Transcript IMATINIB X 36 Months

Twelve versus 36 months of adjuvant
imatinib as treatment of operable GIST with
a high risk of recurrence: Final results of a
randomized trial (SSGXVIII/AIO)
Authors: Joensuu H et al.
Reviewed By: Dr. Vincent Tam
Abstract: ASCO 2011 Abstract 1
Date posted: June 2011
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Study Design
N= 400 (1:1 randomization)
Stratification:
1) R0 resection, no tumor rupture
2) R1 resection, tumor rupture
Treatment A:
IMATINIB 400mg daily x 12 months
R
Treatment B:
IMATINIB 400mg daily x 36 months
Primary Outcome: RFS
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INCLUSION CRITERIA
- Histologically confirmed GIST, KIT-positive
- High risk of recurrence according to the
Modified Consensus Criteria:
• Tumor diameter > 10cm or
• Tumor mitosis count >10/50 HPF or
• Size >5cm and mitosis count >5/50 HPF or
• Tumor rupture spontaneously or at surgery
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RESULTS*
IMATINIB
X 12
Months
IMATINIB
X 36
Months
Hazard
Ratio
p-value
5Y-RFS
(%)
47.9%
65.6%
0.46
p<0.0001
5Y-OS (%)
81.7%
92.0%
0.45
p=0.019
* Intention-to-treat analysis
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TOXICITY
IMATINIB
X 12 Months
(n = 194)
IMATINIB
X 36 Months
(n = 198)
P
Any adverse event
99%
100%
0.24
Any grade 3/4 event
20%
33%
0.006
Grade 3/4 periorbital
edema
1%
1%
1.00
Grade 3/4 fatigue
1%
1%
0.62
Grade 3/4 diarrhea
1%
2%
0.37
Discontinued imatinib,
no GIST recurrence
13%
26%
0.001
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STUDY COMMENTARY
• Well designed adjuvant study which
demonstrated a statistically significant increase
in RFS and OS with 36 months of imatinib
• Higher rate of discontinuing imatinib prior to
complete course in 36 month arm due to
adverse events, but also due to “other reasons”
possibly related to patients not willing to take a
drug for years without any evidence of disease
• Is there additional benefit of continuing
imabinib beyond 36 months, perhaps
indefinitely?
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BOTTOM LINE FOR CANADIAN MEDICAL
ONCOLOGISTS
• The standard of care for adjuvant treatment of
GIST at high risk of recurrence is now 3 years of
imatinib
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