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Prediction of PFS using a dynamic assessment of ctDNA in patients with EGFR mutated NSCLC with osimertinib therapy
abstracts
Annals of Oncology
41P
Customisation of therapeutic strategy in metastatic colorectal cancer by use of liquid biopsies: Updated results of an observational study
M. Kastrisiou1, G. Zarkavelis1, A. Kougioumtzi2, C. Tzallas3, E. Saloustros4, A. Kotsakis4, E. Papadopoulou5, G. Nasioulas5, A. Batistatou6, A. Magklara2, G. Pentheroudakis1 1 Department of Medical Oncology, University General Hospital of Ioannina, Ioannina, Greece, 2Laboratory of Clinical Chemistry, University of Ioannina Medical Faculty, Ioannina, Greece, 3Laboratory of Clinical Chemistry, University General Hospital of Ioannina, Ioannina, Greece, 4Department of Medical Oncology, University General Hospital of Larissa, Larissa, Greece, 5Genekor Medical S.A., Gerakas, Greece, 6 Department of Pathology, University of Ioannina Medical Faculty, Ioannina, Greece Background: Metastatic colorectal cancer (mCRC) affects 20% of patients diagnosed with colorectal malignancy and is a major cause of cancer-related death worldwide. Epidermal growth factor receptor (EGFR) blockade with monoclonal antibodies, in combination with chemotherapy, has been shown to benefit patients with RAS wild type tumours. Our project explores real-time assessment of mCRC mutational profile, by use of two methods of circulating tumour DNA (ctDNA) analysis, and its potential to better guide therapeutic decisions. Methods: Baseline plasma samples were prospectively collected from 64 patients at diagnosis of mCRC and at disease progression. Analysis of KRAS and NRAS exons 2, 3 and 4 was performed with the highly sensitive BEAMing digital polymerase chain reaction (PCR) and next-generation sequencing (NGS). In a subgroup of patients, with baseline RAS mutations, mid-treatment liquid biopsies were performed, to assess the change in ctDNA RAS mutational load as response biomarker. Mutational status of matched tumour tissue, generated with a conventional PCR-based method or NGS, was prospectively recorded for all patients. Results: Preliminary results of our study, presented at the EACR-ESMO Joint Conference on Liquid Biopsies, have shown detection of RAS mutations in the ctDNA from over 50% of patients, with a satisfactory plasma-tissue concordance. An update on these data, as well as on the predictive value of ctDNA RAS mutational load dynamics, will be presented. Disease progression data, in light of baseline RAS status, will also be revisited, as almost 20% of patients have progressed on first-line treatment. In addition, the concordance of BEAMing and NGS as liquid biopsy methods is to be studied in a subgroup of patients with available plasma samples. Conclusions: The larger sample size and the maturity of this updated analysis further add on the value of our work, the results of which remain in line with the literature. Our study serves as a real-life example of the potential of liquid biopsies to detect RAS mutation status changes, allowing for precision-oncology therapeutic approaches in the continuum of care of metastatic colorectal cancer patients. Legal entity responsible for the study: Department of Medical Oncology, University General Hospital of Ioannina. Funding: Amgen, Hellenic Society of Medical Oncology (HeSMO) and Society for Study of Clonal Heterogeneity of Neoplasia (EMEKEN). Disclosure: G. Pentheroudakis: Research grant / Funding (institution): Amgen. All other authors have declared no conflicts of interest.
