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Clarissa Mathias



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    P1.01 - Advanced NSCLC (Not CME Accredited Session) (ID 933)

    • Event: WCLC 2018
    • Type: Poster Viewing in the Exhibit Hall
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/24/2018, 16:45 - 18:00, Exhibit Hall
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      P1.01-23 - High PD-L1 Expression is Less Common Than Expected Among Advanced NSCLC in Brazil. Are We Missing the Target? (ID 13620)

      16:45 - 18:00  |  Author(s): Clarissa Mathias

      • Abstract
      • Slides

      Background

      Immune checkpoint inhibitors improved outcomes of patients with advanced non-small cell carcinoma (NSCLC). In clinical trials 30% of patients had programmed death receptor ligand-1 (PD-L1) expression above 50% and this frequency may vary through different regions of the world. We aim to describe the real world dada on prevalence of PD-L1 expression, EGFR mutation and ALK translocation in Brazil.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      Immunohistochemistry (IHC) for PD-L1, antibody 22C3 PharmDx Dako, was performed in 5 laboratories in Brazil from Aug/2017 through Apr/2018 in cases of advanced NSCLC considered for treatment with immunotherapy. Mutations in EGFR (exons 18 to 21) by Cobas®(Roche), NGS, or other non-specified tests and ALK by IHC (antibodies 5A4 or D5F3) or FISH (Vysis System) were performed in non-squamous cases. All analyses were with SAS (version 9.4). P-values <0.05 were deemed to be statistically significant.

      4c3880bb027f159e801041b1021e88e8 Result

      PD-L1 expression was assessed in 1382 samples of advanced NSCLC. The median age was 67 years, and 55.6% were male. 56.6% had adenocarcinoma, 18.0%, squamous, 20.7%, non-specified NSCLC, 2.5%, other histologies, 1.9%, missing. Of the 1380 cases, 17.4% presented PD-L1 expression ≥50%, 25.4%, 1-49%, and 57.1% <1%. The histological subtype showed association with the expression of PD-L1 (p=0,0431). In adenocarcinoma, 60.7% had no PD-L1 expression, 23.1%, had 1-49%, and 16.1%, ≥50%, while in squamous, 47.3% had no PD-L1 expression, 30.5% had 1-49%, and 22.0%, ≥50%. Among 885 samples with EGFR data, 10.9% were mutated. Both sex and histology showed association with EGFR mutation (p=0.0410 and p<0.0001). Among the men, 9.7% were mutated, while 13,4% of women were mutated. 16.4% of adenocarcinoma and 3.1% of squamous had EGFR mutation. In 855 samples with ALK data, 3.5% were rearranged. ALK rearrangement was associated with sex and age (p=0.0388 and p=0.0088) and was 2.2% in men and 4.8% in women. The group with age <50 had a higher prevalence of ALK rearrangement (8.6%). Among 735 patients without EGFR mutations or ALK rearrangements, 16.8% had PD-L1 ≥50% and 24.0% had 1-49%.

      8eea62084ca7e541d918e823422bd82e Conclusion

      Our results indicate a lower overall prevalence of PD-L1 expression in advanced NSCLC in Brazil as compared with clinical trial data. Among other potential factors, inadequate sample handling, pre-analytical issues, or epidemiology of the biomarker may impact PD-L1 expression. Prevalence of EGFR mutations and ALK translocations was within the range of prior publications in the country. Further regional and institutional analysis will be presented to better characterize the variations in prevalence of these biomarkers outside clinical trials.

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    P2.01 - Advanced NSCLC (Not CME Accredited Session) (ID 950)

    • Event: WCLC 2018
    • Type: Poster Viewing in the Exhibit Hall
    • Track:
    • Presentations: 2
    • Moderators:
    • Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
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      P2.01-128 - Low Positivity Rate in T790M Detection with ctDNA in NSCLC and Post EGFR-TKI Progression – Timing or Sensitivity? (ID 14293)

      16:45 - 18:00  |  Author(s): Clarissa Mathias

      • Abstract
      • Slides

      Background

      The approval of Osimertinib in Brazil in 2016 for post EGFR-TKI progression T790M+ NSCLC treatment allowed offering to the patient the best available therapy, when, it is mandatory to identify the occurrence of T790M mutation before initiating the treatment. The prevalence of T790M mutation as resistance mechanism post EGFR-TKI treatment is estimated to be around 60%. Considering the limitations for tumor tissue biopsy in progressive disease setting, identifying molecular changes by using alternative tumor DNA sources, such as blood samples, serum, and plasma can become an interesting strategy in cases where a tissue specimen or acceptable quality biopsy is not available. However, the sensitivity of ctDNA analysis for T790M may be disappointingly low.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      We performed a retrospective analysis of ctDNA samples database collected between June 2016 and December 2017 in Brazil. Blood samples of patients with post EGFR-TKI progression were submitted, at discretion of attending physicians, for EGFR mutation testing by cobas®.

