Immune-related Response Research Articles

Phase II study of maintenance pembrolizumab (pembro) in extensive stage small cell lung cancer (ES-SCLC) patients (pts).

8504 Background: The median progression free survival (PFS) and overall survival (OS) following initial chemotherapy in ES-SCLC pts are 2 and 7 months, respectively (Ready N, J Clin Oncol 2015). We evaluated the benefits of maintenance pembro in ES-SCLC pts who had response/stable disease after 4-6 cycles of platinum/etoposide. Methods: Pts were required to begin pembro within 8 weeks of completion of chemotherapy, with restaging scans no more than 3 weeks prior to start of pembro. Prophylactic cranial radiation was permitted. Pts were treated with pembro 200 mg I.V. every 3 weeks for a maximum of 2 years. Disease assessment was done every 2 cycles for the first 6 cycles and then as per investigator discretion. Primary end point of the study was PFS. PFS according to immune related response criteria (irPFS) and OS were also assessed. Tumor tissue was analyzed for PD-L1 expression by the DAKO 22C3 antibody. Any level of expression was considered as positive for PDL1. Blood for circulating tumor cells (CTCs) was collected prior to first, second and third cycle of pembro. Results: Of the 45 pts enrolled, 55% were males and 22% had brain metastases. Median age was 66 years. The median time from end of chemotherapy to start of pembro was 5 weeks. Median number of pembro cycles was 4 (1-20 cycles). 35 pts had measurable disease at study entry. The disease control rate with pembro was 42% (1 CR, 3 PR, 15 SD). At a median follow up of 6 months, the median PFS was 1.4 months (90% CI-1.3-4.0) and the irPFS was 4.7 months (90% CI- 1.8-6.7). The median OS was 9.2 months (90% CI-6.1-15.2). 11 pts are still on therapy (3-20 cycles). The median CTC prior to pembro was 1 (0-256, n=37 pts). Each unit increase in baseline CTC correlated with worse PFS (p = 0.052; adjusted for brain mets, age and sex). PDL1 could be assessed in 35 pts and was positive in 1 pt. Most common adverse events were fatigue, nausea, cough and dyspnea. One pt developed atrio-ventricular conduction block and 1 pt type 1 diabetes. Conclusions: Maintenance pembro did not improve PFS in these patients but favorable OS suggests that some SCLC patients can benefit from maintenance pembro. Biomarkers to identify patients most likely to benefit from pembro need to be defined. Clinical trial information: NCT02359019.

Immune response, safety, and survival impact from CMB305 in NY-ESO-1+ recurrent soft tissue sarcomas (STS).

11006 Background: CMB305 is an active immunotherapy regimen designed to generate and expand anti-NY-ESO-1 T cells. It consists of LV305, a dendritic cell targeting lentiviral vector encoding NY-ESO-1, and a boost with G305, an NY-ESO-1 recombinant protein plus GLA-SE, a TLR-4 agonist. An LV305 phase 1 study demonstrated a 1-yr survival of 81% and induction of anti-NY-ESO-1 T cells in sarcoma patients (pts). This first-in-human study of CMB305 examined safety, immunogenicity, and efficacy in pts with NY-ESO-1 positive (+) solid tumors. Methods: Adults with previously treated NY-ESO-1+ sarcomas, NSCLC, ovarian cancer were enrolled in a 3+3 dose-escalation with an expansion phase 1 study. The CMB305 regimen included 4 intradermal injections of LV305 at 109 or 1010 vector genomes, alternating with 3 intramuscular G305 injections at 250 µg for 3 months, then bimonthly G305 injections up to 1 yr. Results: As of 31Dec2016, 25 pts with STS (15 synovial (SS), 8 myxoid/round cell liposarcoma (MRCL), 2 other) were evaluable for safety; 23 SS/MRCL pts were evaluable for immune response (IR) and efficacy. All SS and MRCL pts received prior therapy for locally advanced/metastatic disease, 67% > = 2 prior chemo regimens. No DLTs were observed; treatment related AEs were grade 1 and 2, except 1 pt with grade 3 SAE (prostatic pain). Of 11 SS/MRCL pts tested, 64% pts developed NY-ESO-1 specific T cells and 72% pts anti-NY-ESO-1 antibodies. T cell receptor sequencing indicated increased clonality, and antigen spreading after CMB305. Best response by immune related response criteria was stable disease in 8/15 (53%) SS pts and 6/8 (75%) MRCL pts. The 3 month PFS rate was 74% and 75% for SS and MRCL pts. Median survival has not been reached with 1-yr survival rate of 86% and 100% for SS and MRCL pts. Conclusions: CMB305 is safe, well tolerated, and demonstrates a survival rate that is favorable when compared with approved agents for recurrent STS. CMB305 resulted in a stronger and broader integrated IR than LV305, including antigen spreading. These data warrant further investigation of CMB305 as a monotherapy in a randomized clinical study in STS. A randomized study of CMB305 in combination with atezolizumab in SS/MRCL pts is ongoing. Clinical trial information: NCT02387125.

Validation of the Princess Margaret immune oncology prognostic index (PM-IPI) for patients (pts) treated in immune oncology (IO) early phase trials.