42P
Prediction of PFS using a dynamic assessment of ctDNA in patients with EGFR mutated NSCLC with osimertinib therapy
F. Moiseenko, M. Stepanova, A. Zhabina, A. Myslik, V. Klimenko, N. Rysev, E. Artemieva, K. Shelekhova, A. Bogdanov, N. Volkov, V. Moiseenko St. Petersburg Clinical Research Center of Specialized Types of Care (Oncology), St. Petersburg, Russian Federation
23%) and tumor tissue (sensitivity of 88%). The appointment of osimertinib in the second line allows to increase ORR, but also PFS relative to standard chemotherapy. Methods: In this study we investigated the effect on PFS by the dynamic determination of ctDNA. Included patients with metastatic EGFR-associated NSCLC, in whom, a T790M mutation was detected during treatment TKIs of 1-2 generations.Patients received osimertinib therapy 80 mg / day, daily, until progression of the disease appears. Blood test was taken to conduct a qualitative assessment of ctDNA in dynamics by the RT-PCR method, fist test was done before starting treatment, and then every 2 months. Results: From August 2016 to December 2018, 22 patients were identified T790M þ associated progression of EGFR þ NSCLC. 81.9% (18/22) are women, 18.1% (4/22) are men. The average age is 61.2 years (50-75). 1/22 had smoking experience for more than 30 years. The molecular genetic profile in 16 is represented by ex19del, 5 L858R, 1 - a combination of rare mutations G719S þ S768I. The effect of therapy was evaluated in 20/22 patients. PR and SD were registered in 9/20 (45%) and 10/20 (50%) patients, respectively. Median PFS – 18.9 months (CI 95%, 10.6 - 27.1). In 12/22 patients was observed the disappearance of ctDNA T790M þ after 2 months of osimertinib therapy. PFS is 24.4 months (CI calculation is NA), in patients with no mutation detected in the second month of treatment compared with the group of patients in which the ctDNA was determined (PFS 7.6 months) (CI 95%, 3.0 –12.9) (p ¼ 0.003). The confidence interval for one of the medians cannot be calculated the 75% percentile was 3.4 þ/- 3.3 and 18.8 þ/- 6.3. Conclusions: The disappearance of ctDNA in plasma after 2 months of treatment with osimertinib is associated with an increase in PFS and can be considered as a predictive marker in patients with metastatic NSCLC EGFR T790M þ Grant supported RUSSCO / RakFond 2018-01-YS-ECI. Legal entity responsible for the study: St. Petersburg Clinical Research Center of Specialized Types of Care (Oncology). Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.
43P
Targeted high-throughput sequencing for somatic mutations identification in thyroid cancer management
V. Yakushina1, L. Lerner2, T. Avdeeva3, T. Kazubskaya4, T. Kondrat’ieva4, A. Lavrov1 Research Centre for Medical Genetics, Moscow, Russian Federation, 2PreMed-European Technologies, Moscow, Russian Federation, 3Moscow City Clinical Hospital after V.M. Buyanov, Moscow, Russian Federation, 4N.N. Blokhin Russian Cancer Research Center, Moscow, Russian Federation
1
Background: Main challenges in thyroid cancer management are low sensitivity of preoperative differential diagnostics and absence of sufficient prognostic markers for choosing of therapeutic strategy, including decision regarding radioiodine therapy. The study aims evaluation of clinical utility of analyses of comprehensive set of driver and secondary mutations with targeted high-throughput sequencing. Methods: Point mutations in 52 genes, CNVs at 1q, 9q, 17q, 22q, and fusions of 66 genes were analyzed with targeted high-throughput sequencing. The analyzed mutations included well known driving and putatively driving mutations selected from TCGA project and literature, and secondary mutations with known or putative prognostic significance. Enrichment of regions of interest was performed with AmpliSeq technology. Fusions were detected by the presence of chimeric transcripts. Sequencing was performed on Illumina NextSeq (for point mutations and CNVs) or MiSeq (for fusions). Samples included 64 confirmed cancer samples (41 samples with Bethesda IVV cytology, and 23 samples - Bethesda VI cytology), 16 confirmed benign samples, 12 normal tissue samples. Results: Mutations detected in carcinomas included, in addition to BRAF and RASs: CDKN2B, ZFHX3, PDGFRA, KIT, NTRK3, ECM2, TERT, KDR, KMT2A, TP53, RNF213, APC, CHEK2, PTEN, PPM1D, ATR, CDKN2A, CTNNB1, ARID1B, KMT2C, ALK, DICER1, fusions of NTRK3, NTRK1, PPARG and RET, and CNVs 22q-del b 9qdel. The detected mutations allow to characterize all studied cancer cases. In benign nodules mutations in NRAS, TSC2, KDR, EIF1AX, ARID1B, TSHR, ZFHX3, GRIN3A, DICER1, HRAS, CHEK2 were found. Conclusions: Tests limited to BRAF, K/N/HRAS, RET-PTC1/3, PAX-PPARG mutations have low diagnostic value. The developed panel allows analyzing an expanded range of mutations, including recently described rearrangements and CNV. Design of the panel, initial validation and sequencing of cancer samples were funded by Foundation for Assistance to Small Innovative Enterprises in Science and Technology (@ 442U2/9119 - 3-40846); sequencing of benign samples was supported by the grant of the Russian Science Foundation (Agreement 19-75-00053). Legal entity responsible for the study: The authors. Funding: Foundation for Assistance to Small Innovative Enterprises in Science and Technology (442UC2/9119 - C3-40846); Russian Science Foundation (Agreement 1975-00053). Disclosure: All authors have declared no conflicts of interest.
