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Annual Meeting Proceedings Part 1 - American Society of Clinical ...

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486s Lung Cancer—Non-small Cell Metastatic<br />

7524 Poster Discussion Session (Board #14), Tue, 8:00 AM-12:00 PM and<br />

11:30 AM-12:30 PM<br />

Chemotherapy with erlotinib or chemotherapy alone in advanced NSCLC<br />

with acquired resistance to EGFR tyrosine kinase inhibitors (TKI). Presenting<br />

Author: Sarah B. Goldberg, Massachusetts General Hospital Cancer<br />

Center, Boston, MA<br />

Background: EGFR-mutant NSCLC has an oncogene-addicted phenotype<br />

that confers sensitivity to EGFR TKIs. Prior data suggests EGFR addiction<br />

persists after development <strong>of</strong> TKI resistance, leading many clinicians to<br />

continue TKI along with chemotherapy (chemo); however, this strategy has<br />

not been formally evaluated. Methods: An institutional database was<br />

reviewed to identify patients (pts) with advanced NSCLC and acquired<br />

resistance to EGFR TKIs by Jackman criteria. Pts were included if they<br />

subsequently received chemo. Objective response rate (RR) to chemo/<br />

erlotinib or chemo alone was assessed by blinded radiographic review and<br />

compared by Fisher’s exact test and multivariable logistic regression.<br />

Progression-free survival (PFS) and overall survival (OS) from TKI failure<br />

(defined as chemo initiation date) were compared by log-rank test and<br />

multivariable Cox analysis. Results: 78 pts were eligible (34 chemo/<br />

erlotinib, 44 chemo alone). 70 pts (90%) had a documented EGFR<br />

mutation and were on TKI for a median <strong>of</strong> 15 months (range 4-51); in the 8<br />

pts with unknown genotype the median duration on TKI was 11 months<br />

(range 5-16). Baseline characteristics were well balanced except more pts<br />

received erlotinib as initial TKI in the chemo/erlotinib group. RR was<br />

evaluable in 57 pts and was higher with chemo/erlotinib compared to<br />

chemo alone (41% vs 18%; OR 0.31, 95% CI 0.09, 1.04; p�0.08). RR<br />

adjusted for chemo regimen and time to TKI failure yielded OR 0.20 (95%<br />

CI 0.05, 0.78; p�0.02), favoring chemo/erlotinib. Median PFS was 4.4<br />

months in the chemo/erlotinib group and 4.2 months in the chemo alone<br />

group (crude HR�0.84, 95% CI 0.52, 1.38; p�0.50; adjusted HR 0.79,<br />

95% CI 0.48, 1.29; p�0.34). There was no significant difference in OS in<br />

the crude or adjusted analyses. Conclusions: This is the first study, to our<br />

knowledge, to show that continuation <strong>of</strong> an EGFR TKI with chemo<br />

compared to chemo alone significantly increases the RR in pts with<br />

advanced NSCLC and acquired TKI resistance, though we did not observe<br />

an impact on PFS or OS. Continued concurrent TKI may be a valuable<br />

strategy, particularly for pts with symptomatic progression, when a higher<br />

response rate may be beneficial. Further study is warranted.<br />

7526 Poster Discussion Session (Board #16), Tue, 8:00 AM-12:00 PM and<br />

11:30 AM-12:30 PM<br />

Continuation <strong>of</strong> EGFR/ALK inhibition after local therapy <strong>of</strong> oligoprogressive<br />

disease in EGFR mutant (Mt) and ALK� non-small cell lung cancer (NSCLC).<br />

Presenting Author: Andrew James Weickhardt, University <strong>of</strong> Colorado Cancer<br />

Center, Denver, CO<br />

Background: This study aimed to investigate the benefits <strong>of</strong> local treatment <strong>of</strong><br />

limited disease progression and continuation <strong>of</strong> crizotinib (C) or EGFR-TKI in<br />

patients with ALK� or EGFR-Mt metastatic NSCLC, respectively. Methods:<br />

Patients with advanced ALK� NSCLC treated with C (n�38) and EGFR-Mt<br />

NSCLC treated with EGFR TKIs (erlotinib or gefitinib) (n�27) were identified.<br />

Patients were evaluated for initial response, site <strong>of</strong> first progression (CNS or extra<br />

