Ute Hoch

Supplementary Figures, Tables, and Methods

Supplementary Figures, Tables, and Methods

PURPOSE: Therapies that produce deep and durable responses in patients with metastatic melanoma are needed. This phase II cohort from the international, single-arm PIVOT-02 study evaluated the CD122-preferential interleukin-2 pathway agonist bempegaldesleukin (BEMPEG) plus nivolumab (NIVO) in first-line metastatic melanoma. METHODS: A total of 41 previously untreated patients with stage III/IV melanoma received BEMPEG 0.006 mg/kg plus NIVO 360 mg once every 3 weeks for ≤ 2 years; 38 were efficacy-evaluable (≥ 1 postbaseline scan). Primary end points were safety and objective response rate (blinded independent central review); other end points included progression-free survival, overall survival (OS), and exploratory biomarkers. RESULTS: At 29.0 months' median follow-up, the objective response rate was 52.6% (20 of 38 patients), and the complete response rate was 34.2% (13 of 38 patients). Median change in size of target lesions from baseline was −78.5% (response-evaluable population); 47.4% (18 of 38 patients) experienced complete clearance of target lesions. Median progression-free survival was 30.9 months (95% CI, 5.3 to not estimable). Median OS was not reached; the 24-month OS rate was 77.0% (95% CI, 60.4 to 87.3). Grade 3 and 4 treatment-related and immune-mediated adverse events occurred in 17.1% (7 of 41) and 4.9% (2 of 41) of patients, respectively. Increased polyfunctional responses in CD8+ and CD4+ T cells were seen in blood after treatment, driven by cytokines with effector functions. Early on-treatment blood biomarkers (CD8+ polyfunctional strength difference and eosinophils) correlated with treatment response. CONCLUSION: BEMPEG in combination with NIVO was tolerated, with relatively low rates of grade 3 and 4 treatment-related and immune-mediated adverse events. The combination had encouraging antitumor activity in first-line metastatic melanoma, including an extended median progression-free survival. Exploratory analyses associated noninvasive, on-treatment biomarkers with response, before radiologic evidence was observed.

Purpose: Preplanned exploratory analyses were performed to identify biomarkers in circulating tumor cells (CTC) predictive of response to the topoisomerase 1 inhibitor etirinotecan pegol (EP). Experimental Design: The BEACON trial treated patients with metastatic breast cancer (MBC) with EP or treatment of physician's choice (TPC). Blood from 656 of 852 patients (77%) was processed with ApoStream to enrich for CTCs. A multiplex immunofluorescence assay measured expression of candidate response biomarkers [topoisomerase 1 (Top1), topoisomerase 2 (Top2), Ki67, RAD51, ABCG2, γH2AX, and terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling (TUNEL)] in CTCs. Patients were classified as Top1 low (Top1Lo) or Top1 high (Top1Hi) based on median CTC Top1 expression. Correlation of CTC biomarker expression at baseline, cycle 2 day 1 (C2D1), and cycle 4 day 1 with overall survival (OS) was investigated using Cox regression and Kaplan–Meier analyses. Results: Overall, 98% of samples were successfully processed, of which 97% had detectable CTCs (median, 47–63 CTCs/mL; range, 0–2,020 CTCs/mL). Top1, Top2, and TUNEL expression was detected in 52% to 90% of samples; no significant associations with OS were observed in pretreatment samples for either group. EP-treated patients with low C2D1Top1⁺ CTCs had improved OS compared with those with higher positivity (14.1 months vs. 11.0 months, respectively; HR, 0.7; P = 0.02); this difference was not seen in TPC-treated patients (HR, 1.12; P = 0.48). Patients whose CTCs decreased from Top1Hi to Top1Lo at C2D1 had the greatest OS benefit from EP (HR, 0.57; P = 0.01). Conclusions: CTC Top1 expression following EP treatment may identify patients with MBC most likely to have an OS benefit. Clin Cancer Res; 24(14); 3348–57. ©2018 AACR.

