scholarly journals IMMU-18. FAVORABLE OUTCOME IN REPLICATION REPAIR DEFICIENT HYPERMUTANT BRAIN TUMORS TO IMMUNE CHECKPOINT INHIBITION: AN INTERNATIONAL RRD CONSORTIUM REGISTRY STUDY

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii363-iii363
Author(s):  
Eric Bouffet ◽  
Sumedha Sudhaman ◽  
Jiil Chung ◽  
Jacalyn Kelly ◽  
Ailish Coblentz ◽  
...  

Abstract Pediatric brain tumors with replication repair deficiency (RRD) are hypermutant and may respond to immune checkpoint inhibition (ICI). We performed a consortium registry study of ICI in recurrent RRD cancers. Clinical and companion biomarkers were collected longitudinally on all patients. Biomarkers included tumor mutational burden (TMB), neoantigens and genetic signatures obtained from whole genome and exome sequencing. Immune inference was obtained by RNAseq and T cell rearrangement was collected in the tumor and in blood throughout treatment. Of the 46 tumors on the study, 32 were brain tumors with glioblastoma in 96%. Rapid, objective responses (>50%) were observed in 50% of glioblastomas. Three year overall survival for the whole cohort was 48+/-8% which compares favorably with historical controls. Brain tumors fared worse with OS of 39+/-10% and late recurrences observed even after 2 years of therapy (p=0.02). Tumor size and acute “flare” constitute poor outcome throughout all cancers. While all tumors are hypermutant, TMB and predicted neoantigens correlated with response to ICI (p=0.02). Specific signatures extracted from SNVs and total mutations predicted response to ICI and favorable outcome (p=0.005). RNA inference and TCR reveal that the FLARE phenotype is mostly acute nonspecific immune response and not true progression. Finally, glioblastomas (n=8) which failed single agent ICI had favorable responses to combinational immunotherapies with prolonged survival of 65%+/-8% at one year after failure vs 0 for other patients (p=0.01). RRD glioblastomas exhibit favorable outcome and responses to ICI. Combinational therapies based on tumor and immune signatures of these cancers are necessary.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 9049-9049
Author(s):  
Noura J. Choudhury ◽  
Jaime Laurel Schneider ◽  
Tejas Patil ◽  
Viola Weijia Zhu ◽  
Debra A. Goldman ◽  
...  

9049 Background: ROS1 fusions are oncogenic drivers in various cancers types, including 1-3% of non-small cell lung cancers (NSCLCs). Immunotherapy approvals for NSCLC include ROS1-rearranged carcinomas, but the activity of immune checkpoint inhibition (ICI) as monotherapy or in combination with chemotherapy (chemo-ICI) therapy, as well as the immunophenotypic characteristics of these tumors, have not been described in a large data set. Methods: In this multi-institutional study, patients with ROS1-rearranged NSCLC were identified retrospectively. Tumor PD-L1 expression and tumor mutational burden (TMB) were assessed as part of routine clinical care. In patients who received ICI monotherapy or chemo-ICI in the metastatic setting, time to treatment discontinuation (TTD) and objective response rate (ORR; RECIST v. 1.1) were calculated. TTD was assessed with Kaplan-Meier methods; patients remaining on treatment were censored at last follow up. Results: 184 patients with ROS1-rearranged NSCLC were identified. Among 146 PD-L1 evaluable cases, PD-L1 expression was < 1% in 60 (41%), 1-49% in 35 (24%) and ≥50% in 51 (35%) tumors. Ninety-two of 100 (92%) TMB-evaluable tumors had < 10 mutations/megabase (mut/Mb). TMB was significantly lower for ROS1-rearranged NSCLCs (n = 97) vs. ROS1-wild type tumors (n = 5,380) evaluated with next-generation sequencing using MSK-IMPACT (median 2.6 vs. 5.9 mut/Mb, p < 0.001). Twenty-eight patients received ICI monotherapy and 11 patients received chemo-ICI. The median TTD was 2.1 months (95% CI: 1.0-4.2; n = 28) for single-agent ICI therapy and 10 months (95% CI: 4.7-14.1; n = 11) for chemo-ICI therapy. The ORR was 13% (2/16 RECIST-evaluable; 95% CI: 2-38%) for ICI monotherapy and 83% (5/6 RECIST-evaluable; 95% CI: 36-100%) for chemo-ICI therapy. There was no difference in PD-L1 tumor expression (p = 0.9) or TMB (p = 0.8) between responders and non-responders and no correlation between PD-L1 tumor expression (rho = 0.16, p = 0.6) or TMB (rho = 0.03, p = 0.9) and maximum change in sum of target lesions. Conclusions: Most ROS1-rearranged NSCLCs have low or no PD-L1 expression and low TMB. The activity of checkpoint inhibitor monotherapy is disappointing in ROS1-driven NSCLC. In contrast, combination chemoimmunotherapy can achieve clinically meaningful activity.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 1091-1091
Author(s):  
Sarah Sammons ◽  
Andrew Elliott ◽  
Jeremy Meyer Force ◽  
Nicholas C. DeVito ◽  
Paul Kelly Marcom ◽  
...  