3070 Background: We previously developed the PM-IPI (ECOG performance status [PS] > / = 1, albumin < lower limit of normal [LLN] and > 2 metastatic sites) from a retrospective cohort of 192 pts treated in phase I IO trials (development cohort). The PM-IPI prognosticated for overall survival (OS), 90-day mortality (90DM) and was associated with improved overall response rate (ORR) and progression free survival (PFS). Our aim was to prospectively validate the PM-IPI in an independent cohort of pts treated on IO trials. Methods: We included 152 consecutively treated advanced solid tumor pts at PM from Aug 2015 to Aug 2016 in 24 IO early phase trials, targeting immune checkpoints and/or co-stimulatory molecules. Pts from the development cohort were excluded. The ability of the PM-IPI to prognosticate OS and 90DM, and predict PFS and ORR was compared with the previously published Royal Marsden Hospital prognostic score (RMI: albumin < 35g/L, LDH > upper limit of normal and > 2 metastatic sites) using the C-index (0.5 = no discrimination, 1 = perfect discrimination) and Area Under the Curve (AUC). Results: Median age was 59y (range 20-86), 28%/72% of pts were ECOG PS 0/1, and 88% had at least 1 prior systemic therapy (range 0-7). The most common tumor sites were gastrointestinal (23%), gynecological (16%), head and neck (15%) and urological (10%). Median PFS and OS were 9.0 and 39.7 wk respectively and 90DM was 14%. ORR was 7% by RECIST 1.1, immune related RECIST or immune related response criteria. In multivariable analysis, ECOG PS > / = 1 (HR 2.7, p = 0.01), albumin < LLN (HR 2.1, p = 0.01) and > 2 metastatic sites (HR 1.8, p = 0.04) were independently prognostic for OS. Pts with a PM-IPI score of 2-3 compared to 0-1 had significantly shorter OS (HR 3.3, p < 0.0001), PFS (HR 1.7, p = 0.005) and higher 90DM (OR 12.2, p = 0.019), and a trend towards lower ORR (OR 0.4, p = 0.15). The prognostic performance of PM-IPI was superior to the RMI for OS and 90DM, but not PFS and ORR (Table). Conclusions: In this independent validation cohort, the PM-IPI prognosticated for OS and 90DM and was associated with PFS. Validation in a large external cohort is ongoing. [Table: see text]

A dose escalation phase 1 study of radiotherapy (RT) in combination with anti-cytotoxic-T-lymphocyte-associated antigen 4 (CTLA-4) monoclonal antibody ipilimumab in patients (pts) with metastatic melanoma.

9549 Background: Preclinical findings have shown a synergy between RT and anti-CTLA-4 monoclonal antibody in several tumor animal models for both local tumor control and distant effects. Preliminary clinical data suggest that it could be due to an abscopal effect of RT. The Mel-Ipi-Rx phase 1 study aimed to determine the maximum tolerated dose (MTD) and safety profile of RT combined with ipilimumab in pts with metastatic melanoma. Methods: A 3+3 dose escalation design was used with 9, 15, 18 and 24 Gy dose of RT (in 3 fractions) at week 4 combined with 10 mg/kg ipilimumab (every 3 weeks for 4 doses). Pts with evidence of clinical benefit at week 12 were eligible for maintenance ipilimumab at 10 mg/kg every 12 weeks starting at week 24 until severe toxicity or disease progression based on immune-related response criteria (irRC). Results: 19 pts with advanced melanoma received ipilimumab between August 2011 and July 2015. Nine pts received the 4 doses of ipilimumab and 2 pts received maintenance ipilimumab (1 and 2 cycles respectively). All pts received the combined RT at week 4 in 3 fractions. All pts presented at least one AE of any grade. The most common AEs were asthenia, diarrhea, desease-related pain and fever. Grade 3 AEs occurred in 8 pts. They included colitis (n = 3), hepatitis (n = 2), anemia (n = 2), asthenia (n = 1), thyroid disorders (n = 1) and nausea/vomiting (n = 1). Nine pts discontinued the study owing to treatment-related adverse events including colitis (n = 6), hepatitis (n = 2) and DRESS (Drug Rash with Eosinophilia and systemic syndrome) (n = 1). DLT occurred in 2/6 pts in the cohort receiving 15 Gy. No drug-related death occurred. According to irRC, 4 partial responses (ORR: 21%) and 4 stable diseases were observed at week 24. The MTD was 9 Gy dose. One pt out of 12 treated in the 9 Gy cohort presented a DLT (grade 3 colitis). The median progression-free survival [95% CI] was 7.2 months [2.4 – 16.8]. The median overall survival [95% CI] was 14.4 months [7.2 – 20.4]. Conclusions: When combined with ipilimumab at 10 mg/kg, in the present design, the MTD of RT was 9 Gy. This combination appears to be associated with antitumor activity. Clinical trial information: 2010-020317-93.

Phase II trial of pembrolizumab in patients (pts) with incurable platinum refractory germ cell tumors (GCT).

