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Therapeutic antibodies to immune checkpoints show promising results. Programmed death-ligand 1 (PD-L1), an immune checkpoint ligand, blocks the cancer immunity cycle by binding the PD-L1 receptor (programmed death 1). We investigated PD-L1 protein expression and messenger RNA (mRNA) levels in SCLC.PD-L1 protein expression and mRNA levels were determined by immunohistochemistry (IHC) with SP142 and Dako 28-8 PD-L1 antibodies and in situ hybridization in primary tumor tissue microarrays in both tumor cells and tumor-infiltrating immune cells (TIICs) obtained from a limited-disease SCLC cohort of 98 patients. An additional cohort of 96 tumor specimens from patients with extensive-disease SCLC was assessed for PD-L1 protein expression in tumor cells with Dako 28-8 antibody only.The overall prevalence of PD-L1 protein expression in tumor cells was 16.5%. In the limited-disease cohort, the prevalences of PD-L1 protein expression in tumor cells with SP142 and Dako 28-8 were 14.7% and 19.4% (tumor proportion score cutoff ≥1%) and PD-L1 mRNA ISH expression was positive in 15.5% of tumor samples. Increased PD-L1 protein/mRNA expression was associated with the presence of more TIICs (p0.05). The extensive-disease cohort demonstrated a 14.9% positivity of PD-L1 protein expression in tumor cells with Dako 28-8 antibody.A subset of SCLCs is characterized by positive PD-L1 and/or mRNA expression in tumor cells. Higher PD-L1 and mRNA expression correlate with more infiltration of TIICs. The prevalence of PD-L1 in SCLC is lower than that published for NSCLC. The predictive role of PD-L1 expression in SCLC treatment remains to be established.

This phase III, multicenter, single-arm trial investigated the impact of 90 min rituximab infusions on infusion-related reactions (IRRs) in patients with untreated diffuse large B-cell lymphoma (DLBCL) or follicular lymphoma (FL). Patients received six or eight cycles of rituximab plus cyclophosphamide, vincristine, doxorubicin and prednisone for DLBCL or plus cyclophosphamide, vincristine and prednisolone for FL. A total of 425 patients received the first rituximab infusion per standard guidelines; median duration 240 min. Patients who did not experience grade ≥ 3 IRRs received subsequent infusions over 90 min (363 patients). A total of 303 patients received ≥ 6 cycles of rituximab. Fifty-three patients withdrew after cycle 1; 10 for grade 3 or 4 IRRs and one for a grade 3 adverse event. During cycle 2, 139 patients had IRRs, including four grade 3 IRRs. A 90 min rituximab infusion is well tolerated and feasible for patients with DLBCL or FL who tolerate the first standard rate infusion.

e20567Background: Limited 2L therapy options and no established 3L standard of care make treating relapsed ED-SCLC challenging. This study explores current treatment and outcomes in patients receiv...

Meeting abstracts The majority of lung cancer in the U.S. is treated in the community. A prospective cohort study of stage IV NSCLC and extensive disease (ED) SCLC is being conducted in 70 U.S. community practices to assess outcomes during the pre- and post-immunotherapy eras of lung cancer

Background: The current study explores T-cell (TC) clonality and molecular factors associated with this metric. Tumors employ multiple mechanisms to evade antitumor immune responses. One process involves TC inhibition via upregulation of immune checkpoint (IC) ligands in the tumor microenvironment (TME). Gradual upregulation of inhibitory receptor at their cellular surface results in a decreased capacity to proliferate and activate cytotoxic pathways against tumor cells presenting antigenic peptides.1 In melanoma, this subset of exhausted TCs has been described as highly clonal, where the majority of PD-1-expressing TC population shares the same TCR sequence specific against the same antigenic fragment.2 Previous studies have demonstrated that a clonal TCR repertoire appears to be associated in part with therapeutic responses during IC blockade.3 Methods: We performed TCR sequencing on 82 blood and 73 archival tumor tissue samples collected from ED SCLC patients (pts) in an ongoing longitudinal cohort study in US community oncology practices. Of these, 82 blood and 48 tissue samples had sufficient material available to quantify a clonality metric. To quantify TC abundance as a fraction of total nucleated cells, 82 blood and 58 tissue samples had sufficient material available. Results: Within the subset of 48 tumor samples, a more clonal (ie, less diverse) TCR repertoire was associated with less necrosis (P≤0.012) and lower levels of inflammatory cell infiltration in the local TME (P≤0.021). When pts were divided into 2 equal groups according to the median clonality level, pts with a less clonal TCR repertoire (n = 24/48) who were treated with non-immune-targeted therapy trended toward a longer overall survival (OS; 446 vs 301 days; P≤0.039). In contrast, the percentage of TCs in the TME did not correlate with improved survival (P≤0.412), necrosis (P≤0.131), and inflammation (P≤0.615). This observation differs from results in melanoma describing the impact of IC blockade where pts responding to therapy were associated with a more clonal TME TC population and increased CD8 TCs in the tumor compartment and at the invasive margin.3 In blood, while a less clonal TCR repertoire was associated with a similar but non-significant trend toward longer survival (P≤0.148), pts with increased TC abundance had longer OS (P≤0.025). No association was observed between clonality in TME and clonality (P≤0.571) or TC abundance (P≤0.965) in blood. Conclusion: We hypothesize that a diverse TCR repertoire in the TME and increased peripheral TC abundance are 2 predictors of longer OS in ED SCLC. To further explore factors that may influence TC responses in ED SCLC, the current TCR sequencing results will be integrated with transcriptome and whole genome sequencing analyses. References 1. Wherry EJ. Nat Immunol. 2011;12:492-99. 2. Gros A, et al. J Clin Invest. 2014;124:2246-59. 3. Tumeh PC, et al. Nature. 2014;515:568-71. Citation Format: Maen Hussein, Sharon Wilks, Marc Monte, Donald A. Richards, Jerome H. Goldschmidt, David Waterhouse, Lisu Wang, Saumya Pant, Erik Yusko, Ryan O. Emerson, Darin M. Taverna, Kaushal Desai, Spyro Mousses, Zhenhao Qi, Jason D. Hipp, Harlan Robins, Kimary Kulig, Cory Batenchuk. Characterization of the T-cell receptor (TCR) repertoire in extensive disease small cell lung cancer (ED SCLC). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4159.

