Abstract P224: Update from the Phase 2 registrational trial of repotrectinib in TKI-pretreated patients with ROS1+ advanced non-small cell lung cancer and with NTRK+ advanced solid tumors (TRIDENT-1)

Background: Repotrectinib is a next-generation ROS1/TRK tyrosine kinase inhibitor (TKI) that is currently in a registrational Phase 2 trial (TRIDENT-1). A previous update from the TRIDENT-1 trial showed a generally well tolerated safety profile in 185 treated patients. Interim efficacy data were previously presented. In ROS1+ NSCLC patients with 1 prior TKI and prior platinum-based chemotherapy (EXP-2), confirmed overall response rate (cORR) was 40% (2 of 5 patients); in ROS1+ NSCLC patients with 1 prior TKI without prior platinum-based chemotherapy (EXP-4), cORR was 67% (4 of 6 patients); in ROS1+ NSCLC patients with 2 prior TKIs without prior platinum-based chemotherapy (EXP-3), cORR was 40% (2 of 5 patients). In NTRK+ TKI-pretreated advanced solid tumor patients (EXP-6), cORR was 50% (3 of 6 patients). In addition, efficacy was demonstrated in patients who developed solvent front mutations (SFM) following prior ROS1/TRK TKI treatment. cORR was 67% (4 of 6 patients) and 50% (2 of 4 patients) in ROS1+ NSCLC and NTRK+ solid tumors patients with SFMs, respectively. One patient who developed a SFM after entrectinib treatment (EXP-2) had a cCR with 5.6+ months duration of response. Methods: TRIDENT-1 (NCT03093116) is an ongoing registrational Phase 2 trial enrolling patients whose cancers harbor a ROS1 or NTRK gene fusion. Patients are enrolled into 6 defined expansion cohorts (EXP 1-6), based on cancer type and prior therapy. The primary endpoint is cORR by Blinded Independent Central Review using RECIST v1.1. Results: An updated safety analysis across Phase 1 and Phase 2 patients (n=243) based on a data cut-off date of 4 May 2021 was conducted. Treatment-emergent adverse events (TEAEs) observed in ≥20% of patients were dizziness (62%), dysgeusia (43%), constipation (33%), dyspnea (30%), paresthesia (28%), anemia (26%), and fatigue (26%). Grade ≥3 treatment-related AEs (TRAEs) were observed in 17% of patients; no Grade 5 TRAEs were observed. The majority (77%) of dizziness TEAEs were Grade 1 and 4% were Grade 3; none of the dizziness events led to treatment discontinuation. Dose modifications remained infrequent including 24% of patients with a TEAE that led to a dose reduction and 10% of patients with a TEAE that led to drug discontinuation. Updated efficacy information for TKI-pretreated ROS1+ NSCLC and NTRK+ advanced solid tumor patients is being collected and will be available for presentation. Conclusions: Repotrectinib is a next-generation ROS1/TRK inhibitor. In an ongoing registrational Phase 2 trial, repotrectinib was generally well tolerated with low frequency of dose modifications. Updated Phase 2 efficacy data will be available for presentation.

Citation Format: Jessica J. Lin, Byoung Chul Cho, Christoph Springfeld, D. Ross Camidge, Benjamin Solomon, Christina Baik, Vamsidhar Velcheti, Young-Chul Kim, Victor Moreno, Anthonie J. van der Wekken, Enriqueta Felip, Dipesh Uprety, Denise Trone, Shanna Stopatschinskaja, Alexander Drilon. Update from the Phase 2 registrational trial of repotrectinib in TKI-pretreated patients with ROS1+ advanced non-small cell lung cancer and with NTRK+ advanced solid tumors (TRIDENT-1) [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P224.

Abstract P02-01: Repotrectinib in patients with NTRK fusion-positive advanced solid tumors: update from the registrational phase 2 TRIDENT-1 trial

Background: NTRK fusions drive a broad range of solid tumors. Two FDA approved TRK tyrosine kinase inhibitors (TKIs) have demonstrated efficacy in patients (pts) with NTRK fusion+ advanced solid tumors; however, emergent TRK solvent front (SF) and gatekeeper resistance mutations occur. Repotrectinib is a next-generation ROS1/TRK TKI with potency against wildtype and mutant forms of ROS1 and TRK. In preclinical studies, repotrectinib was more potent than larotrectinib, entrectinib, and selitrectinib against wildtype TRK, SF and gatekeeper mutations. Early interim data from the Phase 1/2 TRIDENT-1 trial led to Fast Track designation by the FDA for repotrectinib in TRK TKI-pretreated pts. This abstract is an updated analysis of this population and the first presentation of repotrectinib activity in TRK TKI-naïve pts. Methods: Pts with NTRK fusion+ advanced solid tumors were enrolled into the ongoing registrational Phase 2 TRIDENT-1 trial (NCT03093116). Pts with no prior TRK TKIs were enrolled into Expansion Cohort 5 (EXP-5) and pts who received up to 2 lines of prior TRK TKIs were enrolled into EXP-6. Prior chemotherapy and/or immunotherapy were allowed in both cohorts. The primary endpoint is cORR by Blinded Independent Central Review using RECIST v1.1. Results: As of efficacy data cutoff date of 28 July 2021, 8 pts in EXP-5 and 19 pts in EXP-6 had at least 2 post-baseline scans and were evaluable for efficacy analysis. Median age was 63 y (range 33–80) in EXP-5 and 50 y (range 23–81) in EXP-6; median number of prior lines of chemo/immunotherapy was 1 (range 0–2) in EXP-5 and 1 (range 0–4) in EXP-6. In EXP-6, 79% (15/19) of pts received 1 prior TRK TKI. Confirmed responses were reported by physician assessment. In EXP-5, cORR was 63% (5 of 8 pts; 95% CI: 24–91%) with DOR from 1.9+ to 7.4+ months (mo). In EXP-6, cORR was 47% (9 of 19 pts; 95% CI: 24–71%) with DOR from 1.9+ to 15.1 mo. In 10 pts enrolled in EXP-6 with a SF mutation, the cORR was 60% (6 of 10 pts; 95% CI: 26–88%). Median duration of treatment was 6.3 mo (range 0.9–13.4+) in EXP-5 and 8.1 mo (range 1.1–20.8) in EXP-6. An updated safety analysis for Phase 1 and Phase 2 (n=243) based on a data cut-off date of 4 May 2021 was conducted. Repotrectinib was generally well tolerated. Treatment-emergent adverse events (TEAEs) observed in ≥20% of patients were dizziness (62%), dysgeusia (43%), constipation (33%), dyspnea (30%), paresthesia (28%), anemia (26%), and fatigue (26%). The majority (77%) of dizziness TEAEs were Grade 1 and 4% were Grade 3; none of the dizziness events led to treatment discontinuation. Dose modifications remained infrequent (24% of pts had a dose reduction and 10% of pts discontinued study drug due to a TEAE). Conclusions: Repotrectinib is a next-generation ROS1 and TRK inhibitor. In an ongoing registrational Phase 2 trial, repotrectinib demonstrated efficacy in TRK TKI-naïve and TKI-pretreated pts and was generally well tolerated. Enrollment in the multi-cohort Phase 2 trial is ongoing.

