Chromosome 8q arm overexpression is associated with worse prostate cancer prognosis

OBJECTIVE

Chromosome 8q arm (chr8q) is the most amplified chromosomal segment in advanced metastatic castration-resistant prostate cancer after chXq12. These regions harbor important oncogenes driving prostate cancer progression, including MYC that plays a role in various hallmarks of cancer, including cell cycle progression and immune surveillance. Herein we characterize the co-expression patterns of chr8q genes and their clinical utility in more than 7,000 radical prostatectomy samples.

MATERIALS AND METHODS

Copy Number alterations of 336 genes on chr8q21 to chr8q24 were extracted from 2 primary prostate cancer cohorts (TCGA, n = 492; MSK-primary, n = 856) and 3 metastatic prostate cancer cohorts (MSK-met, N = 432; MSK-mCSPC, N = 424; SU2CPNAS, n = 444) from cBioPortal. Expression data for the 336 genes was extracted from 6,135 radical prostatectomy samples from Decipher GRID registry. For survival analysis, patients were grouped into top 10% and top 25% by band expression and were compared with the remaining cohort. Hazard ratios were calculated using Cox proportional hazards models.

RESULTS

Genes on chr8q were highly co-amplified and co-expressed. Copy number alterations and overexpression of chr8q genes in primary disease were associated with higher Gleason scores, increased risk of metastases, and increased prostate cancer specific mortality. Additionally, our data demonstrated high expression of MYC alone was not associated with differences in metastases free survival while high expression of other chr8q bands was associated with decreased metastases free survival. By combining chr8q data with an established genomic classifier like Decipher, we were able to develop a new model that was better at predicting metastases than Decipher alone.

CONCLUSIONS

Our findings highlight the clinical utility of chr8q data, which can be used to improve prognostication and risk prediction in localized prostate cancer.

APOBEC Mutational Signatures in Hormone Receptor-Positive Human Epidermal Growth Factor Receptor 2-Negative Breast Cancers Are Associated With Poor Outcomes on CDK4/6 Inhibitors and Endocrine Therapy

PURPOSE

APOBEC mutagenesis underlies somatic evolution and accounts for tumor heterogeneity in several cancers, including breast cancer (BC). In this study, we evaluated the characteristics of a real-world cohort for time-to-treatment discontinuation (TTD) and overall survival on CDK4/6 inhibitors (CDK4/6i) plus endocrine therapy (ET) and immune checkpoint inhibitors.

METHODS

Comprehensive genomic profiling results from 29,833 BC samples were analyzed for tumor mutational burden and APOBEC signatures. For clinical outcomes, a deidentified nationwide (United States-based) BC Clinico-Genomic Database (CGDB) was evaluated with log-rank and Cox models. Patients with hormone receptor-positive (HR+) human epidermal growth factor receptor 2-negative (HER2-) BC who received first-line ET and CDK4/6i were included. Eligible patients from Mayo Clinic and Duke University were HR+ HER2- BC with sequencing data between September 2013 and July 2020.

RESULTS

Of 29,833 samples sequenced, 7.9% were APOBEC+ with a high rate in invasive lobular carcinoma (16.7%) and in metastatic tumors (9.7%) relative to locally biopsied BC (4.3%; P < .001). In CGDB, 857 patients with HR+ HER2- BC received ET plus CDK4/6i in the first line. APOBEC+ patients had significantly shorter TTD on ET plus CDK4/6i than APOBEC- patients, 7.8 (95% CI, 4.3 to 14.6) versus 12.4 months (95% CI, 11.2 to 14.1; hazard ratio, 1.6; 95% CI, 1.03 to 2.39; P = .0036). Clinical benefit to immune checkpoint inhibitors was observed in HR+ HER2-, APOBEC+, tumor mutational burden-high patients, with four of nine CGDB patients (TTD 0.3-11.3 months) and four of six patients in Duke/Mayo cohorts (TTD 0.9-40.5 months) with a TTD of ≥ 3 months.

CONCLUSION

APOBEC+ HR+ HER2- patients had shorter TTD on first-line ET plus CDK4/6i relative to APOBEC- patients. Further research is needed to optimize the treatment of APOBEC+ HR+ HER2- BC and to investigate the efficacy of immunotherapeutic strategies in this population.

Clinical genomic profiling in the management of patients with soft tissue and bone sarcoma

There are more than 70 distinct sarcomas, and this diversity complicates the development of precision-based therapeutics for these cancers. Prospective comprehensive genomic profiling could overcome this challenge by providing insight into sarcomas' molecular drivers. Through targeted panel sequencing of 7494 sarcomas representing 44 histologies, we identify highly recurrent and type-specific alterations that aid in diagnosis and treatment decisions. Sequencing could lead to refinement or reassignment of 10.5% of diagnoses. Nearly one-third of patients (31.7%) harbor potentially actionable alterations, including a significant proportion (2.6%) with kinase gene rearrangements; 3.9% have a tumor mutational burden ≥10 mut/Mb. We describe low frequencies of microsatellite instability (<0.3%) and a high degree of genome-wide loss of heterozygosity (15%) across sarcomas, which are not readily explained by homologous recombination deficiency (observed in 2.5% of cases). In a clinically annotated subset of 118 patients, we validate actionable genetic events as therapeutic targets. Collectively, our findings reveal the genetic landscape of human sarcomas, which may inform future development of therapeutics and improve clinical outcomes for patients with these rare cancers.

The Genomics of Colorectal Cancer in Populations with African and European Ancestry

Blacks have a higher incidence of colorectal cancer (CRC) and worse survival rates when compared to Whites. Comprehensive genomic profiling was performed in 46,140 colorectal adenocarcinoma cases. Ancestry-informative markers identified 5,301 patients of African descent (AFR) and 33,770 patients of European descent (EUR). AFR were younger, had fewer MSI-H tumors, and had significantly more frequent alterations in KRAS, APC, and PIK3CA. AFR had increased frequency of KRAS mutations specifically KRAS G12D and KRAS G13. There were no differences in rates of actionable kinase driver alterations (HER2, MET, NTRK, ALK, ROS1, RET). In patients with young onset CRC (&lt;50 years), AFR and EUR had similar frequency of MSI-H and TMB-H tumors, and strikingly different trends in APC mutations by age, as well as differences in MAPK pathway alterations. These findings inform treatment decisions, impact prognosis, and underscore the need for model systems representative of our diverse US population.

ERBB2 Copy Number as a Quantitative Biomarker for Real-World Outcomes to Anti-Human Epidermal Growth Factor Receptor 2 Therapy in Advanced Gastroesophageal Adenocarcinoma

PURPOSE

Human epidermal growth factor receptor 2 (HER2) overexpression or amplification (ERBB2amp) are biomarkers for approved anti-HER2 therapies. ERBB2amp may better predict response compared with immunohistochemistry or in situ hybridization, and quantitative copy number (CN) may further stratify patients. We characterized ERBB2amp in advanced gastroesophageal adenocarcinomas (GEA) and hypothesized that increased CN was associated with better outcome to trastuzumab.

METHODS

Comprehensive genomic profiling, including assessment of ERBB2amp, was performed for 12,905 GEA tissue cases. Clinical outcomes were assessed using a clinicogenomic database linking deidentified electronic health record–derived clinical data to genomic data. Multivariable Cox proportional hazard models were used for real-world progression-free survival (rwPFS) comparisons.