4520 Background: Despite remarkable results with salvage standard-dose (SDCT) or high-dose chemotherapy (HDCT), about 15% of pts with relapsed GCT are incurable. Immune therapy with Pembrolizumab is a novel approach for salvage in pts with metastatic GCT. Methods: Single arm phase 2 trial investigating pembrolizumab 200mg IV Q3weeks until disease progression in pts with relapsed GCT and no curable options. Pts age≥18 with metastatic GCT who progressed after first line cisplatin-based chemotherapy and after at least 1 salvage regimen (HDCT or SDCT) were eligible. Centrally assessed PD-L1 on tumor infiltrating immune cells using PD-L1 (22C3) assay was scored as 0, 1, 2, 3 along with PD-L1 expression score (H-score) incorporating intensity of staining. Pts were eligible irrespective of PD-L1 expression status. The primary endpoint was overall response rate using immune-related response criteria. Simon’s 2-stage design required response in ≥ 1/12 pts to proceed to stage 2 enrolling 8 more pts for a total of 20. Results: 12 male pts were enrolled. Median age 38 (range, 27-55). All pts had non-seminoma. Primary tumor site was testis in 11 pts and mediastinum in 1. Median AFP 615 (range, 1-32,760) and hCG 4 (range, 0.6-37,096). 5 pts had late relapse ( > 2years). Median number of previous chemotherapy regimens was 3 (range, 1-6). 6 pts received prior HDCT. 2 pts had positive PD-L1 staining (H-score 90 and 170). Median number of deliverable pembrolizumab doses was 2 (range, 1-8). There were 5 grade 3 adverse events, with 3 events possibly related to study treatment (chest pain, hyperglycemia, abdominal pain). No partial or complete responses were observed. 2 pts achieved stable disease for 12 and 9 weeks respectively; 10 pts had progression of disease as their best response. The 2 pts with stable disease had continued rising AFP level despite radiographic stability; both had negative PD-L1 staining. Conclusions: This is the first reported trial evaluating immune checkpoint inhibitors in GCT. Although 2 pts had stable disease, each had rising tumor markers suggesting continued treatment resistance. Pembrolizumab is well tolerated but does not appear to have clinically meaningful single-agent activity in refractory GCT. Clinical trial information: NCT02499952.

Association of autologous AdHER2 dendritic cell vaccination with antitumor activity and number of circulating tumor cells.

3089 Background: We achieved cure of large established tumors in syngeneic BALB/c mice using an adenoviral vector vaccine expressing rodent HER2 extracellular (EC) and transmembrane (TM) domains mediated by the induction of anti-HER2 antibodies. We report clinical translation utilizing an autologous adenoviral- transduced dendritic cell (DC) vaccine expressing human HER2 EC and TM domains (AdHER2ECTM) in adults with advanced metastatic tumors with 1-3+ HER2 expression. Methods: In this two-part phase I study (NCT01730118) subjects with HER2+ metastatic solid tumors naïve to HER2-targeted therapies (Part 1) or HER2+ treatment-experienced breast cancer (Part 2) received 5 doses of vaccine at Weeks 0, 4, 8, 16 and 24. Part 1 dose escalation involved 3 cohorts of 6 patients utilizing 5x106, 10x106 and 20x106 viable DCs per dose, respectively. With no DLTs or evidence of cardiac toxicity, dose escalation to 40x106 viable DCs per dose was allowed in the Part 1 Expansion Cohort and Part 2 treatment was begun at a starting dose of 20x106 viable DCs per vaccine. Adjuvant muscle-invasive bladder cancer patients were allowed to enroll with safety documented out to 12 weeks in > 10 treated patients. Re-staging was assessed using immune-related response criteria (irRC). Remaining study accrual: Part 1 (N = 9), Part 2 (N = 24). Results: A total of 27 cancer patients (7 colon, 6 breast, 5 ovarian, 3 bladder, 6 other) have received > 2 vaccine doses (median 4): 19F, 8M, median age 60 yrs, median 3 prior treatment regimens (range 1-11); HER2 IHC 1+ N = 6, 2+ N = 9, 3+ N = 12. Of metastatic patients receiving 10x106viable DCs per dose or higher, 7 of 19 (37%) had evidence of response by irRC: 1 CR (ongoing at 100 weeks), 1 PR (-71% lasting 44 weeks) and 5 SD (median duration 24 weeks, range 8 to 48 weeks). Two adjuvant bladder cancer patients remain without disease at 100 weeks. Adverse events were limited to local injection site reactions < G2. Of patients with paired baseline samples, 40% (8/20), 83% (5/6) and 100% (2/2) exhibited decreases in circulating tumor cells at 12, 28 and 48 weeks, respectively. Conclusions: AdHER2 DC vaccination is safe and is associated with evidence of clinical benefit and anti-tumor activity. Clinical trial information: NCT01730118.

Phase 1 trial of CA-170, a novel oral small molecule dual inhibitor of immune checkpoints PD-1 and VISTA, in patients (pts) with advanced solid tumor or lymphomas.