Background: Resistance on the 1st or 2nd generation TKIs in patients with EGFR mutated NSCLC to the therapy occurs on average after 8-12 months. The most common (49-60%) resistance mechanism is the appearance of the T790M. Its determination is possible by different methods of examination: ctDNA (false-negative probability
Volume 30 | Supplement 7 | November 2019
doi:10.1093/annonc/mdz413 | vii13
Downloaded from https://academic.oup.com/annonc/article-abstract/30/Supplement_7/mdz413.047/5613320 by guest on 20 December 2019
(13.37). There were 470 patients who were white, 30 of other races and 10 patients with missing race information. A total of 246 patients were grade 2 while 264 patients were grade 3. On univariable analysis, all APOBEC3 genes high expression were significantly associated with worse prognosis. However, on multivariable analysis, only APOBEC3B, APOBEC3C, APOBEC3D, APOBEC3F, APOBEC3G and APOBEC3H high expression were significantly associated with worse survival where the HR (95% CI) were 1.63 (1.1-2.42), 2.16 (1.47-3.19), 1.72 (1.19-2.49), 2.6 (1.78-3.86), 2.3 (1.61-3.45) and 1.67 (1.17-2.4) respectively. Using the group of low expression of all six APOBEC3 proteins as reference, Patients with high expression of six APOBEC3 proteins had the worst prognosis with a HR (95% CI) of 5.66 (2.74-11.68). Conclusions: mRNA expression of APOBEC3 (B,C,D,F,G,H) genes can be effective molecular markers for the prognosis of LGG patients. A joint analysis of APOBEC3 genes expression might improve its sensitivity. Legal entity responsible for the study: Khaled Ismaeil. Funding: Has not received any funding. Disclosure: The author has declared no conflicts of interest.
Annals of Oncology
41P
Customisation of therapeutic strategy in metastatic colorectal cancer by use of liquid biopsies: Updated results of an observational study
M. Kastrisiou1, G. Zarkavelis1, A. Kougioumtzi2, C. Tzallas3, E. Saloustros4, A. Kotsakis4, E. Papadopoulou5, G. Nasioulas5, A. Batistatou6, A. Magklara2, G. Pentheroudakis1 1 Department of Medical Oncology, University General Hospital of Ioannina, Ioannina, Greece, 2Laboratory of Clinical Chemistry, University of Ioannina Medical Faculty, Ioannina, Greece, 3Laboratory of Clinical Chemistry, University General Hospital of Ioannina, Ioannina, Greece, 4Department of Medical Oncology, University General Hospital of Larissa, Larissa, Greece, 5Genekor Medical S.A., Gerakas, Greece, 6 Department of Pathology, University of Ioannina Medical Faculty, Ioannina, Greece Background: Metastatic colorectal cancer (mCRC) affects 20% of patients diagnosed with colorectal malignancy and is a major cause of cancer-related death worldwide. Epidermal growth factor receptor (EGFR) blockade with monoclonal antibodies, in combination with chemotherapy, has been shown to benefit patients with RAS wild type tumours. Our project explores real-time assessment of mCRC mutational profile, by use of two methods of circulating tumour DNA (ctDNA) analysis, and its potential to better guide therapeutic decisions. Methods: Baseline plasma samples were prospectively collected from 64 patients at diagnosis of mCRC and at disease progression. Analysis of KRAS and NRAS exons 2, 3 and 4 was performed with the highly sensitive BEAMing digital polymerase chain reaction (PCR) and next-generation sequencing (NGS). In a subgroup of patients, with baseline RAS mutations, mid-treatment liquid biopsies were performed, to assess the change in ctDNA RAS mutational load as response biomarker. Mutational status of matched tumour tissue, generated with a conventional PCR-based method or NGS, was prospectively recorded for all patients. Results: Preliminary results of our study, presented at the EACR-ESMO Joint Conference on Liquid Biopsies, have shown detection of RAS mutations in the ctDNA from over 50% of patients, with a satisfactory plasma-tissue concordance. An update on these data, as well as on the predictive value of ctDNA RAS mutational load dynamics, will be presented. Disease progression data, in light of baseline RAS status, will also be revisited, as almost 20% of patients have progressed on first-line treatment. In addition, the concordance of BEAMing and NGS as liquid biopsy methods is to be studied in a subgroup of patients with available plasma samples. Conclusions: The larger sample size and the maturity of this updated analysis further add on the value of our work, the results of which remain in line with the literature. Our study serves as a real-life example of the potential of liquid biopsies to detect RAS mutation status changes, allowing for precision-oncology therapeutic approaches in the continuum of care of metastatic colorectal cancer patients. Legal entity responsible for the study: Department of Medical Oncology, University General Hospital of Ioannina. Funding: Amgen, Hellenic Society of Medical Oncology (HeSMO) and Society for Study of Clonal Heterogeneity of Neoplasia (EMEKEN). Disclosure: G. Pentheroudakis: Research grant / Funding (institution): Amgen. All other authors have declared no conflicts of interest.
