James M. Carroll

Patient HLA class I genotype influences cancer response to checkpoint blockade immunotherapy

HLA genotype affects response Immunotherapy works by activating the patients own immune system to fight cancer. For effective tumor killing, CD8+ T cells recognize tumor peptides presented by human leukocyte antigen class I (HLA-I) molecules. In humans, there are three major HLA-I genes (HLA-A, HLA-B, and HLA-C). Chowell et al. asked whether germline HLA-I genotype influences how T cells recognize tumor peptides and respond to checkpoint inhibitor immunotherapies (see the Perspective by Kvistborg and Yewdell). They examined more than 1500 patients and found that heterozygosity at HLA-I loci was associated with better survival than homozygosity for one or more HLA-I genes. Thus, specific HLA-I mutations could have implications for immune recognition and for the design of epitopes for cancer vaccines and immunotherapies. Science, this issue p. 582; see also p. 516 Human leukocyte antigen superfamilies predict immunotherapy response. CD8+ T cell–dependent killing of cancer cells requires efficient presentation of tumor antigens by human leukocyte antigen class I (HLA-I) molecules. However, the extent to which patient-specific HLA-I genotype influences response to anti–programmed cell death protein 1 or anti–cytotoxic T lymphocyte–associated protein 4 is currently unknown. We determined the HLA-I genotype of 1535 advanced cancer patients treated with immune checkpoint blockade (ICB). Maximal heterozygosity at HLA-I loci (“A,” “B,” and “C”) improved overall survival after ICB compared with patients who were homozygous for at least one HLA locus. In two independent melanoma cohorts, patients with the HLA-B44 supertype had extended survival, whereas the HLA-B62 supertype (including HLA-B*15:01) or somatic loss of heterozygosity at HLA-I was associated with poor outcome. Molecular dynamics simulations of HLA-B*15:01 revealed different elements that may impair CD8+ T cell recognition of neoantigens. Our results have important implications for predicting response to ICB and for the design of neoantigen-based therapeutic vaccines.

Treatment-Related Adverse Events Predict Improved Clinical Outcome in NSCLC Patients on KEYNOTE-001 at a Single Center

A retrospective analysis of non–small cell lung carcinoma patients treated with pembrolizumab found that treatment-related adverse events predicted improved clinical outcome. This observation could identify the patients most likely to benefit from anti–PD-1 therapy. We retrospectively analyzed non–small cell lung cancer (NSCLC) patients from a single center treated with pembrolizumab on the KEYNOTE-001 trial and evaluated the association between treatment-related adverse events (trAEs) and clinical outcomes. Investigators reported AEs on trial and graded them according to Common Terminology Criteria for Adverse Events v4.0, labeling them as unlikely, possibly, or probably treatment-related. AEs labeled as possibly/probably related were considered trAEs for this analysis. The relationship between the incidence of a trAE and clinical outcomes was evaluated. Ninety-seven NSCLC patients treated on KEYNOTE-001 at the University of California, Los Angeles were evaluated. Ten percent (85/826) of AEs were trAEs, occurring in 40% (39/97) of patients. The most frequent trAEs were rash (21% patients), fatigue (6% patients), and hypothyroidism (6% patients). The 39 patients that experienced a trAE had increased objective response rate (ORR, 38.5%), progression-free survival (PFS: median, 248 days), and overall survival (OS: median, 493 days), compared with the 58 patients that did not (ORR: 8.9%, PFS: median 60 days, OS: median 144.5 days). The observed association between trAEs and improved clinical outcome persisted when using Cox proportional hazards regression models to assess the confounding effect of covariates and mitigate guarantee-time bias. The association also remained when data were substratified by grade, degree of association, and treatment-related select AE designation. This single-center analysis revealed that trAEs predicted for improved clinical outcome with pembrolizumab, and when controlling for guarantee-time bias and plausible confounders, this association remained. This observed relationship adds to our understanding of anti–PD-1 therapy and could aid clinicians in identifying patients most likely to benefit from therapy. Cancer Immunol Res; 6(3); 288–94. ©2018 AACR.

A Phase II Study of Pembrolizumab in EGFR-Mutant, PD-L1+, Tyrosine Kinase Inhibitor Naïve Patients With Advanced NSCLC