RESULTS

ERBB2amp (CN ≥ 5) was detected in 15% (1,934 of 12,905) of GEA; median CN 22 (interquartile range 9-73). Median ERBB2 amplicon size was 0.27 megabase (interquartile range 0.13-0.95), and smaller amplicons were associated with higher CN (P < .001). In the clinicogenomic database, of 101 evaluable first-line trastuzumab-treated patients, ERBB2 CN was a significant predictor of rwPFS as a continuous variable (adjusted hazard ratio = 0.73; 95% CI, 0.60 to 0.89; P = .002), whereas ERBB2 CN was not predictive of rwPFS on chemotherapy (adjusted hazard ratio = 0.93; 95% CI, 0.73 to 1.20; P = .59). Among trastuzumab-treated patients, no significant associations with ERBB2 CN were observed for disease site, age, stage at advanced diagnosis, or most selected coalterations.

CONCLUSION

ERBB2amp was detected in 15% of GEA tissue samples, with significant diversity in ERBB2 CN and amplicon focality. ERBB2 CN was predictive of rwPFS as a continuous variable for patients treated with trastuzumab. Further studies exploring the clinical utility of quantitative ERBB2 CN, particularly in the setting of the evolving anti-HER2 landscape and combination therapies, are warranted.

ERBB2 copy number is a quantitative biomarker for outcomes to anti-HER2 therapy in advanced gastroesophageal cancer.

Predictive Genomic Biomarkers of Hormonal Therapy Versus Chemotherapy Benefit in Metastatic Castration-resistant Prostate Cancer

BACKGROUND

Biomarkers predicting second-generation novel hormonal therapy (NHT) benefit relative to taxanes are critical for optimized treatment decisions for metastatic castration-resistant prostate cancer (mCRPC) patients. These associations have not been reported simultaneously for common mCRPC genomic biomarkers.

OBJECTIVE

To evaluate predictive associations of common genomic aberrations in mCRPC using an established comprehensive genomic profiling (CGP) system.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study used data from a deidentified US-based clinicogenomic database comprising patients treated in routine clinical practice between 2011 and 2020, evaluated with Foundation Medicine CGP in tissue biopsies obtained around the time of treatment decision. The main cohort included 180 NHT and 179 taxane lines of therapy (LOTs) from 308 unique patients. The sequential cohort comprised a subset of the main cohort NHT LOTs immediately followed by taxane from 55 unique patients.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Prostate-specific antigen (PSA) response, time to next treatment (TTNT), and overall survival (OS) were assessed. Main cohort analyses were adjusted for known treatment assignment biases via inverse probability of treatment weighting (IPTW) in treatment interaction models.

RESULTS AND LIMITATIONS

In the main cohort, patients with AR amplification (ARamp) or PTEN aberrations (PTENalt) had worse relative PSA response on NHT versus taxanes compared with patients without. Patients with ARamp, PTENalt, or RB1 aberrations (RB1alt) also had worse relative TTNT and OS on NHT but not on taxanes. In multivariable models for TTNT and OS adjusted via IPTW, ARamp, PTENalt, and RB1alt were shown as poor prognostic factors overall and demonstrated significant treatment interactions, indicating reduced hazards of therapy switch and death on taxanes versus NHT. Consistent associations favoring increased benefit from subsequent taxane despite prior NHT treatment line were observed only for ARamp in the sequential cohort, in which very few patients had RB1alt for assessment.

CONCLUSIONS

ARamp status is a candidate biomarker to predict poor effectiveness of NHT relative to taxanes in mCRPC in scenarios where both options are considered.

PATIENT SUMMARY

Specific alterations in the DNA of tumors may assist in choosing between novel oral hormonal therapies and standard chemotherapy in advanced prostate cancer patients.

Characterization of Non-Small-Cell Lung Cancers With MET Exon 14 Skipping Alterations Detected in Tissue or Liquid: Clinicogenomics and Real-World Treatment Patterns

PURPOSE

MET exon 14 (METex14) skipping alterations are oncogenic drivers in non–small-cell lung cancer (NSCLC). We present a comprehensive overview of METex14 samples from 1,592 patients with NSCLC, associated clinicogenomic characteristics, potential mechanisms of acquired resistance, treatment patterns, and outcomes to MET inhibitors.

METHODS

Hybrid capture–based comprehensive genomic profiling (CGP) was performed on samples from 69,219 patients with NSCLC. For treatment patterns and outcomes analysis, patients with advanced METex14-altered NSCLC were selected from the Flatiron Health-Foundation Medicine clinicogenomic database, a nationwide deidentified electronic health record–derived database linked to Foundation Medicine CGP for patients treated between January 2011 and March 2020.

RESULTS

A total of 1,592 patients with NSCLC (2.3%) were identified with 1,599 METex14 alterations spanning multiple functional sites (1,458 of 60,244 tissue samples and 134 of 8,975 liquid samples). Low tumor mutational burden and high programmed death ligand 1 expression were enriched in METex14-altered samples. MDM2, CDK4, and MET coamplifications and TP53 mutations were present in 34%, 19%, 11%, and 42% of tissue samples, respectively. Comparing tissue and liquid cohorts, coalteration frequency and acquired resistance mechanisms, including multiple MET mutations, EGFR, ERBB2, KRAS, and PI3K pathway alterations, were generally similar. Positive percent agreement with the tissue was 100% for METex14 pairs collected within 1 year (n = 7). Treatment patterns showed increasing adoption of MET inhibitors in METex14-altered NSCLC after receipt of CGP results; the real-world response rate to MET inhibitors was 45%, and time to treatment discontinuation was 4.4 months.

CONCLUSION

Diverse METex14 alterations were present in 2%-3% of NSCLC cases. Tissue and liquid comparisons showed high concordance and similar coalteration profiles. Characterizing common co-occurring alterations and immunotherapy biomarkers, including those present before or acquired after treatment, may be critical for predicting responses to MET inhibitors and informing rational combination strategies.

Real-world association of HER2/ERBB2 concordance with trastuzumab clinical benefit in advanced esophagogastric cancer

Aim: To assess concordance between HER2 status measured by traditional methods and ERBB2 amplification measured by next-generation sequencing and its association with first-line trastuzumab clinical benefit in patients with advanced esophagogastric cancer. Methods: Retrospective analysis of HER2/ERBB2 concordance using a deidentified USA-based clinicogenomic database. Clinical outcomes were assessed for patients with HER2⁺ advanced esophagogastric cancer who received first-line trastuzumab. Results: Overall HER2/ERBB2 concordance was 87.5%. Among patients who received first-line trastuzumab, concordant HER2/ERBB2 was associated with longer time to treatment discontinuation (adjusted hazard ratio [aHR]: 0.63; 95% CI: 0.43-0.90) and overall survival (aHR: 0.51; 95% CI: 0.33-0.79). ERBB2 copy number ≥25 (median) was associated with longer time to treatment discontinuation (aHR: 0.56; 95% CI: 0.35-0.88) and overall survival (aHR: 0.52; 95% CI: 0.30-0.91). Conclusion: HER2/ERBB2 concordance and higher ERBB2 copy number predicted clinical benefit from trastuzumab.

Contrasting genomic profiles from metastatic sites, primary tumors, and liquid biopsies of advanced prostate cancer

BACKGROUND

This study assessed the contrasting genomic profiles from the primary tumors (PTs), metastatic (MET) sites, and circulating tumor DNA (ctDNA) of patients with prostate cancer (PC).

METHODS

A total of 1294 PC tissue specimens and 2462 ctDNA specimens underwent hybrid capture-based comprehensive genomic profiling (CGP). Specimens included tissue from PTs; MET biopsies from bone, liver (LIV), lung (LU), brain (BN), lymph node, and soft tissue sites; and ctDNA.

