Safety Biomarkers Research Articles

L-citrulline: A preclinical safety biomarker for the small intestine in rats and dogs in repeat dose toxicity studies

IntroductionGastrointestinal (GI) toxicity is still an issue within drug development, especially for novel oncology drugs. The identification of GI mucosal damage at an early stage with high sensitivity and specificity across preclinical species and humans remains difficult. To date, in preclinical studies, no qualified mechanistic, diagnostic or prognostic biomarkers exist for GI mucosal toxicity. L-citrulline is one of the most promising biomarker candidates used in clinical settings to quantify enterocyte integrity in various small intestinal diseases. L-citrulline is an intermediate metabolic amino acid produced mainly by functional enterocytes of the small intestine, whereby enterocyte loss will cause a drop in circulating L-citrulline. MethodsIn several repeat-dose toxicity studies, plasma L-citrulline has been evaluated as a potential safety biomarker for intestinal toxicity in beagle dogs and Wistar (Han) rats treated with different oncological drug candidates in drug development. Clinical observations and body weight determinations were performed during the pretreatment, treatment and treatment-free recovery period as well as toxicokinetic, gross and histopathology examinations. The quantitative determination of plasma L-citrulline levels during the pretreatment (only dogs), treatment and treatment-free recovery period were performed using an HPLC MS/MS assay. In cynomolgus monkeys, the first investigations on baseline L-citrulline levels were performed. ResultsIn dogs, a dose- and exposure-dependent decrease of up to 50% in plasma L-citrulline was seen without histopathological alterations. However, a decrease of more than 50% in comparison to the individual animal pretreatment value of L-citrulline correlated very well with histopathological findings (intestinal crypt necrosis, villus atrophy, enterocyte loss) and clinical signs (bloody faeces and diarrhoea). During a treatment-free recovery period, a trend of increasing levels was observed in dogs. In rats, absolute L-citrulline plasma levels of treated animals decreased compared to the values of the concurrent control group. This decrease also correlated with the histopathological findings in the small intestine (single cell necrosis and mucosa atrophy). Because of a large physiological variation in L-citrulline plasma levels in dogs and rats, a clear cut-off value for absolute L-citrulline levels predictive of intestinal mucosal toxicity was difficult to establish. However, a > 50% decrease in L-citrulline plasma levels during the treatment period strongly correlated with histopathological findings. DiscussionBased on the performed analysis, a longitudinal investigation of L-citrulline plasma levels for individual animals in the control and treatment groups is essential and pretreatment values of L-citrulline levels in rodents would be highly informative. Overall, further cross-species comparison (Cynomolgus monkey, mouse) and implementation in clinical trials as exploratory biomarker is essential to foster the hypothesis and to understand completely the clinical relevance of L-citrulline as a small intestine biomarker.

Pembrolizumab for patients with leptomeningeal metastasis from solid tumors: efficacy, safety, and cerebrospinal fluid biomarkers

BackgroundThe benefit of immune checkpoint inhibitors (ICIs) in patients with leptomeningeal metastases (LMM) is unknown.MethodsWe undertook a phase II trial of pembrolizumab in patients with LMM from solid tumors. Eligible...

Exploring the efficacy and safety of polyene phosphatidylcholine for treatment of drug-induced liver injury using the Roussel Uclaf causality assessment method: a propensity score matching comparison.

Objective In China, polyene phosphatidylcholine (PPC) is widely used to treat alanine aminotransferase (ALT) elevation associated with various liver diseases. Here, we assessed the efficacy and safety of PPC in treating drug-induced liver injury (DILI).Methods Data from a multicenter retrospective cohort study (DILI-R) were analyzed to compare PPC and magnesium isoglycyrrhizinate (MgIG) for treatment of DILI. We used the Roussel Uclaf causality assessment method (RUCAM) to evaluate patients with DILI. Patients with RUCAM scores ≥6 were included in the study, while those with RUCAM scores <6 were further evaluated by a panel of hepatologists. The primary outcome was the proportion of patients with ALT normalization at discharge. Propensity score matching was used to identify 183 matched pairs of patients (366 patients in total) from 25,927 patients with DILI.Results Among the DILI patients, 64 of 183 (34.97%) achieved normal ALT levels after treatment in both the PPC and the MgIG groups.Conclusion There were no significant differences in safety biomarkers including serum creatinine, blood urea nitrogen, white blood cells, platelets, hemoglobin, and albumin between patients treated with PPC or MgIG. The safety and efficacy of these two agents for treatment of DILI were comparable.