TPS3099 Background: Programmed-death 1 (PD-1) and V-domain Ig suppressor of T-cell activation (VISTA) are independent immune checkpoints that negatively regulate T-cell function and are implicated in various malignancies. Preclinical studies have demonstrated that dual blockade of these pathways is synergistic. CA-170 is a first-in-class oral small molecule that directly targets both PD-1/PD-L1 and VISTA pathways and has shown anti-tumor activity in multiple preclinical models. Methods: The dose escalation phase has a target enrollment of 50 pts with advanced solid tumors or lymphomas onto escalating doses; the first four single-pt cohorts are accelerated titration but then switch to 3+3 design. The dose expansion phase has a target enrollment of 250 pts with select tumor types known to be responsive to anti-PD-1/L1 inhibitors and/or known to express PD-L1 or VISTA. Key eligibility criteria include: age ≥ 18 years, ECOG ≤1, adequate organ function, and ineligible for/did not respond to standard therapy including anti-PD-1/L1 inhibitors, where available. Primary objectives of this first-in-human study: safety, maximum tolerated dose, and recommended phase 2 dose. Secondary objectives: pharmacokinetics (PK) and anti-tumor activity. Exploratory endpoints: biomarkers and pharmacodynamic (PD) effects, which include changes in immune cell and peripheral cytokine populations in tumor (IHC/mRNA) and blood (flow cytometry/mRNA). Oral CA-170 is administered once daily in 21-day cycles. Response will be evaluated every other cycle per RECIST (v1.1) and Immune-related Response Criteria or by Cheson criteria (2007). Patients who discontinue treatment for reasons other than progressive disease will be followed for progression-free survival. Serial plasma, blood, and tumor samples will be collected for PK and PD evaluation. Clinical trial identifier: Clinical trial information: NCT02812875.

A phase 1b/2 study of ARRY-382, an oral inhibitor of colony stimulating factor 1 receptor (CSF1R), in combination with pembrolizumab (Pembro) for the treatment of patients (Pts) with advanced solid tumors.

TPS3110 Background: CSF1, which signals via CSF1R, regulates tumor-associated macrophages and myeloid-derived suppressor cells, both critical drivers of immune escape in the tumor microenvironment. ARRY-382 is a highly selective, oral inhibitor of the CSF1R intracellular tyrosine kinase. The first-in-human study of ARRY-382 monotherapy identified the maximum tolerated dose (MTD) of 400 mg QD, with biologic activity at doses ≥200 mg QD (Bendell JC et al. Mol Cancer Ther. 2013;12:A252). Preclinical data supports combining a PD-1 inhibitor with a CSF1R inhibitor (Zhu Y et al. Cancer Res. 2014;74:5057-69). This study is designed to evaluate ARRY-382 in combination with pembro, a potent and highly selective humanized monoclonal antibody that targets PD-1. Methods: This is an open-label, multicenter, phase 1b/2 study (NCT02880371) to determine the MTD and/or recommended phase 2 dose (RP2D) of ARRY-382 + pembro and to evaluate the activity of the combination in select indications. In phase 1b (Part A), the primary objective is to identify the MTD/RP2D. Up to 18 pts with select advanced solid tumors (Part A) will be enrolled in 2 successive cohorts evaluating ARRY-382 at doses of 200 mg QD and 400 mg QD, respectively, in combination with pembro 2 mg/kg Q3W. Once the MTD/RP2D has been determined in phase 1b, phase 2 will concurrently evaluate the combination in up to 20 pts with advanced unresectable/metastatic melanoma (Part B) and in up to 33 pts with PD-L1-positive (tumor proportion score ≥50) non-small cell lung cancer (NSCLC) (Part C). The primary objective of Part B is to assess the pharmacodynamics and antitumor activity of ARRY-382 + pembro in pts with advanced unresectable/metastatic melanoma, and the endpoints include effects of treatment on circulating growth factors and cytokines, markers of bone resorption, and objective response rate (ORR). The primary objective of Part C is to assess the efficacy of ARRY-382 + pembro in pts with PD-L1–positive NSCLC (Part C). The primary endpoint is ORR. Immune-related response rate and safety will be evaluated in all pts in the study. Clinical trial information: NCT02880371.

Initial phase 1 study of WT2725 dosing emulsion in patients with advanced malignancies.

2066 Background: WT2725 is a Wilms’ tumor (WT1)-derived-oligopeptide vaccine intended to induce WT1 specific cytotoxic T-lymphocytes against WT1 positive tumors in HLA-A*0201+ or HLA-A*0206+. This first in human study of WT2725 was conducted to evaluate the safety, tolerability, and efficacy. Methods: Subjects with progressive or recurrent glioblastoma (GBM), acute myeloid leukemia (AML) (patients in morphologic remission with minimal residual disease determined by WT1 RT-PCR were allowed), non-small cell lung cancer (NSCLC), or ovarian cancer despite standard therapy were treated with 0.3, 0.9, 3, and 9 mg of WT2725 subcutaneously (s.c.) every week for 4 weeks, then every other week for 6 weeks, and every 4 weeks thereafter until progression or other discontinuation event (part 1); and with 18 mg and 27 mg of WT2725 s.c. every week for 8 weeks, then every other week for 10 weeks, and every 4 weeks thereafter until progression or other discontinuation event (part 2). Responses were evaluated by Immune-related Response Criteria (irRC) for solid tumors and modified International Working Group (IWG) for AML. Results: 62 subjects were dosed, the most frequent adverse events were grade 1 injection site reactions (no grade 3 injection site reactions or dose limiting toxicities observed). Of the 21 GBM subjects who were dosed, seven survived for ≥ 1 year (33%). Of these seven subjects, three survived for ≥18 months (14%), and two for ≥2 years (both in complete radiologic remission, 9.5%). One of the seven subjects with ≥1 year survival had previous treatment with bevacizumab. Two subjects continue dosing (1 complete response with no measurable disease >3 years and 1 partial response > 13 months on study). Results in subjects with non-GBM tumors (12 subjects with AML, 21 with ovarian CA, 7 with NSCLC, and 1 other cancer) are not presented here. WT1-specific CTLs and tumor burden was monitored. WT1 specific CTLs were associated with decrease of tumor burden in two patients with low tumor burden. Some patients with high disease burden did not respond. Conclusions: Preliminary data suggests WT2725 is well tolerated with potential antitumor activity in GBM patients, supporting future development of WT2725 for treatment of GBM in selected subjects. Clinical trial information: NCT01621542.