RESULTS

Differences in alteration frequencies between PT, MET, and ctDNA specimens for selected genes were observed. TMPRSS2:ERG fusion frequencies were similar between PTs and MET sites (35% vs 33%) but varied among MET sites. Genomic alterations (GAs) in AR were lowest in PTs (2%) and highest in MET sites (from 24% in LU to 50% in LIV). BN had the highest genomic alterations/tumor (8) and enrichment for PTEN GAs. The BRCA2 GA frequency varied from 0% in BN to 15% in LIV. ERBB2 amplification was increased in MET sites in comparison with PTs. RB1 GAs were increased in LIV. Biomarkers potentially associated with an anti-PD(L)1 response included CDK12 GAs (16% in LU) and a microsatellite instability-high status (29% in BN). Analyses of ctDNA featured a broad spectrum of GAs similar to those detected across MET sites.

CONCLUSIONS

CGP of PTs, MET sites, and ctDNA in PC exhibited differences most likely associated with tumor progression, clonal evolution, and exposure to systemic therapies; ctDNA can also capture a broad range of potential therapeutic opportunities for patients with PC.

Individualized genetic makeup that controls natural killer cell function influences the efficacy of isatuximab immunotherapy in patients with multiple myeloma

BACKGROUND

Phase IIb clinical trial with isatuximab (Isa)-lenalidomide (Len)-dexamethasone (Dex) showed an improved progression-free survival (PFS) in patients with relapsed or refractory multiple myeloma (RRMM), but the efficacy varied by patient. Antibody-dependent cell-mediated cytotoxicity (ADCC) by natural killer (NK) cells plays a crucial role in arbitrating antitumor activities of therapeutic-antibodies. We tested if patient-specific genetic makeup known to set NK cell functional threshold influence response to Isa-Len-Dex therapy.

METHODS

We characterized 57 patients with RRMM receiving Isa-Len-Dex for polymorphisms of killer-cell immunoglobulin-like receptors (KIR), human leukocyte antigen (HLA) class I, and FCGR3A loci. In vitro ADCC assay, coincubating primary NK cells expressing specific KIR repertoire with multiple myeloma cell lines (MM cells) expressing selected HLA class I ligands, was used to confirm the identified genetic correlatives of clinical response.

RESULTS

Patients with KIR3DL2+ and its cognate-ligand HLA-A3/11+ had superior PFS than patients missing this combination (HR=0.43; p=0.02), while patients carrying KIR2DL1+ and HLA-C2C2+ compared with to patients missing this pair showed short PFS (HR=3.54; p=0.05). Patients with KIR3DL2+ and HLA-A3/11+ plus high-affinity FCGR3A-158V allele showed the most prolonged PFS (HR=0.35; p=0.007). Consistent with these clinical data, mechanistic experiments demonstrated that NK cells expressing KIR3DL2 trigger greater ADCC when MM cells express HLA-A3/11. Inversely, NK cells expressing KIR2DL1 do not kill if MM cells express the HLA-C2C2 ligand. NK cells expressing high-affinity FCGR3A-158VV-induced greater ADCC compared with those with low-affinity FCGR3A-158FF.

CONCLUSIONS

Our results suggest that KIR3DL2+ and HLA-A3/11+ with FCGR3A-158V markers lead to enhanced Isa-dependent NK-mediated cytolysis against MM cells and results in improved PFS in patients with RRMM treated by Isa-Len-Dex. Moreover, the presence of KIR2DL1+ and HLA-C2C2+ identifies patients who may have a lower response to Isa-Len-Dex therapy linked to a reduced NK-mediated ADCC. These biomarkers could potentially identify, via precision medicine, patients more likely to respond to Isa-Len-Dex immunotherapy.

TRIAL REGISTRATION NUMBER

NCT01749969.

Genomic Analysis of Circulating Tumor DNA in 3,334 Patients with Advanced Prostate Cancer Identifies Targetable BRCA Alterations and AR Resistance Mechanisms

PURPOSE

Comprehensive genomic profiling (CGP) is of increasing value for patients with metastatic castration-resistant prostate cancer (mCRPC). mCRPC tends to metastasize to bone, making tissue biopsies challenging to obtain. We hypothesized CGP of cell-free circulating tumor DNA (ctDNA) could offer a minimally invasive alternative to detect targetable genomic alterations (GA) that inform clinical care.

EXPERIMENTAL DESIGN

Using plasma from 3,334 patients with mCRPC (including 1,674 screening samples from TRITON2/3), we evaluated the landscape of GAs detected in ctDNA and assessed concordance with tissue-based CGP.

RESULTS

A total of 3,129 patients (94%) had detectable ctDNA with a median ctDNA fraction of 7.5%; BRCA1/2 was mutated in 295 (8.8%). In concordance analysis, 72 of 837 patients had BRCA1/2 mutations detected in tissue, 67 (93%) of which were also identified using ctDNA, including 100% of predicted germline variants. ctDNA harbored some BRCA1/2 alterations not identified by tissue testing, and ctDNA was enriched in therapy resistance alterations, as well as possible clonal hematopoiesis mutations (e.g., in ATM and CHEK2). Potential androgen receptor resistance alterations were detected in 940 of 2,213 patients (42%), including amplifications, polyclonal and compound mutations, rearrangements, and novel deletions in exon 8.

CONCLUSIONS

Genomic analysis of ctDNA from patients with mCRPC recapitulates the genomic landscape detected in tissue biopsies, with a high level of agreement in detection of BRCA1/2 mutations, but more acquired resistance alterations detected in ctDNA. CGP of ctDNA is a compelling clinical complement to tissue CGP, with reflex to tissue CGP if negative for actionable variants.See related commentary by Hawkey and Armstrong, p. 2961.

Abstract PS5-04: Therapeutic considerations in microsatellite instability high (MSI- H) breast cancers (BC) identified by comprehensive genomic profiling (CGP)

Background: Non-colorectal MSI-H tumors are increasingly identified by CGP. Rare types such as MSI-H BC remain poorly defined with an evidence gap on how to optimally sequence or combine with standard of care treatment. MSI can be measured by either IHC, PCR, or CGP and can be caused by both sporadic and germline variants within different tumor types. Prior studies in BC have shown evidence of dMMR by IHC cases MSS based on PCR. This could be due to intra-tumor heterogeneity, specific microsatellite loci evaluated, or penetrance of germline, somatic, or epigenetic alterations. Published data suggests carriers of germline pathogenic MMR variants have a BC risk equivalent to the normal population and currently germline testing is recommended only for BRCA. Currently in advanced BC, standard tumor biomarker testing includes IHC, PCR, and FISH; however, with increasing use of CGP we demonstrate additional actionable biomarkers as well as potential germline variants in MSI-H BC. Methods: DNA was extracted and hybrid capture CGP was performed on 29,160 BC cases. TMB was determined on 0.8-1.2 Mb of DNA and MSI status on 95-114 loci. Genomic LOH was also evaluated. Comparative analysis was done with 101 MSI-H BC, 841 MSS BC and 4,988 non-breast MSI-H cancers. Histological subtype was obtained from the pathology along with orthogonal testing for ER/PR/HER2 status. Somatic-germline-zygosity (SGZ) status was predicted using a published research use algorithm. Select case reports with clinical outcomes will be presented. Results: We identified 101 (0.35% of total) MSI-H BC cases: 29 ER+/HER2-, 5 HER2+, 29 TNBC, and 28 unknown. Amongst BC cases with known subtype, TNBC was enriched for MSI-H vs MSS (53.4 vs 35.8%, p=0.005). The median TMB in MSI-H BC (26.1 mut/Mb, IQR 17.4;42.8) was significantly lower than that of MSI-H colon (46.1mut/MB) and higher than that of MSI-H uterine tumors (22.6mut/Mb) in our comparison group (p&lt;0.001 for both, Kruskal-Wallis test). Pathogenic variants in an MMR gene were found in 61.4% of MSI-H BC with MLH1 loss being the most common (13.6%) and much higher vs. the non-breast MSI-H cohort (2.4%, p&lt;0.0001). Germline mutations in MMR genes in BC are rare yet 5/52 MMR short variants identified in 101 MSI-H BCs were predicted to be germline, 34 somatic, and 13 could not be determined. We identified 21 MSI-H BC patients with a total of 25 pathogenic BRCA1/2 alterations of which 4 were likely germline, 10 were homozygous, and were enriched in TNBC. These were mainly frameshift mutations, including BRCA2 T3033fs* in 5/18 (28%) cases; however, 7/25 were deletions, rearrangements, or nonsense mutations. Median gLOH was significantly higher in BRCA altered (19.7%) compared to BRCA wild-type MSI-H BC cases (9.6%) (p=0.007, Wilcox test). Additional potentially targetable biomarkers included 26 CDx eligible PIK3CA mutations, 11 ERBB2 activating point mutations in the TKD or ECD domain, 1 FGFR2 rearrangement, and 6 AKT1 E17K mutations. Four cases also had concurrent (CD274) PD-L1 amplifications. Conclusion: MSI-H BC is rare but CGP can identify additional therapeutic options for rational combination with targeted therapies such as PI3K, PARP, and HER2 inhibitors. BRCA alterations may be of germline or somatic origin and they may be targetable, as demonstrated by gLOH, rather than passenger mutations. Further characterization of these tumors and comparison to both MSS BC and non-breast MSI-H tumor types, combined with treatment outcomes, can provide insights on rationale combinations and/or sequencing of therapeutic agents.

