Abstract 4525: YAP1 in relapsed pulmonary high-grade neuroendocrine carcinomas (NEC) is associated with CDKN2A loss, intact RB1, EMT and therapeutic vulnerability to MEK1 and CDK4/6 inhibition

Neuroendocrine carcinomas (NECs) are clinically aggressive carcinomas commonly arising from the respiratory and gastrointestinal tracts, typically categorized as large-cell neuroendocrine carcinomas (LCNECs) or small cell carcinomas (most commonly small cell lung cancer (SCLC)). Clinically, pulmonary LCNECs (pLCNECs) mirror the course common to SCLC - initial response followed by rapid and insurmountable resistance to one-size-fits-all approaches. Recently, SCLC has been subdivided into four subtypes with unique vulnerabilities, three of which are defined by the transcription factors ASCL1, NEUROD1, and POU2F3, while a fourth group exhibits an inflamed signature. We hypothesize that pLCNEC may be similarly classified into molecularly distinct subsets with unique therapeutic vulnerabilities - a fundamental step toward personalized medicine. We applied our SCLC 1300 gene signature to pLCNEC patient tumors and, as in SCLC, found three distinct subtypes determined by differential expression of ASCL1, NEUROD1, and POU2F3, but with a unique fourth subtype marked by expression of the transcription factor YAP1. Unlike in treatment-naïve SCLC, where YAP1 is absent, YAP1 expression clearly defines pLCNEC as two, roughly equal subsets with the YAP1-low tumors encompassing tumors expressing the other three transcription factors. Conversely, YAP1-high pLCNEC is more mesenchymal and inflamed, and less neuroendocrine (NE), reminiscent of inflamed SCLC. Additionally, YAP1-high status is associated with smoking exposure (P<0.001, FC=81), high frequency of CDKN2A homozygous deletion and SMARCA4 mutations, as well as intact RB1. These features are distinct from SCLC, wherein transcriptional subtypes lack distinct genomic characteristics. Consistent with CDKN2A deletion, YAP1-high pLCNEC cell lines have increased sensitivity to MEK1 and CDK4/6 inhibition. We also demonstrate that RB1 loss downregulates YAP1 expression, which may account for the absence of YAP1 in treatment-naïve SCLC due to ubiquitous loss of RB1. In contrast to treatment-naïve SCLC, where our group and others have been unable to detect YAP1, single-cell RNAseq analysis of biopsies from patients with relapsed SCLC identified emerging YAP1-positive cancer cell populations, which are similarly associated with increased EMT, immune cell infiltration (CD8+ T-cells), and loss of NE gene expression. This suggests that the ability for cancer cells to acquire YAP1 expression and, perhaps, pLCNEC-like features, may be a resistance mechanism in relapsed SCLC, contributing to the abundant intratumoral heterogeneity and highlighting potential vulnerabilities to overcome resistance. In summary, YAP1 may be a predictive biomarker of intact RB1 and response to cellular and checkpoint immunotherapy and MEK1/CDK4/6 inhibition in pLCNEC and relapsed SCLC.

Citation Format: C. Allison Stewart, Lixia Diao, Yuanxin Xi, Runsheng Wang, Kavya Ramkumar, B. Leticia Rodriguez, Benjamin B. Morris, Li Shen, Bingnan Zhang, Yan Yang, Azusa Tanimoto, Veronica Y. Novegil, Luisa M. Solis Soto, Pedro F. Simoes da Rocha, Natalie Vokes, Don L. Gibbons, Michael Frumovitz, Junya Fujimoto, Jing Wang, Bonnie Glisson, Lauren A. Byers, Carl M. Gay. YAP1 in relapsed pulmonary high-grade neuroendocrine carcinomas (NEC) is associated with CDKN2A loss, intact RB1, EMT and therapeutic vulnerability to MEK1 and CDK4/6 inhibition. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4525.

Optimal Combination of Neuroendocrine Markers for the Detection of High-Grade Neuroendocrine Tumors of the Sinonasal Tract and Lung

PURPOSE OF REVIEW

Identification of neuroendocrine (NE) differentiation is critical to the classification of head and neck (HN) and lung tumors. In combination with tumor morphology, immunohistochemical (IHC) documentation of NE differentiation is necessary for the diagnosis of NE tumors. The purpose of this study is to determine the sensitivity and concordance of two novel NE markers (mASH1, INSM1) across a group of high-grade NE tumors of the sinonasal tract and lung, and to compare their expression with the current widespread use of conventional NE markers, synaptophysin (SYN) and chromogranin A (CGA). In addition, expression of PARP1 is examined as a potential novel therapeutic target.

RECENT FINDINGS

Thirty-nine high-grade NE tumors, 23 of the HN and 16 of the lung, were reevaluated by two subspecialized HN and thoracic pathologists, and subsequently stained with mASH1, INSM1, and PARP1. Sensitivity and degree of concordance of all possible combinations of markers were assessed. Sensitivities (standard error) were as follows: mASH1 41% (0.08), INSM1 44% (0.08), SYN 56% (0.08), and CGA 42% (0.09); combination of all four NE markers: 73% (0.08). Sensitivity and standard error for PARP1 was 90% and 0.05, respectively. Highest sensitivity to detect NE differentiation in high-grade NE tumors of the HN and thoracic region was achieved with a combination of four NE markers. Moderate concordance was found with combinations of mASH1 and INSM1 and traditional NE markers, respectively. Consistent overexpression of PARP1 in high-grade tumors with NE differentiation in the HN and lung opens eligibility for PARP1 inhibitor trials.

Outcomes of Critically Ill Lung Cancer Patients Initiating Targeted Therapy or Immunotherapy in the Intensive Care Unit: A Single-Center Report

Introduction: Targeted therapy and immune checkpoint inhibitors (ICI) have drastically improved outcomes of metastatic non-small cell lung cancer (NSCLC) patients in outpatient settings. Because trials on critically ill patients are improbable, little is known about their efficacy among patients admitted to intensive care units (ICU). Methods: We retrospectively analyzed the clinical outcomes of critically-ill NSCLC patients receiving either ICI or targeted therapy during ICU admission at the MD Anderson Cancer Center from April 2016 to August 2020. We collected data on ICU admission diagnoses, sequential organ failure assessment (SOFA), previous cancer therapies, tumor gene mutations or translocations, and PD-L1 expression. Overall survival (OS) was calculated from the date of drug initiation using the Kaplan-Meier method. Results: Of 9898 ICU admissions, 9 patients with metastatic NSCLC who received either targeted therapy (5) or PD-1 ICI (4) during ICU admission were included. The most common reasons for ICU admissions were tumor visceral crisis (3/9) and sepsis (3/9). The median (range) admission SOFA was 4 (2-11). Six patients were naïve to systemic therapy. Five patients required mechanical ventilation. The median OS was 77 days (95%CI, 36-NA), and 5 patients were discharged alive (all received targeted therapy). The median OS of patients who received ICI was 25.5 days (95%CI, 8-NA) and for those who received targeted therapy was 218 days (95%CI, 77-NA). At 6 and 12 months follow-up, 3 and 2 patients who received targeted therapy were still alive, respectively. Conclusions: Our exploratory findings indicate a possible benefit of targeted therapy but suggest a lack of clinical utility of PD-1 ICI for critically ill metastatic NSCLC patients. Because of the small sample size, further studies are needed to expand on this topic.

Cold and heterogeneous T cell repertoire is associated with copy number aberrations and loss of immune genes in small-cell lung cancer

Small-cell lung cancer (SCLC) is speculated to harbor complex genomic intratumor heterogeneity (ITH) associated with high recurrence rate and suboptimal response to immunotherapy. Here, using multi-region whole exome/T cell receptor (TCR) sequencing as well as immunohistochemistry, we reveal a rather homogeneous mutational landscape but extremely cold and heterogeneous TCR repertoire in limited-stage SCLC tumors (LS-SCLCs). Compared to localized non-small cell lung cancers, LS-SCLCs have similar predicted neoantigen burden and genomic ITH, but significantly colder and more heterogeneous TCR repertoire associated with higher chromosomal copy number aberration (CNA) burden. Furthermore, copy number loss of IFN-γ pathway genes is frequently observed and positively correlates with CNA burden. Higher mutational burden, higher T cell infiltration and positive PD-L1 expression are associated with longer overall survival (OS), while higher CNA burden is associated with shorter OS in patients with LS-SCLC.

438 A phase 1 trial of CUE-101, a novel HPV16 E7-pHLA-IL2-Fc fusion protein, alone and in combination with pembrolizumab in patients with recurrent/metastatic HPV16+ head and neck cancer

Background

Immuno-STATsTM are novel, modular fusion proteins designed to selectively activate tumor-antigen-specific CD8+ T cells. CUE-101 is comprised of a human leukocyte antigen (HLA) complex, HLA-A*0201, a peptide epitope derived from the HPV16 E7 protein, and 4 molecules of a reduced affinity human interleukin-2 (IL-2) and is designed to bind and activate HPV16-specific T cells for treatment of HPV16-driven cancers. In preclinical studies CUE-101 demonstrated selective binding, activation, and expansion of HPV16 E7-specific CD8+ T cells, and a murine surrogate activated anti-tumor immunity.1

Methods

CUE-101-01 is a first-in-human study in HLA-A*0201 positive patients with HPV16+ recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC). Safety of escalating monotherapy and combination doses was evaluated to establish the recommended phase 2 dose (RP2D) for expanded enrollment. Patients with R/M HNSCC refractory to 1 or more prior platinum or pembrolizumab based systemic treatments received CUE-101 monotherapy, and patients with R/M HNSCC and PD-L1 tumor expression received combination CUE-101 and 200 mg pembrolizumab as first line treatment. Study treatment was administered intravenously every 3 weeks until progression or toxicity. Objectives included evaluation of safety, pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activity.

