Genomics driven precision oncology in advanced biliary tract cancer improves survival

BACKGROUND

Biliary tract cancers (BTCs) including intrahepatic, perihilar, and distal cholangiocarcinoma as well as gallbladder cancer, are rare but aggressive malignancies with few effective standard of care therapies.

METHODS

We implemented integrative clinical sequencing of advanced BTC tumors from 124 consecutive patients who progressed on standard therapies (N=92 with MI-ONCOSEQ and N=32 with commercial gene panels) enrolled between 2011-2020.

RESULTS

Genomic profiling of paired tumor and normal DNA and tumor transcriptome (RNA) sequencing identified actionable somatic and germline genomic alterations in 54 patients (43.5%), and potentially actionable alterations in 79 (63.7%) of the cohort. Of these, patients who received matched targeted therapy (22; 40.7%) had a median overall survival of 28.1 months compared to 13.3 months in those who did not receive matched targeted therapy (32; P < 0.01), or 13.9 months in those without actionable mutations (70; P < 0.01). Additionally, we discovered recurrent activating mutations in FGFR2, and a novel association between KRAS and BRAF mutant tumors with high expression of immune modulatory protein NT5E (CD73) that may represent novel therapeutic avenues.

CONCLUSIONS

Overall, the identification of actionable/ potentially actionable aberrations in a large proportion of cases, and improvement in survival with precision oncology supports molecular analysis and clinical sequencing for all patients with advanced BTC.

Assessment of Clinical Benefit of Integrative Genomic Profiling in Advanced Solid Tumors

Question

What is the clinical utility of genomic profiling for patients with advanced solid tumors?

Findings

In this cohort study of 1015 patients who underwent integrative genomic profiling, a high rate of pathogenic germline variants and a subset of patients who derive substantial clinical benefit from sequencing information were identified.

Meaning

These findings support (1) directed germline testing for inherited cancer predisposition in all patients with advanced cancer and (2) use of integrative genomic profiling as a component of standard of care for patients with cancer of unknown origin and other rare malignant neoplasms.

Importance

Use of next-generation sequencing (NGS) to identify clinically actionable genomic targets has been incorporated into routine clinical practice in the management of advanced solid tumors; however, the clinical utility of this testing remains uncertain.

Objective

To determine which patients derived the greatest degree of clinical benefit from NGS profiling.

Design, Setting, and Participants

Patients in this cohort study underwent fresh tumor biopsy and blood sample collection for genomic profiling of paired tumor and normal DNA (whole-exome or targeted-exome capture with analysis of 1700 genes) and tumor transcriptome (RNA) sequencing. Somatic and germline genomic alterations were annotated and classified according to degree of clinical actionability. Results were returned to treating oncologists. Data were collected from May 1, 2011, to February 28, 2018, and analyzed from May 1, 2011, to April 30, 2020.

Main Outcomes and Measures

Patients’ subsequent therapy and treatment response were extracted from the medical record to determine clinical benefit rate from NGS-directed therapy at 6 months and exceptional responses lasting 12 months or longer.

Results

During the study period, NGS was attempted on tumors from 1138 patients and was successful in 1015 (89.2%) (MET1000 cohort) (538 men [53.0%]; mean [SD] age, 57.7 [13.3] years). Potentially clinically actionable genomic alterations were discovered in 817 patients (80.5%). Of these, 132 patients (16.2%) received sequencing-directed therapy, and 49 had clinical benefit (37.1%). Exceptional responses were observed in 26 patients (19.7% of treated patients). Pathogenic germline variants (PGVs) were identified in 160 patients (15.8% of cohort), including 49 PGVs (4.8% of cohort) with therapeutic relevance. For 55 patients with carcinoma of unknown primary origin, NGS identified the primary site in 28 (50.9%), and sequencing-directed therapy in 13 patients resulted in clinical benefit in 7 instances (53.8%), including 5 exceptional responses.

Conclusions and Relevance

The high rate of therapeutically relevant PGVs identified across diverse cancer types supports a recommendation for directed germline testing in all patients with advanced cancer. The high frequency of therapeutically relevant somatic and germline findings in patients with carcinoma of unknown primary origin and other rare cancers supports the use of comprehensive NGS profiling as a component of standard of care for these disease entities.