Citation Format: Kimberly McGregor, Natalie Danzinger, Jeffrey S. Ross, Kyle Gowen, Alexa B. Schrock, Garrett M. Frampton, Dean C. Pavlick, Jan W. Davis, Carl R. Gray, Jeffrey M. Venstrom. Therapeutic considerations in microsatellite instability high (MSI- H) breast cancers (BC) identified by comprehensive genomic profiling (CGP) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS5-04.

RAS Amplification as a Negative Predictor of Benefit from Anti-EGFR-Containing Therapy Regimens in Metastatic Colorectal Cancer

BACKGROUND

RAS short variant (SV) mutations in colorectal cancer (CRC) are associated with lack of benefit from epidermal growth factor receptor (EGFR) monoclonal antibody (EGFRmAb). However, the clinical implications for RAS amplification (RASa) as a biomarker for anti-EGFR therapy in CRC remain ill defined.

METHODS

Genomic analysis was performed using the Foundation Medicine (FM) comprehensive genomic profiling database of 37,233 CRC cases. Clinical outcomes were assessed using two independent cohorts: the City of Hope (COH) cohort of 338 patients with metastatic CRC (mCRC) and the Flatiron Health-FM real-world clinicogenomic database (CGDB) of 3,904 patients with mCRC.

RESULTS

RASa was detected in 1.6% (614/37,233) of primarily mCRC. RASa 6-9 (n = 241, 39%), 10-19 (n = 165, 27%), and ≥ 20 (n = 209, 34%) copy number subsets had co-RAS SV/BRAF V600E in 63%/3%, 31%/0.6%, and 4.8%/0% of cases, respectively. In the COH cohort, six patients with RASa (13-54 copies) received EGFRmAb, four of six had progressive disease, two had stable disease, and median time to treatment discontinuation (TTD) was 2.5 months. Of the CGDB EGFRmAb-treated patients, those with RASa (n = 9) had median TTD of 4.7 months and overall survival (OS) of 11.4 months, those with RAS SV (n = 101) had median TTD and OS of 5.3 and 9.4 months, and those with RAS/BRAF wild-type (n = 608) had median TTD and OS of 7.6 and 13.7 months.

CONCLUSION

Patients with RASa without RAS mutations (1.1% of mCRC) may have poor outcomes on EGFRmAb, although numbers herein were small, and interpretation is confounded by combination chemotherapy. Larger independent studies are warranted to determine if RASa, including degree of amplification, may act similarly to RAS mutation as a resistance mechanism to EGFRmAb therapies.

IMPLICATIONS FOR PRACTICE

Genomic data suggest that RAS amplification occurs as the sole RAS/RAF alteration in >1% of colorectal cancer cases and that degree of amplification inversely correlates with co-occurring MAPK pathway alterations. Preliminary clinical evidence suggests that RAS amplification may function similarly to RAS mutation as a negative predictor of benefit from anti-epidermal growth factor receptor therapies in colorectal cancer. More clinical data are needed, and comprehensive genomic profiling, including detection of RAS amplification, should be used in trial design to inform therapy selection.

CDKN2C-Null Leiomyosarcoma: A Novel, Genomically Distinct Class of TP53/RB1-Wild-Type Tumor With Frequent CIC Genomic Alterations and 1p/19q-Codeletion

PURPOSE

Leiomyosarcoma (LMS) harbors frequent mutations in TP53 and RB1 but few actionable genomic alterations. Here, we searched for recurrent actionable genomic alterations in LMS that occur in the absence of common untreatable oncogenic drivers.

METHODS

Tissues from 276,645 unique advanced cancers, including 2,570 uterine and soft tissue LMS, were sequenced by hybrid-capture-based next-generation DNA and RNA sequencing/comprehensive genomic profiling of up to 406 genes. We characterized clinicopathologic features of relevant patient cases.

RESULTS

Overall, 77 LMS exhibited homozygous copy loss of CDKN2C at chromosome 1p32.3 (3.0% of LMS). Genomic alterations (GAs) in TP53, RB1, and ATRX were rare compared with the remainder of the LMS cohort (11.7% v 73.4%, 0% v 54.5%, 2.6% v 24.5%, respectively; all P < .0001). CDKN2C-null LMS patient cases were significantly enriched for GAs in CIC (40.3% v 1.4%) at 19q13.2, CDKN2A (46.8% v 7.0%), and RAD51B (16.9% v 1.7%; all P < .0001). Chromosome arm-level aneuploidy analysis of available LMS patient cases (n = 1,284) found that 81% (58 of 72) of CDKN2C-null LMS exhibited 1p/19q-codeletion, a significant enrichment compared with 5.1% in the remainder of the LMS cohort (P < .0001). In total, 99% of CDKN2C-null LMS were in women; the median age was 61 years at surgery (range, 36-81 years). Fifty-five patient cases were uterine primary, four were nonuterine, and the remaining 18 were of uncertain primary site. Sixty percent of cases showed at least focal epithelioid variant histology. Most patients had advanced-stage disease, with 62% of confirmed uterine primary LMS at International Federation of Gynecology and Obstetrics stage IVB. We further validated our findings in two publicly available datasets: The Cancer Genome Atlas and the Project GENIE initiative.

CONCLUSION

CDKN2C-null LMS defines a genomically distinct tumor that may have prognostic and/or therapeutic clinical implications, including possible use of specific cyclin-dependent kinase inhibitors.

Retrospective analysis of real-world data to determine clinical outcomes of patients with advanced non-small cell lung cancer following cell-free circulating tumor DNA genomic profiling

OBJECTIVES

Liquid biopsy and comprehensive genomic profiling (CGP) of circulating tumor DNA (ctDNA) are increasingly used for detection of targetable genomic alterations (GA) in non-small cell lung cancer (NSCLC). To examine the clinical outcomes for patients following CGP using liquid biopsy versus tissue biopsy, receipt of matched targeted therapy post-CGP and associated outcomes were evaluated in the real-world setting.

METHODS

6491 patients with NSCLC and liquid biopsy (N = 937 tests) and/or tissue (N = 5582 tests) CGP were included in a de-identified commercial clinico-genomic database. Targetable GAs included National Comprehensive Cancer Network NSCLC guideline biomarkers. Clinical characteristics, real-world progression, and real-world response (rwR) were obtained via technology-enabled abstraction of clinician notes and radiology/pathology reports.