2545 Background: NKTR-214 is a CD122-biased agonist designed to provide sustained signaling through the heterodimeric IL-2 receptor pathway (IL-2Rβɣ) to preferentially activate and expand effector CD8+ T and NK cells over T regulatory cells in the tumor microenvironment. Immune changes in the tumor microenvironment after NKTR-214 treatment was assessed in patients with locally advanced or metastatic solid tumors. Methods: NKTR-214 was administered IV in an outpatient setting q2w or q3w. Serial blood and tumor tissue samples were collected to measure immune activation using immunophenotyping including flow cytometry, immunohistochemistry (IHC), T cell clonality and gene expression analyses. Results: 26 patients (pts) have been treated with NKTR-214 at q3w, 4@0.003, 9@0.006, 6@0.009 and 1@0.012 mg/kg. Six pts received 0.006 mg/kg q2w. 58% of pts had prior immunotherapy. The most common Gr1-2 TRAEs were fatigue (73%) and pruritus (65%), and decreased appetite (46%). One pt experienced Gr3 syncope and hypotension at the highest dose tested and continued treatment at a lower dose. No drug-related AEs led to study discontinuation. No immune-related AEs or capillary leak syndrome were observed. 6 pts (23%) experienced tumor shrinkage from 10-30%. Three immunotherapy naïve pts receiving sequential anti-PD1 therapy, after ending treatment with NKTR-214, experienced significant tumor regression at first scan. In all pts evaluated, blood samples showed increases in newly proliferating (Ki67+) T and NK cells 8 days post dose. Flow cytometry and/or IHC revealed an up to 10-fold increase from baseline in tumor CD8+T and NK cells in the tumor microenvironment, with minimal changes to Tregs. PD-1 expression increased 2-fold in TILs. Gene expression analysis of tumor tissue showed increases in several immune checkpoint genes, cytotoxic markers (IFNg, PRF1, and GZMB), as well as a dynamic change in T cell clonality. Conclusions: Based on a favorable safety profile and strong correlative biomarker data, a phase 1/2 trial combining NKTR-214 and nivolumab is currently enrolling. Clinical trial information: NCT02869295.

E14040 Background: NKTR-214 is a CD-122-biased agonist that targets the IL-2 pathway and is designed to provide sustained signaling through the heterodimeric IL-2 receptor pathway (IL-2Rβɣ) to preferentially activate and expand NK and effector CD8+ T cells over T regulatory cells within the tumor microenvironment. In a phase 1 monotherapy trial, pts treated with NKTR-214 demonstrated a substantial increase in CD8+ T and NK cells within the tumor microenvironment even when pretreated with multiple prior immunotherapeutic agents (abstract submitted). Based on this biomarker data and a favorable safety profile, a trial combining NKTR-214 and nivolumab was initiated. Methods: This is an on-going phase 1/2 study of NKTR-214 plus nivolumab in Pts with either melanoma (Mel), NSCLC, renal, bladder, or TNBC. Pts who are immunotherapy naïve or checkpoint therapy relapse/refractory are being studied separately. NKTR-214 and nivolumab are administered IV on a q2w or q3w schedule. Cohort 1 received NKTR-214 0.006 mg/kg q3w with nivolumab 240 mg q2w. Blood and tumor tissue were collected to measure immune activation using flow cytometry, immunohistochemistry, T cell clonality and gene expression analyses. Results: As of February 7, 2017, 5 Pts have been treated with the combination and all Pts were naïve to checkpoint inhibitors. There have been no dose limiting toxicities, no drug-related or immune related grade 3-5 adverse events (TRAEs) and no Pts have discontinued treatment. The most common TRAEs were pruritis and rash. Radiographic scans were available for 2 Pts. On treatment, Pt 1 with Mel had a mixed radiographic response at 1st scan, a ~40% decrease in LDH and a robust tumor immune cell infiltrate at week 3 the majority being newly proliferating CD8+ T cells expressing PD-1. Pt 2 with Mel had an unconfirmed complete response per RECIST 1.1 after 6 weeks of treatment; follow up tumor response data will be presented. Conclusions: Preliminary data demonstrate that NKTR-214 and nivolumab combination therapy is well tolerated with early evidence of clinical activity. Updated safety, pharmacokinetics, tumor response and biomarker data will be presented. Clinical trial information: NCT02983045.