Citation Format: Benjamin Besse, Christina Baik, Christoph Springfeld, Alice Hervieu, Victor Moreno, Lyudmila Bazhenova, Jessica J. Lin, D. Ross Camidge, Benjamin Solomon, Vamsidhar Velcheti, Anthonie J. van der Wekken, Enriqueta Felip, Dipesh Uprety, Denise Trone, Shanna Stopatschinskaja, Byoung Chul Cho, Alexander Drilon. Repotrectinib in patients with NTRK fusion-positive advanced solid tumors: update from the registrational phase 2 TRIDENT-1 trial [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P02-01.

Pharmacokinetically-guided dosing to improve the efficacy of brigatinib in non-small cell lung cancer patients

Brigatinib was recently approved for the treatment of anaplastic lymphoma kinase-positive non-small cell lung cancer and is dosed according to a one-dose-fits-all paradigm. We aimed to identify a pharmacokinetically-guided precision dosing strategy to improve treatment response with brigatinib through simulations using a previously published pharmacokinetic-pharmacodynamic model. Dosing strategies explored were the approved 180 mg QD; the highest tolerable dose tested in clinical trials: 240 mg QD; and two precision dosing strategies targeting the median trough concentrations following 180 mg QD, and 240 mg QD. We investigated the impact of alternative dosing regimens on progression-free survival (PFS), overall survival (OS) and the probability of developing a grade ≥2 rash or grade ≥2 amylase increase. Median PFS and OS increased by 1.6 and 7.8 months, respectively between the currently approved dosing strategy and precision dosing to the median trough concentration of the 240 mg dosing strategy, with only a minor increase in the probability of developing toxicity.

Multicenter Comparison of Molecular Tumor Boards in The Netherlands: Definition, Composition, Methods, and Targeted Therapy Recommendations

BACKGROUND

Molecular tumor boards (MTBs) provide rational, genomics-driven, patient-tailored treatment recommendations. Worldwide, MTBs differ in terms of scope, composition, methods, and recommendations. This study aimed to assess differences in methods and agreement in treatment recommendations among MTBs from tertiary cancer referral centers in The Netherlands.

MATERIALS AND METHODS

MTBs from all tertiary cancer referral centers in The Netherlands were invited to participate. A survey assessing scope, value, logistics, composition, decision-making method, reporting, and registration of the MTBs was completed through on-site interviews with members from each MTB. Targeted therapy recommendations were compared using 10 anonymized cases. Participating MTBs were asked to provide a treatment recommendation in accordance with their own methods. Agreement was based on which molecular alteration(s) was considered actionable with the next line of targeted therapy.

RESULTS

Interviews with 24 members of eight MTBs revealed that all participating MTBs focused on rare or complex mutational cancer profiles, operated independently of cancer type-specific multidisciplinary teams, and consisted of at least (thoracic and/or medical) oncologists, pathologists, and clinical scientists in molecular pathology. Differences were the types of cancer discussed and the methods used to achieve a recommendation. Nevertheless, agreement among MTB recommendations, based on identified actionable molecular alteration(s), was high for the 10 evaluated cases (86%).

CONCLUSION

MTBs associated with tertiary cancer referral centers in The Netherlands are similar in setup and reach a high agreement in recommendations for rare or complex mutational cancer profiles. We propose a "Dutch MTB model" for an optimal, collaborative, and nationally aligned MTB workflow.

IMPLICATIONS FOR PRACTICE

Interpretation of genomic analyses for optimal choice of target therapy for patients with cancer is becoming increasingly complex. A molecular tumor board (MTB) supports oncologists in rationalizing therapy options. However, there is no consensus on the most optimal setup for an MTB, which can affect the quality of recommendations. This study reveals that the eight MTBs associated with tertiary cancer referral centers in The Netherlands are similar in setup and reach a high agreement in recommendations for rare or complex mutational profiles. The Dutch MTB model is based on a collaborative and nationally aligned workflow with interinstitutional collaboration and data sharing.

A Nationwide Study on the Impact of Routine Testing for EGFR Mutations in Advanced NSCLC Reveals Distinct Survival Patterns Based on EGFR Mutation Subclasses

EGFR mutation analysis in non-small-cell lung cancer (NSCLC) patients is currently standard-of-care. We determined the uptake of EGFR testing, test results and survival of EGFR-mutant NSCLC patients in the Netherlands, with the overall objective to characterize the landscape of clinically actionable EGFR mutations and determine the role and clinical relevance of uncommon and composite EGFR mutations. Non-squamous NSCLC patients diagnosed in 2013, 2015 and 2017 were identified in the Netherlands Cancer Registry (NCR) and matched to the Dutch Pathology Registry (PALGA). Overall, 10,254 patients were included. Between 2013-2017, the uptake of EGFR testing gradually increased from 72.7% to 80.9% (p < 0.001). Multi-gene testing via next-generation sequencing (increased from 7.8% to 78.7% (p < 0.001), but did not affect the number of detected EGFR mutations (n = 925; 11.7%; 95% confidence interval (CI), 11.0-12.4) nor the distribution of variants. For patients treated with first-line EGFR inhibitors (n = 651), exon 19 deletions were associated with longer OS than L858R (HR 1.58; 95% CI, 1.30-1.92; p < 0.001) or uncommon, actionable variants (HR 2.13; 95% CI, 1.60-2.84; p < 0.001). Interestingly, OS for patients with L858R was similar to those with uncommon, actionable variants (HR 1.31; 95% CI, 0.98-1.75; p = 0.069). Our analysis indicates that grouping exon 19 deletions and L858R into one class of 'common' EGFR mutations in a clinical trial may mask the true activity of an EGFR inhibitor towards specific mutations.

Actionability of on-target ALK Resistance Mutations in Patients With Non-Small Cell Lung Cancer: Local Experience and Review of the Literature

INTRODUCTION

Non-small cell lung cancer (NSCLC) patients with Anaplastic Lymphoma Kinase (ALK) gene fusions respond well to ALK inhibitors but commonly develop on-target resistance mutations. The objective of this study is to collect clinical evidence for subsequent treatment with ALK inhibitors.