Results

As of June 30, 2021, 39 patients have received CUE-101 monotherapy ranging from 0.06 to 8 mg/kg. The maximum tolerated dose (MTD) was not identified. Based on PK, PD and clinical data, a monotherapy RP2D of 4 mg/kg was selected. The combination cohort of 1 mg/kg CUE-101 and pembrolizumab has been tested and dose escalation is ongoing. Adverse events have included CTCAE grade 2 or less fatigue (41%), anemia (31%), lymphopenia (24%), chills (21%), decreased appetite (19%) and dyspnea (17%). CUE-101 PK data demonstrate dose-dependent increases in drug exposure that are sustained upon repeat dosing. PD data demonstrate dose-dependent expansion of HPV-16 E711-20-specific CD8+ T cells, sustained increase in natural killer cells and transient increase in Treg cells. An increase in CD3+ GZMB+ tumor infiltrating T cells was observed in tissue following treatment with CUE-101 in one patient with available pre- and post-treatment biopsies. One patient at the CUE-101 monotherapy RP2D has an ongoing partial response and 8 of 33 patients have experienced stable disease ≥ 12 weeks based on RECIST 1.1 criteria.

Conclusions

CUE-101 is a novel immunotherapeutic demonstrating acceptable safety and tolerability with encouraging PD signals, supporting selective activation of tumor-specific T cells, and promising antitumor activity. Enrollment continues in both monotherapy and combination cohorts.

Acknowledgements

The authors would like to thank all the patients who are participating in this study. The study is sponsored by Cue Biopharma.

Trial Registration

ClinicalTrials.

gov NCT03978689

References

Quayle SN, Girgis N, Thapa DR, et al. CUE-101, a Novel HPV16 E7-pHLA-IL-2-Fc fusion protein, enhances tumor antigen specific T cell activation for the treatment of HPV16-driven malignancies. Clin Cancer Res 2020;26:1953–64.

Ethics Approval

This study was approved by Ethics and Institutional Review Boards (IRBs) at all study sites. IRB reference numbers: Advarra Pro00037736 (Moffitt Cancer Center), IRB 52744 (Stanford University School of Medicine), IRB 191714 (Vanderbilt University Medical Center Vanderbilt-Ingram Cancer Center), HRPO# 201905108 (Washington University School of Medicine), 2019–087 Karmanos Cancer Institute, DF/HCC IRB# 19-374 (Massachusetts General Hospital), WIRB 2000026098 (Yale Cancer Center), WIRB 1908869642 (University of Arizona Cancer Center), WIRB STUDY00008948 (University of Washington, Seattle), IRB(IRBMED) HUM00165746 (University of Michigan Comprehensive Cancer Center), WIRB IRB00112341(Winship Cancer Institute/Emory University), 2019–0578 (The University of Texas MD Anderson Cancer Center), IRB 20-073 (Memorial Sloan Kettering Cancer Center), IRB00255391 (Johns Hopkins University School of Medicine).

Abstract 770: High-grade neuroendocrine carcinoma of the oropharynx: A rare entity with prognosis unaffected by HPV

Background: Human Papilloma Virus (HPV) infection is associated with a better prognosis in oropharynx squamous cell carcinomas. Neuroendocrine carcinoma (NEC) of the oropharynx is a rare variant that can be associated with HPV infection, however little is known regarding clinical behavior and the impact of HPV infection on its prognosis. This study aims to evaluate clinical and pathologic features of oropharyngeal high-grade NEC and to investigate the prognostic value of HPV and smoking in this rare histological subtype. Methods: Patients with high-grade NEC from oropharynx were identified through electronic medical records queries from 1997 to 2020. A cohort of 27 patients with sufficient pathological and clinical data were included in the analysis. Neuroendocrine differentiation was confirmed by immunoreactivity for synaptophysin, chromogranin and/or CD56. P16 immunohistochemistry staining or HPV in situ hybridization or polymerase chain reaction were performed in all patients' samples. Disease-free survival (DFS) and overall survival (OS) were calculated using the Kaplan-Meier method. The log-rank test was used to assess difference in survival between groups. Results: Of 27 patients, 25 were male and 10 had a heavy smoking history (≥10-pack-years). P16 staining was positive in 24 (89%) samples and HPV was confirmed in 15 (62.5%). Most patients (22/27; 81.5%) presented with locoregional disease, 8 (35%) received induction chemotherapy, and 18 of 23 (78%) achieved a complete response after definitive therapy (surgery and/or radiation); among them, 7 (30%) recurred. Most recurrences were distant and common sites of metastasis was liver (56%), bone (56%) and lymph nodes (50%). In the palliative setting, 85% of patients received platinum-based chemotherapy and preferred combined agents were etoposide (6/14) and docetaxel (5/14). The overall response rate to first- and second-line systemic therapy were 50% and 0%, respectively. The median DFS for those patients who achieved a complete response to definitive therapy was 61.0 months (95% CI 13.0-NA) and 1- and 2-year DFS rates were 73.3% and 56.4%, respectively. The median OS was 28.8 months (95%CI 14.3-NA) for the overall population. Metastasis at diagnosis was associated with lower median survival (9.5 versus 62.0 months, p= 0.016). We have not found differences in median OS according to HPV status(positive 28.9 versus negative 28.8 months, p= 0.93) or smoking exposure (≥10pack/year 47.2 versus <10pack/year 14.3 months, p= 0.8). Conclusions: Distinct from oropharynx squamous cell carcinoma, HPV status is not an independent prognostic factor for high-grade NEC of the oropharynx. Although high-grade NEC is usually associated with a dismal prognosis, most patients with loco-regional disease were cured, suggesting primary disease site has biologic implications. This represents the largest case series of oropharyngeal high-grade NEC.

Citation Format: Luana Sousa, Felippe Lazar, Danice Torman, Kaiyi Li, Andrew Sikora, Amy Moreno, Ehab Hanna, Jack Phan, Bonnie Glisson, Diana Bell, Renata Ferrarotto. High-grade neuroendocrine carcinoma of the oropharynx: A rare entity with prognosis unaffected by HPV [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 770.

Association of Immunosuppression With Outcomes of Patients With Cutaneous Squamous Cell Carcinoma of the Head and Neck

Importance

Patients with immunosuppression have a higher incidence of cutaneous squamous cell carcinoma (cSCC) and often present with more aggressive, multifocal disease.

Objectives

To determine the risks for mortality in patients with cSCC and immunosuppression compared with nonimmunosuppression and to compare the difference in mortality risk based on the cause of immunocompromise.

Design, Setting, and Participants

This retrospective cohort study of patients with cSCC of the head and neck recruited participants from a tertiary cancer care center. Patients who underwent no treatment, wide local excision, or biopsy of the lesions were eligible for inclusion from January 1, 1995, to September 30, 2015. Data were analyzed from March 21, 2018, to April 4, 2019.

Exposures

Immunocompromise, defined as having solid organ transplant, stem cell transplant, hematopoetic malignant disease, autoimmune disease requiring treatment with immunosuppressive therapy, type 1 or 2 diabetes treated with insulin, HIV or AIDS, or other hematoproliferative disorder.

Main Outcomes and Measures

Patients were divided into 2 groups according to their immune status (immunosuppression vs no immunosuppression). The primary outcome measure was disease-specific survival. A Cox proportional hazards regression model was used to determine the association of immune status with disease outcome.

Results

A total of 796 patients (680 men [85.4%]; median age, 69 [range, 27-98] years), including 147 with and 649 without immunosuppression (IS and non-IS groups, respectively), constituted the final cohort. In the IS group, 77 (52.4%) had diabetes, 39 (26.5%) had lymphoma or leukemia, 25 (17.0%) had an organ or stem cell transplant, and 3 (2.0%) had HIV. Five-year disease-specific survival was 68.2% in the IS group compared with 84.1% in the non-IS group (difference, 15.9%; 95% CI, 3.5%-27.4%). Immunosuppression was independently associated with worse disease-specific survival (hazard ratio, 2.32; 95% CI, 1.53-3.50).

Conclusions and Relevance

This study's findings suggest that immunosuppression is independently associated with a worse outcome in cSCC, with a 2.32 times increased risk of disease-specific death after adjusting for age, history of skin cancer, recurrent or persistent disease status, disease stage, and treatment.

Phase 1/2 Trial of Pembrolizumab and Concurrent Chemoradiation Therapy for Limited-Stage SCLC

INTRODUCTION

Few advancements in treating limited-stage SCLC (LS-SCLC) have been made in decades. We report here a phase 1/2 trial of concurrent chemoradiotherapy (CRT) and pembrolizumab.

METHODS

This single-center, open-label phase 1/2 study recruited adults with LS-SCLC or other neuroendocrine tumors and good performance status (Eastern Cooperative Oncology Group ≤ 2). The primary end point was safety, as assessed by dose-limiting toxicities. Concurrent CRT consisted of etoposide and a platin with 45 Gy radiotherapy (30 twice daily). Prophylactic cranial irradiation (25 Gy, 10 fractions) was given at the physician's discretion. Pembrolizumab was started concurrently with CRT and continued for up to 16 cycles. The phase 1 portion consisted of a 3 + 3 design. Toxicity was assessed with Common Terminology Criteria for Adverse Events version 4.0. Secondary outcomes were progression-free survival, overall survival, and tumor response as measured by the immune-related response criteria.

RESULTS

A total of 45 patients were screened, and 40 were enrolled. All completed radiation therapy and received greater than or equal to one cycle of pembrolizumab. A total of 27 (61%) received percutaneous coronary intervention. One dose-limiting toxicity was observed in the phase 1 portion. There were no grade 5 toxicities, but there were three grade 4 events (two neutropenia, one respiratory failure). Pneumonitis rate was 15% (three grade 2 and three grade 3). All 17 esophagitis events (42.5%) were grades 1 to 2. At median follow-up time of 23.1 months, the median progression-free survival time was 19.7 months (95% confidence interval: 8.8‒30.5) and the median overall survival time was 39.5 months (95% confidence interval: 8.0‒71.0).

CONCLUSION

Concurrent CRT and pembrolizumab for LS-SCLC was well tolerated and yielded favorable outcomes, providing a basis for randomized studies.