Abstract 1508: Characterization of a novel clonal neoantigen reactive T cell (cNeT) product through a comprehensive translational research program

Abstract Adoptive cell therapy (ACT) using ex vivo expanded tumor infiltrating lymphocytes (TIL) has shown great promise as a treatment for metastatic melanoma and has the potential to deliver durable responses in other solid tumors. Clonal neoantigens, which are derived from mutations occurring very early in the tumor development, are present in all cancer cells within a patient and therefore could be the optimal targets for TIL-based therapies. Recently it was shown that the number of clonal neoantigens within a tumor is associated with improved clinical outcomes following checkpoint inhibition in patients with non-small cell lung cancer (NSCLC) and melanoma. An approach that targets multiple clonal neoantigens with specific T cells has the potential to demonstrate high specificity and efficacy whilst mitigating the risk of immune escape. Achilles Therapeutics is developing a personalized ACT product, ATL001, to target clonal neoantigens, which are identified using tumor exome sequencing and the PELEUS™ bioinformatics platform. Clonal neoantigen reactive T cells (cNeTs) are then manufactured from TIL using the VELOS™ manufacturing process. Two Phase I/IIa clinical trials of ATL001 are ongoing in patients with advanced NSCLC and metastatic or recurrent melanoma. In common with the development of other ACT products, the key to characterizing and improving cNeT products relies on evaluating a diverse set of exploratory endpoints in early clinical trials, including understanding the procedural, clinical and biological factors that influence cNeT manufacturing rate and product reactivity; monitoring the expansion, persistence and phenotype of the infused cells in vivo and identifying potential biomarkers of clinical activity or safety of cNeTs in treated patients. These insights may suggest further improvements to cNeT product development in ensuing iterations. The evaluation of these endpoints requires the collection of a rich longitudinal dataset that traces each patient's journey from tissue procurement and cNeT manufacture, to final product infusion and follow up. The data collected will include clinical and disease characteristics, tumor microenvironment insights from exome sequencing and immunohistochemistry of procured tumor, and metrics from the VELOS™ manufacturing process, along with a comprehensive immune-monitoring programme comprising immuno-sequencing, immunophenotyping, bespoke ctDNA panels and reactivity assays at specified timepoints, all to be evaluated against clinical outcomes data. The amalgamation of diverse streams of data requires the development of robust processes and systems for data collection, processing and storage. Furthermore, the evaluation of multiple exploratory endpoints will require integration and modelling of baseline covariates, time-series immune-monitoring and efficacy data, all of which will be described Citation Format: Michael Epstein, Rebecca Pike, Emma Leire, Jen Middleton, Megan Wileman, Lylia Ouboussad, Leah Manning, Theres Oakes, Eva Pekle, Amy Baker, Mark Brown, Daisy Melandri, Pablo Becker, Anabel Ramirez, Natasa Hadjistephanou, Samra Turaljic, Mariam Jamal-Hanjani, Martin Forster, Iraj Ali, Jane Robertson, Karl Peggs, Sergio Quezada. Characterization of a novel clonal neoantigen reactive T cell (cNeT) product through a comprehensive translational research program [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 1508.

Abstract CT131: A Phase I safety and tolerance study of FN-1501, a novel FLT3 inhibitor, in patients with advanced solid tumors and acute myeloid leukemia