      4c3880bb027f159e801041b1021e88e8 Result

      761 tests were included. The positivity rate was 43.9% for EGFRm and 10.4% for T790M. Considering EGFRm positive tests, the positivity rate for T790M among EGFRm positive was 23.7%. Data are shown in Table-1. This positive rate is lower than expected and may be explained by three factors: T790M ctDNA cobas® low sensitivity; test request before progression; or T790M prevalence lower in Brazilian population. Still, more detailed testing using tissue and/or more sensitive methods are needed before definitive conclusion. Tissue test should continue being recommended as gold standard in T790M detection on this patient setting.

      Table 1- Frequency and mutations detected by ctDNA cobas® test in Brazil.

      Exon

      18

      19

      20

      21

      19 + 20

      21 + 20

      Mutation

      G719X

      19Del

      19Ins

      T790M

      L858R

      L861Q

      19Del + T790M

      L858R

      +

      T790M

      Number

      9

      183

      1

      9

      60

      2

      53

      17

      Positivity rate (%)

      1.2

      24.1

      0.1

      1.2

      7.9

      0.3

      7.0

      2.2

      % of EGFRm

      2.7

      54.8

      0.3

      2.7

      18.0

      0.6

      15.9

      5.1

      8eea62084ca7e541d918e823422bd82e Conclusion

      Our findings suggest that ctDNA approach in post EGFR-TKI progression may not be the best diagnostic strategy to identify resistance T790M mutation as first option. When patient cannot be submitted to tissue biopsy at progression, ctDNA test is an acceptable alternative.

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      P2.01-31 - Updated EGFR Mutation Frequency in 1,689 NSCLC Brazilian Patients – A National-Wide Study (ID 14267)

      16:45 - 18:00  |  Author(s): Clarissa Mathias

      • Abstract
      • Slides

      Background

      EGFR mutation status is crucial to improving therapeutic results in advanced NSCLC, due to the development of highly effective EGFR-TKIs. Recent local data suggest that EGFR mutation frequency is lower in Brazil ( 22%-33%) than in Asia and higher than in North America and Europe. We intended to describe the EGFR mutation frequency in a large national-wide Brazilian population.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      This retrospective analysis evaluated a database composed of samples collected between January and August 2017, from all Brazilian regions. Tumor tissue samples of patients with advanced NSCLC were submitted, at discretion of attending physicians, for EGFR mutation testing. EGFR exons 18 to 21 were analyzed by cobas®, NGS, or other non-specified test. Unfortunately, smoking status data was not available and was not included in this analysis.

      4c3880bb027f159e801041b1021e88e8 Result

      1,689 tests were included. Table-1 demonstrates EGFR mutation rates according to test used. Mean age (±SD) was 64.5 (±11.3) for female and 66.0 (±11.1) for male population. From all detected mutations, exon 19 deletion was the most frequent (49.2%), followed by L858R (25.6%), exon 20 insertion (8.4%), T790M (4,7%), and G719X (3.0%). Patients with multiple EGFR variants (more than one EGFR mutation) corresponded to 10.3% of cases. Among different Brazilian geographic macro-regions, EGFRm rate was 33.3% in North (36 tests only), 25.1% in Northeast (307 tests), 30.9% in Central-West (175 tests), 25.8% in Southeast (841 tests), and 20.6% in the South (330 tests) region.

      Table1 – EGFR mutation rate divided by gender and EGFR mutation detection method.

      cobas®

      NGS

      Other

      Overall

      Female

      58/183

      (31.7%)

      223/586

      (38.1%)

      25/159

      (15.7%)

      306/928

      (33.0%)

      Male

      25/167

      (15.0%)

      89/447

      (19.9%)

      9/147

      (6.1%)

      123/761

      (16.2%)

      Overall

      83/350

      (23.7%)

      312/1,033

      (30.2%)

      34/306

      (11.1%)

      429/1689

      (25.4%)

      8eea62084ca7e541d918e823422bd82e Conclusion

      Our findings confirm that EGFR mutation rate among Brazilian is higher than observed in Western countries, women have a higher EGFR mutation rate than men, and detection rate using NGS is higher than cobas®. Frequency of EGFR mutation was lower in South region, what could be explained by a higher smoking rate (not evaluated in this study) and a larger Caucasian population.