We observed increased hemoglobin A2 (HbA2) levels in an asymptomatic human immunodeficiency virus-1 (HIV1) patient with no previous history of beta-thalassemia. He was treated only with zidovudine (AZT). In an attempt to understand this observation, a retrospective study was initiated to determine whether mean HbA2 levels are higher in AZT-treated patients than in subjects not receiving this drug and to assess if other hematologic alterations are associated with elevated HbA2. One hundred fifty-one HIV-positive cases were investigated; AZT was administered to 81 of them. The mean value of HbA2 was 0.032 (SD +/- 0.005) for the treated group vs. 0.027 (SD +/- 0.004) for the controls. This difference was highly significant (P < 0.001). Twenty-four patients (31%) in the treated group had elevated HbA2 levels vs. none in the controls. Bone marrow toxicity seemed to be more significant in patients with heightened HbA2 values, and HbA2 levels did not increase with CDC clinical stage. We conclude that AZT may be linked to high HbA2 levels in some patients.

Lorazepam, dexamethasone and high-dose metoclopramide were given to 54 patients to prevent emesis induced by cisplatin (50-120 mg/m2) on day 1, while prochlorperazine and dexamethasone were administered on days 2 and 3 for control of delayed emesis. Nausea and emesis were recorded from day 1 to day 8. This combination was well tolerated. Prevention on day 1 was complete for 72% of patients and satisfactory (less than or equal to 2 emeses on day 1) in 85%. From days 2 to 8, no emesis, less than or equal to 2 and greater than 2 episodes occurred in 70, 11 and 19%, respectively. Overall control (days 1-8) was complete in 55.5% and satisfactory (less than or equal to 2 emeses on day 1 and/or less than or equal to 2 emeses from days 2 to 8) in 74%. Delayed emesis started on days 2-5. Mean duration was 2.6 days. Delayed nausea or emesis were more frequent when emesis occurred on day 1. Based on data previously reported and on these observations, better ways to prevent delayed events are discussed. Further trials must record systematically delayed side effects.

Two homosexual HIV1-positive male patients with thrombotic thrombopenic purpura (TTP) were found to have past history of immune thrombocytopenia (ITP). The first patient had ITP 10 months prior to TTP and was successfully treated by splenectomy. The second patient had ITP 32 months before TTP. No specific treatment was given for his asymptomatic ITP. Association of HIV infection to TTP seems to be frequent. These two types of purpura have different pathogenic mechanisms but share a common altered immune response to antigenic challenge. The occurrence of ITP and TTP in HIV-positive patients may lead to errors in diagnosis and therapy.

Seventeen AIDS patients were enrolled in a prospective open-label dose-finding study of octreotide (Sandostatin) therapy for refractory diarrhea. Five were nonevaluable due to progression of AIDS symptomatology, and one was excluded because of lack of confirmation of HIV infection. Five of 11 evaluable patients responded to therapy (45%); two each at 50 micrograms and 100 micrograms, and one at 250 micrograms thrice daily doses. A sixth patient demonstrated a moderate reduction in stool volume at 250 micrograms thrice daily, which, although deemed clinically relevant, did not meet the criteria for response. On discontinuation of therapy, diarrhea recurred in all patients within 1-12 days, and responded to reinitiation of octreotide in those five patients who resumed treatment. Only one of the three patients with concurrent cryptosporidial infection responded to treatment. The drug was well tolerated, with mild symptomatology in three patients. Long-term treatment at a stable dose was effective in three of five treated patients for periods for seven months in one (moderate responder) and one year in two. One patient required dose increases to control symptoms, but after one year of treatment developed severe nausea following injections, which required dose cessation. One patient had partial control of his diarrhea for only three months despite two dose increases. These data suggest that octreotide may be of useful therapeutic value in HIV-associated diarrhea and that further studies are indicated.

The relative mobilities of serveral human hemoglobin variants were studied by use of an isoelectric focusing method in a thin-layer horizontal polyacrylamide gel. The technic is described in detail and a preliminary mapping of these variants is presented. It appears that thin-layer gel isoelectric focusing is a method that is rapid, highly reproducible and easily applicable in laboratories concerned with the study of hemoglobinopathies.