1. Strategies to overcome resistance in NSCLC with driver mutations
Federico Cappuzzo
Istituto Toscano Tumori
Ospedale Civile
Livorno-Italy

2. First-line therapy for metastatic NSCLC in 2012
Stratification for EGFR, ALK and histology
EGFR mutated
ALK+
EGFR WT non-squamous
EGFR WT squamous
EGFR-TKI
Crizotinib
Platinum + pemetrexed
+/- bevacizumab
Platinum-based doublet

3. Mut+ NSCLC: EGFR-TKI Acquired Resistance
Malgrado gli TKIs siano la terapia di prima scelta in presenza di mutazioni di EGFR, nessun paziente viene guarito e tutti inevitablmente recidivano e muoiono. Questo è quello che tipicamente avviene in un paziente con mutazione di EGFR. Inizialmente si verifica una rapida regressione, sino al 90% dei casi, e dopo mediamente 9 mesi la malattia progredisce. In questi pazienti si pone il problema delle terapie successive e della sospensione del trattamento con TKIs. Si pone quindi il problema deela “disease flare”, ossia ………..
Baseline
Tumor regression
(RR up to 90%)
Progression
(median 9 months)
Disease Flare: Hospitalization and/or death attributable to disease progression
after discontinuation of gefitinib or erlotinib and before initiation of study drug

4. Risk of disease flare in EGFR mut+ NSCLC with acquired resistance: Chaft J et al. (O 19.05)
Characteristic: Total patients=61
N (% or range)
Male sex – N (%)
13 (21)
Age at diagnosis (years)
Median (range)
58 (26-78)
EGFR mutation – N (%)
Exon 19 deletion
Exon 18 G719A
Exon 21 L858R
41 (67)
1 (2)
19 (31)
Time on gefitinib or erlotinib (months)
19 (7-78)
Age in years - Median (Range)
61 (27-80)
Karnofsky Performance Status (%)
90%
80%
70%
37 (61)
11 (18)
Il rischio di disease flare è significativamente + alto in coloro che hanno avuto un più basso PFS (9 verso 15 mesi, p=0.002)
Questi dati chiaramente indicano due cose:
Se si dispone di una terapia ulteriore il tempo di sospensione deve essere + breve possibile
Se no si hanno terapie ulteriori è preferibile continuare con un inibitore anche in presenza di PD. Infatti ……dati Reily
14 of 61 patients (23%, 95% CI 14-35%) had a disease flare (hospitalization or death)
Flare & no flare group – same 30 day pretrial hospitalization rate
Median time from last TKI to flare was 8 days (range 3-21 days)
3 patients went on to trial treatment

5. Changes in Tumor Diameter (RECIST) After Discontinuation and Re-introduction of EGFR TKI
50%
20%
Change from baseline 0%
-30%
EGFR TKI
stop
re-start
3 weeks
3 weeks
Riely et al, CCR 2007

6. Mechanisms responsible for EGFR-TKI resistance
Sequist et al, Science Transl Med 2011

7. EGFR-TKI resistance A B

8. T790M Mutation causes drug resistance by increasing affinity for ATP
Yun PNAS 2008

9. T790M mutations in EGFR-TKI naive NSCLC
Present in up to 50% of NSCLC with EGFR-TKI acquired resistance
Rare event in EGFR-TKI naive NSCLC (<3%) using low sensitive methods
Detected in up to 40% of EGFR-TKI naive patients using high sensitive methods

10. Presence of T790M mutation predicts poor outcome to EGFR-TKI
Detected using high sensitive methods
Su et al. JCO 2012; Rosell et al. Clin Cancer Res 2011;

11. T790M mutation and acquired resistance to gefitinib therapy
Irreversible EGFR-TKI are still effective
Kobayashi et al. NEJM, 352, , 2005

12. Afatinib: Dual irreversible EGFR-HER2 inhibitor
Orally bioavailable, small molecule
tyrosine kinase inhibitor (TKI)
Designed to irreversibly bind to the
ATP binding pocket of EGFR and
HER2
Highly specific for EGFR and HER2
EGFR IC50: nM
HER2 IC50: nM
Afatinib
EGFR or HER2
ATP binding pocket +

13. Afatinib: active against resistance mutation
BIBW2992 but not erlotinib is active against cells expressing T790M EGFR mutation:
NCI-H1975
Li et al. Oncogene. 2008;27:4702–4711