Background: Despite the significant antitumor activity of pembrolizumab in NSCLC, clinical benefit has been less frequently observed in patients whose tumors harbor EGFR mutations compared to EGFR wild‐type patients. Our single‐center experience on the KEYNOTE‐001 trial suggested that pembrolizumab‐treated EGFR‐mutant patients, who were tyrosine kinase inhibitor (TKI) naïve, had superior clinical outcomes to those previously treated with a TKI. As TKI naïve EGFR‐mutants have generally been excluded from pembrolizumab studies, data to guide treatment decisions in this patient population is lacking, particularly in patients with programmed death ligand 1 (PD‐L1) expression ≥50%. Methods: We conducted a phase II trial (NCT02879994) of pembrolizumab in TKI naive patients with EGFR mutation–positive, advanced NSCLC and PD‐L1–positive (≥1%, 22C3 antibody) tumors. Pembrolizumab was administered 200 mg every 3 weeks. The primary endpoint was objective response rate. Secondary endpoints included safety of pembrolizumab, additional pembrolizumab efficacy endpoints, and efficacy and safety of an EGFR TKI after pembrolizumab. Results: Enrollment was ceased due to lack of efficacy after 11 of 25 planned patients were treated. Eighty‐two percent of trial patients were treatment naïve, 64% had sensitizing EGFR mutations, and 73% had PD‐L1 expression ≥50%. Only 1 patient had an objective response (9%), but repeat analysis of this patient’s tumor definitively showed the original report of an EGFR mutation to be erroneous. Observed treatment‐related adverse events were similar to prior experience with pembrolizumab, but two deaths within 6 months of enrollment, including one attributed to pneumonitis, were of concern. Conclusions: Pembrolizumab’s lack of efficacy in TKI naïve, PD‐L1+, EGFR‐mutant patients with advanced NSCLC, including those with PD‐L1 expression ≥50%, suggests that it is not an appropriate therapeutic choice in this setting.

Non–small cell lung cancer clinical trials requiring biopsies with biomarker-specific results for enrollment provide unique challenges

Clinical trials in lung cancer increasingly require patients to provide fresh tumor tissue as a prerequisite to enrollment. The effects of this requirement on enrollment rates, enrollment durations, and patient selection have not been fully elucidated.

A Longitudinal Investigation of Internalized Stigma, Constrained Disclosure, and Quality of Life Across 12 Weeks in Lung Cancer Patients on Active Oncologic Treatment

Introduction: Internalized lung cancer stigma (i.e., feelings of regret, shame, and self‐blame about one’s lung cancer) is related to poorer psychological outcomes. Less is known about how internalized stigma relates to physical and functional outcomes or how constrained disclosure (i.e., avoidance of or discomfort about disclosing one’s lung cancer status to others) relates to well‐being. Furthermore, no study has examined whether internalized stigma and constrained disclosure predict changes in well‐being for lung cancer patients. This longitudinal study characterized relationships of internalized stigma and constrained disclosure with emotional and physical/functional outcomes. Methods: Participants (N = 101, 52.4% male, 63.4% currently/formerly smoked) were lung cancer patients on active medical treatment who completed questionnaires on stigma and well‐being at study entry and at 6‐ and 12‐week follow‐up. Multivariable linear regressions characterized relationships of internalized stigma and constrained disclosure with emotional and physical/functional well‐being at study entry and across time. Results: Participants who currently or formerly smoked reported higher levels of internalized stigma (but not constrained disclosure), compared to never smokers (p < 0.001). Higher internalized stigma and constrained disclosure were uniquely associated with poorer emotional and physical/functional well‐being at study entry (all p < 0.05), beyond sociodemographic characteristics, time elapsed since diagnosis, and smoking status. Higher internalized stigma predicted significant declines in emotional well‐being across 6 and 12 weeks (all p < 0.01) and declines in physical/functional well‐being across 6 weeks (p < 0.05). Conclusions: Internalized lung cancer stigma and constrained disclosure relate to emotional and physical/functional maladjustment. Findings carry implications for provider‐ and patient‐focused interventions to reduce internalized stigma and promote well‐being.

Clinical Implications of the T790M Mutation in Disease Characteristics and Treatment Response in Patients With Epidermal Growth Factor Receptor (EGFR)-Mutated Non–Small-Cell Lung Cancer (NSCLC)

Background The secondary T790M mutation accounts for more than 50% of acquired tyrosine kinase inhibitor (TKI) resistance in patients with EGFR‐mutated non–small‐cell lung cancer (NSCLC). Recent reports suggest this resistance mutation may be more common among patients with longer progression‐free survival (PFS) on first‐line TKI therapy, but much is still unknown. Materials and Methods Our group collected medical records from patients who underwent a biopsy for T790M mutation testing while screening for clinical trials involving the drug rociletinib (CO‐1686), a T790M mutation–specific TKI. Medical records were retrospectively analyzed for demographic data, PFS, and best response to previous therapies. Results Our patient cohort included 69 T790M+ patients and 28 T790M− patients. Patients who later developed a T790M mutation had a longer PFS on first‐line TKI therapy (12.0 vs. 9.0 months, P = .021), but overall response rate (ORR) was the same (75.0% vs. 81.0%, P = .76). There was no difference in PFS on TKI rechallenge (4.0 vs. 3.0 months, P = .94), although there was a trend toward higher ORR in T790M+ patients (22.2% vs. 0%, P = .12). T790M+ patients had a longer PFS on initial chemotherapy treatment (5.0 vs. 4.0 months, P = .025) and a trend toward higher ORR (40.0% vs. 21.4%, P = .31). Conclusion Our study confirms that tumors expressing T790M have a more indolent progression of disease compared with their T790M− counterparts when treated with both first‐line TKI and cytotoxic chemotherapy. Micro‐Abstract We characterized differences in the natural history of patients with EGFR‐mutated NSCLC whose tumors develop a T790M resistance mutation compared with those whose tumors do not. We found T790M+ patients had a longer PFS with first‐line TKI and chemotherapy, but no difference with TKI rechallenge. Response rate was similar for all therapies evaluated, even when differences in PFS were seen.

