ssb on asco: Amgen (AMGN)/Abgenix (ABGX): Another EGF-R inhibitor of interest is the
fully human monoclonal antibody called ABX-EGF being developed by Amgen and
Abgenix. Full details from a Phase II study of Amgen/Abgenix's ABX-EGF as a
monotherapy in refractory colorectal cancer patients will be presented at
this meeting. As a reminder, interim results were presented on the first 44
patients (40 evaluable) at the 2003 ASCO meeting, which demonstrated a 9-10%
response rate, a similar response rate that has been demonstrated with
commercially-available Bristol-Myers Squibb's Erbitux, a chimeric monoclonal
antibody. Last year, this study was expanded to enroll approximately 100
patients, including patients failing an Eloxatin-based chemotherapy regimen
called FOLFOX, which has been become more broadly utilized. As a reminder,
in late January, Abgenix announced that a pivotal Phase III trial of ABX-EGF
as a monotherapy in advanced colorectal cancer patients had been initiated by
partner, Amgen. A second pivotal study has also been initiated in Europe.
In our opinion, the initiation of these pivotal studies imply that the
results from the Phase II study were sufficiently positive to proceed with
these studies. Amgen and Abgenix indicated that the study design was
reviewed and approved by the FDA under a Special Protocol Assessment (SPA)
with the plan to submit an application under accelerated approval guidelines.
As a reminder, an SPA provides clear regulatory guidelines of approval if a
study as followed under its submitted design achieves the targeted endpoints.
We believe the study is designed to be conducted in patients who have become
refractory to oxaliplatin (Sanofi Synthelabo's Eloxatin) as a third line
therapy. Earlier this year, Eloxatin was approved as a first line treatment
for metastatic colorectal cancer in combination with Fluorouracil (5-FU) and
Leucovorin (LV). While the exact details of the pivotal study for ABX-EGF
have not been provided, we believe that the trial is targeted to enroll a
couple of hundred patients with potential endpoints of response rate,
duration of response and tumor progression. Other endpoints may include
survival. We estimate that the study is likely to complete enrollment this
year with a potential for submission next year leading to a possible approval
in late 2005 or early 2006. |
