Title: Jon Trent, MD, PhD
1Gastrointestinal Stromal Tumor Life Fest 2006
Jon Trent, MD, PhD Assistant Professor Dept. of
Sarcoma Medical Oncology The University of Texas,
M. D. Anderson Cancer Center jtrent_at_mdanderson.o
rg
www.ctos.org
2Background
3GIST Overview
- Most common GI sarcoma
- 0.2 of all GI tumors, but 80 of GI sarcomas
- Distinct clinical and histopathologic entity
- Highest incidence in the 40-60 year age group
- Similar male/female incidence
- Many misclassified as leiomyosarcoma
- GIST have an incidence of 14.5 per million
annually and a prevalence of 129 per million - Clinical presentation is variable
- pain, hemorrhage, anemia, anorexia, nausea,
perforation
4Median Overall Survival in Metastatic GIST
5Chemotherapy TrialsAdvanced GIST
Number of Partial
Response Regimen Patients n () DOX
DTIC 43 3 (7) DOX DTIC / IF 60 10
(15) IF VP-16 10 0 (0) Paclitaxel 15 1
(7) Gemcitabine 17 0 (0) Liposomal
DOX 15 0 (0) DOX 12 0 (0) DOX or
docetaxel 9 0 (0) High-dose IF 26 0
(0) EPI IF 13 0 (0) Various 40 4
(10) DTIC/MMC/DOX/ CDDP/GMCSF 21 1
(5) Temozolamide 19 0 (0) TOTAL 280 19
(6.8)
6GIST Overview
- GIST share several characteristics with ICC
- Neuromuscular pacemaker cell of the GI tract
- Found in myenteric plexus throughout GI tract
- Expression of CD34 in 80 of cases
- Expression of KIT (CD117) in 95 of cases
ICC interstitial cells of Cajal. Corless et al.
J Clin Oncol. 2004223813. Sircar et al. Am J
Surg Pathol. 199923377.
7Kit Receptor Structure
Extracellular Domain (exon 9, 10.2)
Juxtamembrane Domain (exon 11, 66.1)
ATP
Tyrosine Kinase Domain I (exon 13/14, 1.2)
Tyrosine Kinase Domain II (exon 17, 0.6)
common mutation site
8Kit Receptor Phenotype
ADP P
ATP
Proliferation Survival Adhesion Invasion Metastasi
s Angiogenesis
9Imatinib Mesylate
Formula C30H35N7SO4 MW 589.7
Inhibitor of selective tyrosine
kinases bcr-abl PDGF-R c-kit
- Rational drug design
- 2-phenylamino pyrimidine
- Based on structure of ATP binding site
- Highly water soluble
- Oral bioavailability
Potent (IC50 ? 0.1?M)
10Kit Receptor Phenotype
ATP
Imatinib
Proliferation Survival Adhesion Invasion Metastasi
s Angiogenesis
imanitib contact point
11(No Transcript)
12The First GIST Patient Histology
HE (at diagnosis) HE Ki 67 CD117
One month of therapy
Pretreatment
Joensuu H et al. N Engl J Med. 20013441052-1056.
13What is the chance of imatinib helping me?
14Clinical Trials of Imatinib in GIST
Courtesy Dejka Steinert, M.D.
15Phase III dose-randomized study of Imatinib
mesylate (Gleevec, STI571) for GIST NA
Intergroup S0033 early results. Robert S.
Benjamin, UT MD Anderson Cancer Center and SWOG,
Houston, TX, Cathryn Rankin, SWOG, Christopher
Fletcher, Dana Farber Cancer Institute, Charles
Blanke, SWOG, Margaret von Mehren, ECOG, Robert
Maki, CALGB, Vivien Bramwell, NCIC, Laurence
Baker, SWOG, Ernest Borden, SWOG, George D.
Demetri, Dana Farber Cancer Institute, CALGB, as
the North American Sarcoma Intergroup
Benjamin et al, ASCO 2003
16North American Sarcoma Intergroup Schema
C R O S S O V E R
R A N D O M I Z A T I O N
Low Dose Imatinib 400 mg/d
High Dose Imatinib
Off Protocol Treatment
Progression
Progression
High Dose Imatinib 800 mg/d
Progression
Off Protocol Treatment
17EORTC Phase III Imatinib for Advanced
GISTSurvival Benefit
Verweij, et al 2004
18How long do I take imatinib?