Promising results from Checkmate 012: better patients or better immunotherapy?

Platinum-based doublet chemotherapy has traditionally been the standard of care as initial therapy in patients with advanced (stage IIIB/IV) non-small cell lung cancer (NSCLC). However, now patients with tumors that harbor genomic abnormalities in the epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK), or have high expression of programmed cell death 1 ligand (PD-L1) initially get non-chemotherapy approaches (1-4). Immunotherapy has emerged as a promising, new approach to cancer treatment and the US FDA has approved several immune checkpoint inhibitors (ICIs) in various malignancies. While these ICIs are promising, only inhibitors of the interaction between programmed cell death 1 (PD-1) and its ligand PD-L1 are approved outside of melanoma. Combination therapies are being pursued in an effort to increase the population of patients that may benefit from ICIs.

Abstract B98: Serial evaluation of PD-L1 expression on circulating tumor cells (CTCs)

BACKGROUND: Metastatic non-small cell lung cancer (NSCLC) tumors have adopted methods to evade immune detection and/or clearance. This can occur via overexpression of programmed cell death ligand 1 (PD-L1). Response rate, progression free survival and overall survival with PD-1 inhibitors are greater in tumors with high tumor PD-L1 expression (Garon et al, NEJM 2015, Paz-Ares et al, ASCO 2015). There has been interest in using PD-L1 tumor expression as a treatment selection criterion. Currently available methods of screening involve invasive tumor biopsy followed by histological grading of PD-L1 levels. Biopsies allow sampling from limited sections of the tumor, which may miss heterogeneity. CTC PD-L1 levels could aid in screening patients, and could supplement tissue PD-L1 biopsy results by evaluating a representative sampling from multiple tumor sites which shed cells into the blood. Additionally, following PD-L1 levels on CTCs serially over time may potentially yield information about modulation of tumor PD-L1 expression in the presence of PD-1 or PD-L1 antibodies or other anti-cancer agents. METHODS: We have developed a microfluidic device for rapid, size-based capture of CTCs from blood called Vortex HT chip. The Vortex HT chip utilizes inertial microfluidic flows to isolate CTCs with capture efficiency up to 40% and high purity (>80%). We used the Vortex HT device to capture CTCs from NSCLC patients undergoing PD-1 immunotherapies, both prior to initiating treatment and during treatment. PD-L1 expression was evaluated on CTCs using immunofluorescence staining. CTC number and PD-L1 expression were correlated with treatment response as evaluated by immune related response criteria (irRC) on serial CT scans. We also measured cell size and intensity levels of cytokeratin (CK) and CD45 on the collected cells. We developed a semi-automated algorithm to quantify fluorescence for these different markers on DAPI positive cells collected from each patient sample. We compared these results to PD-L1 expression on the initial tumor biopsy sections, as assayed by immunohistochemical staining and expression quantified with HALO software (Indica Labs). RESULTS: In patients receiving anti-PD-1 antibodies, PD-L1 expression on CTCs could be quantified and compared to a pre-treatment tumor biopsy, as well as to radiographic treatment response. Evaluating patient CTC count and PD-L1 expression at baseline and over time may lead to simple and non-invasive methods to predict response to immunotherapies. As an assay amenable to repeat testing, CTC PD-L1 levels may also be an important pharmacodynamics marker to assess the synergistic potential of combination immunotherapies. Further work is continuing to better understand this predictive biomarker. At the meeting, we will present correlation data between CTC and tumor biopsy PD-L1 expression assays and between the CTC assay and radiographic response to treatment. Citation Format: Jonathan W. Goldman, Manjima Dhar, James Che, Edward B. Garon, Siwen Hu-Lieskovan, Melissa Matsumoto, Brian R. Wolf, James M. Carroll, Matthew J. Crabtree, D. Andrew Tucker, Jennifer Strunck, Elodie Sollier, Rajan Kulkarni, Dino Di Carlo. Serial evaluation of PD-L1 expression on circulating tumor cells (CTCs). [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B98.