277 Combined neoadjuvant chemo-immunotherapy therapy achieves superior downstaging of resectable non-small cell lung cancer as compared to chemotherapy, mono or dual immunotherapy

Background

Tumor and nodal downstaging following neoadjuvant therapy in resectable non-small cell lung cancer (NSCLC) are important markers of therapeutic response associated with favorable prognosis. We studied the impact of four different systemic neoadjuvant therapies on tumor, nodal and overall pathological downstaging of surgically resectable I-IIIA NSCLC (AJCC 7th edition).

Methods

Our study cohorts consisted of NSCLC patients treated with three cycles of neoadjuvant platinum doublet chemotherapy from 2001–2012 (N=302, 84%), and patients treated on the NEOSTAR study (NCT03158129) who received neoadjuvant nivolumab (N=21,6%), nivolumab plus ipilimumab (N=16, 4%), or platinum doublet chemotherapy plus nivolumab (N=22, 6%). Clinical and pathological (yp) T and N staging were evaluated for downstaging and upstaging; differences were assessed using Fisher’s exact test.

Results

Following neoadjuvant platinum doublet chemotherapy, nivolumab, nivolumab plus ipilimumab and platinum doublet chemotherapy plus nivolumab, the rates of clinical-to-pathological ypT downstaging were 26% (N=79), 29% (N=6), 38% (N=6) and 59% (N=13), respectively, p =0.012 (table 1). The rates of clinical-to-pathological ypN downstaging in patients with clinical N1 or N2 disease with each therapy were 55% (N=96), 50% (N=3), 50% (N=2), and 42% (N=5) respectively, p =0.862. Overall clinical-to-pathological (ypT and/or ypN) downstaging rates were 38% (N=114), 38% (N=8), 38% (N=6), and 68% (N=15) respectively, p=0.048. The proportions of patients being overall upstaged following each therapy were 28% (N=85), 38% (N=8), 38% (N=6) and 14% (N=3), respectively, p=0.251. These results suggest superior downstaging effect and clinically meaningful lower upstaging probability of combined platinum doublet chemotherapy plus nivolumab as compared to other neoadjuvant regimens.

Abstract 277 Table 1

Response to Chemotherapy, Immunotherapy, and Combination Therapy

Conclusions

The combination of neoadjuvant platinum doublet chemotherapy with nivolumab achieves the most robust tumor and overall pathological downstaging and decreases the probability of upstaging at surgery. Whether the overall downstaging effect results in improved survival will be determined with longer follow-up, in conjunction with results from ongoing phase III neoadjuvant chemo-immunotherapy trials.

Trial Registration

NCT03158129

Ethics Approval

This study was approved by the University of Texas MD Anderson Institutional Review Board with a waiver of informed consent, protocol 2020-0337.

High-grade sinonasal carcinomas and surveillance of differential expression in immune related transcriptome

The skull base is the location of a wide variety of malignant tumors. Among them is sinonasal undifferentiated carcinoma (SNUC), a highly aggressive sinonasal neoplasm that was recently reclassified into subgroups of high-grade carcinomas with unique genomic events (e.g., SMARC-deficient carcinoma, nuclear protein in testis NUT carcinoma). Other high-grade carcinomas in this location are neuroendocrine carcinomas, sinonasal adenocarcinomas, and teratocarcinosarcomas. Given the rarity of these tumors, little transcriptomic data is available. The aim of this study was to characterize the immune-oncology gene expression profile in SNUC and other high-grade sinonasal carcinomas. Next-generation sequencing was performed in 30 high-grade sinonasal carcinoma samples using the HTG EdgeSeq Precision Immuno-Oncology Panel. Ingenuity pathway analysis was performed to understand the immunobiology, signaling, and functional perturbations during tumor development. The samples were divided into 3 groups: 21 SNUCs and SMARC-deficient sinonasal carcinomas; 5 high-grade neuroendocrine carcinomas (HGNECs), with small cell and large cell variants; and 4 high-grade sinonasal carcinomas (HGSNCs) of mixed histology (1 NUT carcinoma, 1 teratocarcinosarcoma, and 2 sinonasal adenocarcinomas). PRAME and ASCL1 emerged as upregulated transcripts with strong protein validation for SNUC and HGNEC; other upregulated candidates EZH2 and BRCA1 offer consideration for alternative targeted therapy, and downregulation of major histocompatibility complex molecules and chemokines represent another hurdle in the development of effective immunotherapy. This immune-oncology gene expression analysis of 3 groups of high-grade sinonasal carcinoma with emphasis on SNUC identified a number of differentially expressed transcripts reflecting effects on tumorigenesis. Identification of immune pathways should be further investigated for possible integration of immunotherapy into a multidisciplinary approach to these cancers and personalized treatment.

Abstract 1496: Paired, single-cell profiling of circulating tumor cell-derived xenograft models of small cell lung cancer reveals intratumoral heterogeneity and emergence of new cell clusters following treatment relapse

Small cell lung cancer (SCLC), the most aggressive form of lung cancer, is notable for early dissemination and impressive, yet transient, responses to frontline chemotherapy that are rapidly undone by refractory relapses. To gain a better understanding of resistance mechanisms, we generated circulating tumor cell-derived xenograft (CDX) models from liquid biopsies of SCLC patients and treated them with chemotherapy or targeted agents. As expected, CDXs demonstrate similar chemotherapy response to the patient from whom they were derived. We have previously established that baseline chemosensitive CDXs are molecularly homogeneous at the single cell level, while chemoresistant CDXs exhibit increased intratumoral heterogeneity (ITH) with distinct variations in gene expression between cancer cell populations. We hypothesize that paired analyses of chemosensitive CDXs will demonstrate increased ITH after developing acquired resistance and are likely to offer more specific insights into resistance mechanisms than prior work with unrelated CDX models. Platinum-sensitive CDXs were treated with cisplatin or DNA damage response targeted therapies (PARP inhibitor or CHK inhibitor) continuously until tumor progression was observed. To identify transcriptional changes associated with onset of resistance, single-cell RNAseq analysis was performed on vehicle-treated and relapsed CDX tumors. We found globally increased ITH including heterogeneous expression of therapeutic targets and potential resistance pathways, such as EMT, between cellular subpopulations following treatment-resistance. Relapse was consistently associated with increased ITH score (P<0.001) and cell cluster number. To determine whether transcriptional diversity in either therapeutic targets (ex., MYC, DLL3, TOP2A, PARP1, CHEK1, EZH2, etc.) or EMT genes (ex., ZEB1, ZEB2, TWIST1, VIM, AXL) was detectable between the paired tumors after onset of resistance, we compared transcriptional differences between clusters present in vehicle-treated versus cisplatin or targeted therapy-treated tumors. We discovered the emergence of new cell clusters in relapsed tumors in all CDX models (4 CDXs, 3 distinct treatments), including clusters expressing EMT or NOTCH signaling genes. These data suggest that, in response to treatment, SCLC develops increasing transcriptional ITH marked by concurrent, diverse resistant cell clusters. Clinically, these data underscore the importance of maximizing and maintaining the initial response in platinum-sensitive SCLC tumors and highlight the intrinsic transcriptional fluidity underlying SCLC's profound treatment resistance following initial therapy.

Citation Format: C. Allison Stewart, Carl M. Gay, Yuanxin Xi, Santhosh Sivajothi, Junya Fujimoto, Patrice M. Hartsfield, Hai Tran, Stephen G. Swisher, Jack A. Roth, Jianjun Zhang, Bonnie Glisson, John V. Heymach, Ignacio Wistuba, Paul Robson, Jing Wang, Lauren A. Byers. Paired, single-cell profiling of circulating tumor cell-derived xenograft models of small cell lung cancer reveals intratumoral heterogeneity and emergence of new cell clusters following treatment relapse [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1496.

Single-cell analyses reveal increased intratumoral heterogeneity after the onset of therapy resistance in small-cell lung cancer

The natural history of small cell lung cancer (SCLC) includes rapid evolution from chemosensitivity to chemoresistance, although mechanisms underlying this evolution remain obscure due to scarcity of post-relapse tissue samples. We generated circulating tumor cell (CTC)-derived xenografts (CDXs) from SCLC patients to study intratumoral heterogeneity (ITH) via single-cell RNAseq of chemo-sensitive and -resistant CDXs and patient CTCs. We found globally increased ITH including heterogeneous expression of therapeutic targets and potential resistance pathways, such as EMT, between cellular subpopulations following treatment-resistance. Similarly, serial profiling of patient CTCs directly from blood confirmed increased ITH post-relapse. These data suggest that treatment-resistance in SCLC is characterized by coexisting subpopulations of cells with heterogeneous gene expression leading to multiple, concurrent resistance mechanisms. These findings emphasize the need for clinical efforts to focus on rational combination therapies for treatment-naïve SCLC tumors to maximize initial responses and counteract the emergence of ITH and diverse resistance mechanisms.

Combining Immune Checkpoint Blockade and Tumor-Specific Vaccine for Patients With Incurable Human Papillomavirus 16-Related Cancer: A Phase 2 Clinical Trial

Importance

In recurrent human papilloma virus (HPV)-driven cancer, immune checkpoint blockade with anti-programmed cell death 1 (PD-1) antibodies produces tumor regression in only a minority of patients. Therapeutic HPV vaccines have produced strong immune responses to HPV-16, but vaccination alone has been ineffective for invasive cancer.

Objective

To determine whether the efficacy of nivolumab, an anti-PD-1 immune checkpoint antibody, is amplified through treatment with ISA 101, a synthetic long-peptide HPV-16 vaccine inducing HPV-specific T cells, in patients with incurable HPV-16-positive cancer.

Design, Setting, and Participants

In this single-arm, single-center phase 2 clinical trial, 24 patients with incurable HPV-16-positive cancer were enrolled from December 23, 2015, to December 12, 2016. Duration of follow-up for censored patients was 12.2 months through August 31, 2017.

Interventions

The vaccine ISA101, 100 μg/peptide, was given subcutaneously on days 1, 22, and 50. Nivolumab, 3 mg/kg, was given intravenously every 2 weeks beginning day 8 for up to 1 year.