PATIENTS AND METHODS

Local experience with on-target ALK resistance mutations and review of the literature identified 387 patients with ALK inhibitor resistance mutations. Clinical benefit of mutation-inhibitor combinations was assessed based on reported response, progression-free survival and duration of treatment. Furthermore, this clinical evidence was compared to previously reported in vitro sensitivity of mutations to the inhibitors.

RESULTS

Of the pooled population of 387 patients in this analysis, 239 (62%) received at least 1 additional line of ALK inhibition after developing on-target resistance to ALK inhibitor therapy. Clinical benefit was reported for 177 (68%) patients, but differed for each mutation-inhibitor combination. Agreement between in vitro predicted sensitivity of 6 published models and observed clinical benefit ranged from 64% to 87%. The observed clinical evidence for highest probability of response in the context of specific on-target ALK inhibitor resistance mutations is presented.

CONCLUSION

Molecular diagnostics performed on tissue samples that are refractive to ALK inhibitor therapy can reveal new options for targeted therapy for NSCLC patients. Our comprehensive overview of clinical evidence of drug actionability of ALK on-target resistance mechanisms may serve as a practical guide to select the most optimal drug for individual patients.

Interim results of a phase II single arm trial combining afatinib with cetuximab in patients with EGFRex20ins positive NSCLC

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Background: Epidermal growth factor receptor exon 20 insertions (EGFRex20ins) are identified in 4-10% of all EGFR mutations in non-small cell lung cancer (NSCLC) and are associated with primary resistance to EGFR tyrosine kinase inhibitors (TKIs). Treatment options are limited. A case series showed that dual EGFR blockade with afatinib and cetuximab can induce tumor responses with manageable toxicity. We report on the first seventeen EGFRex20ins patients treated with afatinib in combination with cetuximab. Methods: In this Simon’s two stage, single-arm, phase II trial, patients with advanced NSCLC harboring an EGFRex20ins mutation were treated with afatinib 40 mg once daily, in combination with cetuximab 500 mg/m2, every two weeks, in five institutions in the Netherlands. Supportive medication consisted of minocycline, loperamide and skin creams. No previous line of treatment was required and asymptomatic brain metastases were allowed. The primary endpoint was disease control rate (DCR) after 18 weeks of treatment. Secondary endpoints included safety, response rate (RR), duration of response (DOR) and progression-free survival (PFS). Patients were treated until progression or unacceptable toxicity. A Simon’s two stage optimal design was used in order to minimize the number of patients being treated in the event that the regimen proves to be inactive. The estimated sample size of the first stage was 17 patients. At least four successes were required to enter stage 2 of the trial (alpha = 0.10; power = 0.90). Results: Eighteen patients were enrolled between Jan 2019 and Aug 2020; one patient did not meet the eligibility criteria due to absence of measurable disease. Median age was 66.0 years, 65% female, 53% never smoker. 47% of patients were treated as first-line therapy. Median prior lines of treatment was 1 (range 0-6). 53% received prior platinum-based chemotherapy. The primary endpoint was met as disease control was achieved by 10 patients (59%) after 18 weeks of treatment. Median PFS was 5.5 months. Best responses were partial (n = 8, RR 47%), stable (n = 7) or progressive disease (n = 2). Four patients were still on treatment at the cut-off date (Feb 2021). Most common treatment-related adverse events (TRAEs) were diarrhea (71%), rash (65%), paronychia (59%) and dry skin (53%). Grade III TRAEs were reported in 59% of all patients. Grade III TRAEs ≥ 10% included rash (n = 3; 18%) and diarrhea (n = 3; 18%). No grade IV toxicity was observed. One patient died due to respiratory failure after infusion of study medication, probably related to disease progression, possibly treatment related. 82% of patients required a dose reduction. Rate of treatment discontinuation due to AEs was 12% (n = 2). Conclusions: Combination treatment with afatinib and cetuximab demonstrated antitumor activity with a DCR of 59% at 18 weeks and a 47% RR, with manageable toxicity. Clinical trial information: NCT03727724.

Early circulating tumor (ct) DNA dynamics and efficacy of lorlatinib: Analysis from the CROWN study

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Background: Lorlatinib, a third-generation ALK tyrosine kinase inhibitor, significantly improved progression-free survival (PFS) and overall/intracranial responses vs crizotinib in patients (pts) with previously untreated ALK-positive advanced non-small cell lung cancer (NSCLC) in the ongoing randomized Phase 3 CROWN study (NCT03052608). To identify whether additional molecular biomarker analysis correlated with efficacy, we evaluated early ctDNA dynamics compared with clinical outcomes. Methods: Plasma samples were prospectively collected at screening (SC), week 4 (cycle 2, day 1 [C2D1]), week 24 (C7D1), and end of treatment for ctDNA analysis. ctDNA was analyzed using Guardant360CDx (Guardant Health, Inc., Redwood City, CA, USA). Mean variant allele fraction (VAF) of ALK alterations (fusions and/or mutations) and overall detected alterations at each time point and longitudinal mean change (dVAF) as (VAFC2D1) – (VAFSC) were calculated; dVAF <0 indicated decreased ctDNA at week 4. Objective tumor response and PFS were evaluated according to dVAF. These analyses were repeated vs ctDNA results at week 24. Additional correlation analyses between depth of molecular response and/or ctDNA clearance and clinical outcomes are ongoing. Results: Paired samples were available at SC and week 4 from 232 of 255 pts included in the ctDNA analysis: 118/130 (90.8%) in the lorlatinib arm and 114/125 (91.2%) in the crizotinib arm. ALK alterations were detected in 122/232 (52.6%) pts at SC (62/118 [52.5%] from the lorlatinib arm) but only 19/232 (8.2%) at week 4 (8/118 [6.8%] from the lorlatinib arm). Mean VAF of ALK alterations at week 4 was significantly decreased compared with SC in both treatment arms (lorlatinib -1.54, crizotinib -1.25; both P<0.0001; P=0.4239 between arms). In the lorlatinib arm, mean VAF at week 4 was significantly decreased compared with SC in pts with a complete or partial response (dVAF -1.53; n=47; P<0.0001), or stable disease (dVAF -1.37; n=12; P=0.0304). Similar results were observed in the crizotinib arm. In pts with dVAF <0 for ALK alterations, mean percent change from screening in tumor size was -40.8% with lorlatinib (n=59) and -38.7% with crizotinib (n=58). Only 2 pts had dVAF ≥0, both from the crizotinib arm. Median PFS for pts with dVAF <0 for ALK alterations was not reached in the lorlatinib arm (n=62), and was 7.4 months (95% CI, 7.2–9.3) in the crizotinib arm (n=58). Similar response and PFS data were observed in the analysis of dVAF for ALK alterations at week 24. Conclusions: Early ctDNA dynamics may predict lorlatinib efficacy in pts with previously untreated ALK-positive NSCLC. The magnitude of reduction in ctDNA at 4 weeks may be associated with better responses and potentially longer PFS. These findings further support the utility of dynamic ctDNA monitoring in ALK-positive NSCLC. Reference: Shaw AT, et al. N Engl J Med. 2020;383:2018-2029. Clinical trial information: NCT03052608.

