Citations

9517 Background: Although PD-1/L1 axis directed therapies induce durable responses in some mm patients (pts), biomarkers of response remain elusive. We hypothesized that quantifying key immune suppression mechanisms within the tumor microenvironment would provide superior predictors of response to anti-PD-1 compared with single marker assessment. Methods: Pre-treatment tumor biopsies from 124 mm pts treated with anti-PD-1 at 7 academic centers were fluorescently stained with multiple immune markers in discovery (n = 24) and validation (n = 100) cohorts. Selected biomarker signatures, PD-1/PD-L1 interaction score (proportion of PD-1+ cells co-localized with PD-L1) and IDO1/HLA-DR co-expression were evaluated for anti-PD-1 treatment response and survival. Slides were imaged using Vectra; biomarker positive cells and their co-localization were objectively quantified in pathologist-selected regions using novel Automated Quantitative Analysis (AQUA) algorithms. Results: In the discovery cohort, high levels of PD-1/PD-L1 interaction score and/or IDO1/HLA-DR coexpression was strongly positively associated with response to anti-PD-1 (p = 0.0005). In contrast, other individual biomarkers (PD-1, PD-L1, CD8) were not associated with response or survival (p > 0.10). This finding was replicated in the validation cohort: pts with high PD-1/PD-L1 and/or IDO1/HLA-DR were more likely to respond to treatment (p = 0.009). These pts also experienced a three-fold increase in progression free survival (hazards ratio (HR) = 0.33; p = 0.003) and overall survival (HR = 0.34; p = 0.004). Multivariate analyses revealed that these findings were independent of BRAF mutation, stage, LDH and prior therapy. In the combined cohort (n = 124), 80% of responding pts had higher levels of PD-1/PD-L1 interaction scores and/or IDO1/HLA-DR. In contrast, PD-L1 expression alone (≥1% or ≥50%) was not predictive of PFS or OS (p > 0.1). Conclusions: This novel multiplexed method profiling key tumor-immune suppression pathways identified mm pts likely to respond to anti-PD-1 therapy. This method could help stratify patients for PD-1 monotherapy and be useful in guiding future clinical trials.

Abstract Background: X4P-001 is an orally bioavailable, selective, allosteric inhibitor of the chemokine receptor CXCR4, and has been shown to downregulate hypoxia inducible factor-2α (HIF-2α) and myeloid-derived suppressor cell (MDSC) trafficking in the tumor microenvironment. In multiple RCC xenograft models, the addition of X4P-001 to tyrosine kinase inhibitors (TKIs), including axitinib, has demonstrated increased efficacy and delayed onset of TKI resistance. Methods: This is an ongoing phase 1/2 open-label study of X4P-001 in combination with axitinib in patients (pts) with histologically confirmed clear cell RCC (ccRCC) who have received ≥1 prior systemic therapy. The Ph1 portion of the study evaluates safety, tolerability, PK, PD, and antitumor activity of the combination using a 3+3 dose escalation schema (escalating doses of X4P-001+ axitinib at 5 mg BID). The Ph2 portion is a single-arm expansion cohort evaluating this combination treatment in ~ 45 ccRCC pts. The radiologic assessment is performed every 8 weeks with central review. Results: As of 30 June, 2017, enrollment for the Ph1 portion of the study has been completed. Sixteen (16) pts were enrolled and the median age was 64 years (range 50-76). Pts had received a median of 2 prior lines of therapy (range 1-5). The doses tested were 200 mg BID, 400 and 600 mg QD of X4P-001 + axitinib. There were two dose-limiting toxicities (DLTs) observed at the X4P-001 600 mg QD dose level: one pt had multiple grade (G) 2 adverse events (AEs), including anorexia, cognitive disturbance, fatigue, nausea, vomiting, and somnolence; another pt had G3 dyspnea and fatigue. The MTD/RP2D was determined to be 400 mg QD of X4P-001 + axitinib. Treatment-related AEs (≥ 10%) of any grade were diarrhea, fatigue, hypertension, nausea, headache, anorexia, vomiting, dry eye, dysphonia, abnormal loss of weight, increased lipase, proteinuria, dry mouth, stomatitis, cognitive disorder, dysgeusia, and palmar-plantar erythrodysaesthesia syndrome. Treatment-related G3/4 AEs (≥ 10%) were hypertension. In addition, one pt had SAE due to G2 diarrhea and G2 creatinine elevation. Drug exposures (AUC0-24hr) at steady state (SS) are similar for 200 mg BID and 400 mg QD dose. Mean Cmax and AUC0-24hr at SS increased approximately 1.6- and 1.9-fold, respectively, from 400 mg to 600 mg QD dose. Leukocyte mobilization is a well-established surrogate marker for CXCR4 inhibition. At both 400 mg and 600 mg daily dose levels, X4P-001 demonstrated approximately 2 to 2.5-fold increase of WBC (range: 1.4-4.7 fold) and nearly 4-fold increase of CD34+ progenitor cells (range: 1.8-6.4 fold). The peak elevation of both markers occurred around 2 to 4 hours following dosing. Of the 12 clinically evaluable pts, 3 had confirmed partial response, 8 had stable disease, and 1 had progressive disease. As of 30 June 2017, 9 pts remain on study and median duration on treatment was 27 weeks (range 7.4-60). Conclusions: The combination treatment is well tolerated at a dose of 400 mg QD of X4P-001 + axitinib with preliminary evidence of clinical activity. The doses used in this phase I study were biologically active in inhibiting CXCR4 in peripheral blood as demonstrated by elevating WBC and CD34+ cell counts. The Ph2 portion of the study is ongoing. Citation Format: Michael Atkins, Richard Joseph, Thai Ho, Ulka Vaishampayan, Sarah Ali, Marc Matrana, Robert Alter, Jeff Edenfield, Yan Wang, Sarah Blanchette, Lu Gan, David McDermott. A phase 1 dose-finding study of X4P-001 (an oral CXCR4 inhibitor) and axitinib in patients with advanced renal cell carcinoma (RCC) [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 B201.