Main Outcomes and Measures

Assessment of efficacy reflected in the overall response rate (per Response Evaluation Criteria in Solid Tumors, version 1.1).

Results

Of the 24 patients (4 women and 20 men; 22 with oropharyngeal cancer; median age, 60 years [range, 36-73 years]), the overall response rate was 33% (8 patients; 90% CI, 19%-50%). Median duration of response was 10.3 months (95% CI, 10.3 months to inestimable). Five of 8 patients remain in response. Median progression-free survival was 2.7 months (95% CI, 2.5-9.4 months). Median overall survival was 17.5 months (95% CI, 17.5 months to inestimable). Grades 3 to 4 toxicity occurred in 2 patients (asymptomatic grade 3 transaminase level elevation in 1 patient and grade 4 lipase elevation in 1 patient), requiring discontinuation of nivolumab therapy.

Conclusions and Relevance

The overall response rate of 33% and median overall survival of 17.5 months is promising compared with PD-1 inhibition alone in similar patients. A randomized clinical trial to confirm the contribution of HPV-16 vaccination to tumoricidal effects of PD-1 inhibition is warranted for further study.

Trial Registration

ClinicalTrials.gov identifier: NCT02426892.

Author Correction: Circulating tumor DNA analysis depicts subclonal architecture and genomic evolution of small cell lung cancer

The original version of this Article contained an error in Fig. 2, in which the left y-axis labels 'tDNA' and 'ctDNA' were inadvertently inverted. This has been corrected in the PDF and HTML versions of the Article.

Induction Chemotherapy Response as a Guide for Treatment Optimization in Sinonasal Undifferentiated Carcinoma

PURPOSE

Multimodal therapy is a well-established approach for the treatment of sinonasal undifferentiated carcinoma (SNUC); however, the optimal sequence of the various treatments modalities is yet to be determined. This study aimed to assess the role of induction chemotherapy (IC) in guiding definitive therapy in patients with SNUC.

METHODS

Ninety-five previously untreated patients diagnosed with SNUC and treated between 2001 and 2018 at The University of Texas MD Anderson Cancer Center were included in the analysis. Patients were treated with curative intent and received IC before definitive locoregional therapy. The primary end point was disease-specific survival (DSS). Secondary end points included overall and disease-free survival, disease recurrence, and organ preservation.

RESULTS

A total of 95 treatment-naïve patients were included in the analysis. For the entire cohort, the 5-years DSS probability was 59% (95% CI, 53% to 66%). In patients who had partial or complete response to IC, the 5-year DSS probabilities were 81% (95% CI, 69% to 88%) after treatment with definitive concurrent chemoradiotherapy (CRT) after IC and 54% (95% CI, 44% to 61%) after definitive surgery and postoperative radiotherapy or CRT after IC (log-rank P = .001). In patients who did not experience at least a partial response to IC, the 5-year DSS probabilities were 0% (95% CI, 0% to 4%) in patients who were treated with concurrent CRT after IC and 39% (95% CI, 30% to 46%) in patients who were treated with surgery plus radiotherapy or CRT (adjusted hazard ratio of 5.68 [95% CI, 2.89 to 9.36]).

CONCLUSION

In patients who achieve a favorable response to IC, definitive CRT results in improved survival compared with those who undergo definitive surgery. In patients who do not achieve a favorable response to IC, surgery when feasible seems to provide a better chance of disease control and improved survival.

Abstract 990: Single-cell profiling of small cell lung cancer circulating tumor cell-derived xenograft models reveals intratumoral heterogeneity among mediators of chemoresistance

Small cell lung cancer (SCLC) accounts for 14% of lung cancer diagnoses in the United States and is characterized by rapid onset of chemoresistance and poor clinical outcomes. Once considered a homogeneous disease, recent analyses of SCLC have identified intratumoral heterogeneity (ITH) with respect to NOTCH signaling, ASCL1/NEUROD1 balance and MYC amplification - all of which are potential mechanisms underlying SCLC's aggressive and refractory biology. Unfortunately, patient-derived models of SCLC with which to better characterize the molecular profiles of refractory SCLC are scarce. To address this, we generated circulating tumor cell-derived xenograft (CDX) models from liquid biopsies of patients with treatment-naïve or relapsed SCLC. Each CDX model underwent pathological review to confirm tumors were consistent with SCLC based on histology and standard immunohistochemical markers (e.g., TTF1, chromogranin A, synaptophysin, NCAM). Sequencing of these models revealed mutations typical of SCLC (e.g. TP53, RB1), which were maintained in vivo over multiple passages. Importantly, each model's in vivo response to cisplatin matched the patient's platinum response at the time of CDX generation. At the proteomic level, platinum-resistant models exhibited mTOR activation, increased SOX2 and ATM, and reduced E-cadherin, suggesting a shift toward EMT and cancer stem cell expansion may contribute to resistance. To investigate ITH, we analyzed single-cell gene expression profiles by RNAseq using a droplet-based Chromium Single Cell system that analyzed a filtered subsample of 2000 cells per tumor. Consistent with SCLC, all CDX models contained large numbers of cells expressing neuroendocrine-specific genes (SYP, CHGA). However, Principle Component Analysis revealed that cells from chemosensitive CDX models had distinct expression profiles from resistant models. Using our published EMT gene signature, we found that resistant models had higher proportions of mesenchymal (vs. epithelial) cells. Several other distinctions between sensitive and resistant models were detected at the single-cell level but not in bulk RNA and protein analyses, suggesting that single-cell resolution can identify occult platinum-resistant subpopulations. For example, higher proportions of ASCL1- and DLL3-expressing cells were associated with platinum sensitivity, whereas a shift toward predominant NEUROD1-expression was observed with resistance. Cells expressing each of these three genes were identified across all tumors, suggesting platinum-sensitive and resistant subpopulations are ubiquitous but that even subtle shifts in the fractional distribution of these subsets can exert significant impact on response. These data support further use of single-cell analysis to explore the role of ITH as a driver of drug resistance in SCLC.

Citation Format: C. Allison Stewart, Carl M. Gay, Yuanxin Xi, Siva V., Junya Fujimoto, Pan Tong, Lixia Diao, Lerong Li, Mohan Bolisetty, Neda Kalhor, Patrice Lawson, Mayra Vasquez, Hai Tran, Ignacio I. Wistuba, Bonnie Glisson, Jianjun Zhang, Stephen G. Swisher, Jack A. Roth, John V. Heymach, Paul Robson, Jing Wang, Lauren A. Byers. Single-cell profiling of small cell lung cancer circulating tumor cell-derived xenograft models reveals intratumoral heterogeneity among mediators of chemoresistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 990.

Abstract 2956: Mechanisms of resistance for osimertinib for patients with EGFR-mutant lung cancer: MD Anderson Cancer Center single institution experience with osimertinib resistance

PURPOSE: Osimertinib was initially approved for treating epidermal growth factor receptor (EGFR) T790M positive non-small cell lung cancer (NSCLC), and recently is moving forward as the first-line treatment for EGFR sensitizing mutation positive NSCLC. However, the types and frequencies of resistance mechanisms to osimertinib have been incompletely described, and currently there are no guidelines for managing these patients. We evaluated clinical and genetic characteristics of patients who received osimertinib for EGFR-mutant NSCLC. We also provide treatment experience after progression on osimertinib.

PATIENTS AND METHODS: Using the MD Anderson Lung Cancer Moon Shot GEMINI database, we identified patients treated with osimertinib and performed clinical outcome analysis. Molecular profiling analysis was performed at the time of progression when available.

RESULTS: Eighty two patients were identified. Median PFS on osimertinib was 8.8 months (95% CI, 6.7 to 10.9). Fifty three of the 82 patients had disease progression on osimertinib. Among them, 30 had molecular profiling upon progression. Other than two cases with germline T790M, 11 cases preserved and 17 cases lost T790M mutation. In T790M preserved cases, tertiary mutations of C797S (5 cases) and L792H (2 cases) in EGFR gene, as well as MET amplification (4 cases), were the most common mechanisms of resistance. In T790M lost cases, 12 cases were without known resistance mechanisms. Upon progression, osimertinib was continued in 34 of 51 patients and 17 (50%) of them received local consolidation radiation. The osimertinib continued patients had longer PFS2 compared to the patients who discontinued on osimertinib upon first progression.

CONCLUSION: T790M loss is common (61%) in osimertinib resistance cases. In T790M-preserved cases, tertiary mutation within EGFR was the most common mechanism of resistance. MET amplification was observed in both T790M preserved and loss cases. In T790M loss cases, the mechanisms of resistance were mostly EGFR independent, highlighting the importance of understanding T790M-negative resistance mechanisms in the osimertinib era.

Citation Format: Xiuning Le, Marcelo Vailati Negrao, Monique Nilsson, Jacqulyne Robichaux, Emily Roarty, Waree Rinsurongkawong, Bonnie Glisson, Jianjun Zhang, John V. Heymach. Mechanisms of resistance for osimertinib for patients with EGFR-mutant lung cancer: MD Anderson Cancer Center single institution experience with osimertinib resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2956.