Abstract Background: FLT3 mutations are found in approximately 30% of adult patients with Acute Myeloid Leukemia (AML) and to a lesser degree, in certain solid tumors. FN-1501 is a potent inhibitor of FLT3 and other tyrosine kinases such as CDK4/6, KIT, PDGFR, ALK and RET proteins, with demonstrated anti-tumor activity in several leukemia and colon cancer xenograft models. An ongoing, open-label, Phase I study (NCT03690154) is evaluating FN-1501 as monotherapy in patients with various advanced solid tumors and relapsed, refractory (R/R) AML. The objectives of the trial are to assess safety and tolerability, establish a Recommended Phase 2 Dose (RP2D), and evaluate preliminary anti-tumor activity. Methods: Pts received FN-1501 by IV thrice weekly for 2 weeks followed by 1 week off treatment in 21-day cycles. The dose escalation phase follows a standard 3+3 design. Primary objectives include determinations of dose-limiting toxicity (DLT), maximum tolerated dose (MTD), safety, and RP2D. Secondary objectives include pharmacokinetics (PK) and anti-tumor activity. Exploratory objectives include the relationship between pharmacogenetic mutations (e.g. FLT3, TP53, KRAS, NRAS, etc) and safety/efficacy. Expansion cohorts have been added to the ongoing protocol amendment to confirm safety and evaluate preliminary efficacy at RP2D. Results: At the time of data cut-off (Nov 17, 2020), 40 pts (n=1 AML; n=39 solid tumors) were enrolled at doses ranging from 2.5 to 128 mg. Median number of prior lines of treatment was 5 (range 1-12). Thirty-four patients met the minimum exposure criterion for DLT assessment. No DLTs were reported and MTD was not reached. Treatment-related adverse events (TRAEs) were reported in 58% of pts. The most common TRAEs in ≥10% of patients included fatigue (20%), nausea (15%), infusion related reaction (10%), mostly reversible grade 1 or 2. Grade ≥3 TRAEs consisting of anemia, fatigue and serum creatinine increase were observed in 3 pts. TRAEs resulted in dose delay/interruption in 4 pts (10%) but no treatment discontinuations. No serious TRAEs were observed. The exposure of FN-1501 (AUC and Cmax) increased in a dose proportional manner. Mean t1/2 was estimated to be 12-19 hours. Among 25 response-reportable pts, 1 had a best overall response of PR (47% target lesion shrinkage), 10 had stable disease and 14 had progressive disease. The confirmed PR (duration &amp;gt; 4 months) occurred at the 40 mg dose level in a pt with endometrial carcinoma. Conclusion: FN-1501 has demonstrated reasonable safety/tolerability across all doses tested, with promising anti-tumor activity in pts with certain advanced, heavily pre-treated solid tumors. Enrollment of pts into the dose escalation part of the study is continuing and updated safety, PK and molecular biomarker results will be presented at the meeting. Citation Format: Gary Edward Richardson, Stephen K. Williamson, Misako Nagasaka, Viviana Bozon, Maria Margarita Corvez, Chao Li, Wei Li, Jiao Wei, Ai-Min Hui. A Phase I safety and tolerance study of FN-1501, a novel FLT3 inhibitor, in patients with advanced solid tumors and acute myeloid leukemia [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 CT131.

O-9 5-FU/LV + cetuximab + vemurafenib as maintenance therapy for BRAF-mutant (BRAFmut) metastatic colorectal cancer: Efficacy, safety, and exploratory biomarker findings from Cohort 1 of the MODUL trial

O-9 5-FU/LV + cetuximab + vemurafenib as maintenance therapy for BRAF-mutant (BRAFmut) metastatic colorectal cancer: Efficacy, safety, and exploratory biomarker findings from Cohort 1 of the MODUL trial

Long-term safety and efficacy of emtricitabine and tenofovir alafenamide vs emtricitabine and tenofovir disoproxil fumarate for HIV-1 pre-exposure prophylaxis: week 96 results from a randomised, double-blind, placebo-controlled, phase 3 trial

In DISCOVER, a multinational, randomised controlled trial, emtricitabine and tenofovir alafenamide compared with emtricitabine and tenofovir disoproxil fumarate showed non-inferior efficacy for HIV prevention and improved bone mineral density and renal safety biomarkers at week 48. We report outcomes analysed after all participants had completed 96 weeks of follow-up. This study is an ongoing, randomised, double-blind, multicentre, active-controlled, phase 3, non-inferiority trial done at 94 community, public health, and hospital-associated clinics located in Europe and North America. Adult cisgender men and transgender women who have sex with men, both with a high risk of acquiring HIV as determined by self-reported sexual behaviour or recent sexually transmitted infections, were randomly assigned (1:1) to receive either emtricitabine and tenofovir alafenamide (200/25 mg) tablets daily, with matched placebo tablets (emtricitabine and tenofovir alafenamide group), or emtricitabine and tenofovir disoproxil fumarate (200/300 mg) tablets daily, with matched placebo tablets (emtricitabine and tenofovir disoproxil fumarate group). The primary efficacy outcome was incident HIV infection. Incidence of HIV-1 infection per 100 person-years was assessed when the last participant had completed 96 weeks of follow-up. This trial is registered with ClinicalTrials.gov, number NCT02842086. Between Sept 13, 2016, and June 30, 2017, 5387 participants were randomly assigned to receive emtricitabine and tenofovir alafenamide (n=2694) or emtricitabine and tenofovir disoproxil fumarate (n=2693), contributing 10 081 person-years of follow-up. At 96 weeks of follow-up, there were eight HIV infections in participants who had received emtricitabine and tenofovir alafenamide (0·16 infections per 100 person-years [95% CI 0·07-0·31]) and 15 in participants who had received emtricitabine and tenofovir disoproxil fumarate (0·30 infections per 100 person-years [0·17-0·49]). Emtricitabine and tenofovir alafenamide maintained its non-inferiority to emtricitabine and tenofovir disoproxil fumarate for HIV prevention (IRR 0·54 [95% CI 0·23-1·26]). Approximately 78-82% of participants reported taking study medication more than 95% of the time across all study visits. Rates of sexually transmitted infections remained high and similar across groups (21 cases per 100 person-years for rectal gonorrhoea and 28 cases per 100 person-years for rectal chlamydia). Emtricitabine and tenofovir alafenamide continued to show superiority over emtricitabine and tenofovir disoproxil fumarate in all but one of the six prespecified bone mineral density and renal biomarkers. There was more weight gain among participants who had received emtricitabine and tenofovir alafenamide (median weight gain 1·7 kg vs 0·5 kg, p<0·0001). Emtricitabine and tenofovir alafenamide is safe and effective for longer-term pre-exposure prophylaxis in cisgender men and transgender women who have sex with men. Gilead Sciences.