Safety and efficacy of pralsetinib in patients with advanced RET fusion-positive non-small cell lung cancer: Update from the ARROW trial

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Background: RET fusions are targetable oncogenic drivers in 1–2% of non-small cell lung cancer (NSCLC). ARROW (NCT03037385) supported the US FDA approval of pralsetinib, a highly potent oral selective RET inhibitor for RET-altered NSCLC and thyroid cancer. Here, we present updated results for a larger population of patients with RET fusion–positive NSCLC enrolled in ARROW. Methods: ARROW is a phase 1/2 open-label study conducted at 84 sites in 13 countries. Phase 2 expansion cohorts included patients with RET fusion–positive NSCLC. Initially, all treatment-naïve patients were not candidates for platinum-based therapy, a requirement removed by protocol amendment in July 2019. Primary objectives are overall response rate (ORR; blinded independent central review [BICR] per RECIST v1.1), assessed for patients with baseline measurable disease, and safety. Results: Updated analyses were completed as of Nov 6, 2020 (data cut-off), for patients who initiated pralsetinib 400 mg QD by May 22, 2020 (enrollment cut-off). Efficacy results, including analyses for treatment-naïve patients enrolled after eligibility criteria were revised to allow candidates for platinum-based therapy, are shown in the Table. Conclusions: Pralsetinib showed rapid, potent, and durable clinical activity in patients with RET fusion-positive NSCLC (regardless of prior therapies), including poor prognosis patients not eligible for platinum-based therapy. Overall, pralsetinib was well-tolerated. These data highlight the need for RET testing early in the course of disease to identify candidates who may benefit from treatment with pralsetinib. Clinical trial information: NCT03037385. [Table: see text]

Clinical Value of EGFR Copy Number Gain Determined by Amplicon-Based Targeted Next Generation Sequencing in Patients with EGFR-Mutated NSCLC

BACKGROUND

The clinical relevance of epidermal growth factor receptor (EGFR) copy number gain in patients with EGFR mutated advanced non-small cell lung cancer on first-line tyrosine kinase inhibitor treatment has not been fully elucidated.

OBJECTIVE

We aimed to estimate EGFR copy number gain using amplicon-based next generation sequencing data and explored its prognostic value.

PATIENTS AND METHODS

Next generation sequencing data were obtained for 1566 patients with non-small cell lung cancer. EGFR copy number gain was defined based on an increase in EGFR read counts relative to internal reference amplicons and normal controls in combination with a modified z-score ≥ 3.5. Clinical follow-up data were available for 60 patients treated with first-line EGFR-tyrosine kinase inhibitors.

RESULTS

Specificity and sensitivity of next generation sequencing-based EGFR copy number estimations were above 90%. EGFR copy number gain was observed in 27.9% of EGFR mutant cases and in 7.4% of EGFR wild-type cases. EGFR gain was not associated with progression-free survival but showed a significant effect on overall survival with an adjusted hazard ratio of 3.14 (95% confidence interval 1.46-6.78, p = 0.003). Besides EGFR copy number gain, osimertinib in second or subsequent lines of treatment and the presence of T790M at relapse revealed significant effects in a multivariate analysis with adjusted hazard ratio of 0.43 (95% confidence interval 0.20-0.91, p = 0.028) and 0.24 (95% confidence interval 0.1-0.59, p = 0.001), respectively.

CONCLUSIONS

Pre-treatment EGFR copy number gain determined by amplicon-based next generation sequencing data predicts worse overall survival in EGFR-mutated patients treated with first-line EGFR-tyrosine kinase inhibitors. T790M at relapse and subsequent treatment with osimertinib predict longer overall survival.

Concomitant mutation status of ALK-rearranged non-small cell lung cancers and its prognostic impact on patients treated with crizotinib

Background

In non-small cell lung cancer (NSCLC), anaplastic lymphoma kinase (ALK) rearrangement characterizes a subgroup of patients who show sensitivity to ALK tyrosine kinase inhibitors (TKIs). However, the prognoses of these patients are heterogeneous. A better understanding of the genomic alterations occurring in these tumors could explain the prognostic heterogeneity observed in these patients.

Methods

We retrospectively analyzed 96 patients with NSCLC with ALK detected by immunohistochemical staining (VENTANA anti-ALK(D5F3) Rabbit Monoclonal Primary Antibody). Cancer tissues were subjected to next-generation sequencing using a panel of 520 cancer-related genes. The genomic landscape, distribution of ALK fusion variants, and clinicopathological characteristics of the patients were evaluated. The correlations of genomic alterations with clinical outcomes were also assessed.

Results

Among the 96 patients with immunohistochemically identified ALK fusions, 80 (83%) were confirmed by next-generation sequencing. TP53 mutation was the most commonly co-occurring mutation with ALK rearrangement. Concomitant driver mutations [2 Kirsten rat sarcoma viral oncogene homolog (KRAS) G12, 1 epidermal growth factor receptor (EGFR) 19del, and 1 MET exon 14 skipping] were also observed in 4 adenocarcinomas. Echinoderm microtubule associated protein-like 4 (EML4)-ALK fusions were identified in 95% of ALK-rearranged patients, with 16.2% of them also harboring additional non-EML4-ALK fusions. Nineteen non-EML4 translocation partners were also discovered, including 10 novel ones. Survival analyses revealed that patients concurrently harboring PIK3R2 alterations showed a trend toward shorter progression-free survival (6 vs. 13 months, P=0.064) and significantly shorter overall survival (11 vs. 32 months, P=0.004) than did PIK3R2-wild-type patients. Patients with concomitant alterations in PI3K the signaling pathway also had a shorter median overall survival than those without such alterations (23 vs. 32 months, P=0.014), whereas progression-free survival did not differ significantly.