14. Afatinib + cetuximab as the best option in presence of EGFR T790M mutation
Regales et al. JCI 2009

15. Afatinib + cetuximab for metastatic NSCLC: Study Design
Phase Ib, open-label, multicenter trial in the US and The Netherlands
Stop erlotinib/ gefitinib for ≥72 hours3
Disease progression2
NSCLC with
EGFR mutation1 OR
SD 6 months
with erlotinib/gefitinib
Partial or complete response
to erlotinib/gefitinib
MTD cohort expanded up to 80 EGFR mutation-positive patients4:
40 T790M+ and 40 T790M–
Dose escalation schema 3–6 patients per cohort
Afatinib p.o. daily + escalating doses of i.v. cetuximab q 2 weeks
Dose levels starting at:
afatinib 40 mg + cetuximab 250 mg/m2
Predefined maximum dose:
afatinib 40 mg +
cetuximab 500 mg/m2
This was a Phase Ib, open-label, multicenter trial in the US and the Netherlands
Protocol-defined dose reductions were as follows:
First reduction
• Decrease afatinib 40 → 30 mg and cetuximab 500 → 450 mg/m2
Second reduction
• Continue afatinib 30 mg, decrease cetuximab 450 → 400 mg/m2
1EGFR G719X, exon 19 deletion, L858R, L861Q; 2Progression of disease (Response Evaluation Criteria in Solid Tumors v1.1) on continuous treatment with erlotinib or gefitinib within the last 30 days; 3Amended from original 14-day interval; 4Acquisition of tumor tissue after the emergence of acquired resistance was mandated.
i.v.=intravenous; MTD=maximum tolerated dose; NSCLC=non-small cell lung cancer; SD=stable disease.

16. Tumor Regression by T790M Mutation Status at Recommended Dose
39 patients with proven EGFR T790M mutation: confirmed RR=31%

17. Acquired resistance to EGFR-TKIs
Acquired drug resistance is almost inevitable (~10 months)
About 30% of resistant mechanisms are unknown.
Mitsudomi, et al. Cancer Sci., 2007

18. Resistant mechanisms in 33 tumors from 6 patients with EGFR-TKI acquired resistance
Number of Tumors
MET gene copy numbers (folds)
Tumors with T790M
Tumors without T790M
< < 4.0
93% 8%
80%
Suda et al. Clin Cancer Res 2010

19. Inhibition of both EGFR and MET is necessary for growth inhibition of HCC827 GR cells
125
Gefitinib
100
PHA665752
Gefitinib/PHA665752 75
% of control 50 25
0.01
0.1 1 10
Drug Concentration ( μ M)
Irreversible EGFR inhibitors have no effect on HCC827 GR
MET shRNA restores sensitivity to gefitinib
Engelman et al. Science 2007

20. EML4-ALK fusion oncogene in NSCLC
3–7% of patients with NSCLC have an EML4-ALK gene fusion1
detection test available
mainly seen in adenocarcinomas (mutually exclusive with EGFR mutations)2
phase I/II trial of crizotinib, oral c-MET and ALK inhibitor in selected patients: DCR = 70%3
further potential for personalising therapy in NSCLC
1. Koivunen, et al. Clin Cancer Res 2008
2. Shaw, et al. ASCO 2009; 3. Bang, et al. ASCO 2010

21. ALK secondary mutations and crizotinib resistance
Sasaki et al. Cancer Res 2011

22. New ALK inhibitors TAE684 and AP26113 overcome crizotinib resistance in H3122 CR cell line
Ci sono nuovi inibitori attivi sulle mutazioni secondarie di ALK ma altre strategie sembrano offrire risultati molto promettenti come la combinazione con anti-EGFR o gli inibitori di HSP90
Katayama et al. PNAS 2011

23. Cell lines with ALK secondary mutation and ALK and EGFR co-dependency
In alcuni modelli sperimentali, linee cellulari con mutazione secondaria di ALK sono risultati dipendenti da ALK e anche da EGFR. Questo ha risvolti clinici interessanti in quanto offre la possibilità di ripristinare la sensibilità tumorale utilizzando una combinazione di anti-ALK e anti-EGFR.
Sasaki et al. Cancer Res 2011

24. ALK amplification or ALK FISH loss as mechanisms of crizotinib resistance
Katayama et al. PNAS 2011, Katayama et al Science Transl Med 2012, Doebele et al. Clin Cancer Res 2012

25. Several mechanisms responsible for crizotinib resistance: clinical implications
L’esistenza di multipli meccanismi responsabili di resistenza a crizotinib ha delle importanti conseguenze cliniche in quanto rende necessario identificare nel singlo paziente l’evento che ha causato la resistenza e sulla base di questo pianificare il programma di trattamento. Inoltre la presenza nello stesso paziente di di eventi driver differenti general la domanda se tali eventi sono presenti nella stessa cellula tumorale o in cellule diverse. Nel modello uno viene mostratta la prima ipotesi, ovvero nella stessa cellula sono presenti due drivers differenti: questo è quanto sappiamo succede nel NSCLC con mutazione secondaria MET amplification. Nel modello due si ammette che più drivers siano presenti nello stesso paziente ma in popolazioni cellulari differenti. Questo è il caso almeno di alcuni pazienti ALK positivi dove abbiamo sia la traslocazione ALK che la mutazione di EGFR o di KRAS.
Doebele et al. Clin Cancer Res 2012

26. Conclusions
Different mechanisms are responsible for acquired resistance to novel targeted therapies
So far no proven efficacy of irreversible EGFR-TKIs in NSCLC with acquired resistance to reversible agents
No clinically available strategies for crizotinib resistant patients
New drugs and new strategies are under investigation