Exploring the Clinical Utility of Renal Safety Biomarkers during Iron Chelation Therapy in Patients with β-Thalassemia and Other Anemias

Background: Close monitoring of renal function is recommended before and during treatment with the iron chelators deferasirox and deferoxamine (DFO), by assessment of serum creatinine (SCr) and estimated creatinine clearance. To identify patients at increased risk for acute kidney injury while on therapy, efforts are focused on protein biomarkers to predict changes in renal function before SCr increases and to understand the pathophysiology involved. Alpha-1 microglobulin (alpha1M), beta-2 microglobulin (beta2M), retinol-binding protein (RBP), and (urinary) cystatin C increases may reflect proximal tubular dysfunction. Changes in kidney injury molecule-1 (KIM-1), lipocalin-2 (also called NGAL), N-acetyl-beta-glucosaminidase (NAG), clusterin, osteopontin, and tissue inhibitor of metalloproteinase-1 (TIMP-1) may reflect localized pathological processes in the renal nephron. KIM-1 is upregulated dramatically upon epithelial injury and is specific for the proximal tubule. Urinary total protein, microalbumin, and immunoglobulin G (IgG) may reflect either glomerular or tubular injury. The current exploratory analysis assessed 19 renal protein biomarkers as early indicators for an increased risk of acute renal dysfunction in chelated, transfusion-dependent patients with β-thal or other anemias. Objectives were to explore: 1) changes in biomarker profiles over time; 2) correlations between baseline biomarker levels and changes in SCr during treatment; 3) the correlation of changes in biomarker levels with changes in SCr during treatment; 4) correlations between early biomarker changes during treatment with subsequent changes in serum creatinine.Methods: Archived urine samples collected at baseline and every 3-6 months during two deferasirox clinical trials (comparative 1-year 107 study of β-thal patients randomized to deferasirox or DFO; non-comparative 2-year 108 study including β-thal or other anemia [MDS, DBA, rare anemias] patients, excluding SCD) were used. All patients enrolled were aged ≥2 years, received at least 8 blood transfusions/year, and had LIC ≥2 mg Fe/g dw. No patient had baseline SCr >upper limit normal. Patients at risk of acute renal dysfunction were defined as having SCr increased >33% from baseline on ≥2 consecutive visits during the trials. ROC curves were generated by treatment and by underlying disease to determine whether urinary renal markers at baseline (pre-treatment) or change from baseline could predict an increased risk of acute renal dysfunction.Results: 586 β-thal patient samples were assessed from the comparative trial (n=296 deferasirox, n=290 DFO) and 184 from the non-comparative trial (n=85 β-thal; n=99 other non-β-thal anemias [MDS, n=47; DBA, n=30; other rare anemias, n=22]). No significant progressive changes in any renal biomarkers were observed; including acute renal injury (KIM-1, NGAL) and inflammatory (clusterin, osteopontin) biomarkers. Biomarker levels at baseline showed little/no correlation with changes in SCr. Area under the ROC curve (AUC) values were 0.45-0.60, suggesting limited predictive value for urinary renal biomarkers at baseline (pre-treatment) to predict an increased risk of acute renal dysfunction (1.0 = a perfect test, 0.5 = no better than a random test). Weak, though consistent positive correlations were identified between logged fold-change from baseline for biomarkers of renal protein reabsorption and glomerular filtration (alpha1M, beta2M, RBP, microalbumin, total protein, IgG) versus relative change in SCr from baseline over time (r=0.1-0.3) across patient groups. Better associations were identified in non-β-thal patients. Confirmed increase in SCr had the most association with RBP (Fig 1A) and beta2M (Fig 1B) in deferasirox- and DFO-treated patients, respectively. In the non-comparative trial, AUC values were 0.4-0.6 for β-thal patients; most association with NGAL (Fig 1C). In patients with other anemias, nine renal biomarkers had AUCs >0.6; most association with alpha1M (Fig 1D).Conclusions: Without definitive associations with SCr, findings do not support the clinical utility of any of the 19 renal protein biomarkers assessed for monitoring kidney function. The absence of progressive renal biomarker changes at the population level indicates that chelation therapy with deferasirox or DFO did not lead to acute/chronic or progressive renal dysfunction in these studies. [Display omitted] DisclosuresCappellini:Vifor: Honoraria; Celgene: Honoraria; Sanofi-Genzyme: Honoraria, Research Funding, Speakers Bureau; Novartis: Speakers Bureau. Quebe-Fehling:Novartis: Employment. Dieterle:Novartis: Employment. Porter:Bluebird Bio: Consultancy; Agios Pharmaceuticals: Consultancy, Honoraria; Shire: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Celegene: Consultancy.