Natural killer cells as a predictive biomarker for response to anti-PD-1 therapy in patients with advanced solid tumors.

e21055 Background: Assessment of PD-L1 expression in tumor biopsy has been widely used for predicting anti-PD-1 therapy. Several factors, including tumor heterogeneity, false negative staining and unavailability of biopsy samples limit the application. Natural killer (NK) cells exert cytotoxicity against cancer cells. Therefore, we explored using NK cells percentage in peripheral blood (PB) as a biomarker to identify pts who are more likely to benefit from anti-PD-1 therapy. Methods: Pts treated with anti-PD-1 antibody (JS001) 1 mg/kg, 3mg/kg or 10mg/kg every 2 weeks in a Phase I clinical trial (ClinicalTrials.gov Identifier: NCT02836795) had PB collected at baseline and at time of radiographic evaluation performed every 8 wks. Disease status (shrinking stable disease, growing stable disease, partial response, complete response, or progressive disease) was characterized using RECIST v1.1 and immune-related response criteria. Frequencies of NK cells (CD3-CD16+CD56+) were measured by flow cytometry. Results: Thirty-six patients were enrolled in this trial, including 22 melanoma, 9 urothelial carcinoma and 5 renal cell carcinoma. As of 1/27/2017, median treatment duration: 3.92 months. Radiographic tumor evaluation has been performed in 32 pts: 1/32 CR, 6/32 PR, 6/ 32 shrinking SD, 4/32 growing SD and 15/32 PD. Pts with high NK cells at baseline observed 60% (6/10) Clinical Benefit Rate (CR/PR/ shrinking SD) versus 40% (13/32) in overall pts. Patients with clinical benefit had higher frequency of NK cells at baseline compared to pts with radiographic growing SD and PD (mean 24.3% vs. 17.9%, P = 0.076). Furthermore, pts with NK cell level consistently above UN or increasing above UN during treatment are more likely to get clinical benefit than those under UN (7/10 vs 3/22, P = 0.013). Conclusions: Baseline high NK cells frequency may predict a favorable response to anti-PD-1 therapy, which provides a non-invasive way to monitor response to PD-1 blockade. These results are being validated in a phase II trial. Clinical trial information: NCT02836795.

Nonconventional responses and survival benefit of immunotherapy in advanced lung cancer.

e14572 Background: Objective response rates (ORR) utilizing RECIST or WHO criteria have been traditionally used as clinical endpoints to assess efficacy of cytotoxic chemotherapy. However in the era of immunotherapeutic agents, response rate assessment can be misleading due to nonconventional responses resulting in premature discontinuation of treatment. Wolchok et al proposed immune-related response criteria (irRC) to assess immune responses in melanoma. He also noted that stable disease which is not indicative of antitumor activity could be a potential surrogate marker of better clinical outcome. Brahmer et al reported nonconventional pattern of responses with Nivolumab in lung cancer. Methods: A retrospective chart review was done to assess differences in responses utilizing both RECIST v1.1 and irRC criteria in lung cancer patients treated with Nivolumab. Patients who received minimum of 4 cycles of Nivolumab were included in the study. The CT scans were reviewed by a senior radiologist. We reviewed 64 patients treated with Nivolumab between 4/30/2015 to 6/21/2016 and 30 patients were found eligible. Results: Patient characteristics. Male 53%; median age 61 years; squamous 47%; adeno 40%; small cell 13%; Median cycles of Nivolumab 6. Response rates utilizing both criteria was essentially similar with only 2 patients showing dis-concordant responses (6.6%). We utilized RECIST responses criteria for further analysis. Partial response (PR) 2/30; stable disease (SD) 12/30; progressive disease (PD) 15/30 and not evaluable (NE) 1/30. ORR 6.6%. Kaplan–Meier curve was used to analyze difference in survival between patients with PR+SD and PD. The median survival for PD was 9 months and PR+SD was not reached at median follow up of 1 year. Overall survival at 1 year for PD 33% and PR+SD 60% (p = 0.048). Hazard ratio for PD was 3.060 (p = 0.60). Conclusions: Patients with stable disease had a better survival and should be considered as responders though traditionally not included in the ORR. However irRC did not help in differentiating nonconventional immune responses in lung cancer patients. [Table: see text]

Phase I/III trial of atezolizumab with carboplatin and etoposide in ES-SCLC in first-line setting (IMpower133).