Conclusions

The spectrum of ALK-fusion variants and the landscape of concomitant genomic alterations were delineated in 96 NSCLC patients. Our study also demonstrated the prognostic value of concomitant alterations in crizotinib-treated patients, which could facilitate improved stratification of ALK-rearranged NSCLC patients in the selection of candidates who could optimally benefit from therapy.

Relevance and Effectiveness of Molecular Tumor Board Recommendations for Patients With Non–Small-Cell Lung Cancer With Rare or Complex Mutational Profiles

PURPOSE

Molecular tumor boards (MTBs) provide physicians with a treatment recommendation for complex tumor-specific genomic alterations. National and international consensus to reach a recommendation is lacking. In this article, we analyze the effectiveness of an MTB decision-making methodology for patients with non–small-cell lung cancer (NSCLC) with rare or complex mutational profiles as implemented in the University Medical Center Groningen (UMCG).

METHODS

The UMCG-MTB comprises (pulmonary) oncologists, pathologists, clinical scientists in molecular pathology, and structural biologists. Recommendations are based on reported actionability of variants and molecular interpretation of pathways affected by the variant and supported by molecular modeling. A retrospective analysis of 110 NSCLC cases (representing 106 patients) with suggested treatment of complex genomic alterations and corresponding treatment outcomes for targeted therapy was performed.

RESULTS

The MTB recommended targeted therapy for 59 of 110 NSCLC cases with complex molecular profiles: 24 within a clinical trial, 15 in accordance with guidelines (on label) and 20 off label. All but 16 recommendations involved patients with an EGFR or ALK mutation. Treatment outcome was analyzed for patients with available follow-up (10 on label and 16 off label). Adherence to the MTB recommendation (21 of 26; 81%) resulted in an objective response rate of 67% (14 of 21), with a median progression-free survival of 6.3 months (interquartile range, 3.2-10.6 months) and an overall survival of 10.4 months (interquartile range, 6.3-14.6 months).

CONCLUSION

Targeted therapy recommendations resulting from the UMCG-MTB workflow for complex molecular profiles were highly adhered to and resulted in a positive clinical response in the majority of patients with metastatic NSCLC.

An All-In-One Transcriptome-Based Assay to Identify Therapy-Guiding Genomic Aberrations in Nonsmall Cell Lung Cancer Patients

The number of genomic aberrations known to be relevant in making therapeutic decisions for non-small cell lung cancer patients has increased in the past decade. Multiple molecular tests are required to reliably establish the presence of these aberrations, which is challenging because available tissue specimens are generally small. To optimize diagnostic testing, we developed a transcriptome-based next-generation sequencing (NGS) assay based on single primed enrichment technology. We interrogated 11 cell lines, two patient-derived frozen biopsies, nine pleural effusion, and 29 formalin-fixed paraffin-embedded (FFPE) samples. All clinical samples were selected based on previously identified mutations at the DNA level in EGFR, KRAS, ALK, PIK3CA, BRAF, AKT1, MET, NRAS, or ROS1 at the DNA level, or fusion genes at the chromosome level, or by aberrant protein expression of ALK, ROS1, RET, and NTRK1. A successful analysis is dependent on the number of unique reads and the RNA quality, as indicated by the DV200 value. In 27 out of 51 samples with >50 K unique reads and a DV200 >30, all 19 single nucleotide variants (SNVs)/small insertions and deletions (INDELs), three MET exon 14 skipping events, and 13 fusion gene transcripts were detected at the RNA level, giving a test accuracy of 100%. In summary, this lung-cancer-specific all-in-one transcriptome-based assay for the simultaneous detection of mutations and fusion genes is highly sensitive.

Tepotinib in Non-Small-Cell Lung Cancer with MET Exon 14 Skipping Mutations

BACKGROUND

A splice-site mutation that results in a loss of transcription of exon 14 in the oncogenic driver MET occurs in 3 to 4% of patients with non-small-cell lung cancer (NSCLC). We evaluated the efficacy and safety of tepotinib, a highly selective MET inhibitor, in this patient population.

METHODS

In this open-label, phase 2 study, we administered tepotinib (at a dose of 500 mg) once daily in patients with advanced or metastatic NSCLC with a confirmed MET exon 14 skipping mutation. The primary end point was the objective response by independent review among patients who had undergone at least 9 months of follow-up. The response was also analyzed according to whether the presence of a MET exon 14 skipping mutation was detected on liquid biopsy or tissue biopsy.

RESULTS

As of January 1, 2020, a total of 152 patients had received tepotinib, and 99 patients had been followed for at least 9 months. The response rate by independent review was 46% (95% confidence interval [CI], 36 to 57), with a median duration of response of 11.1 months (95% CI, 7.2 to could not be estimated) in the combined-biopsy group. The response rate was 48% (95% CI, 36 to 61) among 66 patients in the liquid-biopsy group and 50% (95% CI, 37 to 63) among 60 patients in the tissue-biopsy group; 27 patients had positive results according to both methods. The investigator-assessed response rate was 56% (95% CI, 45 to 66) and was similar regardless of the previous therapy received for advanced or metastatic disease. Adverse events of grade 3 or higher that were considered by investigators to be related to tepotinib therapy were reported in 28% of the patients, including peripheral edema in 7%. Adverse events led to permanent discontinuation of tepotinib in 11% of the patients. A molecular response, as measured in circulating free DNA, was observed in 67% of the patients with matched liquid-biopsy samples at baseline and during treatment.

CONCLUSIONS

Among patients with advanced NSCLC with a confirmed MET exon 14 skipping mutation, the use of tepotinib was associated with a partial response in approximately half the patients. Peripheral edema was the main toxic effect of grade 3 or higher. (Funded by Merck [Darmstadt, Germany]; VISION ClinicalTrials.gov number, NCT02864992.).

Abstract 4335: Clinical value of EGFR gene amplifications detected using amplicon based targeted next generation sequencing data in lung adenocarcinoma patients

Objective The relevance of EGFR gene amplification in patients with EGFR-mutated advanced non-small cell lung cancer (NSCLC) has not been fully elucidated. Moreover, a limited number of studies have been published on methods to estimate gene amplifications based on routinely performed targeted next generation sequencing (NGS). In this study we aimed to determine whether PCR-based targeted NGS data on tumor tissue can be used to estimate presence of gene amplifications and explored the prognostic value of EGFR gene amplification in EGFR mutated NSCLC patients.