Relevance of Platinum-free Interval and BRCA Reversion Mutations for Veliparib Monotherapy after Progression on Carboplatin/Paclitaxel for gBRCA Advanced Breast Cancer (BROCADE3 Crossover).

Safety, efficacy, and exploratory biomarker analyses were evaluated in patients with advanced HER2-negative germline breast cancer susceptibility gene (gBRCA)-associated breast cancer enrolled in the BROCADE3 trial who received crossover veliparib monotherapy after disease progression on placebo plus carboplatin/paclitaxel. Eligible patients (N = 513) were randomized 2:1 to veliparib plus carboplatin/paclitaxel or placebo plus carboplatin/paclitaxel; patients had variable platinum-free intervals (PFI) at progression. In the placebo arm, patients were eligible to receive crossover veliparib monotherapy (300-400 mg twice daily continuous). Antitumor activity and adverse events were assessed during crossover veliparib treatment. BRCA reversion mutations at crossover were analyzed retrospectively using next-generation sequencing on plasma circulating tumor DNA (ctDNA). Seventy-five patients in the placebo plus carboplatin/paclitaxel arm received ≥1 dose of crossover veliparib postprogression (mean treatment duration: 154 days). Eight of 50 (16%) patients with measurable disease had a RECIST v1.1 response. Activity was greater in patients with PFI ≥180 days compared with <180 days [responses in 23.1% (3/13) vs. 13.5% (5/37) of patients]. BRCA reversion mutations that restored protein function were detected in ctDNA from 4 of 28 patients tested, and the mean duration of crossover veliparib monotherapy was <1 month in these 4 patients versus 7.49 months in patients lacking reversion mutations. The most frequent adverse events were nausea (61%), vomiting (29%), and fatigue (24%). Crossover veliparib monotherapy demonstrated limited antitumor activity in patients who experienced disease progression on placebo plus carboplatin/paclitaxel. PFI appeared to affect veliparib activity. BRCA reversion mutations may promote cross-resistance and limit veliparib activity following progression on platinum.

106-OR: A First-in-Human Single Ascending Dose Study of Oxyntomodulin Analog LY3305677 in Healthy Subjects

LY3305677 (LY) is an acylated single chain peptide analog of mammalian oxyntomodulin designed for once weekly dosing. It has dual pharmacology of GLP-1 and glucagon and has therapeutic potential for T2D, obesity and NASH. This randomized, double blind, placebo-controlled phase 1 study assessed safety and tolerability of single ascending doses of LY. Healthy subjects (N=48) were randomized (6:2) and 47 received subcutaneous LY (6 doses: 0.03 mg to 5.0 mg) or placebo. Safety biomarkers, LY pharmacokinetics (PK), and key exploratory pharmacodynamic (PD) biomarkers were assessed including fasting insulin, glucagon, triglyceride levels, and body weight. Most common LY-related AEs were gastrointestinal events. Dose-dependent increase in nausea, decreased appetite, and vomiting were seen. Most of the events were mild and transient. Increase in heart rate was noted, which returned to baseline for most groups at follow-up visit. No injection site reactions were seen. Median time to maximum LY concentration ranged from 18.2 to 72.1 h, and geometric mean half-life ranged from 7.5 to 9.8 days. Generally, mean fasting insulin level increased within 24 h and lasted over 8 days. At Day 8, LY 2.5 mg and 5.0 mg reduced mean fasting glucagon levels by 2.33 pmol/L and 2.67 pmol/L, respectively as compared with placebo. At Day 5, mean fasting triglyceride levels reduced from baseline by 0.5 mmol/L with LY 5.0 mg as compared to 0.1 mmol/L with placebo. Change from baseline in body weight reached a maximum -2.4 kg with the 5 mg dose, versus -0.5 kg for placebo at Day 8 and this effect was sustained through Day 29 at 5 mg. LY3305677 PK properties are suitable for once-weekly dosing with a safety and tolerability profile similar to other incretins in Phase 1 trials, supporting future clinical evaluation. Disclosure L. Tham: Employee; Self; Eli Lilly and Company. M. K. Thomas: Employee; Self; Eli Lilly and Company, Stock/Shareholder; Self; Eli Lilly and Company. C. Benson: Employee; Self; Eli Lilly and Company. R. Bray: None. C. Tang: Employee; Self; Eli Lilly and Company, Employee; Spouse/Partner; Novartis AG. C. Loghin: Employee; Self; Eli Lilly and Company. Funding Eli Lilly and Company

Perspectives on statistical strategies for the regulatory biomarker qualification process.