TPS8584 Background: The first-line standard of care for the majority of patients (pts) with extensive-stage small-cell lung cancer (ES-SCLC) is platinum-based chemotherapy with etoposide, but survival outcomes remain poor (median OS, < 1 year) despite initial response rates ranging from 50-70%. Atezolizumab (atezo), an anti–PD-L1 mAb, prevents the binding of PD-L1 with its receptors PD-1 and B7.1 and restores anticancer T-cell activity. Tolerable safety with promising durability of response has been shown with atezo in pts with ES-SCLC: confirmed ORR was 6% (n = 1/17 [partial response]; DOR of 7 mo) by RECIST v1.1 and 24% by immune-related response criteria (irRC; n = 4/17, with 2 pts on atezo for ≥ 12 mo). Preliminary data also indicate the potential synergy between atezo and platinum-based chemotherapy in NSCLC, whereby durable responses may translate into improved survival over atezo alone. IMpower133 (NCT02763579), a global, Phase I/III, randomized, multicenter, double-blinded, placebo-controlled trial will evaluate the efficacy and safety of 1L atezo + carboplatin + etoposide compared with placebo + carboplatin + etoposide in treatment-naive pts with ES-SCLC. Methods: Pts with measurable (RECIST v1.1) ES-SCLC, who have ECOG PS 0-1 and no prior systemic anticancer treatment, are eligible for the study. Exclusion criteria include untreated CNS metastases and history of autoimmune disease. The study requires submission of tumor tissue, but pts will be enrolled regardless of biomarker status. Pts will be stratified by sex, ECOG PS and presence of treated brain metastases. Eligible pts will be randomized 1:1 to receive four 21-day cycles of atezo (1200 mg IV) or placebo in combination with carboplatin (AUC 5 mg/mL/min IV, d 1) and etoposide (100 mg/m2 IV, d 1-3), followed by maintenance therapy with atezo or placebo until PD per RECIST v1.1. Pts can continue with treatment until persistent radiographic PD, symptomatic deterioration or unacceptable toxicity. Co-primary endpoints are investigator-assessed PFS per RECIST v1.1 and OS. Secondary efficacy endpoints include investigator-assessed ORR and DOR. Safety and tolerability will also be assessed. Approximately 400 pts will be enrolled. Clinical trial information: NCT02763579.

Long-term outcomes in patients (pts) with ipilimumab (ipi)-naive advanced melanoma in the phase 3 KEYNOTE-006 study who completed pembrolizumab (pembro) treatment.

9504 Background: Pembro demonstrated superior PFS and OS vs ipi in ipi-naive pts with advanced melanoma in the phase 3 KEYNOTE-006 study (NCT01866319). Here, we present long-term outcomes for all pts and in those pts who completed pembro therapy. Methods: Eligible pts (N = 834) were randomized 1:1:1 to pembro 10 mg/kg Q2W, pembro 10 mg/kg Q3W, or ipi 3 mg/kg Q3W for 4 doses. Treatment was continued for 2 yr (pembro only) or until disease progression, intolerable toxicity, or pt/investigator decision to discontinue. Per protocol, pts could interrupt pembro for ≤12 wk before discontinuation was required. Tumor imaging was performed at wk 12, then every 6 wk up to wk 48 and every 12 wk thereafter. After the prespecified final analysis, response assessments were per immune-related response criteria (irRC) by investigator review. Results: As of the data cutoff (Nov 3, 2016), median follow-up in the total population was 33.9 mo (range, 32.1-37.6). 33-mo OS rates were 50% in the pooled pembro arms (n = 556) and 39% in the ipi arm (n = 278); 33-mo PFS rates were 31% and 14%. ORR was 42% and 16%. Median duration of response was not reached for pembro (range 1.0+ to 33.8+ mo) or ipi (1.1+ to 34.8+ mo); 46 (68%) pembro-treated pts and 7 (58%) ipi-treated pts had a response lasting ≥30 mo. Among the 104/556 (19%) pts who completed pembro, median exposure to pembro was 24.0 mo (range 22.1-25.9). After a median follow-up of 9.0 mo after completion of pembro, 102 (98%) pts were alive. Responses were durable in pts who completed pembro; 9.7 mo after completion of pembro, estimated PFS (95% CI) was 91% (80-96) in all 104 pts, 95% (69-99) in pts with complete response (n = 24), 91% (74-97) in pts with partial response (n = 68), and 83% (48-96) in pts with stable disease (n = 12). Conclusions: Pembro provides durable efficacy after stopping the protocol-specified duration of treatment in pts with ipi-naive advanced melanoma in KEYNOTE-006. The estimated risk for progression or death nearly 10 mo after completing pembro is 9% and does not appear to differ by best response to pembro. Clinical trial information: NCT01866319.

Tumor response dynamics of advanced non-small-cell lung cancer (NSCLC) patients (pts) treated with commercial PD-1 inhibitors in the clinical setting.

