Promising interim results of a double-blind
placebo-controlled trial of the monoclonal antibody
OvaRex in 345 patients with ovarian cancer were presented at the 37th annual
meeting of the American Society of Clinical Oncology (ASCO) in San Francisco.
Dr. Jonathan Berek, MD, PhD, professor and vice chair at the University of
California-Los Angeles Medical Center and coprincipal investigator of the
study made the presentation.
High-Risk Patients Show Greatest Benefit
Among the highlights of Dr. Berek’s presentation was the
recent breakthrough in the understanding of the correlation between circulating
levels of the ovarian tumor marker CA-125 and the efficacy of OvaRex.
At the initiation of the trial, the CA-125 levels of
participants were assumed to be in the normal range for this patient population.
One notable observation was that patients on the high end of this range are at
significantly increased risk of relapsing. OvaRex is proving to be most
beneficial in these patients.
The proportion of high-risk patients who achieved a
disease-free survival of 6 months is significantly higher (P = .0397) among
those treated with OvaRex (79%) than among those receiving placebo (39%).
Approximately 50% of patients developed a specific immune
response to OvaRex that correlated directly with clinical benefit.
Results of Phase II Trials
In addition to the interim analysis, AltaRex Inc (manufacturer
of OvaRex) has analyzed final data from two phase II trials. These results
demonstrate that in late-stage ovarian cancer patients with recurrent disease,
treatment with OvaRex can provide comparable efficacy to salvage chemotherapies
but without the associated toxicities.
An analysis of the primary end point of time to disease relapse
for all 345 patients in the lead trial is scheduled to begin in the
third-quarter of this year. Clinical data from this trial and five other
complementary and supporting trials will form the basis for a simultaneous
filing for product approval with both the United States and Canadian regulatory