Qualification of a biomarker for use in a medical product development program requires a statistical strategy that aligns available evidence with the proposed context of use (COU), identifies any data gaps to be filled and plans any additional research required to support the qualification. Accumulating, interpreting and analyzing available data is outlined, step-by-step, illustrated by a qualified enrichment biomarker example and a safety biomarker in the process of qualification. The detailed steps aid requestors seeking qualification of biomarkers, allowing them to organize the available evidence and identify potential gaps. This provides a statistical perspective for assessing evidence that parallels clinical considerations and is intended to guide the overall evaluation of evidentiary criteria to support a specific biomarker COU.

Preliminary clinical and biologic results of GB1275, a first-in-class oral CD11b modulator, alone and with pembrolizumab, in advanced solid tumors (KEYNOTE A36).

2505 Background: GB1275 is a first-in-class, oral CD11b modulator that reduced myeloid-derived suppressor cells (MDSCs) and tumor associated macrophages (TAMs), repolarized M2 immunosuppressive TAMs to an M1 phenotype, resulting in increased tumor infiltration of activated CD8+ T cells and antitumor efficacy in preclinical models. Here, we report preliminary results from an ongoing, first-in-human dose-escalation study in specific advanced tumors using GB1275 alone or with pembrolizumab. (NCT04060342) Methods: Phase 1 comprises dose escalation and expansion. During dose escalation, cohorts of 3 to 6 subjects were sequentially assigned to ascending dose levels of GB1275 from 100 mg to 1200 mg BID in one of two dosing regimens: Regimen A [GB1275 monotherapy orally (PO) twice a day (BID)] and Regimen B [GB1275 PO BID plus pembrolizumab 200 mg IV every 3 weeks (q3wks)]. Dose escalation was based on safety including dose-limiting toxicities (DLTs). Following dose escalation, up to 40 subjects with specific tumor types are to be treated in expansion with the selected GB1275 dose plus pembrolizumab to assess safety, pharmacokinetics, and preliminary clinical and biomarker activity. Results: As of January 8, 2021, 45 subjects were treated [44 in dose escalation: 23, Regimen A; 21, Regimen B. 1 in expansion, Regimen B], with median (range) GB1275 exposure of 42.0 days (4-263). No DLTs were reported. GB1275-related adverse events occurred in 24/45 (53.3%) subjects; photosensitivity reaction (20.0%), dysesthesia (13.3%) and pruritus (13.3%) were most frequent (≥10%). Stable disease was reported in 6/19 (31.6%) response-evaluable subjects in Regimen A and 9/16 (56.3%) in Regimen B. In Regimen B (800 mg), one partial response was reported in a subject with MSS-CRC treated for 263 days, and one prolonged stable disease (227 days) was reported in a gastric cancer (GC) subject previously treated with pembrolizumab plus bavituximab for less than 3 months due to progression; both subjects are continuing study treatment. A dose-dependent increase in GB1275 systemic exposure was observed up to 800 mg BID. Down-regulation of peripheral MDSCs was seen with both regimens. Regimen-dependent gene clusters in whole blood were noted. An increase in tumor infiltrating lymphocyte (TIL) counts was noted in both Regimens A and B. Conclusions: Dose escalation of GB1275, up to 1200 mg in Regimens A and B, demonstrated tolerability as monotherapy and combined with pembrolizumab in subjects with advanced cancers. Encouraging antitumor activity in Regimen B (800 mg) was observed in subjects with MSS-CRC and GC. Biological activity reflected by MDSC modulations in blood and TIL Increases in tumor biopsies with GB1275 alone and with pembrolizumab supports the mechanism of GB1275. GB1275 800 mg BID plus pembrolizumab 200 mg IV q3wks was selected for evaluation in the expansion phase. Clinical trial information: NCT04060342.