RESULTS

At the time of liquid biopsy CGP, 53% (496/937) of patients were documented to have received ≥1 line of prior therapy (tissue CGP: 13%, 735/5582). 90% (832/928) of liquid biopsy cases had evidence of ctDNA. A targetable GA was detected in 20% (188/937) of liquid biopsy and 22% (1215/5582) of tissue CGP cases. Use of matched targeted therapy overall was similar post-liquid biopsy or post-tissue CGP but varied considerably across emerging (25%, 79/317) versus standard of care (SOC) (74%, 475/640) GA. Real-world-progression free survival for patients receiving SOC first line matched targeted therapy administered following liquid biopsy (n = 33) and tissue (n = 229) CGP were similar (13.8 vs 10.6 months; aHR = 0.68 [0.36-1.26]). Among patients evaluated for rwR, overall response rate (partial/complete response) to matched targeted therapy post-liquid biopsy CGP was 75% (39/52) versus 66% post-tissue CGP (254/385, P = 0.51).

CONCLUSION

Retrospective analysis of real-world clinico-genomic data demonstrated that clinical outcomes on matched targeted therapy were similar following liquid biopsy and tissue CGP in NSCLC, which suggests routine clinical use of liquid biopsy CGP can reliably guide therapy selection.

Prognostic Impact of Natural Killer Cell Count in Follicular Lymphoma and Diffuse Large B-cell Lymphoma Patients Treated with Immunochemotherapy

PURPOSE

Natural killer (NK) cells are key effector cells for anti-CD20 monoclonal antibodies (mAb), such as obinutuzumab and rituximab. We assessed whether low pretreatment NK-cell count (NKCC) in peripheral blood or tumor tissue was associated with worse outcome in patients receiving antibody-based therapy.

PATIENTS AND METHODS

Baseline peripheral blood NKCC was assessed by flow cytometry (CD3^-CD56⁺ and/or CD16⁺ cells) in 1,064 of 1,202 patients with follicular lymphoma treated with obinutuzumab or rituximab plus chemotherapy in the phase III GALLIUM trial (NCT01332968) and 1,287 of 1,418 patients with diffuse large B-cell lymphoma (DLBCL) treated with obinutuzumab or rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (G-CHOP or R-CHOP) in the phase III GOYA trial (NCT01287741). The prognostic value of tumor NK-cell gene expression, as assessed by whole-transcriptome gene expression using TruSeq RNA sequencing, was also analyzed. The association of baseline variables, such as treatment arm, was evaluated using multivariate Cox regression models using a stepwise approach.

RESULTS

In this exploratory analysis, low baseline peripheral blood NKCC was associated with shorter progression-free survival (PFS) in both follicular lymphoma [hazard ratio (HR), 1.48; 95% confidence interval (CI), 1.02-2.14; P = 0.04] and DLBCL (HR, 1.36; 95% CI, 1.01-1.83; P = 0.04), and overall survival in follicular lymphoma (HR, 2.20; 95% CI, 1.26-3.86; P = 0.0058). Low tumor NK-cell gene expression was associated with shorter PFS in G-CHOP-treated patients with DLBCL (HR, 1.95; 95% CI, 1.22-3.15; P < 0.01).

CONCLUSIONS

These findings indicate that the number of NK cells in peripheral blood may affect the outcome of patients with B-cell non-Hodgkin lymphoma receiving anti-CD20-based immunochemotherapy.

HLA Mismatching Favoring Host-Versus-Graft NK Cell Activity Via KIR3DL1 Is Associated With Improved Outcomes Following Lung Transplantation

Chronic lung allograft dysfunction (CLAD) is linked to rejection and limits survival following lung transplantation. HLA-Bw4 recipients of HLA-Bw6 grafts have enhanced host-versus-graft (HVG) natural killer (NK) cell activity mediated by killer cell immunoglobulin-like receptor (KIR)3DL1 ligand. Because NK cells may promote tolerance by depleting antigen-presenting cells, we hypothesized improved outcomes for HLA-Bw4 recipients of HLA-Bw6 grafts. We evaluated differences in acute cellular rejection and CLAD-free survival across 252 KIR3DL1+ recipients from University of California, San Francisco (UCSF). For validation, we assessed survival and freedom from bronchiolitis obliterans syndrome (BOS), retransplantation, or death in 12 845 non-KIR typed recipients from the United Network for Organ Sharing (UNOS) registry. Cox proportional hazards models were adjusted for age, gender, ethnicity, transplant type, and HLA mismatching. HVG-capable subjects in the UCSF cohort had a decreased risk of CLAD or death (hazard ratio [HR] 0.57, 95% confidence interval [CI] 0.36-0.88) and decreased early lymphocytic bronchitis. The HVG effect was not significant in subjects with genotypes predicting low KIR3DL1 expression. In the UNOS cohort, HVG-capable subjects had a decreased risk of BOS, retransplant, or death (HR 0.95, 95% CI 0.91-0.99). Survival improved with the higher-affinity Bw4-80I ligand and in Bw4 homozygotes. Improved outcomes in HVG-capable recipients are consistent with a protective NK cell role. Augmentation of NK activity could supplement current immunosuppression techniques.

Abstract 2772: BCL-2 family expression profiling may identify distinct molecular subtypes of multiple myeloma with increased susceptibility to single agent Venetoclax

Venetoclax (VEN) is being evaluated in relapsed/refractory multiple myeloma (R/R MM) patients as a single agent (NCT01794520). Improved objective response rates were observed in t(11;14) patients (40% in t(11;14)+ vs 6% in t(11;14)-), which were shown to associate with a favorable BCL-2 family expression profile (high BCL2:BCL2L1 (BCL-XL). Forty percent of t(11;14)+ population exhibited VEN favorable biomarker profile with an 88% ORR compared to 20% in t(11;14)+ patients with unfavorable profile. Thus, a favorable BCL-2 family expression profile may identify certain MM subgroups with increased sensitivity to the anti-tumor activity of VEN as a single agent. To better understand and identify the patient populations that may benefit from VEN, we retrospectively analyzed the prevalence of a favorable BCL-2 family expression profile in t(11;14)+ and other MM molecular subtypes in two published cohorts (GSE4581 and GSE9782). Our results showed that BCL2 expression varied significantly across molecular and cytogenetic subgroups. The t(11;14)+ subgroup expressed high BCL2 and the lowest BCL2L1 and MCL1 in both newly diagnosed (NDMM) and R/R MM patients. Correspondingly, the t(11;14) MM was enriched for the highest ratios of BCL2/MCL1 and BCL2/BCL2L1, further supporting the single agent VEN activity observed in this patient population. Based on prevalence study in cohort GSE9782, we observed 40% of t(11;14)+ R/R MM patients exhibited a favorable BCL-2 family expression profile, using clinical defined cutoffs, thus highly consistent with the VEN single agent trial. Furthermore, this favorable profile existed in other molecular subtypes, especially the ones that harbor abnormal MAF (23%) and D3 (37.5%) translocations, as well as dysregulated expression of cyclinD1 (21.2%)/D1+D2 (26.7%). The molecular subgroup with overexpression of cyclin D2 had the lowest prevalence of the favorable profile (7.5%). In the NDMM cohort, overall 27% patients had favorable profile. More specifically, the t(11;14) patients had the highest (61%) and D2 patients had the lowest (13%) prevalence of a favorable BCL-2 family profile. Collectively, our data suggests that MM subgroups are associated with distinct BCL-2 family expression profiles, and that the t(11;14) subgroup is particularly suited for single agent VEN treatment as indicated by the high prevalence of a favorable BCL-2 family expression profile. In addition, we further identified patients in the non t(11;14) MM subgroups with a favorable BCL-2 family expression profile that may also potentially benefit from VEN monotherapy.

