTL clonal expansion is a valid biomarker for CR in patients treated with NeuVax. In the SN-33 trial, the 60-month Landmark Analysis demonstrated a 5.6% recurrence rate with NeuVax vs. a 25.9% recurrence rate in the control arm—a recurrence reduction of 78.4%.
NeuVax Companion Diagnostic Increases Accuracy
On December 6, 2012, GALE announced a partnership with Leica Biosystems to develop a companion diagnostic for Galena's NeuVax (nelipepimut-S or E75) breast cancer therapeutic.
Leica Biosystems is a global leader in workflow solutions and laboratory automation for anatomic pathology, bringing clinicians and researchers high workflow efficiency and confidence in cancer diagnostics. Leica Biosystems provides a comprehensive product range with easy-to-use and consistently reliable solutions for the entire laboratory.
Leica's Bond Oracle™ HER2 IHC System companion diagnostic will be used to support the selection of the appropriate patients for the NeuVax Phase III PRESENT study. Bond Oracle™ HER2 IHC System is an FDA cleared semi-quantitative immunohistochemical (IHC) assay to determine HER2 (Human Epidermal Growth Factor Receptor 2) oncoprotein status in breast cancer tissue processed for histological evaluation. NeuVax targets HER2 negative patients (IHC 1+, or 2+ and FISH < 2.2) who achieve remission with current standard of care, but have no available HER2-targeted adjuvant treatment options to maintain their disease-free status.
At the ASCO meeting, GALE reported preliminary results from Leica Biosystems entitled, "Bond Oracle(TM) HER2 IHC assay for identifying low to intermediate HER2-expressing breast cancer."
In Galena's Phase III PRESENT study, Leica's Bond Oracle HER2 IHC System is under evaluation to reliably identify IHC HER2 1+ and 2+ cases by correlating to independent analytical measures of HER2 expression. To date, no companion diagnostic test is validated to differentiate HER2 at these levels of expression.
Testing by Leica Biosystems is ongoing to demonstrate the relationship between HER2 receptor load, HER2 copy number, and HER2 IHC status on four-assay control breast cancer cell lines. Testing is also underway to show that HER2 mRNA expression correlates with IHC staining with the BOND Oracle HER2 IHC Assay in breast cancer tissue samples. The testing will hopefully demonstrate that the Bond Oracle HER2 IHC assay can improve the discrimination of HER2 protein expression (IHC 1+, 2+) in breast cancer tumors and can be used to identify patients for new treatments in development, such as NeuVax.
Update on FBP Phase I/IIa Trail
GALE also provided an update on the first portion of the Phase I/IIa FBP (E39) clinical trial which has enrolled 20 patients to date.
As a reminder, GALE initiated its Phase I/IIa study of its Folate Binding Protein (E39) vaccine in two gynecological cancers: ovarian and endometrial adenocarcinomas in Feb, 2012.
The FBP vaccine consists of the E39 peptide combined with the immune adjuvant, granulocyte macrophage-colony stimulating factor (GM-CSF). The Phase I/IIa study will test whether the FBP vaccine is safe and effective at inducing an anti-tumor immune response. Furthermore, the study will determine the optimal dose of the vaccine to produce this immunity most efficiently, and whether immunity to FBP will prevent clinical recurrence in patients with ovarian and aggressive endometrial cancer.
FBP is over-expressed (20-80 fold) in more than 90% of ovarian and aggressive endometrial cancers, as well as 20-50% of breast, lung, colorectal, and renal cell carcinomas. FBP has very limited tissue distribution and expression in non-malignant tissue and has many years of validation as an ideal immunotherapy target.
In the trial, E39 + GM-CSF is being administered in the adjuvant setting with the goal of preventing recurrences in high-risk, endometrial (EC) and ovarian cancer (OC) patients rendered disease-free with standard-of-care therapy. The Phase I/IIa trial is being performed initially as a 3x3, dose-escalation, safety trial enrolling EC and OC patients with tumors expressing any level of FBP. HLA-A2+ patients are enrolled into the vaccine group (VG) while HLA-A2- patients are being followed prospectively as the untreated control group (CG). Six monthly intradermal inoculations (R1-R6) of 100/500/1000mcg of E39 + 250 mcg GMCSF (immunoadjuvant) are administered to the VG during the primary vaccine series (PVS). Local reactions (LR) are measured as the orthogonal mean (OM), after each inoculation. IR in the VG is assessed in vivo by delayed type hypersensitivity (DTH) test, measured as the OM. DTH is measured pre-vaccination (R0) and after the PVS (R6).
The study arms are well-balanced with no differences in age, grade, stage III, or node positivity status between groups. Overall, E39 was well-tolerated and the study to date has demonstrated a 11.1% recurrence rate with E39 vs. a 27.3% recurrence rate in the control group—a recurrence reduction of 59.3%.
A copy of the full research report can be downloaded here >> Galena Biopharma Report
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