west asco clin mgmt acquired resistance tk is
TRANSCRIPT
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Clinical Perspective on Acquired Resistance: Defining and Overcoming Barriers
Howard (Jack) West, MDSwedish Cancer Institute
Seattle, WA
ASCO Annual MeetingChicago, IL
June 1, 2013
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Acquired Resistance to Targeted Therapies In NSCLC: Management in the Clinic Today
• Detectable vs. clinically significant progression?
• Role of local therapy?
• Continue targeted therapy?
• Value to re-challenge?
• Repeat biopsy?
Outline of key questions
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Acquired Resistance to Targeted Therapy: Heterogeneous Patterns
Diverse molecular mechanisms of resistance diverse clinical patterns of progression
•Single focus of progression •Slow, minimal multifocal progression
•Rapid, more diffuse progression
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Does Detectable Progression Require a Treatment Change?
NOT necessarily clinically significant progression
Disease burden
Time
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Is it clinically significant progression?
Questionable/dubious indicators
Mild increase in metabolic activity on PET
Rising serum tumor marker
Slow, slight increase in tumor size
(1-2 small new nodules vs. otherwise excellent disease control?)
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Continued treatment beyond progression, Dana Farber Experience
• 42 EGFR mutn-pos pts s/p 1st line erlotinib on one of 3 clinical trials
• 45% continued without significant progression > 3 months• 21% required no further treatment change for > 12 months
Oxnard, ASCO 2012, A#7524
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If significant progression, is it isolatedor more diffuse?
Is “oligoprogression” analogous to oligometastatic/precocious metastatic disease?
Perhaps especially for CNS disease
• Poor CNS penetration of both EGFR TKIs and crizotinib, so brain mets may not represent resistance to drug (Bronischer CCR, 2007; Costa JCO 2011)
• T790M seen in 60% of progressing lesions in acquired resistance, but only 10% of lesions from CNS progression (Hata, ASCO 2012, A#7528)
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Local Therapy in Acquired Resistance: University of Colorado Experience
• 65 pts (38 ALK+, 27 EGFR mut’n+) of whom 51 (28 ALK, 23 EGFR) progressed
• 25 (49%) with CNS (no LMC) or <4 extracranial sites of progression
Weickhardt, J Thorac Oncol 2013
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Chen, Oncologist 2012
Variability of Molecular Markers Over Timeand Across Disease Sites
• Heterogeneity of molecular changes across lesions
• Acquired resistance may be anatomically isolated
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Local Therapy in Acquired Resistance: Extracranial Oligoprogression
• 18/184 pts local therapy for extracranial PD (CNS PD excluded)
Yu, J Thorac Oncol 2013
• Median time to new systemic Rx: 22 months
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Rapid acceleration of PD hospitalization and/or death after discontinuation of EGFR seen in up to ~1/4 of pts in MSKCC series (Chaft, Clin Cancer Res, 2011)
Also reported after discontinuation of crizotinib after acquired resistance in ALK-positive NSCLC (Pop, J Thorac Oncol, 2012)
Last day of TKI Off EGFR TKI Resumed TKI
Day 0 Day 21 Day 42
Rapid Progression with Discontinuation of EGFR TKI after Prolonged PFS
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For Cancers with a Known Driver Mutation, ContinuingInhibition of that Target is Beneficial after Progression
• Progression of CML on imatinib increase dose, or dasatinib, or nilotinib lead to consistent response
• Solid tumor example: HER2+ breast cancer
von Minckwitz, JCO 2009
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Treatment Options after Acquired Resistance to EGFR (or other) TKI
Oxnard, Clin Cancer Res, 2011
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Chemo/Erlotinib vs. Chemo Alone at Progression after Acquired Resistance
• N = 78 retrospective review of outcomes – chemo alone (N = 44) or– chemo/erlotinib (N = 34)
• RR 18% (chemo) vs. 41% with chemo/erlotinib)
• No differences in PFS or OS between these two strategies
Goldberg, ASCO 2012, A#7524
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Chemo with Concurrent TKI
• Studies in unselected or clinically selected populations show no benefit but no signal of increased harm
• Combinations of chemo and TKIs are certainly feasible
• Little prospective study in setting of acquired resistance yet
• ph II trial of pem/EGFR TKI as 3rd line (Yoshimura, JTO 2013)