Citation Format: Jenny Wu, Caleb Stein, Jeremy A. Ross, Franklin Peale, John D. Shaughnessy, Ryan Van Laar, Gareth Morgan, Jeffrey M. Venstrom, Elizabeth A. Punnoose, Yanwen Yanwen Jiang. BCL-2 family expression profiling may identify distinct molecular subtypes of multiple myeloma with increased susceptibility to single agent Venetoclax [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 2772. doi:10.1158/1538-7445.AM2017-2772

Licensing delineates helper and effector NK cell subsets during viral infection

Natural killer (NK) cells can be divided into phenotypic subsets based on expression of receptors that bind self-MHC-I molecules, a concept termed licensing or education. Here we show NK cell subsets with different migratory, effector, and immunoregulatory functions in dendritic cell and antigen (ag)-specific CD8+ T cell responses during influenza and murine cytomegalovirus infections. Shortly after infection, unlicensed NK cells localized in draining lymph nodes and produced GM-CSF, which correlated with the expansion and activation of dendritic cells, and resulted in greater and sustained ag-specific T cell responses. In contrast, licensed NK cells preferentially migrated to infected tissues and produced IFN-γ. Importantly, human NK cell subsets exhibited similar phenotypic characteristics. Collectively, our studies demonstrate a critical demarcation between the functions of licensed and unlicensed NK cell subsets, with the former functioning as the classical effector subset and the latter as the stimulator of adaptive immunity helping to prime immune responses.

Rituximab treatment circumvents the prognostic impact of tumor-infiltrating T-cells in follicular lymphoma patients

Previous immunohistochemical (IHC) studies showed controversial data about the prognostic value of tumor-infiltrating lymphocytes (TILs) in follicular lymphoma (FL). To clarify this issue, a large series of FL samples from rituximab-treated patients enrolled in the randomized PRIMA trial was examined. IHC was quantified using automated image analysis in 417, 287, 418, 406, 379, and 369 patients for CD3, CD4, CD8, PD1, ICOS, and FOXP3, respectively. RNAseq analysis was used to quantify TIL-related mRNA transcripts from 148 patients. When each IHC marker was used as a continuous variable in the whole cohort, high CD3 counts were associated with better progression-free survival (PFS) (P = .025). When an optimal IHC cut point was applied to the whole patient population, high CD3 counts and high PD1 counts were associated with better PFS (P = .011 and P = .044, respectively), whereas none of the other TIL markers had any significant correlation with outcome. When a stringent analysis was performed by dividing the whole cohort into a training set and a validation set, none of the TIL markers showed a prognostic significance in both groups. RNAseq analysis showed a significant correlation between high levels of CD3 and CD8 transcripts and better PFS (P = .001 and P = .037, respectively). No prognostic correlation was found as to the level of other immune gene transcripts. These results suggest that the IHC prognostic value of TILs is circumvented by rituximab treatment, although there is a trend for high numbers of CD3+ TILs to correlate with better PFS.

Recipient HLA-C Haplotypes and microRNA 148a/b Binding Sites Have No Impact on Allogeneic Hematopoietic Cell Transplantation Outcomes

Natural killer cells are important in graft-versus-leukemia responses after hematopoietic cell transplantation (HCT). A variety of surface receptors dictates natural killer cell function, including killer cell immunoglobulin-like receptor recognition of HLA-C. Previous single-center studies show that HLA-C epitopes, designated C1 and C2, were associated with allogeneic HCT outcomes; specifically, recipients homozygous for the C1 epitope (C1/C1) experienced a survival benefit. Additionally, mismatching at HLA-C was beneficial in recipients possessing at least 1 C2 allele, whereas the opposite was true for homozygous C1 (C1/C1) recipients where HLA-C mismatching resulted in worse outcomes. In this analysis we aimed to validate these findings in a large multicenter study. We also set out to determine whether surface expression of recipient HLA-C, determined by polymorphism in a microRNA (miR-148a/b) binding site within the 3'-region of the HLA-C transcript, was associated with transplant outcomes. In this large registry cohort, we were unable to confirm the prior findings regarding recipient HLA-C epitope status and outcome. Additionally, HLA-C surface expression (ie, surface density), as predicted by the miR-148a/b binding single nucleotide polymorphism, was also not with associated transplant outcomes. Collectively, neither HLA-C surface expression, as determined by miR-148a/b, nor recipient HLA-C epitopes (C1, C2) are associated with allogeneic HCT outcomes.

KIR and HLA genotypes predictive of low-affinity interactions are associated with lower relapse in autologous hematopoietic cell transplantation for acute myeloid leukemia

Killer cell Ig-like receptors (KIRs) bind cognate HLA class I ligands with distinct affinities, affecting NK cell licensing and inhibition. We hypothesized that differences in KIR and HLA class I genotypes predictive of varying degrees of receptor-ligand binding affinities influence clinical outcomes in autologous hematopoietic cell transplantation (AHCT) for acute myeloid leukemia (AML). Using genomic DNA from a homogeneous cohort of 125 AML patients treated with AHCT, we performed KIR and HLA class I genotyping and found that patients with a compound KIR3DL1(+) and HLA-Bw4-80Thr(+), HLA-Bw4-80Ile(-) genotype, predictive of low-affinity interactions, had a low incidence of relapse, compared with patients with a KIR3DL1(+) and HLA-Bw4-80Ile(+) genotype, predictive of high-affinity interactions (hazard ratio [HR], 0.22; 95% confidence interval [CI], 0.06-0.78; p = 0.02). This effect was influenced by HLA-Bw4 copy number, such that relapse progressively increased with one copy of HLA-Bw4-80Ile (HR, 1.6; 95% CI, 0.84-3.1; p = 0.15) to two to three copies (HR, 3.0; 95% CI, 1.4-6.5; p = 0.005) and progressively decreased with one to two copies of HLA-Bw4-80Thr (p = 0.13). Among KIR3DL1(+) and HLA-Bw4-80Ile(+) patients, a predicted low-affinity KIR2DL2/3(+) and HLA-C1/C1 genotype was associated with lower relapse than a predicted high-affinity KIR2DL1(+) and HLA-C2/C2 genotype (HR, 0.25; 95% CI, 0.09-0.73; p = 0.01). Similarly, a KIR3DL1(+) and HLA-Bw4-80Thr(+), HLA-Bw4-80Ile(-) genotype, or lack of KIR3DL1(+) and HLA-Bw4-80Ile(+) genotype, rescued KIR2DL1(+) and HLA-C2/C2 patients from high relapse (p = 0.007). These findings support a role for NK cell graft-versus-leukemia activity modulated by NK cell receptor-ligand affinities in AHCT for AML.

A phase I study of targeted, dose-escalated intravenous busulfan in combination with etoposide as myeloablative therapy for autologous stem cell transplantation in acute myeloid leukemia

BACKGROUND

Busulfan and etoposide have been used as myeloablative therapy for autologous hematopoietic stem cell transplantation (HSCT) in adults with acute myeloid leukemia (AML) for > 20 years. The use of targeted intravenous (I.V.) busulfan has significantly improved the tolerability and efficacy of this regimen. We designed a dose-escalation study to examine the maximum tolerated dose (MTD) of targeted I.V. busulfan with bolus etoposide as preparative therapy for autologous HSCT in AML.

PATIENTS AND METHODS

In this single-center, phase I study, adult AML patients received I.V. busulfan targeted to either an area under the curve (AUC) of 1250 (cohort 1) or 1400 (cohort 2) μmol/min over 16 doses. Dose adjustments based on plasma pharmacokinetics occurred before doses 2 and 11. Etoposide 60 mg/kg I.V. was administered 24 hours after the last busulfan dose and 3 days before stem cell infusion.