1091 Background: Tumor mutational burden (TMB) has emerged as an imperfect biomarker of immune checkpoint inhibition (ICI) outcomes in solid tumors. Despite the approval for pembrolizumab in all TMB-high (TMB-H) solid tumors, the optimal clinical approach to TMB-H or hypermutated advanced/metastatic breast cancer (MBC) is unknown with sparse prospective data. We hypothesize that TMB-H MBC will have unique genomic alterations compared to TMB-low (TMB-L) breast cancer that could inform novel therapeutic approaches. Methods: Tumor samples (N = 5621) obtained from patients with MBC were analyzed by next-generation sequencing (NGS) of DNA (592-gene panel or whole exome sequencing) and RNA (whole transcriptome sequencing) at Caris Life Sciences (Phoenix, AZ). TMB was calculated based on recommendations from the Friends of Cancer Research TMB Harmonization Project (Merino et al., 2020), with the TMB-H threshold set to ≥ 10 muts/Mb. IHC was performed for PD-L1 (Ventana SP142 ≥1% immune cells). Deficient mismatch repair (dMMR)/high microsatellite instability (MSI-H) was tested by IHC and NGS, respectively. Results: TMB-H was identified in 8.2% (n = 461) of MBC samples, with similar frequencies observed across molecular subtypes (7.8-8.6%, p = 0.85): HR+/HER2- (n = 3087) 7.8%, HR+/HER2+ (n = 266) 8.3%, HR-/HER2+ (n = 179) 7.8%, TNBC (n = 1476) 8.6%. The frequency of TMB-H was significantly increased in lobular (16%) versus ductal (5%) MBC (p < 0.01). TMB-H samples were enriched in genitourinary (42%), soft tissue (20%), and gastrointestinal non-liver (16%) biopsy specimens. Compared to TMB-L tumors, TMB-H tumors exhibited significantly higher mutation rates for TP53 (60 v 52%), PIK3CA (55 vs 31%), ARID1A (34 vs 11%), CDH1 (27 vs 11%), NF1 (22 vs 9%), RB1 (14 vs 5%), KMT2C (12 vs 7%), PTEN (12 vs 7%), ERBB2 (7 vs 2.9%), and PALB2 (3.3 vs 1%) genes (p < 0.05 each). Copy number alteration and fusion rates did not differ between TMB-H and TMB-L breast cancers. PI3K/AKT/MTOR, TP53, Histone/Chromatin remodeling, DNA damage repair (DDR), RAS, and cell cycle pathway alterations were detected in > 25% TMB-H MBCs (p < 0.05 each). dMMR/MSI-High (7.2 vs 0.3%, p < 0.01) and PD-L1 positivity (36 vs 28%, p < 0.05) frequencies were significantly increased in TMB-H tumors. DNA signature analyses including APOBEC and homologous recombination repair deficiency, as well as gene expression profiling to assess immune-related signatures and tumor microenvironment are underway. Conclusions: TMB-H breast cancers contain a unique genomic profile enriched with targetable mutations such as PIK3CA, ARID1A, NF1, PTEN, ERBB2, and PALB2. Concurrent predictive biomarkers of response to immune checkpoint inhibition such as MSI-H and PDL-1 positivity are also more prevalent in TMB-H MBC. These findings suggest novel combination strategies within TMB-H MBC could be explored.


2016 ◽  
Vol 34 (19) ◽  
pp. 2206-2211 ◽  
Author(s):  
Eric Bouffet ◽  
Valérie Larouche ◽  
Brittany B. Campbell ◽  
Daniele Merico ◽  
Richard de Borja ◽  
...  

Purpose Recurrent glioblastoma multiforme (GBM) is incurable with current therapies. Biallelic mismatch repair deficiency (bMMRD) is a highly penetrant childhood cancer syndrome often resulting in GBM characterized by a high mutational burden. Evidence suggests that high mutation and neoantigen loads are associated with response to immune checkpoint inhibition. Patients and Methods We performed exome sequencing and neoantigen prediction on 37 bMMRD cancers and compared them with childhood and adult brain neoplasms. Neoantigen prediction bMMRD GBM was compared with responsive adult cancers from multiple tissues. Two siblings with recurrent multifocal bMMRD GBM were treated with the immune checkpoint inhibitor nivolumab. Results All malignant tumors (n = 32) were hypermutant. Although bMMRD brain tumors had the highest mutational load because of secondary polymerase mutations (mean, 17,740 ± standard deviation, 7,703), all other high-grade tumors were hypermutant (mean, 1,589 ± standard deviation, 1,043), similar to other cancers that responded favorably to immune checkpoint inhibitors. bMMRD GBM had a significantly higher mutational load than sporadic pediatric and adult gliomas and all other brain tumors (P < .001). bMMRD GBM harbored mean neoantigen loads seven to 16 times higher than those in immunoresponsive melanomas, lung cancers, or microsatellite-unstable GI cancers (P < .001). On the basis of these preclinical data, we treated two bMMRD siblings with recurrent multifocal GBM with the anti–programmed death-1 inhibitor nivolumab, which resulted in clinically significant responses and a profound radiologic response. Conclusion This report of initial and durable responses of recurrent GBM to immune checkpoint inhibition may have implications for GBM in general and other hypermutant cancers arising from primary (genetic predisposition) or secondary MMRD.


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