Materials and methods A total of 3,194 good quality targeted NGS data files were retrieved from 2014 to 2017. Among those, 1,729 NSCLC samples originated from 1,586 NSCLC patients of whom 134 had an EGFR mutation (8.2%). Clinical data were available for 66 of the patients. Raw sequencing data were re-analyzed using a custom designed pipeline. The presence of an amplification was based on the read depth of a given amplicon relative to a set of reference amplicons from the sample or relative to a set of normal control samples. Reference amplicons were selected based on low degree of variation in read depth amongst all tested samples. Amplifications were regarded significant when the ratio was ≥3 and the z score was ≥3.5. Technical validation was done by FISH and MLPA. Cox regression analysis on overall survival was done with each of the amplification parameters using SPSS.

Results No amplifications were detected for the ALK, KIT, NRAS, PDGFRA, GNAQ and MAP2K1 gene loci, whereas amplifications for BRAF, ESR1, GNA11, HRAS, KRAS, MET and PIK3CA were observed at a low frequency. Depending on the amplification analysis strategy (within sample or relative to normal controls), 19% and 13% of the EGFR mutated group had an EGFR amplification, respectively. In EGFR wild type patients, amplifications were detected in 5% and 4% of the patients using the two methods, respectively. The sensitivity and specificity of the NGS based estimation of amplifications for EGFR was 94% (14/15) and 97% (34/35) respectively for both data analysis approaches. Patients with concurrent EGFR mutations and amplifications (estimated within sample) treated with EGFR-TKI had a significantly worse overall survival compared with those without concurrent EGFR amplifications (ratio, p=0.047 and z score, p=0.015). Cox regression analysis indicated a borderline significant interaction between ratio and z score (p=0.052).

Conclusion Routinely obtained amplicon-based NGS data can be used to identify gene amplifications. The presence of EGFR amplifications in EGFR mutant patients is predictive of a worse overall survival.

Keywords: Lung adenocarcinoma, EGFR, survival, tyrosine kinase inhibitor

Citation Format: Pei Meng, Jiacong Wei, Miente Martijn Terpstra, Anke van Rijk, Menno Tamminga, Frank Scherpen, Arja ter Elst, Mohamed Z. Alimohamed, Lennart F. Johansson, T. Jeroen N. Hiltermann, Harry J. Groen, Klaas Kok, Anthonie J. van der Wekken, Anke van den Berg. Clinical value of EGFR gene amplifications detected using amplicon based targeted next generation sequencing data in lung adenocarcinoma patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4335.

Combined osimertinib, dabrafenib and trametinib treatment for advanced non-small-cell lung cancer patients with an osimertinib-induced BRAF V600E mutation

INTRODUCTION

Previous studies have reported an acquiredBRAF V600E mutation as a potential resistance mechanism to osimertinib treatment in advanced NSCLC patients with an activating mutation in EGFR. However, the therapeutic effect of combining dabrafenib and trametinib with osimertinib remains unclear. Here we report treatment efficacy in two cases with acquired BRAF V600E mutations.

METHODS

Two patients with anEGFR exon 19 deletion and a T790 M mutation, both treated with osimertinib, acquired a BRAF V600E mutation at disease progression. Following the recommendation of the molecular tumor board, a concurrent combination of dabrafenib and trametinib plus osimertinib was administered.

RESULTS

Because of toxicity, one patient ultimately received a reduced dose of dabrafenib and trametinib combined with a normal dose of osimertinib. Clinical response in this patient lasted for 13.4 months. Re-biopsy upon tumor progression revealed loss ofBRAF V600E and emergence of EGFR C797S. The other patient, treated with full doses of the combined therapy, had progression with metastases in lung and brain one month after starting therapy.

CONCLUSION

BRAF V600E may be a resistance mechanism induced by osimertinib in EGFR-mutated advanced NSCLC. Combined treatment using dabrafenib/trametinib concurrently with osimertinib needs to be explored for osimertinib-induced BRAF V600E mutation.

Molecular imaging biomarkers for immune checkpoint inhibitor therapy

Immune checkpoint inhibitors (ICIs) have substantially changed the field of oncology over the past few years. ICIs offer an alternative treatment strategy by exploiting the patients' immune system, resulting in a T cell mediated anti-tumor response. These therapies are effective in multiple different tumor types. Unfortunately, a substantial group of patients do not respond to ICIs. Molecular imaging, using single-photon emission computed tomography (SPECT) and positron emission tomography (PET), can provide non-invasive whole-body visualization of tumor and immune cell characteristics and might support patient selection or response evaluations for ICI therapies. In this review, recent studies with 18F-fluorodeoxyglucose-PET imaging, imaging of immune checkpoints and imaging of immune cells will be discussed. These studies are until now mainly exploratory, but the first results suggest that molecular imaging biomarkers could have a role in the evaluation of ICI therapy.

Abstract 2989: An all-in-one transcriptome-based assay to identify therapy-related biomarkers in lung cancer

Background. In the past decade, treatment of advanced stage lung cancer patients guided by somatic aberrations has become routine practice. Different molecular tests are being applied to detect all targetable mutations and fusions. However, in most cases tissue biopsies are small, hampering multiple independent diagnostic tests. To optimize diagnostic testing we developed an all-in-one transcriptome-based assay.

Methods. We have developed a targeted next generation sequencing protocol that uses total RNA as input and is based on the Single Primed enrichment Technology (SPET). We included 11 cell lines, four frozen biopsies, 12 pleural effusion samples and 32 FFPE samples with in total 41 known mutations (including EGFR n=15; KRAS n=11; BRAF n=2; PIK3CA n=3 ), 21 fusion genes (including ALK n=15; ROS n=3) and 3 cases of MET exon14 skipping.

Results. We confirmed presence of 32 out of 41 mutations, 19 out of 23 fusions and all three cases of exon skipping by our assay. Besides confirming the fusions, we were also able to identify the fusion gene partner for all detected fusion transcripts. For the samples for which we failed to detect the mutations or fusions, the read depth of the target region was less than four, indicating low expression, low tumor content or insufficient unique reads. Independent RNA-based ddPCR on six unconfirmed mutations were all positive, albeit with low numbers of mutant droplets in some cases. One of three undetected fusions was positive in a NanoString fusion gene detection assay. For one of two negative cases, the fusion was most likely false positive by FISH, as this patient was FISH-break positive for both ALK and RET, which is never reported before.

Conclusions. This study proved feasibility of this targeted all-in-one transcriptome-based assay for simultaneous detection of mutations and fusions even in relatively small FFPE tissue biopsies. Moreover, we were able to detect the fusion partner genes in all positive cases. We expect that for routine diagnostic testing using an enrichment for tumor cell-rich areas of recently prepared FFPE blocks, the success rate of the all-in-one transcriptome approach will reach similar sensitivity as currently used diagnostic tests.