Abstract Purpose: PD-1/L1 axis–directed therapies produce clinical responses in a subset of patients; therefore, biomarkers of response are needed. We hypothesized that quantifying key immunosuppression mechanisms within the tumor microenvironment by multiparameter algorithms would identify strong predictors of anti–PD-1 response. Experimental Design: Pretreatment tumor biopsies from 166 patients treated with anti–PD-1 across 10 academic cancer centers were fluorescently stained with multiple markers in discovery (n = 24) and validation (n = 142) cohorts. Biomarker-positive cells and their colocalization were spatially profiled in pathologist-selected tumor regions using novel Automated Quantitative Analysis algorithms. Selected biomarker signatures, PD-1/PD-L1 interaction score, and IDO-1/HLA-DR coexpression were evaluated for anti–PD-1 treatment outcomes. Results: In the discovery cohort, PD-1/PD-L1 interaction score and/or IDO-1/HLA-DR coexpression was strongly associated with anti–PD-1 response (P = 0.0005). In contrast, individual biomarkers (PD-1, PD-L1, IDO-1, HLA-DR) were not associated with response or survival. This finding was replicated in an independent validation cohort: patients with high PD-1/PD-L1 and/or IDO-1/HLA-DR were more likely to respond (P = 0.0096). These patients also experienced significantly improved progression-free survival (HR = 0.36; P = 0.0004) and overall survival (HR = 0.39; P = 0.0011). In the combined cohort, 80% of patients exhibiting higher levels of PD-1/PD-L1 interaction scores and IDO-1/HLA-DR responded to PD-1 blockers (P = 0.000004). In contrast, PD-L1 expression was not predictive of survival. Conclusions: Quantitative spatial profiling of key tumor-immune suppression pathways by novel digital pathology algorithms could help more reliably select melanoma patients for PD-1 monotherapy. Clin Cancer Res; 24(21); 5250–60. ©2018 AACR.

