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Jianjun Zhang



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    MA14 - The Adequate MTarget Is Still the Issue (ID 140)

    • Event: WCLC 2019
    • Type: Mini Oral Session
    • Track: Advanced NSCLC
    • Presentations: 1
    • Now Available
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      MA14.10 - Clinical Outcomes in Metastatic Squamous Lung Cancer with Targetable Driver Alterations (Now Available) (ID 527)

      15:45 - 17:15  |  Author(s): Jianjun Zhang

      • Abstract
      • Presentation
      • Slides

      Background

      Genomic profiling is not routinely performed for metastatic squamous (SCC) and adenosquamous (ASC) NSCLC. However molecular profiling may be ordered if demographic features suggest a higher likelihood of a targetable driver alteration (e.g. never or remote smoking history). Response and survival data are scant in pts with actionable alterations treated with targeted therapy.

      Method

      We reviewed the clinical data and molecular profiling (FISH, PCR, tissue NGS, ctDNA) of metastatic SCC and ASC pts treated at our institution from Feb 2010-Dec 2018. Pts with typical sensitizing mutations in EGFR or BRAF V600E or fusions in ALK or ROS1 treated with matched targeted therapy for ≥ 2 months were included in this analysis. Response assessment was based on RECIST v1.1.

      Result

      Among 261 metastatic SCC or ASC pts with available molecular profiling, 16 total pts (6%) were found to have actionable targets, consisting of 13 SCC and 2 ASC (median age 53, 81% female, 88% never-smoker). The distribution of driver alterations in this cohort was 56% (9/16) EGFR ex19del/L858R/G719A, 38% (6/16) ALK fusion, and 6% (1/16) BRAF. The overall objective response rate (ORR) and median progression free survival (PFS) to targeted therapy was 69% and 5.2 months respectively. By mutational subgroup, ORR was 67% (6/9) for EGFR, 67% (4/6) for ALK, and 100% (1/1) for BRAF. Median PFS was only 4.5 months (95% CI 3.0 – 6.0) for EGFR pts and 2.8 months (95% CI 0 – 6.4) for ALK pts, and the lone BRAF pt had a PFS of 8.5 months. In EGFR pts with available NGS, co-mutations in TP53 (75% [6/8]) and PIK3CA (38% [3/8]) were seen at rates higher than previously reported in EGFR+ ADC (TP53 55%, PIK3CA 12%; Blakely et al, Nat Gen 2017). In ALK pts with available NGS, co-mutations in TP53 (80% [4/5]) were also higher than recently reported in ALK+ ADC (24%; Kron et al, Ann Oncol 2018).

      Conclusion

      Despite initial responses comparable to those previously reported in ADC, matched targeted therapy in pts with SCC and ASC histology is associated with shorter PFS. A higher prevalence of adverse co-mutations such as TP53 and PIK3CA may contribute to early targeted therapy resistance in these histologies. These findings may have implications for the use of targeted therapy in squamous lung cancer.

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    OA15 - Targeted Agents and Immunotherapy for Small Cell Lung Cancer (ID 152)

    • Event: WCLC 2019
    • Type: Oral Session
    • Track: Small Cell Lung Cancer/NET
    • Presentations: 1
    • Now Available
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      OA15.04 - Genomic and TCR Intratumor Heterogeneity of Small-Cell Lung Cancer by Multiregion Sequencing: An Association with Survival (Now Available) (ID 1458)

      14:30 - 16:00  |  Presenting Author(s): Jianjun Zhang

      • Abstract
      • Presentation
      • Slides

      Background

      Small cell lung cancer (SCLC) is an aggressive cancer. Although sensitive to initial therapy, recurrence is almost inevitable. The molecular mechanisms underlying recurrence are unknown. We have previously demonstrated that complex genomic and T cell receptor (TCR) intratumor heterogeneity (ITH) was associated with increased risks of relapse in non-small cell lung cancers (NSCLC). Genomic ITH and TCR architecture of SCLC and its clinical impact have not been well studied, largely due to lack of tumor specimens as surgery is rarely used to treat SCLC.

      Method

      We performed multiregion whole-exome sequencing and TCR sequencing of 49 tumor samples from 18 resected limited-stage SCLCs to delineate the immunogenomic ITH of SCLC. We compared the results to those in NSCLC and assessed the association of genomic and TCR attributes with patient’s survival.

      Result

      On average, 544 mutations/sample were detected. The median proportion of trunk mutations (mutations identified in all regions within the same tumors) was 80.4% versus 70% in NSCLC (TRACERx, Jamal-Hanjani, NEJM, 2017, p=0.08) and all TP53 and RB1 mutations were trunk mutations, suggesting these mutations were early events during carcinogenesis of this cohort of SCLCs. A higher non-synonymous tumor mutational burden (TMB) was associated with a higher T cell density (infiltration) in the tumor (r=0.46, p=0.005). Compared to the TCR repertoire of NSCLC (Reuben, WCLC, 2017), these SCLC tumors demonstrated significantly lower T-cell density (0.05 versus 0.24, p<0.0001), richness (diversity, 1,043 versus 3,666, p<0.0001) and clonality (reactivity, average 0.02 versus 0.15, p<0.0001) despite similar non-synonymous TMB (average 187 in SCLC versus 176 mutations/sample in NSCLC). Only 0.2% to 14.6% of T cells were detectable across all regions from the same tumors, suggesting substantial TCR ITH. Jaccard index (JI), a parameter quantifying TCR ITH was significantly lower in SCLC than in NSCLC (0.06 versus 0.1, p<0.0001) implying higher level of TCR ITH in SCLC than NSCLC. Interestingly, higher T-cell density, richness or clonality appeared to be associated with lower risk of recurrence numerically. Furthermore, higher TCR JI (less degree of ITH) was associated with significantly longer overall survival (HR=0.15, p=0.04).

      Conclusion

      Limited-stage SCLC tumors have distinct TCR repertoire and genomic ITH architecture. Overall, SCLC may have a more pronounced immunosuppressive microenvironment and higher level of TCR repertoire ITH than NSCLC. Nevertheless, higher degree of T cell infiltration and clonal expansion as well as more homogeneous T cell response may be associated with more favorable clinical outcome in patients with limited-stage SCLC.

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