9087 Background: PD-1 inhibitors have shown promising activity in advanced NSCLC, with increasing clinical use. We evaluated tumor burden dynamics in advanced NSCLC pts treated with commercial PD-1 inhibitors to identify imaging markers for clinical benefit. Methods: The study included 160 advanced NSCLC pts (79 males; median age: 65) treated with commercial nivolumab or pembrolizumab monotherapy at DFCI as a part of routine clinical care. Tumor burden dynamics were assessed on serial CT scans during therapy by irRECIST1.1, which uses unidimensional measures and includes new lesions in tumor burden [Clin Cancer Res. 2013;19:3936-43]. Results: Tumor burden change at best overall response (BOR) ranged from -100% to +278% (median: +3.5%). Objective response rate (ORR) was 18% (29/160). Current and former smokers had higher ORR than never smokers (ORR:14% (8/58), 25% (20/79), 4% (1/23); Fisher p = 0.04). Durable disease control with tumor burden < 20% increase from baseline for at least 6 months was noted in 27 pts (17%), which included 11 pts with stable disease as their irBOR. Using an 8-week landmark analysis, pts with < 20% tumor burden increase from baseline at 8 weeks had longer OS than pts with ≥20% increase (median OS:12.4 vs. 4.6 months, p < 0.001). In Cox models using a time varying covariate, pts with < 20% tumor burden increase during therapy had significantly reduced hazards of death (HR = 0.24, p < 0.0001) after adjusting for smoking (HR = 1.77, p = 0.016) and baseline tumor burden (HR = 1.66, p = 0.032). Two pts (1.3%) had atypical response pattern or “pseudoprogression”, where tumor burden showed initial increase and subsequent decrease, which was noted after confirmed irPD on consecutive scans in both pts. Conclusions: An objective response or durable disease control was noted in 25% of advanced NSCLC pts treated with PD-1 inhibitors in the clinical setting. Tumor burden increase of < 20% from the baseline during therapy was associated with longer OS, proposing a practical marker of clinical benefit. Pseudoprogression was uncommon, with tumor decrease noted after confirmed irPD, indicating a limitation of the current strategy for immune-related response evaluation.

Primary results from a randomized (1:1), open-label phase II study of talimogene laherparepvec (T) and ipilimumab (I) vs I alone in unresected stage IIIB- IV melanoma.

9509 Background: T is a HSV-1-based oncolytic virus designed to selectively replicate in tumors and produce GM-CSF to stimulate antitumor immune responses. I is an anti-CTLA-4 Ab that blocks inhibition of activated T cells. This is the first randomized study to evaluate the addition of an oncolytic virus to a checkpoint inhibitor. Methods: The 1o endpoint was ORR by immune-related response criteria. Key 2o endpoints: duration of response, disease control rate (DCR), PFS, OS, and safety. Prior treatment was allowed but not required. Pts had unresected stage IIIB-IV melanoma with measurable/injectable tumor(s) and no evidence of immunosuppression. T was given at approved dosing until no injectable tumors, disease progression (PD), or intolerance. I was started at w6 in T+I and at w1 in I at 3 mg/kg IV q3w x 4. Primary analysis occurred 6 m after last pt enrolled. Results: 198 pts were randomized: 98 T+I; 100 I. Characteristics were similar: 54% stage IIIB-IVM1a, 46% IVM1b/c. Median follow up time was 68 w (T+I) and 58 w (I). ORR was 38.8% (T+I) and 18.0% I, P = 0.002, Odds ratio (OR) 2.9. 89% T+I and 83% I pts remain in response. Unconfirmed visceral lesion response was 35.5% T+I vs 13.6% I. OS is immature. Of 190 pts (safety set: 95 T+I, 95 I), most common adverse events (AEs) for T+I, I (%) were fatigue (59, 42), chills (53, 3), and diarrhea (42, 35). 28% T+I and 18% I pts had gr ≥3 tx-related AE. There were 3 deaths (all unrelated) in T+I: 1 myocardial infarction and 2 PD. Conclusions: The study met the 1o endpoint. ORR was significantly higher for T+I vs I; responses were not limited to injected lesions. Toxicity of T+I combination was tolerable with no unexpected AEs. Clinical trial information: NCT01740297. [Table: see text]

A review of intestinal microbes in grass carpCtenopharyngodon idellus(Valenciennes)

Grass carp, Ctenopharyngodon idellus, harbours complex intestinal bacterial communities, which are important in several physiological processes of their host. Intestinal microbiota of grass carp have been previously described in numerous studies. However, an overview on the bacterial community diversity, including their establishment, their functions in host's nutritional processes and immune-related responses, and use as probiotics, is absent. This study aimed to summarize the current understanding of the grass carp intestinal microbiota. In this review, we provide general information on the establishment and composition of intestinal microbial communities and factors influencing the diversity of gut microbiota. Also, this review covers the dietary effects of probiotics, prebiotics and/or synbiotics on the grass carp intestinal microbial communities and physiological characteristics. Although our knowledge of the grass carp intestinal microbiota is expanding rapidly, further studies on the factors affecting the diversity of intestinal microbes, interactions between intestinal microbiota and their hosts and application of probiotics/prebiotics/synbiotics in aquaculture industry, are needed.

Prolactin as a Potential Early Predictive Factor in Metastatic Non-Small Cell Lung Cancer Patients Treated with Nivolumab

Background/Aims: Prolactin (PRL) is a peptide hormone and several studies have demonstrated its role as a cytokine in human T cell-mediated immunity. We are unaware if PRL is a positive or negative immunomodulator, but its effects on the regulation of T cells could inhibit the antitumor activity elicited by nivolumab (NIVO). We aimed to assess whether the occurrence of hyperprolactinemia in metastatic non-small cell lung cancer (mNSCLC) patients treated with NIVO is associated with poor clinical outcomes. Methods: We evaluated 26 mNSCLC patients treated with NIVO. Blood samples were collected in every patient to evaluate PRL basal levels before starting the therapy with NIVO and before each following administration of NIVO. All patients underwent a conventional CT to investigate the effect of therapy according to Immune-related Response Evaluation Criteria in Solid Tumors (IrRECIST). Results: Twenty patients (77%) developed hyperprolactinemia during the treatment, whereas 6 patients (23%) had stable levels of PRL during the therapy (p = 0.001). A total of 95% of the 20 patients with hyperprolactinemia had progressive disease (PD), according to CT results, whereas only 2 patients (33%) out of 6 with stable PRL levels had PD (p = 0.004). Conclusions: Hyperprolactinemia in mNSCLC patients treated with NIVO could potentially represent a negative early predictive factor for poor clinical outcomes, thus anticipating PD shown by CT scan.