Citation Format: Klaas Kok, Jiacong Wei, Anna A. Rybczynska, Pei Meng, Martijn M. Terpstra, Anthonie J. van der Wekken, Jeroen T. Hiltermann, Ed Schuuring, Harry J. Groen, Anke van den Berg. An all-in-one transcriptome-based assay to identify therapy-related biomarkers in lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2989.

Abstract 1398: Modeling of drug-protein interactions to support clinical decision making for therapy-resistant EGFR or ALK-positive non-small cell lung carcinoma

Background Activating mutations in epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) rearrangements are drugable targets in respectively 10% and 4% of advanced non-small cell lung cancer (NSCLC) patients. Different EGFR and ALK inhibitors are available for target-dependent and sometimes independent drug resistance. Mutations in the EGFR or ALK kinase domain are major mechanisms of drug-induced resistance. Prediction of protein-drug interactions using protein modeling of these mutated domains in EGFR and ALK could provide valuable information for the selection of drugs for subsequent treatment. Methods Biopsies from advanced NSCLC patients with an activating EGFR mutation or ALK rearrangement that were taken at therapy resistance were analyzed by targeted panel sequencing. In case of unknown or accumulating mutations in the EGFR and ALK kinase domains, docking poses and binding affinities of drug-protein interactions were determined. The outcome of both calculations were used to create a likelihood ranking of currently available ALK and EGFR inhibitors to bind to specific mutated targets. Follow-up data was available for a limited number of patients who were treated based on this prediction. Results Prediction Protein-drug interactions were modeled for 59 EGFR mutations and 24 ALK mutations that were detected at therapy resistance. Prediction of therapeutic activities for gefitinib, afatinib, dacomitinib, for EGFR mutations, and alectinib, ceritinib, entrectinib and lorlatinib for ALK mutations will be shown. Case example Female (35y), never-smoker, cT1bN2M1c NSCLC with metastases in lymph nodes, liver, bones and asymptomatic brain metastases, ALK translocation-positive without known ALK gatekeeper mutations. Treatment with crizotinib was started, but unacceptable liver enzyme toxicity developed after 6 weeks. Switching therapy to alectinib resulted in a complete metabolic response with absence of brain metastases by MRI. After 9 months the patient progressed with liver, brain and leptomeningeal metastases. Treatment with ceritinib had no effect. A liver biopsy revealed the ALK p.(L1196M) gatekeeper mutation. The case was discussed in the molecular tumor board, because this gatekeeper variant was reported to be sensitive to ceritinib. In contrast, ALK-drug interaction modeling indicated a better binding profile of lorlatinib than ceritinib, not only based in binding affinity but also in the ability of lorlatinib to reproduce the bioactive conformation found in literature. The patient was treated with lorlatinib and recovered in 5 days with a persistent partial response at 2 month follow up and significant clinical benefit. Conclusion Modeling of the protein-drug interactions supports clinical decision making for treatment of NSCLC patients in case of therapy resistance to EGFR and ALK inhibitors.

Citation Format: Juliana F. Vilacha Madeira R Santos, Birgitta I. Hiddinga, Leon C. van Kempen, Arja ter Elst, Lucie B. Hijmering, Thijo J. Hiltermann, Ed Schuuring, Matthew R. Groves, Harry J. Groen, Anthonie J. van der Wekken. Modeling of drug-protein interactions to support clinical decision making for therapy-resistant EGFR or ALK-positive non-small cell lung carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1398.

CX Chemokine Receptor 7 Contributes to Survival of KRAS-Mutant Non-Small Cell Lung Cancer upon Loss of Epidermal Growth Factor Receptor

KRAS-driven non-small cell lung cancer (NSCLC) patients have no effective targeted treatment. In this study, we aimed to investigate targeting epidermal growth factor receptor (EGFR) as a therapeutic approach in KRAS-driven lung cancer cells. We show that ablation of EGFR significantly suppressed tumor growth in KRAS-dependent cells and induced significantly higher expression of CX chemokine receptor 7 (CXCR7) and activation of MAPK (ERK1/2). Conversely, rescue of EGFR led to CXCR7 downregulation in EGFR^−/− cells. Dual EGFR and CXCR7 inhibition led to substantial reduction of MAPK (pERK) and synergistic inhibition of cell growth. Analysis of two additional EGFR knockout NSCLC cell lines using CRISPR/Cas9 revealed genotype dependency of CXCR7 expression. In addition, treatment of different cells with gefitinib increased CXCR7 expression in EGFR^wt but decreased it in EGFR^mut cells. CXCR7 protein expression was detected in all NSCLC patient samples, with higher levels in adenocarcinoma as compared to squamous cell lung carcinoma and healthy control cases. In conclusion, EGFR and CXCR7 have a crucial interaction in NSCLC, and dual inhibition may be a potential therapeutic option for NSCLC patients.

89Zr-atezolizumab imaging as a non-invasive approach to assess clinical response to PD-L1 blockade in cancer

Programmed cell death protein-1/ligand-1 (PD-1/PD-L1) blockade is effective in a subset of patients with several tumor types, but predicting patient benefit using approved diagnostics is inexact, as some patients with PD-L1-negative tumors also show clinical benefit^1,2. Moreover, all biopsy-based tests are subject to the errors and limitations of invasive tissue collection^3-11. Preclinical studies of positron-emission tomography (PET) imaging with antibodies to PD-L1 suggested that this imaging method might be an approach to selecting patients^12,13. Such a technique, however, requires substantial clinical development and validation. Here we present the initial results from a first-in-human study to assess the feasibility of imaging with zirconium-89-labeled atezolizumab (anti-PD-L1), including biodistribution, and secondly test its potential to predict response to PD-L1 blockade (ClinicalTrials.gov identifiers NCT02453984 and NCT02478099). We imaged 22 patients across three tumor types before the start of atezolizumab therapy. The PET signal, a function of tracer exposure and target expression, was high in lymphoid tissues and at sites of inflammation. In tumors, uptake was generally high but heterogeneous, varying within and among lesions, patients, and tumor types. Intriguingly, clinical responses in our patients were better correlated with pretreatment PET signal than with immunohistochemistry- or RNA-sequencing-based predictive biomarkers, encouraging further development of molecular PET imaging for assessment of PD-L1 status and clinical response prediction.