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    P2.13 - Targeted Therapy (Not CME Accredited Session) (ID 962)

    • Event: WCLC 2018
    • Type: Poster Viewing in the Exhibit Hall
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
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      P2.13-09 - Efficacy and Safety of Osimertinib After Prior EGFR TKI: Analysis of Patients Underrepresented in Randomized Clinical Trials (ID 14036)

      16:45 - 18:00  |  Author(s): Clarissa Mathias

      • Abstract
      • Slides

      Background

      Osimertinib is a new standard of care in non-small cell lung cancer (NSCLC) after progression to an EGFR TKI in the presence of T790M mutation. Following results of the phase III study AURA 3, which led to the approval of osimertinib worldwide, we have conducted ASTRIS in Brazil.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      This is a phase IV, international, multicentric, open trial, with the aim of confirming the efficacy and safety of osimertinib at a dose of 80 mg daily, orally. Eligible patients presented with diagnosis of T790M-positive NSCLC on progression after prior EGFR TKI. Herein, we present the Brazilian experience at ASTRIS, including subsets that were underrepresented in the phase III trial.

      4c3880bb027f159e801041b1021e88e8 Result

      Eighty-eight patients were enrolled in Brazil between August 2015 and March 2017. The median age was 64 years (34-89), and most were females (66%). Fifty-four patients (61%) had received prior therapy with erlotinib, forty-two (48%) with gefitinib, and 3 (3%) with afatinib. Nineteen patients (22%) were exposed to a EGFR TKI more than 6 months before enrolment. Importantly, 11 patients (12.5%) presented with a PS of 2, 23 (26%) presented with brain metastases, and 3 with leptomeningeal disease. Exon 19 deletions were the most common primary mutation in EGFR, present in 55 cases (62.5%), followed by L858R in 24 cases (27%). Tumor samples were acquired from the primary tumor in 14 cases (45%) and in a metastatic site in 16 (52%); all other cases had T790M detected at plasma. After a median follow-up of 9.3 months, 26 progression events and 23 deaths were documented. The response rate was 58.2% (95%CI 46.6-69.2), and median progression-free survival was 9.4 months (95%CI 8.2-not reached). The 12-month overall survival was 69.7% (95%CI 56.5-79.6). Thirty patients (34%) presented an adverse event, 14 of which led to dose modification and 5 to treatment discontinuation. The most common adverse events were infection in 14 cases (15%), gastrointestinal and hematologic (4 cases each). Nineteen patients (22%) had a serious adverse event, mostly infections (14 cases).

      8eea62084ca7e541d918e823422bd82e Conclusion

      The profile of patients enrolled in Brazilian institutions highlights the presence of cases with poor PS, which was excluded in the AURA 3 trial. Despite these features, the efficacy and safety of osimertinib was confirmed, suggesting that results could be extrapolated to a broad range of subsets. This study also underscores the role of liquid biopsy in the detection of T790M, in detriment to tumor re-biopsy.

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    PL04 - Take Action - Key Messages from WCLC 2018 and Goals for 2019 (ID 852)

    • Event: WCLC 2018
    • Type: Plenary Session
    • Track:
    • Presentations: 1
    • Now Available
    • Moderators:
    • Coordinates: 9/26/2018, 15:15 - 16:30, Plenary Hall
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      PL04.05 - Clinical Research in Latin America (Now Available) (ID 11658)

      15:55 - 16:05  |  Presenting Author(s): Clarissa Mathias

      • Abstract
      • Presentation
      • Slides

      Abstract not provided

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    YI01 - Young Investigators Session (ID 988)

    • Event: WCLC 2018
    • Type: Young Investigator Session
    • Track:
    • Presentations: 1
    • Now Available
    • Moderators:
    • Coordinates: 9/23/2018, 08:00 - 11:30, Room 106
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      YI01.01 - Introduction to the IASLC - Why You Should be a Member (Now Available) (ID 14670)

      08:00 - 08:10  |  Presenting Author(s): Clarissa Mathias

      • Abstract
      • Presentation
      • Slides

      Abstract not provided

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