Integration of Germline Pharmacogenetics Into a Tumor Sequencing Program

PURPOSE

Evidence-based guidelines inform treatment decisions for patients for whom germline genetic information is available. Our real-time tumor sequencing program, which makes precision treatment decisions for patients with cancer, produces matched germline information, providing a unique opportunity to efficiently implement pharmacogenetics and benefit patients.

METHODS

The germline genetic database from the Michigan Oncology Sequencing (MI-Oncoseq) program was searched for 21 clinically actionable polymorphisms in five cancer-relevant genes: TPMT, DPYD, CYP2C19, CYP3A5, and UGT1A1. Residual germ line DNA was sent to an external Clinical Laboratory Improvement Amendments-approved laboratory for confirmatory genotyping. The medical records of MI-Oncoseq patients with actionable phenotypes were searched for receipt of relevant drugs and to determine whether having genetic information at the time of treatment would have led to a treatment recommendation.

RESULTS

All nine variants in TPMT, DPYD, and CYP2C19 that were detected in MI-Oncoseq were confirmed by external genotyping. Genotype determinations could not be made for CYP3A5*3, UGT1A1*28, or UGT1A1*80. On the basis of retrospective assessment of 115 adult and pediatric patient records, 4.3% (n = 5) had a potentially clinically actionable phenotype for TPMT, DPYD, or CYP2C19 and received a relevant medication. After accounting for differences in adult and pediatric recommendations, three of these patients could have received a treatment recommendation at the time of prescribing.

CONCLUSION

Germline genotype determinations for TPMT, DPYD, and CYP2C19 can be used to make evidence-based treatment recommendations in MI-Oncoseq patients. Although the proportion of patients for whom recommendations can be made is small, this added value to MI-Oncoseq and patient care comes at no additional genotyping cost. Pharmacogenetic assessment should be integrated into tumor sequencing programs that genotype matched germline DNA; however, the complexity and additional cost of implementing pharmacogenetics remain challenging.

Identification of novel MECOM gene fusion and personalized therapeutic targets through integrative clinical sequencing in secondary acute myeloid leukemia in a patient with severe congenital neutropenia: a case report and literature review

Severe congenital neutropenia (SCN) is a rare hematologic disorder characterized by defective myelopoiesis and a high incidence of malignant transformation to myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). SCN patients who develop MDS/AML have excessive toxicities to traditional chemotherapy, and safer therapies are needed to improve overall survival in this population. In this report, we outline the use of a prospective integrative clinical sequencing trial (PEDS-MIONCOSEQ) in a patient with SCN and AML to help identify oncogenic targets for less toxic agents. Integrative sequencing identified two somatic cis-mutations in the colony stimulating factor 3 receptor (CSF3R) gene, a p.T640N mutation in the transmembrane region and a p.Q768* truncation mutation in the cytoplasmic domain. A somatic mutation p.H105Y, in the runt homology domain (RHD) of runt-related transcription factor 1 (RUNX1), was also identified. In addition, sequencing discovered a unique in-frame EIF4A2-MECOM (MDS1 and ectopic viral integration site 1 complex) chromosomal translocation with high MECOM expression. His mutations in CSF3R served as potential targets for tyrosine kinase inhibition and therefore provided an avenue to avoid more harmful therapy. This study highlights the utility of integrative clinical sequencing in SCN patients who develop leukemia and outlines a strategy on how to approach these patients in a future clinical sequencing trial to improve historically poor outcomes. A thorough review of leukemia in SCN and the role of CSF3R mutations in oncologic therapy are provided to support a new strategy on how to approach MDS/AML in SCN.

Abstract P2-09-26: Frequency and mechanisms of elevated somatic mutation burden in metastatic breast cancer and response to immune checkpoint blockade

Background: Immune checkpoint blockade (ICB) is effective in the treatment of various malignancies. Thus far, however, results in breast cancer have been mixed. Elevated tumor mutational load, and subsequent increased likelihood of forming immunogenic neoantigens, has been correlated with response to ICB. Mutational load observed in breast cancers varies widely. However, most studies have assessed mutational load using primary tumors. Few studies have explored the frequency of high mutational load, molecular mechanisms accounting for this phenomenon, and its potential impact on response to ICB in metastatic breast cancer (MBC).