19The First GIST Patient Histology
HE (at diagnosis) HE Ki 67 CD117
One month of therapy
Pretreatment
Joensuu H et al. N Engl J Med. 20013441052-1056.
20Phase III Trial US Intergroup S0033 Time to
Progression on Crossover
21Time to Tumor Progression
100 90 80 70 60 50 40 30 20 10 0
Sunitinib (N207)Placebo (N105)
Hazard ratio 0.335Plt0.00001
Median (95 CI)6.3 (3.7, 7.6)1.5 (1.0, 2.3)
Estimated TTP probability ()
0 3 6 9 12
Time (Months)
22Discontinuation of Imatinib Increases the Risk of
Progression (BFR14)
100
Continuous therapy (n23)
80
P0.0001
60
of patients
40
Stop therapy (n25) Median PFS 6 months
20
0
16
14
12
10
8
6
4
2
0
Months after randomization
- Patients who achieved clinical benefit after 12
months were randomized to continue or to stop
imatinib mesylate therapy - Randomization has been suspended
Blay et al. Proc Am Soc Clin Oncol. 200423815.
Abstract 9006.
23What dose of imatinib should I take?
24EORTC Phase III Imatinib for Advanced
GISTProgression-free Survival Benefit
Verweij, et al 2004
25Progression-free Survival By Imatinib Dose
Kit Exon 11 Mutation
26Progression-free Survival By Imatinib Dose
Kit Exon 9 Mutation
27Kit Mutation in GISTBenefit from 800mg Imatinib
Heinrich et al, ASCO 2050
28Tell me about the side effects..
29Side effects 400 vs. 800 mg
Verweij et al, 2004
30Interruptions and Reductions of Therapy
31North American Intergroup Phase III Study of
Imatinib in Advanced GIST
Dileo et al, ASCO 2005
32How do I know if imatinib is working?
33Confirmed Overall Responses with Gleevec
34Best Response (B222)
35 Time to PR by RECIST
Cumulative incidence of CT responses
2 Months
1
0.9
0.8
3 Months
0.7
6 Months
0.6
0.5
CI
0.4
0.3
400 mg
800 mg
0.2
0.1
0
0
0.5
1
1.5
2
Years
Verweij et al, ASCO 2003
36CT Scan Results
Jun 27, 2000
Oct 4, 2000
Before Imatinib
After Imatinib
37Background (cont)
Decrease in GIST intravenous contrast uptake
after patient is treated for 8 weeks with
imatinib mesylate
38Overall Survival by Best Response(B222, Kaplan
Meier Estimate)
SD (n23) Median n/a
PD (n17) Median 36 wks
PR (n98) Median 248 wks
CR (n2 median OS n/a) and unknown/NE (n7
median OS 144 wks) not included
39Effects of Imatinib on GISTCT and PET findings
1/18
3/23
1/26
3/22
10/8
40Pseudoprogression Early During Treatment With
Imatinib Mesylate
Choi et al. AJR Am J Roentgenol. 20041831619.
41Effects of Imatinib on GISTCT findings
1/12
3/30
5/24
42Modified RECIST for GISTCT Size Density (Choi)
- Tumor size decrease of gt10 or tumor density
decrease of gt15 were highly correlated with
decrease in SUV by gt70 to a value lt2.5 on PET. - RECIST criteria substantially underestimate, at
least initially, the value of therapy with
imatinib for GIST.
43What is genotyping?
44Kit Receptor Structure
Extracellular Domain (exon 9, 10.2)
Juxtamembrane Domain (exon 11, 66.1)
ATP
Tyrosine Kinase Domain I (exon 13/14, 1.2)
Tyrosine Kinase Domain II (exon 17, 0.6)
common mutation site
45Kit Mutation in GISTResponse to Imatinib (n332)
46Overall Survival by Genotype(B222, Kaplan Meier
Estimate)
Exon 11
Exon 9
No Mutation
47Kit-Negative GIST
Blackstein et al, ASCO 2005
48How will you know whether my GIST comes back?