RESULTS

Twelve patients with intermediate-risk AML in first complete remission were treated. All patients in cohort 1 and 5 patients (83%) in cohort 2 were within 10% of the target AUC. The MTD was not reached, although Grade ≥ 3 mucositis occurred in 3 patients (50%) in cohort 1 and in 4 patients (66%) in cohort 2, limiting further dose escalation. Two-year relapse-free survival was 33% in cohort 1 versus 67% in cohort 2 (P = .08).

CONCLUSION

Etoposide and targeted, dose-escalated I.V. busulfan as myeloablative therapy for autologous HSCT in AML is safe, with mucositis being the most significant toxicity. A phase II study is warranted to further evaluate the activity and safety of busulfan targeted to AUC 1400 μmol/min.

Delayed hematopoietic recovery after auto-SCT in patients receiving arsenic trioxide-based therapy for acute promyelocytic leukemia: a multi-center analysis

A potential link between arsenic (ATO)-based therapy and delayed hematopoietic recovery after autologous hematopoietic SCT (HSCT) for acute promyelocytic leukemia (APL) has previously been reported. We retrospectively reviewed the clinical histories of 58 patients undergoing autologous HSCT for APL at 21 institutions in the United States and Japan. Thirty-three (56%) of the patients received ATO-based therapy prior to stem cell collection. Delayed neutrophil engraftment occurred in 10 patients (17%): 9 of the 10 patients (90%) received prior ATO (representing 27% of all ATO-treated patients), compared with 1 of the 10 patients (10%) not previously treated with ATO (representing 4% of all ATO-naïve patients; P<0.001). Compared with ATO-naïve patients, ATO-treated patients experienced significantly longer times to ANC recovery (median 12 days vs 9 days, P<0.001). In multivariate analysis, the only significant independent predictor of delayed neutrophil engraftment was prior treatment with ATO (hazard ratio 4.87; P<0.001). Of the available stem cell aliquots from APL patients, the median viable post-thaw CD34+ cell recovery was significantly lower than that of cryopreserved autologous stem cell products from patients with non-APL AML. Our findings suggest that ATO exposure prior to CD34+ cell harvest has deleterious effects on hematopoietic recovery after autologous HSCT.

CALGB 150905 (Alliance): rituximab broadens the antilymphoma response by activating unlicensed NK cells

Natural killer (NK) cells contribute to clinical responses in patients treated with rituximab, but the rules determining NK-cell responsiveness to mAb therapies are poorly defined. A deeper understanding of the mechanisms responsible for antibody-dependent cellular cytotoxicity (ADCC) could yield useful biomarkers for predicting clinical responses in patients. Unlicensed NK cells, defined as NK cells lacking expression of an inhibitory KIR for self-HLA class I ligands, are hyporesponsive in steady state, but are potent effectors in inflammatory conditions. We hypothesized that antitumor antibodies such as rituximab can overcome NK-cell dependence on licensing, making unlicensed NK cells important for clinical responses. Here, we examined the influences of variations in KIR and HLA class I alleles on in vitro responses to rituximab. We tested the clinical significance in a cohort of patients with follicular lymphoma treated with rituximab-containing mAb combinations, and show that rituximab triggers responses from all NK-cell populations regardless of licensing. Neither IL2 nor accessory cells are required for activating unlicensed NK cells, but both can augment rituximab-mediated ADCC. Moreover, in 101 patients with follicular lymphoma treated with rituximab-containing mAb combinations, a "missing ligand" genotype (predictive of unlicensed NK cells) is associated with a higher rate of progression-free survival. Our data suggest that the clinical efficacy of rituximab may be driven, in part, by its ability to broaden the NK-cell repertoire to include previously hyporesponsive, unlicensed NK cells. A "missing ligand" KIR and HLA class I genotype may be predictive of this benefit and useful for personalizing treatment decisions in lymphomas and other tumors.

Hematopoietic cell transplantation comorbidity index (HCT-CI) is predictive of adverse events and overall survival in older allogeneic transplant recipients

OBJECTIVES

Our goal was to evaluate the ability of the hematopoietic cell transplantation comorbidity index (HCT-CI) to predict outcomes after allogeneic stem cell transplant (SCT) within the context of an older patient population, where multiple comorbidities are common.

MATERIALS AND METHODS

We performed a retrospective cohort study of SCT patients ≥50years of age at our institution, identifying 59 patients with complete HCT-CI data collected prospectively.

RESULTS

HCT-CI category distribution in our sample was disproportionate, with almost half of patients having scores ≥3. High HCT-CI score (≥3 vs <3) was associated with significantly inferior OS (median OS not reached for HCT-CI <3 vs 14months for HCT-CI ≥3; hazard ratio (HR) 2.2, p=0.02). HCT-CI score was a better predictor of OS than age, performance status or conditioning intensity. When adjusted for disease relapse risk, HCT-CI score conferred a worse prognosis in the low risk group (HR 1.43, p=0.03) but not in the intermediate/high risk group (HR 1.08, p=0.65). NRM was low in the total sample (6% at one year) and was not associated with HCT-CI score. Grade 3-4 non-hematologic adverse events within the first 100days after SCT were significantly more common in the higher HCT-CI groups (p=0.02).

CONCLUSIONS

In our older patient cohort with a high incidence of multiple comorbidities, HCT-CI score ≥3 was significantly associated with OS, particularly in the subset of patients with a low disease relapse risk.

HLA-C-dependent prevention of leukemia relapse by donor activating KIR2DS1

BACKGROUND

Of the cancers treated with allogeneic hematopoietic stem-cell transplantation (HSCT), acute myeloid leukemia (AML) is most sensitive to natural killer (NK)-cell reactivity. The activating killer-cell immunoglobulin-like receptor (KIR) 2DS1 has ligand specificity for HLA-C2 antigens and activates NK cells in an HLA-dependent manner. Donor-derived NK reactivity controlled by KIR2DS1 and HLA could have beneficial effects in patients with AML who undergo allogeneic HSCT.

METHODS

We assessed clinical data, HLA genotyping results, and donor cell lines or genomic DNA for 1277 patients with AML who had received hematopoietic stem-cell transplants from unrelated donors matched for HLA-A, B, C, DR, and DQ or with a single mismatch. We performed donor KIR genotyping and evaluated the clinical effect of donor KIR genotype and donor and recipient HLA genotypes.

RESULTS

Patients with AML who received allografts from donors who were positive for KIR2DS1 had a lower rate of relapse than those with allografts from donors who were negative for KIR2DS1 (26.5% vs. 32.5%; hazard ratio, 0.76; 95% confidence interval [CI], 0.61 to 0.96; P=0.02). Of allografts from donors with KIR2DS1, those from donors who were homozygous or heterozygous for HLA-C1 antigens could mediate this antileukemic effect, whereas those from donors who were homozygous for HLA-C2 did not provide any advantage (24.9% with homozygosity or heterozygosity for HLA-C1 vs. 37.3% with homozygosity for HLA-C2; hazard ratio, 0.46; 95% CI, 0.28 to 0.75; P=0.002). Recipients of KIR2DS1-positive allografts mismatched for a single HLA-C locus had a lower relapse rate than recipients of KIR2DS1-negative allografts with a mismatch at the same locus (17.1% vs. 35.6%; hazard ratio, 0.40; 95% CI, 0.20 to 0.78; P=0.007). KIR3DS1, in positive genetic linkage disequilibrium with KIR2DS1, had no effect on leukemia relapse but was associated with decreased mortality (60.1%, vs. 66.9% without KIR3DS1; hazard ratio, 0.83; 95% CI, 0.71 to 0.96; P=0.01).

CONCLUSIONS

Activating KIR genes from donors were associated with distinct outcomes of allogeneic HSCT for AML. Donor KIR2DS1 appeared to provide protection against relapse in an HLA-C-dependent manner, and donor KIR3DS1 was associated with reduced mortality. (Funded by the National Institutes of Health and others.).