115P - Immune related adverse events (irAE) and disease response with nivolumab in pre-treated advanced non-small cell lung cancer (NSCLC)

115P - Immune related adverse events (irAE) and disease response with nivolumab in pre-treated advanced non-small cell lung cancer (NSCLC)

145TiP - TTFields combined with PD-1 inhibitors or docetaxel for 2nd line treatment of non-small cell lung cancer (NSCLC): Phase 3 LUNAR study

Background: Tumor Treating Fields (TTFields) are a non-invasive, anti-mitotic treatment modality. TTFields disrupt the formation of the mitotic spindle, and dislocation of intracellular constituents. TTFields significantly extend the survival of newly diagnosed glioblastoma patients when combined with temozolomide. Efficacy of TTFields in NSCLC has been shown preclinically and in a phase I/II pilot study with pemetrexed, where overall survival (OS) improved by > 5 months vs historical controls. Trial design: We hypothesize that adding TTFields to 2nd line therapies in advanced NSCLC will increase OS. Patients (N = 512) with squamous or non-squamous NSCLC are enrolled in this Phase 3 study LUNAR [NCT02973789]. Patients are stratified by 2nd line therapy (PD-1 inhibitor or docetaxel), histology (squamous vs. non-squamous) and geographical region. Key inclusion criteria are 1st disease progression (RECIST 1.1), ECOG 0-1, no prior surgery or radiation therapy, no electronic medical devices in the upper torso, and absence of brain metastasis. Docetaxel or PD-1 inhibitors (either nivolumab or pembrolizumab) are given at standard doses. TTFields are applied to the upper torso for at least 18 hours/day, allowing patients to maintain daily activities. TTFields are continued until progression in the thorax and/or liver according to the immune-related response criteria (irRC). Follow up is performed once q6 weeks, including CT scans of the chest and abdomen. On progression in the upper torso, patients are followed monthly for survival. The primary endpoint is superiority in OS between patients treated with TTFields in combination with either docetaxel or PD-1 inhibitors, compared to docetaxel or PD-1 inhibitors alone. A co-primary endpoint compares the OS in patients treated with TTFields and docetaxel to those treated with PD-1 inhibitors alone in a non-inferiority analysis. Secondary endpoints include progression-free survival, radiological response rate based on the irRC, quality of life based on the EORTC QLQ C30 questionnaire and severity & frequency of adverse events. The sample size is powered to detect a HR of 0.75 in TTFields-treated patients versus control group. Clinical trial identification: NCT02973789 Legal entity responsible for the study: Novocure Ltd Funding: Novocure Ltd Disclosure: U. Weinberg, O. Farber, M. Giladi, Z. Bomzon: Full time employee of Novocure. E.D. Kirson: Full time employee of Novocure Ltd

Prediction of Response to Immune Checkpoint Inhibitor Therapy Using Early-Time-Point18F-FDG PET/CT Imaging in Patients with Advanced Melanoma

The purpose of this study was to evaluate 18F-FDG PET/CT scanning as an early predictor of response to immune checkpoint inhibitors (ICIs) in patients with advanced melanoma. Methods: Twenty patients with advanced melanoma receiving ICI prospectively underwent 18F-FDG PET/CT at 3 scan intervals: before treatment initiation (SCAN-1), at days 21-28 (SCAN-2), and at 4 mo (SCAN-3). This study was approved by the institutional review board, and informed consent was received from all patients who were enrolled between April 2012 and December 2013. Tumor response at each posttreatment time point was assessed according to RECIST 1.1, immune-related response criteria, PERCIST (PERCIST 1.0), and European Organization for Research and Treatment of Cancer (EORTC) criteria. Performance characteristics of each metric to predict best overall response (BOR) at ≥ 4 mo were assessed. Results: Twenty evaluable patients were treated with ipilimumab (n = 16), BMS-936559 (n = 3), or nivolumab (n = 1). BOR at ≥ 4 mo included complete response (n = 2), partial response (n = 2), stable disease (n = 1), and progressive disease (n = 15). Response evaluations at SCAN-2 using RECIST 1.1, immune-related response criteria, PERCIST, and EORTC criteria demonstrated accuracies of 75%, 70%, 70%, and 65%, respectively, to predict BOR at ≥ 4 mo. Interestingly, the optimal PERCIST and EORTC threshold values at SCAN-2 to predict BOR were >15.5% and >14.7%, respectively. By combining anatomic and functional imaging data collected at SCAN-2, we developed criteria to predict eventual response to ICI with 100% sensitivity, 93% specificity, and 95% accuracy. Conclusion: Combining functional and anatomic imaging parameters from 18F-FDG PET/CT scans performed early in ICI appears predictive for eventual response in patients with advanced melanoma. These findings require validation in larger cohorts.