Abstract A108: DNA damage repair targeting upregulates PD-L1 level and potentiates the effect of PD-L1 blockade in small cell lung cancer

Background: Effective targeted therapies for small-cell lung cancer (SCLC), the most aggressive form of lung cancer, are urgently needed. SCLC has a relatively immunosuppressed phenotype with relatively low levels of infiltrating T-cells and reduced antigen presentation. Only a minority of SCLC patients responds to programmed cell death protein 1 (PD-1) or programmed death ligand 1 (PD-L1) inhibitors as monotherapy. Therefore, there is a critical need to develop strategies to enhance the efficacy of immunotherapy in SCLC. We previously discovered that DNA damage repair (DDR) protein, checkpoint kinase 1 (CHK1), is overexpressed in SCLC; CHK1 inhibitor, LY2606368, has activity in preclinical models of SCLC, a finding that supported the phase 2 clinical trial of LY2606368 for SCLC patients (NCT02735980). We hypothesize that targeting CHK1 by inducing DNA damage can enhance immunogenicity, antitumor immunity, and response to immune checkpoint targeting. Methods: SCLC cell lines and immune competent murine models were treated with single agent LY2606368, anti-PD-L1, or combination. End point analyses were done by Western blot, real-time RT-PCR, multicolor flow cytometry, and reverse phase protein array (RPPA). Result: SCLC tumors with higher DDR mutation burden have a higher expression of PD-L1 (p<0.0001). LY2606368 treatment enhanced the protein (but not mRNA) and surface expression of PD-L1 in SCLC cell lines and tumor models. We further observed increased PD-L1 glycosylation post-LY2606368 treatment. LY2606368+/- anti-PD-L1 combination activates mTOR and inactivates GSK3β pathway, thus providing mechanistic insight into CHK1-targeting mediated PD-L1 glycosylation and stabilization. We treated tumor-bearing immune-competent B6129F1 mice with either IgG (control), LY2606368 (10mg/kg, 2 out of 7 days), anti-PD-L1 (300ug, 1 out of 7 days) or combination (n=10/group). At Day 21, anti-PD-L1 did not cause tumor regression and LY2606368 treatment delayed tumor growth [T/C=0.31(p<0.001)]. However, most notably, 60% mice treated with anti-PD-L1+LY2606368 had a complete tumor regression within 15 days of treatment [T/C=0.05(p<0.001)]. Cotargeting CHK1+PD-L1 significantly increases the level of CD8+ cytotoxic-T cell tumor infiltration, decreases exhausted T cell population, and enhances the expression of IFN gamma in SCLC models. CD8 depletion was able to reverse the antitumor effect of the combination, demonstrating the role of cytotoxic T-cell infiltration in CHK1+PD-L1 response. Significance: Our study demonstrates, for the first time, the potential for combining the two promising modalities, immune checkpoint targeting and CHK1 inhibition, in SCLC. This study further demonstrates the novel mechanism of DDR-mediated PD-L1 regulation in SCLC. The immune profiling and correlative biomarker data from our study further provide valuable mechanistic insight and indicate the subset of the patient population who are most likely to respond to these treatments. This study suggests intriguing possibilities for therapeutic synergy and scientific rationale for the evaluation of PD-L1/PD-1 blockade with CHK1i in clinical trials for SCLC, a disease with dismal 5-year survival rate of <5%, which has remained unchanged for >30 years.

Citation Format: Triparna Sen, Limo Chen, B. Leticia Rodriguez, Carl M. Gay, Lerong Li, Yanli Li, Youhong Fan, Bonnie Glisson, Jing Wang, Helen Piwnica-Worms, Julien Sage, John V. Heymach, Don L. Gibbons, Lauren A. Byers. DNA damage repair targeting upregulates PD-L1 level and potentiates the effect of PD-L1 blockade in small cell lung cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A108.

The Impact of Smoking and TP53 Mutations in Lung Adenocarcinoma Patients with Targetable Mutations-The Lung Cancer Mutation Consortium (LCMC2)

Purpose: Multiplex genomic profiling is standard of care for patients with advanced lung adenocarcinomas. The Lung Cancer Mutation Consortium (LCMC) is a multi-institutional effort to identify and treat oncogenic driver events in patients with lung adenocarcinomas.Experimental Design: Sixteen U.S. institutions enrolled 1,367 patients with lung cancer in LCMC2; 904 were deemed eligible and had at least one of 14 cancer-related genes profiled using validated methods including genotyping, massively parallel sequencing, and IHC.Results: The use of targeted therapies in patients with EGFR, ERBB2, or BRAF p.V600E mutations, ALK, ROS1, or RET rearrangements, or MET amplification was associated with a survival increment of 1.5 years compared with those with such mutations not receiving targeted therapy, and 1.0 year compared with those lacking a targetable driver. Importantly, 60 patients with a history of smoking derived similar survival benefit from targeted therapy for alterations in EGFR/ALK/ROS1, when compared with 75 never smokers with the same alterations. In addition, coexisting TP53 mutations were associated with shorter survival among patients with EGFR, ALK, or ROS1 alterations.Conclusion: Patients with adenocarcinoma of the lung and an oncogenic driver mutation treated with effective targeted therapy have a longer survival, regardless of prior smoking history. Molecular testing should be performed on all individuals with lung adenocarcinomas irrespective of clinical characteristics. Routine use of massively parallel sequencing enables detection of both targetable driver alterations and tumor suppressor gene and other alterations that have potential significance for therapy selection and as predictive markers for the efficacy of treatment. Clin Cancer Res; 24(5); 1038-47. ©2017 AACR.

Abstract 70: PARP1 as a potential therapeutic target in Merkel cell carcinoma

Background: Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin tumor. Patients with incurable disease are treated with the same chemotherapy agents utilized in small-cell lung cancer (SCLC) achieving similar responses. Overexpression of PARP1 is common in SCLC and promising antitumor activity of PARP inhibitors is being demonstrated in early clinical trials. Furthermore, PARP inhibitors are active in a subset of tumors harboring mutations in DNA-damage repair (DDR) genes and benefit correlates to response to platinum. Based on its similarities with SCLC, its association with DNA damage by UV light, and its sensitivity to platin, our study explores PARP1 as a therapeutic target in MCC.

Methods: We evaluated the prevalence of PARP1 expression by immunohistochemistry in 19 MCC. Polyoma virus (MCPyV) status was evaluated by staining with anti-MCPyV antibody in the tissue specimens. Exome-sequencing of 263 genes was performed in 14 patients' samples using next-generation sequencing. Only mutations predicted to impair protein function in 17 genes related to DDR or mismatch repair were included in our analysis. Fisher's exact test was used for statistical significance.

Results: The majority of MCC express PARP1 (84%), suggesting underlying defects in DNA damage repair. Approximately half of the tumors (47%) were associated with MCPyV. There was no statistical correlation between PARP1 expression and MCPyV status or primary site of disease. Mutations in genes predicted to impair DDR was identified in 9 samples (64%), occurred exclusively in head and neck primaries, and correlated with mutations in TP53 or RB1 (P=0.03). Mutations in ARID1A predictive to be loss-of-function and potentially confer sensitivity to PARP inhibitors were found in 36% of the patients, exclusively in MCPyV negative samples (P=0.003). Mutations in TP53 and/or RB1 were more frequent in MCPyV negative tumors (P=0.03).

Conclusions: In spite of the small sample size, the high prevalence of PARP1 expression in MCC samples, similarly to SCLC, suggests that patients with MCC might also benefit from PARP1 inhibitors. Furthermore, the frequent mutations in genes involved in DNA-damage repair and ARID1A, particularly in the MCPyV negative cases, merits further characterization. Taken together, we believe clinical trials with PARP inhibitors in MCC patients should be considered.

Citation Format: Renata Ferrarotto, Shirley Su, Lixia Diao, A Karina Eterovic, Victor Prieto, William Morrison, Jing Wang, Bonnie Glisson, Merrill Kies, Diana Bell. PARP1 as a potential therapeutic target in Merkel cell carcinoma [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr 70.

Gefitinib for patients with incurable cutaneous squamous cell carcinoma: A single-arm phase II clinical trial

BACKGROUND

Preclinical data demonstrate a key role for the epidermal growth factor receptor (EGFR) in the carcinogenesis of cutaneous squamous cell carcinomas (CSCCs). There are, however, limited data on the efficacy of EGFR inhibitors in incurable, recurrent, and/or metastatic CSCC.

OBJECTIVE

To determine the response rate to gefitinib in patients with CSCC not amenable to curative therapy including surgery or radiation.

METHODS

This was a single-arm phase II study. A total of 40 patients were treated with gefitinib, 250 mg orally daily, until disease progression or intolerable toxicities. The prespecified target response rate of interest was 20%.

RESULTS

The overall response rate was 16% (95% confidence interval, 0.06-0.32; 6 partial responses in 37 evaluable patients). An additional 13 patients (35%) had stable disease at 8 weeks. The median durations of response and progression-free survival were 31.4 months (95% confidence interval, 3.91-not applicable) and 3.8 months (95% confidence interval, 2.2-5.7), respectively. The side effect profile was consistent with the previous experience with gefitinib in other tumor types.

LIMITATIONS

This was a single-institution, single-arm study. The prespecified target response rate was not met.

CONCLUSION

Gefitinib demonstrated modest activity in incurable CSCC, with a favorable adverse event profile.

Abstract B72: Combining immune checkpoint inhibition and DNA damage repair (DDR) targeted therapy in small cell lung cancer (SCLC)

Background: Small cell lung cancer (SCLC) is a highly aggressive disease for which standard treatment remains virtually unchanged since the 1980s. SCLC has a relatively immunosuppressed phenotype with low levels of infiltrating T-cells and evidence of reduced antigen presentation. Only a minority of SCLC patients responds to programmed cell death protein 1 (PD-1) or programmed death ligand 1 (PD-L1) inhibitors as monotherapy. Therefore, though the clinical data is promising, there is a strong need to develop strategies to enhance the efficacy of immunotherapy in SCLC. Our group previously discovered that the DNA damage repair (DDR) protein, checkpoint kinase 1 (CHK1), is overexpressed in SCLC and that CHK1 inhibitors have activity in preclinical models of SCLC. Based on data from others and our group, we hypothesize that tumor associated neoantigen (TAA) expression is suppressed in SCLC by several mechanisms, including DDR machinery, and that targeting CHK1 may enhance antitumor immunity and response to immune checkpoint targeting.