Unlicensed NK cells target neuroblastoma following anti-GD2 antibody treatment

Survival outcomes for patients with high-risk neuroblastoma (NB) have significantly improved with anti-disialoganglioside GD2 mAb therapy, which promotes NK cell activation through antibody-dependent cell-mediated cytotoxicity. NK cell activation requires an interaction between inhibitory killer cell immunoglobulin-like receptors (KIRs) and HLA class I ligands. NK cells lacking KIRs that are specific for self HLA are therefore "unlicensed" and hyporesponsive. mAb-treated NB patients lacking HLA class I ligands for their inhibitory KIRs have significantly higher survival rates, suggesting that NK cells expressing KIRs for non-self HLA are mediating tumor control in these individuals. We found that, in the presence of mAb, both licensed and unlicensed NK cells are highly activated in vitro. However, HLA class I expression on NB cell lines selectively inhibited licensed NK cell activity, permitting primarily unlicensed NK cells to mediate antibody-dependent cell-mediated cytotoxicity. These results indicate that unlicensed NK cells play a key antitumor role in patients undergoing mAb therapy via antibody-dependent cell-mediated cytotoxicity, thus explaining the potent "missing KIR ligand" benefit in patients with NB.

Abstract 5586: NK cell killer Ig-like receptor (KIR) genotype as a novel biomarker for neuroblastoma patients receiving Anti-GD2 monoclonal antibody 3F8

Background: Natural killer (NK) cells are regulated by inhibitory killer Ig-like receptors (KIRs) that recognize specific HLA class I ligands. KIR-HLA genotypes are tightly linked to NK cell function and clinical outcomes in allogeneic and autologous hematopoietic stem cell transplantation (HSCT). Because NK cells contribute to antibody-dependent cellular cytotoxicity, we hypothesized that specific KIR-HLA genotypes may predict NK cell responsiveness to mAb therapy, and thus, may be useful clinically to identify patients likely to respond to mAb therapy. Methods: 76 children with high risk neuroblastoma received cyclophosphamide-containing induction chemotherapy followed by murine IgG3 monoclonal antibody 3F8 against ganglioside GD2 between 1993 and 2007. HLA and KIR genotyping was performed, and patients were segregated into KIR-HLA groups based on known functional KIR-HLA ligand relationships: KIR2DL2/2DL3 with HLA-CAsn80(HLA-C1 group), KIR2DL1 with HLA-C Lys80(HLA-C2 group), and KIR3DL1 with HLA-Bw4. Overall survival and progression-free survival were estimated by Kaplan-Meier method and hazard ratios by Cox regression. No adjustments were made for multiple comparisons. Comparisons of each end point were based on the log-rank statistics. Results: 63% of the 76 children lacked at least 1 HLA ligand for his/her inhibitory KIR. At 3 years, 80% of patients lacking any KIR ligand (n=46) were alive compared with 69% of patients with all HLA ligands present (n=30) (HR 0.41; 95% CI 0.17-0.98; P=0.04). 23/23 (100%) patients specifically lacking the HLA-Bw4 ligand for KIR3DL1 were alive at 3 years compared with 34/52 (67%) patients exhibiting HLA-Bw4 for KIR 3DL1 (n=52) (HR 0.20; 95% CI 0.05-0.87; P=0.02). Conclusion: KIR-HLA immunogenetics may be a novel biomarker for neuroblastoma patients receiving chemo-immunotherapy. The milieu of HSCT may not be required for NK cells to behave according to “missing ligand,” and KIR-HLA combinations may be predictive of outcome for other malignancies similarly treated with mAb.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5586.

KIR and HLA genotypes are associated with disease progression and survival following autologous hematopoietic stem cell transplantation for high-risk neuroblastoma

PURPOSE

NK cells exhibit cytotoxicity against neuroblastoma. Gene polymorphisms governing NK cell function, therefore, may influence prognosis. Two highly polymorphic genetic loci instrumental in determining NK cell responses encode the NK cell killer immunoglobulin-like receptors (KIR) and their class I human leukocyte antigen (HLA) ligands. We hypothesized that patients with a "missing ligand" KIR-HLA compound genotype may uniquely benefit from autologous hematopoietic stem cell transplantation (HSCT).

EXPERIMENTAL DESIGN

One hundred sixty-nine patients treated with autologous HSCT for stage IV neuroblastoma underwent KIR and HLA genotyping. Patients were segregated according to the presence or absence of HLA ligands for autologous inhibitory KIR. Univariate and multivariate analyses were done for overall and progression-free survival.

RESULTS

Sixty-four percent of patients lacked one or more HLA ligands for inhibitory KIR. Patients lacking a HLA ligand had a 46% lower risk of death [hazard ratio, 0.54; 95% confidence interval (95% CI), 0.35-0.85; P = 0.007] and a 34% lower risk of progression (hazard ratio, 0.66; 95% CI, 0.44-1.0; P = 0.047) at 3 years compared with patients who possessed all ligands for his/her inhibitory KIR. Among all KIR-HLA combinations, 16 patients lacking the HLA-C1 ligand for KIR2DL2/KIR2DL3 experienced the highest 3-year survival rate of 81% (95% CI, 64-100). Survival was more strongly associated with "missing ligand" than with tumor MYCN gene amplification.

CONCLUSION

KIR-HLA immunogenetics represents a novel prognostic marker for patients undergoing autologous HSCT for high-risk neuroblastoma.

Survival after pancreas transplantation in patients with diabetes and preserved kidney function

CONTEXT

Solitary pancreas transplantation (ie, pancreas alone or pancreas-after-kidney) for diabetes mellitus remains controversial due to procedure-associated morbidity/mortality, toxicity of immunosuppression, expense, and unproven effects on the secondary complications of diabetes. Whether transplantation offers a survival advantage over conventional therapies for diabetes is unknown.

OBJECTIVE

To determine the association between solitary pancreas transplantation and survival in patients with diabetes and preserved kidney function.

DESIGN, SETTING, AND PATIENTS

Retrospective observational cohort study conducted at 124 transplant centers in the United States, in 11 572 patients with diabetes mellitus on the waiting list for pancreas transplantation (pancreas alone, pancreas-after-kidney, or simultaneous pancreas-kidney) at the United Network for Organ Sharing/Organ Procurement and Transplantation Network between January 1, 1995, and December 31, 2000. All patients receiving a multiorgan (other than simultaneous pancreas-kidney) transplant were excluded, as were those listed for solitary pancreas transplantation who had a serum creatinine level greater than 2 mg/dL (176.8 micromol/L) at time of listing, or who ultimately received a simultaneous pancreas-kidney transplant.

MAIN OUTCOME MEASURE

All-cause mortality within 4 years following transplantation (or within a comparable time on the waiting list for the group not undergoing transplantation).

RESULTS

Overall relative risk of all-cause mortality for transplant recipients (compared with patients awaiting the same procedure) over 4 years of follow-up was 1.57 (95% confidence interval [CI], 0.98-2.53; P =.06) for pancreas transplant alone, 1.42 (95% CI, 1.03-1.94; P =.03) for pancreas-after-kidney transplant, and 0.43 (95% CI, 0.39-0.48) for simultaneous pancreas-kidney transplant. Transplant patient 1- and 4-year survival rates were 96.5% and 85.2% for pancreas transplant alone, respectively, and 95.3% and 84.5% for pancreas-after-kidney transplant, while 1- and 4-year survival rates for patients on the waiting list were 97.6% and 92.1% for pancreas transplant alone, respectively, and 97.1% and 88.1% for pancreas-after-kidney transplant.

CONCLUSION

From 1995-2000, survival for those with diabetes and preserved kidney function and receiving a solitary pancreas transplant was significantly worse compared with the survival of waiting-list patients receiving conventional therapy.