CNS (eCNS)) and median progression free survival (PFS1). A subset <strong>of</strong> patients<br />

with limited sites <strong>of</strong> progression (oligoprogressive disease) suitable for local<br />

therapy received either radiation or surgery to these sites and continued on the<br />

same TKI. The subsequent pattern <strong>of</strong> progression and median progression free<br />

survival from the time <strong>of</strong> first progression (PFS2) were recorded. Results: In 38<br />

ALK� patients, PFS1�9.0 months on C. In 27 EGFR-Mt patients, PFS1�13.8<br />

months on EGFR-TKI. CNS was the first site <strong>of</strong> progression in 13/28 (46%) <strong>of</strong><br />

ALK� patients and 5/23 (22%) EGFR-Mt patients. 25 <strong>of</strong> 51 patients who<br />

progressed (49%) were deemed suitable for local therapy (15 ALK�, 10<br />

EGFR-Mt; 24 with radiotherapy (Body: 3 XRT, 9 SBRT; CNS: 7 WBRT, 5 SRS), 1<br />

with surgery (adrenalectomy)) and continuation <strong>of</strong> the same targeted therapy.<br />

19/25 patients progressed post local therapy, median PFS2 � 6.2 months. In<br />

patients who progressed at PFS1 only in the CNS, there was a trend to longer<br />

PFS2 than patients who progressed at PFS1 in eCNS (7.1 months vs 4.0<br />

months, p�0.26). 60% who progressed only in the CNS at PFS1, progressed<br />

eCNS at PFS2 (n�10). Conclusions: Progression <strong>of</strong> oncogene addicted NSCLC<br />

on relevant targeted therapies is <strong>of</strong>ten suitable for local therapy (oligoprogressive<br />

disease). Continuation <strong>of</strong> the targeted therapy following local therapy is<br />

associated with �6 months <strong>of</strong> additional disease control.<br />

Sites <strong>of</strong> first progression and median PFS1 and PFS2 in patients continuing TKI<br />

after local therapy <strong>of</strong> oligoprogressive disease.<br />

Site <strong>of</strong> progression Number <strong>of</strong> patients<br />

PFS1<br />

(months)<br />

PFS2<br />

(months)<br />

CNS 1st site <strong>of</strong> prog. 10 10.9 7.1<br />

eCNS 1st site <strong>of</strong> prog. 15 9.6 4.0<br />

All patients 25 10.0 6.2<br />

* Includes 3 patients who prog. eCNS and CNS at PFS1.<br />

7525 Poster Discussion Session (Board #15), Tue, 8:00 AM-12:00 PM and<br />

11:30 AM-12:30 PM<br />

Response to EGFR tyrosine kinase inhibitor (TKI) retreatment after a<br />

drug-free interval in EGFR-mutant advanced non-small cell lung cancer<br />

(NSCLC) with acquired resistance. Presenting Author: Stephanie Heon,<br />

Dana-Farber Cancer Institute, Boston, MA<br />

Background: Patients (pts) with advanced NSCLC and sensitizing EGFR<br />

mutations who initially respond to gefitinib or erlotinib eventually develop<br />

acquired resistance to the TKIs. Anecdotal and retrospective reports<br />

suggest that EGFR-TKI resistant cancers can respond again to gefitinib or<br />

erlotinib after an interval <strong>of</strong>f the TKI. This retrospective study was<br />

undertaken to investigate the impact <strong>of</strong> EGFR-TKI retreatment after a<br />

drug-free interval in EGFR mutant NSCLC with acquired resistance to<br />

gefitinib or erlotinib. Methods: Pts with stage IV or relapsed NSCLC with<br />

sensitizing EGFR mutations and acquired resistance to EGFR-TKI seen at<br />

the DFCI/MGH between 8/00 and 8/11 who were retreated with single<br />

agent gefitinib or erlotinib after an EGFR-TKI-free interval were identified<br />

from a prospective trial. The objective tumor response (CR, PR, SD, PD)<br />

was determined using RECIST 1.1. Results: 19 pts were eligible and had<br />

adequate scans for radiographic assessments after the reinstitution <strong>of</strong> an<br />

EGFR-TKI. The response rate and median PFS to the initial course <strong>of</strong><br />

gefitinib (n�4) or erlotinib (n�15) were 16/19 (84%) and 9.8 months<br />

(95% CI, 7.8-11.3) respectively. All pts were retreated with erlotinib after<br />