454 Background: Patients with low baseline CD8+ T-cells within the tumor microenvironment (TILs) have a poor response to immune checkpoint inhibitors. Agents designed to specifically activate and expand CD8+ T cells may improve clinical outcomes in patients with low TILs. NKTR-214 is a CD-122-biased agonist designed to provide sustained signaling through the heterodimeric IL-2 receptor pathway (IL-2Rβɣ) and preferentially activate and expand NK and effector CD8+ T cells over CD4+ T regulatory cells. Methods: A dose escalation, open-label, trial was initiated to assess the safety of NKTR-214 and explore immune changes in the blood and tumor microenvironment in patients with advanced solid tumors. NKTR-214 was administered IV in an outpatient setting with initial dosing at 0.003 mg/kg. Pre and post treatment blood and tumor samples were analyzed for immune phenotyping, gene expression, T cell receptor diversity, and changes in the tumor microenvironment by immunohistochemistry. Results: Among 25 patients dosed, 15 had RCC (10@0.006mg/kg, 4@0.009mg/kg, and 1@0.012mg/kg). Treatment with NKTR-214 was well tolerated and the MTD was not reached. One patient experienced DLTs (Gr3 syncope and hypotension) at 0.012 mg/kg. There were no immune-related AEs. Of 12 patients evaluable for response, 75% had SD at their first on treatment scan. Of 5 patients, who were immune checkpoint naïve with ≥ 1 prior TKI treatments, 3 experienced tumor shrinkage, 1 with PR per RECIST 1.1 (unconfirmed). Interrogation of the tumor microenvironment revealed many significant immunological changes post treatment, including increase in total and proliferating NK, CD8+, and CD4+ T cells. There was good correlation between increase in activated CD4+ and CD8+ T cells in peripheral blood with an increase in T cell infiltrates within the tumor tissue. Conclusions: NKTR-214 increased immune infiltration in the tumor and anti-tumor activity in patients who previously progressed on TKIs, with a favorable safety profile. The ability to alter the immune environment and increase PD-1 expression on effectors T cells may improve the effectiveness of anti-PD-1 blockade. A trial combining NKTR-214 and nivolumab is enrolling. Clinical trial information: 02869295.

The relationship between incidences of neutropenia and 10-hydroxy-7-ethyl camptothecin (SN38) exposure was explored using SN38 pharmacokinetic and neutrophil count data from toxicology studies of etirinotecan pegol (EP) and irinotecan in beagle dogs.

Brain metastases are an increasing problem in women with invasive breast cancer. Strategies designed to treat brain metastases of breast cancer, particularly chemotherapeutics such as irinotecan, demonstrate limited efficacy. Conventional irinotecan distributes poorly to brain metastases; therefore, NKTR-102, a PEGylated irinotecan conjugate should enhance irinotecan and its active metabolite SN38 exposure in brain metastases leading to brain tumor cytotoxicity. Female nude mice were intracranially or intracardially implanted with human brain seeking breast cancer cells (MDA-MB-231Br) and dosed with irinotecan or NKTR-102 to determine plasma and tumor pharmacokinetics of irinotecan and SN38. Tumor burden and survival were evaluated in mice treated with vehicle, irinotecan (50 mg/kg), or NKTR-102 low and high doses (10 mg/kg, 50 mg/kg respectively). NKTR-102 penetrates the blood-tumor barrier and distributes to brain metastases. NKTR-102 increased and prolonged SN38 exposure (>20 ng/g for 168 h) versus conventional irinotecan (>1 ng/g for 4 h). Treatment with NKTR-102 extended survival time (from 35 days to 74 days) and increased overall survival for NKTR-102 low dose (30 % mice) and NKTR-102 high dose (50 % mice). Tumor burden decreased (37 % with 10 mg/kg NKTR-102 and 96 % with 50 mg/kg) and lesion sizes decreased (33 % with 10 mg/kg NKTR-102 and 83 % with 50 mg/kg NKTR-102) compared to conventional irinotecan treated animals. Elevated and prolonged tumor SN38 exposure after NKTR-102 administration appears responsible for increased survival in this model of breast cancer brain metastasis. Further, SN38 concentrations observed in this study are clinically achieved with 145 mg/m2 NKTR-102, such as those used in the BEACON trial, underlining translational relevance of these results.

The aim of the study was to demonstrate the activity of etirinotecan pegol, a polymer conjugate of irinotecan, in multiple human tumor models and to establish both the pharmacokinetic/pharmacodynamics (PK/PD) relationship and clinical relevance of the findings.