Abstract 1602: Urine cell-free DNA as early biomarker in immunotherapy response in NSCLC

Introduction: Immunotherapy shows a durable tumor response in approximately 20% of advanced NSCLC patients. Imaging by CT is used to evaluate tumor response. PD-L1 immunohistochemistry is generally used to predict survival advantages, however with low predictive value. Therefore, it is important that alternative predictive biomarkers are investigated. Minimal invasive techniques may be a solution. The role of circulating cell-free DNA (cfDNA) was found to be an early biomarker for tumor response in KRAS positive Non-Small Cell Lung Cancer (NSCLC) patients treated with immunotherapy (N=6). In this study we will determine the role of urine cell-free DNA (ucfDNA) in an extended cohort. The non-invasive method of urine collection makes it an excellent source for mutation detection and follow-up.

Methods: In an ongoing study KRAS positive patients treated with immunotherapy, are being tested for cfDNA at baseline (before treatment, 1, 2, 4, 6 and thereafter every 12 weeks until disease progression) with a KRAS G12-13 or Q61H digital droplet PCR (ddPCR) screening assay (BioRad). In a pilot study, urine from these patients is collected in a tube with 5 ml of STRECK reagent at baseline and at 6 weeks.

Results: In 16/27 patients with KRAS positive advanced NSCLC, the mutation was detected in plasma at baseline and subsequent evaluation time points. Urine cfDNA as a predictive marker seems promising and results will be reported and presented at the AACR meeting.

Conclusion: Among patients with advanced NSCLC treated with immunotherapy plasma and urine cfDNA are collected and will be presented as non-invasive early biomarker for tumor response evaluation.

Citation Format: Anthonie J. van der Wekken, Arja ter Elst, Anneke Miedema, Thijo J. Hiltermann, Harry J. Goen, Ed Schuuring. Urine cell-free DNA as early biomarker in immunotherapy response in NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1602.

Response to HER2 Inhibition in a Patient With Brain Metastasis With EGFR TKI Acquired Resistance and an HER2 Amplification

A 62-year-old man was referred to our university hospital for treatment of advanced adenocarcinoma of the lung after disease progression on two lines of EGFR TKI and one line of chemotherapy. Fluorescent in situ hybridization analysis upon progression showed an HER2 amplification. At our weekly Molecular Tumor Board (MTB), a decision was made to treat this patient with afatinib, which resulted in a partial response. However, progression was observed with a facial nerve paresis due to a metastasis in the skull. A biopsy of a location in the thorax revealed the presence of an EGFR-T790M mutation associated with acquired resistance, after which treatment with osimertinib was started. After 6 months, disease progression was observed, and a new biopsy was taken from the pelvic bone, which revealed the original amplification of HER2 together with the EGFR-L858R mutation, the EGFR-T790M mutation was not detected. The MTB decided to treat the patient with trastuzumab/paclitaxel. A partial response was observed in different bone lesions, while the skull metastasis with ingrowth in the brain remained stable for 6 months. Because of progression of the bone metastases after 6 months, a biopsy of a lesion in the thorax wall was taken. In this lesion, the EGFR-T790M mutation could be detected again. The MTB advised to start treatment with a combination of osimertinib and afatinib. This resulted in an impressive clinical improvement and a partial response of the bone metastases on the most recent 18-fluorodeoxyglucose positron emission tomography and computer tomography-scan. In conclusion, adjusting treatment to the mutational make-up of the tumor is a great challenge. For optimal treatment response multiple biopsies and re-biopsy upon progression are imperative. As more genes are investigated, treatment decision becomes increasingly difficult, therefore, expert opinions from an MTB is essential.

Abstract 754: Treatment decision-making of rare ERBB2 (HER2) mutations in lung cancer; a role for multidisciplinary molecular tumor boards

Introduction:

Breakthroughs in cancer research have resulted in mutation-specific targeted therapies (precision medicine). Most of these new drugs are only effective in patients with an actionable molecular profile. Thus, predictive molecular testing enables oncologists to select individual patients for the most appropriate (targeted) therapy and to reduce the burden of overtreatment. The number of clinically relevant predictive markers that are routinely analyzed is growing rapidly, resulting in the identification of rare mutations, mutations with unknown relevance and coexistence of two or more mutations in the same sample. Incorporating these into the optimal treatment for the individual patient can be complex.

Methods: A total of 2461 sequential tumor biopsies were analyzed at our institute using targeted next generation sequencing (Ion Torrent platform). 230 of these patients were discussed at a weekly Molecular Tumor Board (MTB) meeting. Cases involved 170 lung and 21 colorectal carcinomas, 24 melanomas, 1 GIST and a range of other malignancies with uncommon and rare mutations. The board is composed of pulmonologists, medical oncologists, pathologists and clinical scientists in molecular pathology. The goal of the MTB is to discuss the biological and clinical relevance of rare mutations or uncommon profiles and to suggest treatment options based on registered, off-label or trial-based drugs presently available in the Netherlands.

Results: In this abstract we report on four patients with an ERBB2 exon 20 mutation and 1 patient with ERBB2 amplification received anti-HER2 treatment after an MTB consensus decision. Two patients with an insertion in exon 20 of ERBB2: (c.2313_2324dup; p.(Y772_A775dup)) received first line therapy with afatinib and showed a partial response and stable disease respectively. One patient with a c.2524G&gt;A; p.(V842I) mutation received afatinib and showed stable disease for 3 months. A patient with another ERBB2 exon 20 insertion (c.2326_2327insTAT:p.(G776delinsVC)) received afatinib but had progressive disease within two months. One patient with an ERBB2 amplification by FISH and high (3+) HER2(ERBB2) expression, showed a partial response to trastuzumab. All patients had stage IV and would without genomic knowledge been treated with chemotherapy.

Conclusion: Lung cancer patients with sporadic ERBB2 mutations might benefit from targeted ERBB2 therapy. For an optimal treatment decision, patients with rare mutations in general, may benefit from discussion in a multidisciplinary molecular tumor board. In the future, both the considerations for targeted therapy as well as treatment response and toxicity should be registered in an open-access database and shared with other national and international Molecular Tumor Board initiatives to allow comparison with traditional treatments.

Citation Format: Arja ter Elst, Nils A. 't Hart, Anthonie J. van der Wekken, Wim Timens, Lucie B. Hijmering-Kappelle, Geke A. Hospers, Hilde Jalving, Elise M. van der Logt, Leon C. van Kempen, Sjoukje F. Oosting, Matthew R. Groves, T Jeroen Hiltermann, Anke van den Berg, Harry J. Groen, Ed Schuuring. Treatment decision-making of rare ERBB2 (HER2) mutations in lung cancer; a role for multidisciplinary molecular tumor boards [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 754. doi:10.1158/1538-7445.AM2017-754