1 to 4 intervening systemic regimens. The median interval from EGFR-TKI<br />

discontinuation to erlotinib retreatment was 11 months (range, 2-46). 4 <strong>of</strong><br />

the 19 pts (21%) had PD as the best response to erlotinib retreatment, 14<br />

(74%) had SD for at least 1 month, and 1 (5%) had a PR. The median PFS<br />

was 4.4 months (95% CI, 3.0-6.7). 3 pts remained on erlotinib without<br />

progression for 6 months. 3 pts had their tumors rebiopsied before (n�2) or<br />

during (n�1) erlotinib retreatment; 1 <strong>of</strong> the 3 had EGFR T790M in<br />

association with the initial sensitizing EGFR mutation, and another had a<br />

secondary PIK3CA mutation. Conclusions: Our findings suggest that erlotinib<br />

retreatment is an option for EGFR mutated NSCLC with acquired<br />

resistance to EGFR-TKI after a drug-free interval and progression on<br />

intervening therapy. Additional advanced NSCLC pts without a documented<br />

EGFR mutation who fulfill the clinical definition <strong>of</strong> acquired<br />

resistance are undergoing review to expand our cohort.<br />

7527 Poster Discussion Session (Board #17), Tue, 8:00 AM-12:00 PM and<br />

11:30 AM-12:30 PM<br />

Local therapy as a treatment strategy in EGFR-mutant advanced lung<br />

cancers that have developed acquired resistance to EGFR tyrosine kinase<br />

inhibitors. Presenting Author: Helena Alexandra Yu, Memorial Sloan-<br />

Kettering Cancer Center, New York, NY<br />

Background: The utility <strong>of</strong> EGFR directed therapy for the treatment <strong>of</strong> EGFR<br />

mutant lung cancer is limited by the development <strong>of</strong> acquired resistance<br />

(AR) to EGFR tyrosine kinase inhibitor (TKI) therapy, which occurs after a<br />

median <strong>of</strong> 16 months (mos). There are no approved targeted therapies after<br />

disease progression on EGFR TKI therapy. Local therapy for oligometastatic<br />

disease is used with regularity in other solid tumors, and can lead to long<br />

term survival in selected individuals. EGFR mutant lung cancers with AR to<br />

TKI therapy can follow an indolent course that is amenable to local therapy<br />

to treat progression <strong>of</strong> disease when used in conjunction with continued<br />

EGFR inhibition. Outcomes following local therapy in this setting have not<br />

been assessed. Methods: Patients (pts) with AR to EGFR TKI’s who received<br />

local therapy excluding treatment <strong>of</strong> CNS metastases or local therapy prior<br />

to AR were identified in an IRB-approved prospective registry <strong>of</strong> 184 pts<br />

with AR enrolled from August 2004- November 2011. We collected<br />

treatments as well as progression free survival (PFS) and overall survival<br />

(OS) after local therapy. Results: 18 pts received local therapy. Treatments<br />

included surgical resection and radiation to lung, lymph nodes, adrenal<br />

gland or bone. Median age was 57, 56% were women, and 61% were never<br />

smokers. 14 had EGFR Exon 19 deletions, and 4 L858R. The median time<br />

to development <strong>of</strong> AR on TKI was 19 mo (range 5-33). Known mechanisms<br />

<strong>of</strong> AR included T790M (11 pts), MET amplification (1 pt) and small cell<br />

transformation (1 pt). The median PFS after local therapy was 10 mo (95%<br />

CI: 4-NA), median time from local therapy until change in systemic therapy<br />

was 22 mo (95%CI: 6 - 30), and median OS from local therapy was 41 mo<br />

(95% CI: 26-NA). Local therapy was tolerated well, with 85% <strong>of</strong> pts<br />

restarting TKI therapy within one month <strong>of</strong> completing local therapy.<br />

Conclusions: Local therapy is well tolerated and in combination with<br />

continued EGFR TKI therapy prolongs time until change in systemic<br />

therapy is required and may lead to outcomes that are superior to currently<br />

available treatment options in selected individuals.<br />

Visit abstract.asco.org and search by abstract for the full list <strong>of</strong> abstract authors and their disclosure information.

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