Toripalimab with chemotherapy as first-line treatment for advanced biliary tract tumors: Update analytic results of an open-label phase II clinical study (JS001-ZS-BC001).

e16170 Background: A phase II clinical study was conducted to evaluate the safety and efficacy of toripalimab, a novel PD-1 inhibitor, combined with chemotherapy in patients with advanced biliary tract cancers (aBTCs) (NCT03796429). The preliminary results indicated the combination treatment is well tolerable and effective. Methods: Treatment naive patients with aBTCs received toripalimab (240mg intravenously every three weeks) combined with chemotherapy (gemcitabine 1000 mg/m2 d1, d8 + S-1 40-60mg bid D1-14, Q21d). The treatment continued until the disease progress or having intolerable effects. The primary endpoints of the study were progression free survival (PFS) and overall survival (OS). The secondary endpoints were objective response rate (ORR), safety and treatment biomarkers. Results: At data cutoff (January 24, 2021), fifty aBTC patients were enrolled at Shanghai Zhongshan Hospital. Among these patients, 56% are males. The median age of the study participants was 62 years of age. The median follow-up time was 10 months (ranged from 4 to 19 months). The primary tumor type was intrahepatic cholangiocarcinoma (ICC) accounting for 48% of total cases, followed by gallbladder cancer (GBC) (40.0%), and extrahepatic cholangiocarcinoma (ECC) (12.0%). At the time of data collection, 48 eligible patients were included for data analysis. The median PFS was 7.0 months（95%CI, 5.5-9.1 months）and median OS was 16.0 months (95%CI, 12.1 to unreachable). The ORR was 27.1 % and disease control rate was 87.5% including 13 partial response (PR) and 29 stable disease (SD) cases. The most treatment related AEs (TRAE) were leukopenia (92.0%), anemia (86.0%) and rash (52.0%). Grade III/IV non-hematological TRAEs were seen in 12 patients (24.0%), including rash (n = 3), infection (n = 6), immune-related colitis (n = 1), immune-related pneumonitis (n = 1) and mucositis (n = 1). Grade III/IV hematological TRAEs were seen in 62% patients. 6 patients discontinued the study drug due to TRAE. Serious adverse events (SAE) were seen in 8 patients and 2 patients died of biliary obstruction complicated with infection. Forty-nine patients were included in biomarker analysis. The most mutated genes were TP53 (51%), KRAS (20%), CDKN2A (18%) and SMAD4 (16%). Patients with activated PI3K signaling pathway had significantly shorter PFS (P = 0.026). Tumor mutational burden (TMB) could not serve as a predictor for the efficacy of immunotherapy combined with chemotherapy. Conclusions: The clinical study of toripalimab combined with chemotherapy continued to show tolerance and efficacy in patients with aBTCs. Gene mutation profiling by NGS suggested mutated PI3K pathway might assocate with shorter PFS. Clinical trial information: NCT03796429.

A phase 1 study of SGN-B6A, an antibody-drug conjugate targeting integrin beta-6, in patients with advanced solid tumors (SGNB6A-001, Trial in Progress).

TPS3144 Background: The extracellular matrix (ECM) plays an important role in solid tumor pathogenesis and is a major focus of research and therapeutic targeting. Integrin beta-6 is a cell surface receptor that interacts with the ECM to mediate cellular adhesion. Integrin beta-6 is overexpressed in numerous solid tumors and its expression is a negative prognostic marker in cancers including colorectal, non-small cell lung, gastric, and cervical cancers. SGN-B6A is an investigational vedotin, an antibody-drug conjugate directed against integrin beta-6 to selectively deliver the cytotoxic agent monomethyl auristatin E, which binds tubulin and induces apoptosis. In multiple xenograft models, treatment with SGN-B6A resulted in tumor growth delay and regression in tumor volume when compared to non-binding control. Methods: SGNB6A-001 (NCT04389632) is a phase 1, first-in-human, open-label, multicenter study designed to evaluate the safety, tolerability, pharmacokinetics (PK), and antitumor activity of SGN-B6A in adults with select advanced solid tumors. Primary objectives are to evaluate the safety and tolerability of SGN-B6A in patients with advanced solid tumors, identify the maximum tolerated dose, and identify a recommended dose and schedule. The study has 2 parts: dose escalation (Part A) and dose expansion with multiple disease-specific cohorts and a biology cohort (Part B). SGN-B6A will initially be given by intravenous infusion on Days 1, 8, and 15 of 21-day cycles. The dose escalation (Part A) will be conducted using the modified toxicity probability interval method to determine a dose that demonstrates a dose-limiting toxicity rate of 25% with a 5% margin. The dose and schedule for Part B will be determined based on evaluation of safety, PK, and pharmacodynamic biomarkers. Response evaluations will be based on RECIST v1.1. Patients must be ≥18 years old and have histologically or cytologically confirmed metastatic or unresectable solid malignancy within one of the following tumor types: non-small cell lung cancer, head and neck squamous cell cancer, breast cancer, esophageal cancer, ovarian cancer, cutaneous squamous cell cancer, exocrine pancreatic adenocarcinoma, bladder cancer, cervical cancer, or gastric cancer. After an appropriate dose and schedule are determined in Part A, safety and preliminary antitumor efficacy of SGN-B6A will be evaluated in indication-specific cohorts (Part B). This study is ongoing in sites across North America and Europe. Clinical trial information: NCT04389632.