49Type of Progression
Limited progression
Nodular progression
Stable disease
Widespread progression
50Limited Progression
51Resistance to Imatinib Mesylate Recognition of
Clonal Evolution
Courtesy of Dr. G.D. Demetri.
52Secondary Mutation
Heinrich et al, JCO 2006
53What do I do if my GIST is resistant to imatinib?
54Therapy by Type of Progression
- Limited or Nodular Progression
- Hepatic Artery Embolization
- Hepatic Radio-frequency Catheter Ablation
- Surgical Resection
- Widespread progression
- Increase Imatinib to 800 mg daily
- Sunitinib
- Clinical Trial
55Hepatic Artery Embolization
Pre- embolization
Post- embolization
Courtesy of Dr. R. DeMatteo.
56Metastatic GIST Trials
- Phase II studies in advanced GIST
- AMN107 Kit and Abl inhibitor
- AMG 706 High affinity Kit inhibitor and VEGFR
inhibitor - Dasatinib High affinity Kit, Abl and Src
inhibitor (other targets) - Sorafinib High affinity Kit inhibitor
- Perifosine (AKT/MapK/p21 inhibitor)Imatinib
inhibit PI3K activation of AKT - G3139 (antisense bcl-2) Imatinib restore
apoptosis - RAD0001 (mTOR inhibitor)Imatinib
- Phase I studies in GISTs and other solid tumors
- IGF-1R inhibitor
- TRAIL
57SU11248 in Advanced GISTSunitinib Malate, Sutent
Stop imatinib4 weeks
R A N D O M I Z E
SU11248 (207)
PD
PD on imatinib
6 weeks
Off
PD
Placebo (105)
58SU11248 in Advanced GISTObjective Response Rates
Escalation of imatinib from 400 mg to 800 mg
daily.
59Time to Tumor Progression
100 90 80 70 60 50 40 30 20 10 0
Sunitinib (N207)Placebo (N105)
Hazard ratio 0.335Plt0.00001
Median (95 CI)6.3 (3.7, 7.6)1.5 (1.0, 2.3)
Estimated TTP probability ()
0 3 6 9 12
Time (Months)
60Should I take imatinib after my GIST was removed?
61Survival of GIST Patients by Primary Tumor Size
DeMatteo et al, 2000
62Post-operative Imatinib Trials
- Z9000 ACOSOG Study of Adjuvant Imatinib in GIST
- Z9001 ACOSOG Randomized Study of Adjuvant
Imatinib Versus Placebo in GIST - Primary Objective is survival
- Secondary objective to obtain tumor before
Imatinib and at recurrence - Resected lt 10 weeks prior to Imatinib
- High risk for local or distant failure (gt 3 cm
primary, intraperitoneal hemorrhage, tumor
rupture) - Z9002 Adjuvant Duration?
63Preoperative Imatinib Trials
- MDACC ID03-0023 Preop/Postop Imatinib in
Patients with Resectable GIST - Laboratory correlations
- Clinical endpoints of DFS, OS
- RTOG S-0132 Preoperative Imatinib in Patients
with Potentially Resectable GIST - Laboratory correlations
- Clinical endpoints of DFS, OS
- Imatinib to maximum response
64Patient Characteristicsn13
65Preoperative Imatinib ToxicityGrade 3/4
Patients able to finish 1 year of therapy
7/9 Patients with recurrence 1
66PET Response at Day 5
Pre-imatinib Post-imatinib (Day 5)
67PET Response Datan12
PET-CT imaging
Courtesy Homer Macapinlac, M. D.
68Apoptosis After Imatinib
5 days post-imatinib
69Effect of Imatinib on Apoptosis
Post-Imatinib (3 days of therapy)
Pre-Imatinib
Immunofluorescent TUNEL Assay
70Will my kids get GIST?
71Familial GIST
I
II
III
II
I
III
V
VI
VII
IV
VIII
II
III
I
IV
I
II
IV
III
72Gastrointestinal Stromal Tumors
A Paradigm of Targeted Anti-Tumor Therapy
Jon Trent, MD, PhD jtrent_at_mdanderson.org Dept.
of Sarcoma Medical Oncology The University of
Texas, M. D. Anderson Cancer Center