Abstract Purpose: The purpose of this study was to assess the association of baseline tumor size (BTS) with other baseline clinical factors and outcomes in pembrolizumab-treated patients with advanced melanoma in KEYNOTE-001 (NCT01295827). Experimental Design: BTS was quantified by adding the sum of the longest dimensions of all measurable baseline target lesions. BTS as a dichotomous and continuous variable was evaluated with other baseline factors using logistic regression for objective response rate (ORR) and Cox regression for overall survival (OS). Nominal P values with no multiplicity adjustment describe the strength of observed associations. Results: Per central review by RECIST v1.1, 583 of 655 patients had baseline measurable disease and were included in this post hoc analysis. Median BTS was 10.2 cm (range, 1–89.5). Larger median BTS was associated with Eastern Cooperative Oncology Group performance status 1, elevated lactate dehydrogenase (LDH), stage M1c disease, and liver metastases (with or without any other sites; all P ≤ 0.001). In univariate analyses, BTS below the median was associated with higher ORR (44% vs. 23%; P < 0.001) and improved OS (HR, 0.38; P < 0.001). In multivariate analyses, BTS below the median remained an independent prognostic marker of OS (P < 0.001) but not ORR. In 459 patients with available tumor programmed death ligand 1 (PD-L1) expression, BTS below the median and PD-L1–positive tumors were independently associated with higher ORR and longer OS. Conclusions: BTS is associated with many other baseline clinical factors but is also independently prognostic of survival in pembrolizumab-treated patients with advanced melanoma. Clin Cancer Res; 24(20); 4960–7. ©2018 AACR. See related commentary by Warner and Postow, p. 4915

Summary Nivolumab, a monoclonal antibody against programmed cell death-1 receptor, is increasingly used in advanced cancers. While nivolumab use enhances cancer therapy, it is associated with increased immune-related adverse events. We describe an elderly man who presented in ketoacidosis after receiving nivolumab for metastatic renal cell carcinoma. On presentation, he was hyperpneic and laboratory analyses showed hyperglycemia and anion-gapped metabolic acidosis consistent with diabetic ketoacidosis. No other precipitating factors, besides nivolumab, were identified. Pre-nivolumab blood glucose levels were normal. The patient responded to treatment with intravenous fluids, insulin and electrolyte replacement. He was diagnosed with insulin-dependent autoimmune diabetes mellitus secondary to nivolumab. Although nivolumab was stopped, he continued to require multiple insulin injection therapy till his last follow-up 7 months after presentation. Clinicians need to be alerted to the development of diabetes mellitus and diabetic ketoacidosis in patients receiving nivolumab. Learning points: Diabetic ketoacidosis should be considered in the differential of patients presenting with metabolic acidosis following treatment with antibodies to programmed cell death-1 receptor (anti-PD-1). Autoimmune islet cell damage is the presumed mechanism for how insulin requiring diabetes mellitus can develop de novo following administration of anti-PD-1. Because anti-PD-1 works by the activation of T-cells and reduction of ‘self-tolerance’, other autoimmune disorders are likely to be increasingly recognized with increased use of these agents.

689 Background: The role of antiangiogenic agents in advanced RCC is well established. However, it is still not clear whether this benefit can be extrapolated to the adjuvant setting. In this meta-analysis of 3 randomized control trials (RCTs), we sought to determine the efficacy of these agents in RCC patients who underwent nephrectomy with high risk of relapse. Methods: We searched three databases, including Pubmed, Embase, and Cochrane Central Register of Controlled Trials to identify RCTs comparing antiangiogenic agents to placebo in post-nephrectomy RCC patients. We evaluated: 1) the effect of antiangiogenics in highest risk groups as defined by individual studies; 2) the role of each agent separately; and 3) the effect in clear-cell RCC population. Outcomes of interest included overall survival (OS) and disease-free survival (DFS). The overall effect was pooled using the DerSimonian and Laird random effects models Results: Three RCTs (N = 3693 patients) were identified. All studies were comparing placebo to antiangiogenics: sunitinib, sorafenib, and pazopanib. Overall, antiangiogenics did not improve DFS (HR 0.92, 95% CI 0.78 to 1.07) or OS (HR 0.99, 95% CI 0.79 to 1.25). These results persisted when restricting the analysis to patients with clear cell carcinoma and patients with highest risk of relapse. Similarly, sunitinib did not show any improvement in the entire studied group for either DFS (HR 0.89, 95% CI 0.67 to 1.19) or OS (HR 1.11, 95% CI 0.90 to 1.37). In addition, when restricting the analysis to the high risk group, sunitinib did not show any advantage in terms of DFS (HR 0.85, 95% CI 0.67 to 1.07) and OS (HR 1.04, 95% CI 0.83 to 1.31). Conclusions: Based on the available evidence, antiangiogenics do not seem to add an advantage over placebo in terms of OS and DFS in high risk RCC patients after nephrectomy. Further studies are needed to identify the patient population which might derive a benefit from antiangiogenics in the adjuvant setting.