42P
Prediction of PFS using a dynamic assessment of ctDNA in patients with EGFR mutated NSCLC with osimertinib therapy
F. Moiseenko, M. Stepanova, A. Zhabina, A. Myslik, V. Klimenko, N. Rysev, E. Artemieva, K. Shelekhova, A. Bogdanov, N. Volkov, V. Moiseenko St. Petersburg Clinical Research Center of Specialized Types of Care (Oncology), St. Petersburg, Russian Federation
23%) and tumor tissue (sensitivity of 88%). The appointment of osimertinib in the second line allows to increase ORR, but also PFS relative to standard chemotherapy. Methods: In this study we investigated the effect on PFS by the dynamic determination of ctDNA. Included patients with metastatic EGFR-associated NSCLC, in whom, a T790M mutation was detected during treatment TKIs of 1-2 generations.Patients received osimertinib therapy 80 mg / day, daily, until progression of the disease appears. Blood test was taken to conduct a qualitative assessment of ctDNA in dynamics by the RT-PCR method, fist test was done before starting treatment, and then every 2 months. Results: From August 2016 to December 2018, 22 patients were identified T790M þ associated progression of EGFR þ NSCLC. 81.9% (18/22) are women, 18.1% (4/22) are men. The average age is 61.2 years (50-75). 1/22 had smoking experience for more than 30 years. The molecular genetic profile in 16 is represented by ex19del, 5 L858R, 1 - a combination of rare mutations G719S þ S768I. The effect of therapy was evaluated in 20/22 patients. PR and SD were registered in 9/20 (45%) and 10/20 (50%) patients, respectively. Median PFS – 18.9 months (CI 95%, 10.6 - 27.1). In 12/22 patients was observed the disappearance of ctDNA T790M þ after 2 months of osimertinib therapy. PFS is 24.4 months (CI calculation is NA), in patients with no mutation detected in the second month of treatment compared with the group of patients in which the ctDNA was determined (PFS 7.6 months) (CI 95%, 3.0 –12.9) (p ¼ 0.003). The confidence interval for one of the medians cannot be calculated the 75% percentile was 3.4 þ/- 3.3 and 18.8 þ/- 6.3. Conclusions: The disappearance of ctDNA in plasma after 2 months of treatment with osimertinib is associated with an increase in PFS and can be considered as a predictive marker in patients with metastatic NSCLC EGFR T790M þ Grant supported RUSSCO / RakFond 2018-01-YS-ECI. Legal entity responsible for the study: St. Petersburg Clinical Research Center of Specialized Types of Care (Oncology). Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.