Methods: From 2011-2016, 124 patients (pts) with MBC of varying subtypes underwent research biopsy of their metastatic disease for whole genome, exome and transcriptome sequencing of tumor and matched normal sample through the Michigan Oncology Sequencing Center (Mi-OncoSeq). Those pts with elevated somatic mutation load were defined as having greater than 10 mutations per megabase of targeted sequencing and mutational signatures accounting for high mutation load were noted. Pts treated subsequently with ICB were followed to assess response.

Results: Twelve MBC pts had high mutation load (10% of cohort). Eight pts had estrogen receptor (ER) positive MBC and 4 pts had metastatic triple negative breast cancer (TNBC). In 5 cases, a clear mutational signature accounting for high mutation load was evident. Two TNBC cases harbored an APOBEC mutational signature in addition to 1 TNBC and 2 ER positive tumors displaying a microsatellite instability signature (MSI-H). Among the tumors with MSI-H signature, 1 case was associated with a pathogenic germline alteration in MLH1. Two pts were subsequently treated with ICB on a clinical trial. One pt came off study after 3 months due to progressive brain metastases and another had partial response to therapy lasting 7 months.

Conclusions: Elevated somatic mutation burden in MBC is observed in approximately 10% of pts, and is detected in both ER positive and TNBC. Since high mutation burden has been associated with increased likelihood of response to ICB, identification of this genomic feature could have important therapeutic implications for MBC pts.

Citation Format: Cobain EF, Robinson DR, Wu Y-M, Lonigro R, Vats P, Rabban E, Kumar-Sinha C, Schott AF, Smerage JB, Morikawa A, Burness ML, Van Poznak CH, Griggs J, Wicha M, Hayes DF, Chinnaiyan AM. Frequency and mechanisms of elevated somatic mutation burden in metastatic breast cancer and response to immune checkpoint blockade [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-09-26.

Clinical application of comprehensive next generation sequencing in the management of metastatic cancer in adults

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Background: Next generation sequencing (NGS) platforms are frequently utilized in the care of patients (pts) with metastatic cancer to identify tumor genomic alterations that may serve as therapeutic targets. Biomarker driven clinical trials, such as NCI-Molecular Analysis for Therapy Choice (MATCH) and Targeted Agent and Profiling Utilization Registry (TAPUR) have augmented clinicians’ ability use this strategy in clinical practice. Methods: From 2011-2015 over 500 adult pts with metastatic solid tumors of diverse lineage underwent biopsy for whole exome and transcriptome sequencing of tumor and matched normal sample through the Michigan Oncology Sequencing Center (Mi-Oncoseq). Genomic alterations identified were reviewed at Precision Medicine Tumor Board and tiered according to their clinical relevance. Alterations were also classified as being identifiable or not identifiable by a commercially available NGS assay such as Oncomine Focus or FoundationOne. Results: Genomic alterations identified by Mi-Oncoseq provided rationale for enrollment in a clinical trial in 72% (n = 360) of cases. The percentage of pts who did receive therapy informed by NGS results increased over time (5% in 2012 versus 11% in 2015). 11% of pts (n = 55) had a pathogenic germline variant (PGV) conferring increased cancer risk identified, none of which were known prior to study entry. Numerous pts had clinically relevant molecular alterations identified by Mi-Oncoseq that would not have been identifiable utilizing targeted NGS assays, including PGVs and activating/deleterious gene fusions. Conclusions: Comprehensive NGS, including DNA and RNA sequencing, readily identifies potentially actionable alterations in the vast majority of pts beyond what is observed with use of targeted NGS platforms. Observed modest increase in utilization of NGS results to direct subsequent therapy over time is due to clinician employment of this strategy earlier in the therapeutic algorithm, increased availability of biomarker driven clinical trials and changes in physician referral patterns. Comprehensive NGS identified many unanticipated PGVs of clinical importance for pts and their families. Clinical trial information: HUM00067928.