Results: In SCLC models, inhibition of CHK1 by genetic knockdown and small molecule inhibition (LY2606368) induces DNA damage as demonstrated by increased γ-H2AX levels. We also observed increased protein levels of immune checkpoint ligand, PD-L1, following pharmacologic inhibition with LY2606368. We next tested whether co-targeting CHK1+PD-L1 enhances the anti-tumor effect in an immune-competent SCLC model. B6129F1 mice were injected in the flank with TKO.mTmG cells harboring conditional deletion of Trp53, Rb1 and p130. When the tumor volume reached 120mm3, mice were treated with either IgG (control), LY2606368 (10mg/kg, 2/7), anti-PD-L1 (300ug, 1/7) or combination of LY2606368 and anti-PD-L1 antibody. Single agent treatment with anti-PD-L1 antibody did not cause tumor regression in these models with T/C ratio=0.93 (p<0.001) at Day 21. Treatment of single agent LY2606368 at a sub-therapeutic dose significantly delayed tumor growth in these models with T/C=0.31 (p<0.001) at Day 21. However, 3 out of 5 mice treated with anti-PD-L1+LY2606368 had a complete tumor regression within 15 days of treatment with T/C=0.05 (p<0.001) at Day 21. Tumors were collected at the end of 21 days for RPPA analysis, RNA sequencing and flow cytometry to characterize tumor-infiltrating immune cells post treatment with the single agents versus the combination.

Discussion: SCLC has an immunosuppressed phenotype (despite a high mutational burden); however, only a minority of tumors expresses PD-L1, suggesting that immunosuppressive mechanisms other than the PD-1/PD-L1 pathway are likely to contribute. This study shows that targeting CHK1 (by genetic knockdown and pharmacological inhibition) leads to increased DNA damage and increased expression of immune checkpoint ligand, PD-L1. Combining CHK1 inhibition and PD-L1 targeting significantly enhanced the effect of PD-L1 antibody leading to tumor regression in an immune competent SCLC model. Biomarker analyses from these models are ongoing to confirm the expression of immune markers. PD-L1 inhibitors as monotherapy have led to objective responses in only a minority of SCLC patients. The CHK1 inhibitor LY2606368 is currently in clinical trial for SCLC patients. The complementary modes of action of the two promising modalities, immune checkpoint targeting and CHK1 inhibition, suggest intriguing possibilities for therapeutic synergy with combination treatment and warrants further clinical investigation.

Citation Format: Triparna Sen, Limo Chen, Bertha Leticia Rodriguez, Yongbin Yang, You Hong Fan, Catherine Allison Stewart, Bonnie Glisson, Helen Piwnica-Worms, Julien Sage, John V. Heymach, Don L. Gibbons, Lauren A. Byers. Combining immune checkpoint inhibition and DNA damage repair (DDR) targeted therapy in small cell lung cancer (SCLC). [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr B72.

Long-term results of RTOG 91-11: a comparison of three nonsurgical treatment strategies to preserve the larynx in patients with locally advanced larynx cancer

PURPOSE

To report the long-term results of the Intergroup Radiation Therapy Oncology Group 91-11 study evaluating the contribution of chemotherapy added to radiation therapy (RT) for larynx preservation.

PATIENTS AND METHODS

Patients with stage III or IV glottic or supraglottic squamous cell cancer were randomly assigned to induction cisplatin/fluorouracil (PF) followed by RT (control arm), concomitant cisplatin/RT, or RT alone. The composite end point of laryngectomy-free survival (LFS) was the primary end point.

RESULTS

Five hundred twenty patients were analyzed. Median follow-up for surviving patients is 10.8 years. Both chemotherapy regimens significantly improved LFS compared with RT alone (induction chemotherapy v RT alone: hazard ratio [HR], 0.75; 95% CI, 0.59 to 0.95; P = .02; concomitant chemotherapy v RT alone: HR, 0.78; 95% CI, 0.78 to 0.98; P = .03). Overall survival did not differ significantly, although there was a possibility of worse outcome with concomitant relative to induction chemotherapy (HR, 1.25; 95% CI, 0.98 to 1.61; P = .08). Concomitant cisplatin/RT significantly improved the larynx preservation rate over induction PF followed by RT (HR, 0.58; 95% CI, 0.37 to 0.89; P = .0050) and over RT alone (P < .001), whereas induction PF followed by RT was not better than treatment with RT alone (HR, 1.26; 95% CI, 0.88 to 1.82; P = .35). No difference in late effects was detected, but deaths not attributed to larynx cancer or treatment were higher with concomitant chemotherapy (30.8% v 20.8% with induction chemotherapy and 16.9% with RT alone).

CONCLUSION

These 10-year results show that induction PF followed by RT and concomitant cisplatin/RT show similar efficacy for the composite end point of LFS. Locoregional control and larynx preservation were significantly improved with concomitant cisplatin/RT compared with the induction arm or RT alone. New strategies that improve organ preservation and function with less morbidity are needed.

Insulin-like growth factor binding protein-3 suppresses vascular endothelial growth factor expression and tumor angiogenesis in head and neck squamous cell carcinoma

Angiogenesis, the process by which new blood vessels are recruited to existing ones, is essential for tumor development. Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3), which modulates bioavailability of IGF, has been studied for its potential role in angiogenesis during tissue regeneration and cancer development. In this study, we assessed the role of IGFBP-3 in tumor angiogenesis in head and neck squamous cell carcinoma (HNSCC) and human umbilical vein endothelial cells (HUVECs) using adenoviral (Ad-BP3) and recombinant (rBP3) IGFBP-3. Using an in vivo orthotopic tongue tumor model, we confirmed that both Ad-BP3 and rBP3 suppress the growth of UMSCC38 HNSCC cells in vivo. Ad-BP3 inhibited vascularization in tongue tumors and chorio-allantoic membrane, and suppressed angiogenesis-stimulating activities in UMSCC38 cells. In HUVECs, Ad-BP3 decreased migration, invasion, and tube formation. rBP3 also suppressed production of vascular endothelial growth factor (VEGF) in HUVECs and UMSCC38 cells. IGFBP-3-GGG, a mutant IGFBP-3 with loss of IGF binding capacity, suppressed VEGF production. In addition, we found that IGFBP-3 suppressed VEGF expression, even in mouse embryonic fibroblasts from an IGF-1R-null mouse. Finally, we demonstrated that IGFBP-3-GGG inhibits tumor angiogenesis and growth to the same degree as wild-type IGFBP-3. Taken together, these results support the hypothesis that IGFBP-3 has anti-angiogenic activity in HNSCC, at least in part due to IGF-independent suppression of VEGF production from vascular endothelial cells and cancer cells.

Abstract 1901: EGFR and K-Ras mutations and resistance of lung cancers to IGF-1R TKI

Background: Most patients with non-small cell lung cancer (NSCLC) have responded poorly to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). We investigated the involvement of insulin-like growth factor 1 receptor (IGF-1R) signaling in primary resistance to EGFR TKIs and the molecular determinants of resistance to IGF-1R TKIs. Methods: Phosphorylated IGF-1R/insulin receptor (pIGF-1R/IR) was immunohistochemically evaluated in a NSCLC tissue microarray. We analyzed the antitumor effects of an IGF-1R TKI (PQIP or OSI-906), either alone or in combination with a small-molecular inhibitor (PD98059 or U0126) or with siRNA targeting K-Ras or MAPK/extracellular signal-regulated kinase kinase (MEK), in vitro and in vivo in NSCLC cells with variable histologic features and EGFR or K-Ras mutations. Results: pIGF-1R/IR expression in NSCLC specimens was associated with a history of tobacco smoking, squamous cell carcinoma histology, mutant (mut) K-Ras, and wild-type (wt) EGFR, all of which have been strongly associated with poor response to EGFR TKIs. IGF-1R TKIs exhibited significant antitumor activity in NSCLC cells with wt EGFR and wt K-Ras but not in those with mutations in these genes. Introduction of mut K-Ras attenuated the effects of IGF-1R TKIs on NSCLC cells expressing wt K-Ras. Conversely, inactivation of MEK restored sensitivity to IGF-TKIs in cells carrying mut K-Ras. Conclusions: The mutation status of both EGFR and K-Ras could be predictive markers of response to IGF-1R TKIs. Also, MEK antagonism can abrogate primary resistance of NSCLC cells to IGF-1R TKIs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1901. doi:1538-7445.AM2012-1901

Epidermal growth factor receptor and K-Ras mutations and resistance of lung cancer to insulin-like growth factor 1 receptor tyrosine kinase inhibitors

BACKGROUND

Most patients with nonsmall cell lung cancer (NSCLC) have responded poorly to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). The authors investigated the involvement of insulinlike growth factor 1 receptor (IGF-1R) signaling in primary resistance to EGFR TKIs and the molecular determinants of resistance to IGF-1R TKIs.

METHODS

Phosphorylated IGF-1R/insulin receptor (pIGF-1R/IR) was immunohistochemically evaluated in an NSCLC tissue microarray. The authors analyzed the antitumor effects of an IGF-1R TKI (PQIP or OSI-906), either alone or in combination with a small-molecular inhibitor (PD98059 or U0126) or with siRNA targeting K-Ras or mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK), in vitro and in vivo in NSCLC cells with variable histologic features and EGFR or K-Ras mutations.

RESULTS

pIGF-1R/IR expression in NSCLC specimens was associated with a history of tobacco smoking, squamous cell carcinoma histology, mutant K-Ras, and wild-type (WT) EGFR, all of which have been strongly associated with poor response to EGFR TKIs. IGF-1R TKIs exhibited significant antitumor activity in NSCLC cells with WT EGFR and WT K-Ras but not in those with mutations in these genes. Introduction of mutant K-Ras attenuated the effects of IGF-1R TKIs on NSCLC cells expressing WT K-Ras. Conversely, inactivation of MEK restored sensitivity to IGF-TKIs in cells carrying mutant K-Ras.

CONCLUSIONS

The mutation status of both EGFR and K-Ras could be a predictive marker of response to IGF-1R TKIs. Also, MEK antagonism can abrogate primary resistance of NSCLC cells to IGF-1R TKIs.