• N = 27; RR 26%, DCR 78%, med PFS 7.0 mo, med OS 11.4 mo
• Unclear if they are significantly more favorable than chemo alone in acquired resistance
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Chemotherapy +/- Ongoing EGFR TKI for Acquired Resistance
Primary endpoint: progression-free survival
Activating EGFR mutationProgression on gefitinibNo prior chemotherapy
N = 250
RAND
Cisplatin/Pemetrexed
IMPRESS TRIAL
PI: Tony Mok & Jean-Charles Soria
Cisplatin/Pemetrexed+ ongoing gefitinib
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Chemotherapy +/- Ongoing EGFR TKI for Acquired Resistance, with Retreatment
Primary endpoint: progression-free survival
PI: Leora Horn (Vanderbilt)
Advanced NSCLCActivating EGFR mutationResp to EGFR TKI>4 moNo prior chemotherapy
PS 0/1N = 120
RAND
Cis or Carbo/Pemetrexed+ ongoing erlotinib
Stratification by:
EGFR mut’n exon 19 vs. exon 21
Time to progression on EGFR TKI <1 yr vs. >1 yr
PS 0 vs. 1
Cis or Carbo/Pemetrexed
Erlotinib re-treatment
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Chemotherapy +/- Ongoing Crizotinib for Acquired Resistance in ALK-Positive NSCLC
Co-primary endpoints: Progression-free survival Response rate, pemetrexed alone
ALK rearrangementProgression on crizotinib
after response or SD>3 moNo prior pemetrexed
N = 114
RAND
Pemetrexed alone
PI: D. Ross Camidge
Pemetrexed + ongoing+ crizotinib
SWOG 1300 (in development)
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Chemo Without TKI Can Be Followed by Re-treatment
Oxnard, Clin Cancer Res, 2011
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EGFR TKI Re-treatment after Acquired Resistance: DFCI/MGH Experience
• Retrospective, 24 pts (over 9.5 yrs) with activating EGFR mutation after AR to gefitinib (30%) or erlotinib (70%)
• RR 4%, SD 63%
• Median interval off EGFR TKI 5 mo (range 2-46 mo)
• Greater benefit w/longer interval of EGFR TKI (PFS 4.4 vs. 1.9 mo for 6 mo interval off EGFR TKI)
Heon, ASCO 2012, A#7525
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MISSION Trial of Sorafenib vs. Placebo: PFS based on EGFR mutation status
Biomarker*treatment interaction analysis: p-value=0.015
Patients with EGFR mut (in tumor or plasma)• Sorafenib N=44; Placebo N=45 • HR=0.27 (95% CI 0.16,0.46) • P-value<0.001 • Sorafenib median PFS= 2.7 mo (83d)• Placebo median PFS= 1.4 mo (42d)
Patients with EGFR wild type• Sorafenib N=122; Placebo N=136 • HR=0.62 (95% CI 0.48,0.82) • P-value<0.001 • Sorafenib median PFS= 2.7 mo (82d) • Placebo median PFS= 1.5 mo (46d)
Mok, ESMO 2012
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MISSION Trial of Sorafenib vs. Placebo: OS based on EGFR mutation status
Patients with EGFR mut (in tumor or plasma)• Sorafenib N=44; Placebo N=45 • HR=0.48 (95% CI 0.3,0.76) • P-value=0.002 • Sorafenib median OS= 13.9 mo (423d) • Placebo median OS= 6.5 mo (197d)
Patients with EGFR wild type• Sorafenib N=122; Placebo N=136 • HR=0.92 (95% CI 0.7,1.21) • P-value=0.559 • Sorafenib median OS= 8.3 mo (253d)• Placebo median OS= 8.4 mo (256d)
Biomarker*treatment interaction analysis: p-value=0.023
Mok, ESMO 2012
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Are Repeat Biopsies Mandatory, Desirable, or Neither?
Yu, Clin Cancer Res, 2013
Not standard of care, relatively low probability of being immediately actionable, but repeat biopsies are likely to drive our understanding and future treatments in this setting.
• SCLC in 3-15%
• Potential insight re: prognosis (+/- value of ongoing TKI?)
• Otherwise, uncommon to find actionable result with current approved agents
N=155
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Conclusions on Clinical Management of Acquired Resistance (1)
• Clinical as well as molecular heterogeneity • No clear evidence-based best approach defined yet• Not all progression merits change in therapy• “Oligoprogressive” acquired resistance
– Consider local Rx and continue targeted therapy– CNS as pharmacodynamic issue, not acquired resistance
• Diffuse progressive disease– Option of continuing TKI with concurrent chemo to avoid
“flare”, treat different cell populations– Option of switching to chemo only, potentially followed by
re-treatment
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Conclusions on Clinical Management of Acquired Resistance (2)
• Prospective randomized trials are needed– Very real potential for bias in retrospective analyses
• Trials of novel agents or combinations– Very attractive option for prospectively identified special
population – consider clinical trials
• Role for repeat biopsy?– Uncommon to have actionable result today– Very likely to increase our understanding of the field and
identify future treatment options