ASCOA new multicenter international trial is comparing standard
systemic pain management with intrathecal therapy for chronic cancer
Thomas Smith, MD, of the Department of Medical Oncology, Medical
College of Virginia, Richmond, discussed the study design at a poster
session of the 36th Annual Meeting of the American Society
of Clinical Oncology, New Orleans.
Previous studies have shown that intrathecal opiate therapy using an
implantable drug delivery system relieves pain in 64% to 95% of
chronic cancer pain patients with opioid dosages 200 to 300 times
lower than used in systemic therapy, but, he noted, these studies
have not been controlled against adequate systemic therapy.
This randomized controlled trial is comparing the effectiveness of
Comprehensive Medical Management (CMM), defined as standard pain
management using all available non-intraspinal techniques, with
intrathecal therapy using the implantable Medtronic SynchroMed Drug
Delivery System (IDDS) plus CMM. Treatments such as radiation for
palliation, chemotherapy for palliation, bisphosphonates for pain,
etc, will be allowed in both study arms.
To date, the trial has enrolled 79 of a planned 200 patients with
moderate to severe chronic pain secondary to cancer or cancer
therapy, Dr. Smith told ONI. He said that an interim analysis
of results in the first 100 patients should be ready for presentation
at next years ASCO.
The primary endpoint is improvement in pain scores, and the study is
powered to detect a 20% difference in pain scores using a 0 to 10
visual analog scale (VAS). Equal pain scores with improved opioid
side effect scores would also be an acceptable outcome, Dr. Smith
said. Secondary objectives are quality of life, drug side effect
profile, and cost of care.
He noted that in terms of cost, fewer hospital days and expensive
oral/trans-dermal drugs in the CMM group may offset pump and implant
costs in the IDDS group.
Eligible patients have end-stage cancer requiring palliation only and
a life expectancy of 3 months or longer. They must have moderate to
severe cancer pain (VAS of 5 or more) uncontrolled by systemic
opiates equivalent to at least 200 mg of oral morphine daily, or with
intolerable, therapy-resistant side effects at lower opiate doses.
Dr. Smith said that study data will be collected at baseline, 2, 4,
6, 8, 10, and 12 weeks, and then at 4, 5, and 6 months after
enrollment, for a total of 6 months of follow-up.
Crossover is allowed 1 month after enrollment in either arm if
patients continue to have moderate to severe pain despite receiving
the maximum therapy available in their treatment arm. All patient
data will be analyzed according to intention to treat.