Akt/mTOR counteract the antitumor activities of cixutumumab, an anti-insulin-like growth factor I receptor monoclonal antibody

Recent reports have shown limited anticancer therapeutic efficacy of insulin-like growth factor receptor (IGF-1R)-targeted monoclonal antibodies (mAb), but the resistance mechanisms have not been completely identified. Because cooperation between epidermal growth factor receptor (EGFR) and IGF-IR could cause resistance to inhibitors of individual receptor tyrosine kinases, we investigated the involvement of EGFR signaling in resistance to IGF-1R mAb and the underlying mechanisms of action. Most head and neck squamous cell carcinoma (HNSCC) tissues had coexpression of total and phosphorylated IGF-1R and EGFR at high levels compared with paired adjacent normal tissues. Treatment with cixutumumab (IMC-A12), a fully humanized IgG1 mAb, induced activation of Akt and mTOR, resulting in de novo synthesis of EGFR, Akt1, and survivin proteins and activation of the EGFR pathway in cixutumumab-resistant HNSCC and non-small cell lung cancer (NSCLC) cells. Targeting mTOR and EGFR pathways by treatment with rapamycin and cetuximab (an anti-EGFR mAb), respectively, prevented cixutumumab-induced expression of EGFR, Akt, and survivin and induced synergistic antitumor effects in vitro and in vivo. These data show that resistance to IGF-1R inhibition by mAbs is associated with Akt/mTOR-directed enhanced synthesis of EGFR, Akt1, and survivin. Our findings suggest that Akt/mTOR might be effective targets to overcome the resistance to IGF-1R mAbs in HNSCC and NSCLC.

Abstract 4127: EGFR and K-Ras mutations and resistance of lung cancer to the IGF-1R tyrosine kinase inhibitors

Background: The majority of patients with non-small cell lung cancer (NSCLC) has responded poorly to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). We investigated (1) the involvement of insulin-like growth factor 1 receptor (IGF-1R) signaling in primary resistance to EGFR TKIs and (2) the molecular determinants of resistance to IGF-1R TKIs. Methods: Phosphorylated IGF-1R/insulin receptor (pIGF-1R/IR) was immunohistochemically evaluated in NSCLC tissue microarrays. The antitumor effects of IGF-1R TKIs (PQIP, OSI906), either alone or in combination with small-molecular inhibitors or siRNA targeting K-Ras or MAPK/extracellular signal-regulated kinase kinase (MEK) were analyzed in vitro and in vivo in 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-transformed human bronchial epithelial (HBE) cells and in NSCLC cells with variable histologic features and mutations in EGFR or K-Ras. Results: pIGF-1R/IR expression in NSCLC specimens was positively correlated with presence of a history of tobacco smoking, squamous cell carcinoma, mutant (mut) K-Ras, and wild-type (wt) EGFR, all of which have been strongly associated with poor response to EGFR TKIs. IGF-1R TKIs exhibited significant antitumor activity in NNK-transformed HBE cells and in NSCLC cells harboring wt EGFR and wt K-Ras, but not those with mutations in these genes. Introduction of mut K-Ras attenuated the effects of IGF-1R TKIs on wt K-Ras-expressing NSCLC cells. Conversely, inactivation of MEK restored sensitivity to IGFR-TKI in cells carrying mut K-Ras. Conclusions: The mutation status of both EGFR and K-Ras could be a predictive marker for response to IGF-1R TKIs. Also, MEK antagonism can abrogate primary resistance of NSCLC to IGF-1R TKIs. This work was supported by NIH grants R01 CA-109520-01 and CA-100816 (all to H-YL.) and in part by DOD grant W81XWH-04-1-0142 VITAL and W8XWH-06-1-0303 BATTLE (W-K H.)

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 4127.

Intensity-modulated radiation therapy with or without chemotherapy for nasopharyngeal carcinoma: radiation therapy oncology group phase II trial 0225

PURPOSE

To investigate the feasibility of intensity-modulated radiation therapy (IMRT) with or without chemotherapy, and to assess toxicities, failure patterns, and survivals in patients with nasopharyngeal carcinoma (NPC).

PATIENTS AND METHODS

Radiation consisted of 70 Gy given to the planning target volumes of primary tumor plus any N+ disease and 59.4 Gy given to subclinical disease, delivered over 33 treatment days. Patients with stage T2b or greater or with N+ disease also received concurrent cisplatin (100 mg/m(2)) on days 1, 22, and 43 followed by adjuvant cisplatin (80 mg/m(2)) on day 1; fluorouracil (1,000 mg/m(2)/d) on days 1 through 4 administered every 4 weeks for three cycles. Tumor, clinical status, and acute/late toxicities were assessed. The primary objective was to test the transportability of IMRT to a multi-institutional setting.

RESULTS

Between February 2003 and November 2005, 68 patients with stages I through IVB NPC (of which 93.8% were WHO types 2 and 3) were enrolled. Prescribed IMRT (target delineation) was given to 83.8%, whereas 64.9% received chemotherapy per protocol. The estimated 2-year local progression-free (PF), regional PF, locoregional PF, and distant metastasis-free rates were 92.6%, 90.8%, 89.3%, and 84.7%, respectively. The estimated 2-year PF and overall survivals were 72.7% and 80.2%, respectively. Acute grade 4 mucositis occurred in 4.4%, and the worst late grade 3 toxicities were as follows: esophagus, 4.7%; mucous membranes, 3.1%; and xerostomia, 3.1%. The rate of grade 2 xerostomia at 1 year from start of IMRT was 13.5%. Only two patients complained of grade 3 xerostomia, and none had grade 4 xerostomia.

CONCLUSION

It was feasible to transport IMRT with or without chemotherapy in the treatment of NPC to a multi-institutional setting with 90% LRPF rate reproducing excellent reports from single institutions. Minimal grade 3 and lack of grade 4 xerostomia were encouraging.

Phase I study of pemetrexed in recurrent/metastatic head and neck squamous cell cancer (HNSCC) and to assess the need for steroid premedication

e17009

Background: Pemetrexed is a novel antimetabolite that inhibits both purine and pyrimidine biosynthesis. Because its mechanism of action is similar to that of both methotrexate and 5-FU, it may also have activity in recurrent/metastatic HNSCC, a disease with limited treatment options and very poor median survival. Pemetrexed is traditionally prescribed with steroids due to skin toxicities observed in early studies; however vitamin supplementation (B12 and folic acid) was not standard at the time of those studies. No study to date has evaluated the optimal use of steroids with pemetrexed in the era of vitamin supplementation. Methods: All patients had metastatic or recurrent HNSCC, were treated with at least one prior chemotherapy regimen, and had ECOG PS of 0–2. The first cohort of patients received pemetrexed 500 mg/m2 every 3 weeks and the next receiving 600 mg/m2 based on a predefined standard dose escalation design. Within each dose level, patients were randomized to one of 3 premedication regimens: no dexamethasone, 20 mg IV on day 1, or standard 4 mg orally bid for 3 days. All patients received vitamin supplementation. The primary endpoint of the study was to determine the maximum tolerated dose of pemetrexed based on steroid premedication. Results: From October 2005 to March 2008, 36 patients were enrolled and 31 were available for evaluation. Median age was 57 years (range 42–82). 51.5% of patients had more than one prior chemotherapy regimens, 81.8% of patients had prior radiation therapy, and 48.5% of patients had prior surgery. Incidence of rash and combined skin toxicities were: 1/11 (9%) and 3/11 (27%) of patients without steroids, 1/11 (9%) and 3/11 (27%) with single IV dose, and 4/9 (44%) and 5/9 (55%) with oral steroids. No treatment-related grade 3 toxicities were observed. One patient initially received no steroid and required dose reduction and addition of steroid due to grade 2 rash. A partial response was observed in one patient (3.2%), and stable disease in 8 patients (25.8%) for a disease control rate of 29%. Conclusions: This is the first study to report the role of steroids as a premedication for pemetrexed. Our data suggests that no steroid premedication is needed with pemetrexed and vitamin supplementation.

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Phase II study of dasatinib in the treatment of head and neck squamous cell carcinoma (HNSCC)

6022

Background: Dasatinib is a potent inhibitor of src-family kinases, ephA2, PDGFR, Abl, and c-kit. A single-center, open-label, phase II trial was conducted to evaluate the safety, tolerability, pharmacokinetics (PK), and efficacy of dasatinib in recurrent or metastatic HNSCC. Methods: Pts with measurable disease by RECIST, who received 0 or 1 prior regimen for recurrent or metastatic HNSCC with an ECOG performance status 0–1 and tumor tissue appropriate for IHC and FISH were eligible. Dasatinib 100 mg bid was given for 28-day cycles. Primary endpoints were 12-wk progression-free survival (PFS) and objective response rate (ORR). Pts who took at least 1 dose of dasatinib and who died or left study before 12 wks were counted as progressive disease (PD). A 2 stage design, closure after accrual of 15 pts was required if PFS was 45% or less and ORR was 0. Otherwise, planned accrual was 35. Response was assessed at 4 and 12 wks. PK was studied in pts receiving dasatinib per PEG. Biomarkers relevant to Src pathway were planned in tissue and blood. Results: Fifteen pts were accrued. To date, 13 pts are evaluable for response, and 15 pts for toxicity. No grade 3/4 hematologic toxicities were noted. Grade 2–4 nonhematologic toxicities(n): pleural effusion(2), nausea/vomiting(2), dehydration(1), diarrhea(1), dyspnea(1). Toxicity led to hospitalization of 4 pts and drug discontinuation in 5 pts. ORR was 0. One pt was stable at 12 wks (PFS: 7.6%). This pt stopped drug at 15 wks due to toxicity, but also had PD. One pt died on study and cause was deemed unlikely related. Conclusions: Dosed at 100mg bid, dasatinib led to a characteristic toxicity profile in this pt population. Rates of hospitalization and discontinuation for toxicity were fairly high. Final efficacy parameters are pending evaluation of 2 pts. Evaluation of PK and tissue/blood biomarkers is ongoing.

No significant financial relationships to disclose.

IMRT reirradiation of head and neck cancer-disease control and morbidity outcomes

PURPOSE

Institutional and cooperative group experience has demonstrated the feasibility of reirradiation for head and neck cancer. Limited data are available regarding the use of intensity-modulated radiotherapy (IMRT) for this indication. We reviewed our initial experience using IMRT for previously irradiated head and neck cancer patients.