43P
Targeted high-throughput sequencing for somatic mutations identification in thyroid cancer management
V. Yakushina1, L. Lerner2, T. Avdeeva3, T. Kazubskaya4, T. Kondrat’ieva4, A. Lavrov1 Research Centre for Medical Genetics, Moscow, Russian Federation, 2PreMed-European Technologies, Moscow, Russian Federation, 3Moscow City Clinical Hospital after V.M. Buyanov, Moscow, Russian Federation, 4N.N. Blokhin Russian Cancer Research Center, Moscow, Russian Federation
1
Background: Main challenges in thyroid cancer management are low sensitivity of preoperative differential diagnostics and absence of sufficient prognostic markers for choosing of therapeutic strategy, including decision regarding radioiodine therapy. The study aims evaluation of clinical utility of analyses of comprehensive set of driver and secondary mutations with targeted high-throughput sequencing. Methods: Point mutations in 52 genes, CNVs at 1q, 9q, 17q, 22q, and fusions of 66 genes were analyzed with targeted high-throughput sequencing. The analyzed mutations included well known driving and putatively driving mutations selected from TCGA project and literature, and secondary mutations with known or putative prognostic significance. Enrichment of regions of interest was performed with AmpliSeq technology. Fusions were detected by the presence of chimeric transcripts. Sequencing was performed on Illumina NextSeq (for point mutations and CNVs) or MiSeq (for fusions). Samples included 64 confirmed cancer samples (41 samples with Bethesda IVV cytology, and 23 samples - Bethesda VI cytology), 16 confirmed benign samples, 12 normal tissue samples. Results: Mutations detected in carcinomas included, in addition to BRAF and RASs: CDKN2B, ZFHX3, PDGFRA, KIT, NTRK3, ECM2, TERT, KDR, KMT2A, TP53, RNF213, APC, CHEK2, PTEN, PPM1D, ATR, CDKN2A, CTNNB1, ARID1B, KMT2C, ALK, DICER1, fusions of NTRK3, NTRK1, PPARG and RET, and CNVs 22q-del b 9qdel. The detected mutations allow to characterize all studied cancer cases. In benign nodules mutations in NRAS, TSC2, KDR, EIF1AX, ARID1B, TSHR, ZFHX3, GRIN3A, DICER1, HRAS, CHEK2 were found. Conclusions: Tests limited to BRAF, K/N/HRAS, RET-PTC1/3, PAX-PPARG mutations have low diagnostic value. The developed panel allows analyzing an expanded range of mutations, including recently described rearrangements and CNV. Design of the panel, initial validation and sequencing of cancer samples were funded by Foundation for Assistance to Small Innovative Enterprises in Science and Technology (@ 442U2/9119 - 3-40846); sequencing of benign samples was supported by the grant of the Russian Science Foundation (Agreement 19-75-00053). Legal entity responsible for the study: The authors. Funding: Foundation for Assistance to Small Innovative Enterprises in Science and Technology (442UC2/9119 - C3-40846); Russian Science Foundation (Agreement 1975-00053). Disclosure: All authors have declared no conflicts of interest.
Background: Resistance on the 1st or 2nd generation TKIs in patients with EGFR mutated NSCLC to the therapy occurs on average after 8-12 months. The most common (49-60%) resistance mechanism is the appearance of the T790M. Its determination is possible by different methods of examination: ctDNA (false-negative probability
Volume 30 | Supplement 7 | November 2019
doi:10.1093/annonc/mdz413 | vii13
Downloaded from https://academic.oup.com/annonc/article-abstract/30/Supplement_7/mdz413.047/5613320 by guest on 20 December 2019
(13.37). There were 470 patients who were white, 30 of other races and 10 patients with missing race information. A total of 246 patients were grade 2 while 264 patients were grade 3. On univariable analysis, all APOBEC3 genes high expression were significantly associated with worse prognosis. However, on multivariable analysis, only APOBEC3B, APOBEC3C, APOBEC3D, APOBEC3F, APOBEC3G and APOBEC3H high expression were significantly associated with worse survival where the HR (95% CI) were 1.63 (1.1-2.42), 2.16 (1.47-3.19), 1.72 (1.19-2.49), 2.6 (1.78-3.86), 2.3 (1.61-3.45) and 1.67 (1.17-2.4) respectively. Using the group of low expression of all six APOBEC3 proteins as reference, Patients with high expression of six APOBEC3 proteins had the worst prognosis with a HR (95% CI) of 5.66 (2.74-11.68). Conclusions: mRNA expression of APOBEC3 (B,C,D,F,G,H) genes can be effective molecular markers for the prognosis of LGG patients. A joint analysis of APOBEC3 genes expression might improve its sensitivity. Legal entity responsible for the study: Khaled Ismaeil. Funding: Has not received any funding. Disclosure: The author has declared no conflicts of interest.