METHODS AND MATERIALS

Records of 78 consecutive patients reirradiated with IMRT for head and neck cancer between 1999 and 2004 were reviewed; 74 cases were analyzed. Reirradiation was defined as any overlap between original and new radiation treatment volumes regardless of the time interval between initial and subsequent treatment. Severe reirradiation-related toxicity was defined as toxic events resulting in hospitalization, corrective surgery, or patient death. Longitudinal estimates of survival were calculated by Kaplan-Meier technique.

RESULTS

Twenty (27%) patients underwent salvage surgical resection and 36 (49%) patients received chemotherapy. Median follow-up from reirradiation was 25 months. Median time interval between initial radiation and reirradiation was 46 months. Median reirradiation dose was 60 Gy. Median lifetime radiation dose was 116.1 Gy. The 2-year overall survival and locoregional control rates were 58% and 64%, respectively. Severe reirradiation related toxicity occurred in 15 patients (20%); one treatment-related death was observed.

CONCLUSIONS

The use of IMRT for reirradiation of recurrent or second primary head and neck cancers resulted in encouraging local control and survival. Reirradiation-related morbidity was significant, but may be less severe than previously published reports using conventional techniques.

A phase II trial of ZD 1869 for advanced cutaneous squamous cell carcinoma of the head and neck

6038

Background: Advanced HN CSSC carries a 30–40% risk of death by 2 years with standard therapies. A number of patients (pts) with clinically aggressive CSCC tend to have a poor prognosis when treated with standard approaches using surgery and radiation (RT), thus novel therapies are needed. CSSC over expresses the epidermal growth factor receptor (EGFR) and these compounds have activity in head and neck cancers. We are studying the use of gefitinib as an induction therapy in a high-risk patient group prior to definitive therapy to determine the overall efficacy, toxicity and feasibility. Methods: Eligible pts must have HN CSSC >2cm, regional nodal metastases, peri-neural invasion, or deep invasion into cartilage, muscle or bone and must be candidates for definitive local-regional therapy with surgery and/or radiation. Two 30-day cycles of gefitinib 250mg administered orally are given daily prior to definitive therapy. Pts are assessed clinically after the first 30-day cycle. If a response is noted, gefitinib is continued. For patients with stable disease, the dose is escalated to 500mg daily. Pts with progressive disease go off study. Biomarker evaluations including EGFR and Akt expression prior to and after induction are planned. Results: To date, 14 pts have been enrolled. 10 are evaluable for response and 13 for toxicity. A complete clinical response (CR) was noted in 3 pts (30%, one pathological CR), partial response in 2 patients (20%), stable disease in 2 (20%) and progressive disease in 3 (30%). Therapy was well tolerated with 2 patients having grade 3 toxicity (rash, diarrhea, or elevated liver enzymes). Conclusions: Standard definitive surgery and RT are inadequate for patients with advanced HN CSSC. The emergence of targeted therapies has given new hope for many patients with high-risk cancers. The preliminary results from our study suggest that gefitinib is an active agent for HN CSCC, and is well tolerated. Correlative studies may help identify patients most likely to respond to anti- EGFR therapy.

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Toxicities in a phase II study of accelerated high dose thoracic radiation therapy (TRT) with concurrent chemotherapy for limited small cell lung cancer (LSCLC) (RTOG 0239)

7717

Background: Accelerated fractionation proved beneficial in INT0096, but the total dose was low and local recurrence was high with higher acute grade (Gr.) 3+ esophagitis. RTOG 0239 was a phase II trial to improve local control and survival with LSCLC with acceptable acute Gr. 3+ esophagitis using accelerated high dose TRT and concurrent cisplatin/etoposide. This is the first report of acute Gr.3+ esophagitis and Gr.5 toxicities. Methods: Patients (pts) with LSCLC without pleural effusion, contralateral hilar or contralateral supraclavicular nodes and PS 0–1 were enrolled. TRT was given to large fields to 28.8 Gy at 1.8 Gy per fraction, 5 days per week for 16 fractions followed by BID with large field in AM, boost in PM, then off-cord boost BID for last 5 days, all at 1.8 Gy per fx for a total dose of 61.2 Gy in 34 fx in 5 weeks. Concurrent chemotherapy was started with TRT with cisplatin, 60 mg/m2 i.v. day 1; etoposide, 120 mg/m2 i.v. day 1; etoposide, 240 mg/m2 p.o. per day or 120 mg/m2 i.v. per day on days 2 or 3. Cycles were repeated q.3 wks during and for 2 cycles after TRT. Pts who have achieved complete response one month after completion of 4 cycles of chemotherapy were asked to participate in a prophylactic cranial irradiation (PCI) study. Common toxicity criteria (CTC) 2.0 was used for acute toxicity. Results: From 10/2003 to 5/2006, 72 pts were accrued. Median age was 63 yrs with 52% females. Survival data is still maturing. Acute toxicity information is available for 68 pts. Eleven pts (16%) experienced acute Gr. 3 and 1 pt (1%) had acute Gr. 4 esophagitis. 47 pts (69%) had grade 4 blood/bone marrow toxicities. There were 2 (3%) Gr. 5 toxicities reported [1 infection with neutropenia; 1 pulmonary (pneumonia)]. Conclusions: This accelerated high dose TRT with concurrent chemotherapy for LSCLC resulted in 17% acute Gr.3+ esophagitis compared to 27% with BID TRT with 45Gy in 3 weeks by INT0096. There were 3% grade 5 toxicities. This preliminary report suggests that RTOG-0239 has tolerable toxicity. The acute Gr3+ esophageal toxicity correlated with V20 and V40 will be presented. Pts continue to be followed for the primary endpoint of 2-year survival.

No significant financial relationships to disclose.

Long-term results of Intergroup RTOG 91–11: A phase III trial to preserve the larynx—Induction cisplatin/5-FU and radiation therapy versus concurrent cisplatin and radiation therapy versus radiation therapy

5517

Background: The 2-year results of Intergroup RTOG 91–11 were published in 2003 (NEJM 349:2091–8,2003). We now present the 5-year results (after median follow-up for surviving patients of 6.9 years) of 515 eligible pts with resectable stage III or IV (excluding T1 and high volume T4), cancer of the glottic or supraglottic larynx. Methods: Patients were randomized to induction cisplatin/5-FU (CF) with responders then receiving RT (I+RT) (n = 173); or concurrent cisplatin (100 mg/m2 q 21 days × 3) and RT (CRT) (n = 171); or RT alone (R) (n = 171). Laryngectomy was performed for < partial response to induction CF, for persistent/recurrent disease or for laryngeal dysfunction. Results: At 5 years, laryngectomy-free survival (LFS) was significantly better with either I+RT (44.6%, p = 0.011) or CRT (46.6%, p = 0.011) compared to R (33.9%). There was no difference in LFS between I+RT and CRT (p = 0.98). Laryngeal preservation (LP) was significantly better with CRT (83.6%) compared to I+RT (70.5%, p = 0.0029) or R (65.7%, p = 0.00017). Local-regional control (LRC) was significantly better with CRT (68.8%) compared to I+RT (54.9%, p = 0.0018) or R (51%, p = 0.0005). I+RT compared to R for LP and LRC showed no significant difference (p = 0.37 and 0.62, respectively). The distant metastatic rate was low (I+RT 14.3%, CRT 13.2%, R 22.3%) with a trend (p ∼0.06) for benefit from chemotherapy. Disease-free survival (DFS) was significantly better with either I+RT (38.6%, p = 0.016) or CRT (39%, p = 0.0058) compared to R (27.3%). Overall survival rates were similar for the first 5 years (I+RT 59.2%, CRT 54.6%, R 53.5%); thereafter I+RT had a non-significant lower death rate. Compared to CRT, significantly more pts in the R group died of their cancer (34% vs 58.3%, p = 0.0007); the rate for I+RT was 43.8%. Conclusion: These 5-year results differ from the 2-year analysis by a significant improvement in LFS now seen for both I+RT and CRT treatments compared to R. For the endpoints of LP and LRC, CRT is still the superior treatment with no advantage seen to the addition of induction CF to R. There is no significant difference in overall survival.

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Yttrium-90 microsphere treatment for liver dominant hepatic metastases from lung cancer

17122

Background: Hepatic metastases are a common manifestation of primary lung malignancies; the primary and other extrahepatic sites are often less responsive to systemic therapy. A new method of regional therapy for hepatic metastases, called SIR-Spheres, a 32μ resin sphere incorporating a pure Beta emitter, Yttrium - 90, has advantages to older forms of regional hepatic therapy, used to treat colorectal liver metastases. The effectiveness and relatively response durability suggests a favorable alternative to chemotherapy for patients with liver-dominant metastatic lung cancers. We report our experience using SIR-Spheres in this setting. Methods: 6 patients (2 well differentiated carcinoid, 2 well & 1 poorly differentiated adenocarcinoma, 1 poorly differentiated small cell carcinoma) with unresectable hepatic metastases were treated with 8 infusions of SIR-Spheres after failing systemic chemotherapy, radiofrequency ablation or arterial embolization were included in the study. SIR-Spheres were administered as 2nd-6th line therapy. Median interval from diagnosis to SIR-Spheres treatment was 20.5 months (6–51 m). Results: Abdominal visceral arteriography demonstrated vasculature conducive for SIR-Spheres delivery in all patients. The median dose of 36.1 mCi (12.9–54 mCi) was delivered. SPECT - CT fusion Bremsstrahlung scans post therapy confirmed preferential deposition of SIR-Spheres within metastases. Responses to therapy included a decrease in the size of the hepatic metastases in one patient and stable disease in two patients. One patient had a mixed response and two patients had progression of disease. One Gr. III and one Gr. IV hepatic toxicity occurred. All patients experienced transient Gr. 1 or 2 fatigue. Time to progression of liver disease ranged from 3 to 9 months. Conclusion: SIR-Spheres is a feasible alternative to systemic therapy for patients with liver dominant metastases from lung cancers. Although serious hepatotoxicity was noted in patients with advanced liver metastases, the treatment was tolerated with only reversible fatigue in the majority of patients. When the treatment was effective, the duration of local disease control after one treatment equaled or exceeded what would be expected with chemotherapy.

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