Initial results of a first-in-human, dose escalation study of a cell-based vaccine in HLA A*02+ patients (pts) with recurrent, locally advanced or metastatic HPV16+ solid tumors: SQZ-PBMC-HPV-101.

2536 Background: Ineffective MHC-I presentation of tumor antigens to CD8+ T cells limits T cell activation and the efficacy of cancer vaccines. The Cell Squeeze technology drives peripheral blood mononuclear cells (PBMCs) through a microfluidic chip leading to temporary cell membrane disruption and delivery of HPV16 E6 and E7 antigens cytosolically. These antigen presenting cells (APC) were matured with CpG7909 and were not genetically modified. Preclinically, this approach showed improvement in MHC-I presentation for human and murine cells. In murine tumor studies, m-SQZ-PBMC-HPV elicited robust CD8+ T cell responses and improved anti-tumor effects when compared to other vaccine modalities. Methods: SQZ-PBMC-HPV-101 included pts with incurable HPV16+ cancers progressing after unlimited prior therapy, ECOG 0-1, adequate organ function and a biopsiable lesion. After leukapheresis at the study site, manufacturing of the cryopreserved product took &lt; 24 hours with a vein-to-vein time of approx. 1 week. Out-patient SQZ-PBMC-HPV was given IV q 3 weeks without a conditioning regimen. Double antigen priming (DP) was introduced with Cohort 3 and occurred on Cycle 1 Days 1 and 2. Maximum treatment duration for each patient was determined by the cell batch size. Response was assessed via RECIST 1.1 and iRECIST. Investigational biomarkers were measured pre- and post-treatment. Results: 12 pts [anal (7), head and neck (3), and cervical (2)] were dosed in 3 cohorts (3 pts in 0.5 x10e6/kg, 5 pts in 2.5 x10e6/kg, and 4 pts in 2.5x 10e6/kg [DP]). Median lines of prior Tx were 4 (range 1 - 7) and all but one pt were pretreated with checkpoint inhibitors (CPI); 10 pts had liver or lung metastases. All batches of SQZ-PBMC-HPV demonstrated CD8 activation in vitro after thawing, and batch size did not limit therapy duration at dose levels tested to date. Median number of doses were 3 (3 - 10), 3 (2 - 4), and 3 (3 – 4) in the 3 cohorts, respectively. One pt (10 doses) remained on study for 42 weeks. Tx was well-tolerated and there were no DLTs, Grade (G) &gt;3 related SAEs or related G &gt;3 AEs. One pt in cohort 1 experienced both a G2 infusion-related reaction and cytokine release syndrome. One pt in cohort 2 was not evaluable for DLT. Four out of 10 evaluable pts had stable disease per RECIST 1.1 as the best response. Preliminary tumor analyses pre- and post-therapy indicated increased immune activity in some patients after SQZ infusion. Conclusions: SQZ-PBMC-HPV-101 demonstrated clinical feasibility of the Cell Squeeze technology and favorable tolerability of engineered APCs. The study allows for the characterization of the immunogenicity of engineered APCs in humans. Preliminary results warrant the testing in combination with CPI. Efficacy, safety, and correlative biomarker data will be presented, from pre- and post-therapy biopsies and blood samples. Clinical trial information: NCT04084951.

Safety, pharmacokinetics, efficacy, and preliminary biomarker data of first-in-class BI 765063, a selective SIRPα inhibitor: Results of monotherapy dose escalation in phase 1 study in patients with advanced solid tumors.

2623 Background: BI 765063 is a humanized IgG4 monoclonal antibody antagonist of SIRPα (Signal Regulatory Protein α), which blocks the “don't eat me” signal of the SIRPα/CD47 axis, a critical innate immune checkpoint. SIRPα is expressed on myeloid cells. BI 765063 binds to the V1 SIRPα allele with high affinity and to the V2 SIRPα allele with low affinity. BI 765063 lacks SIRPγ binding to preserve T-cell activation. We report results of the completed BI 765063 monotherapy dose escalation in patients with advanced solid tumors. Methods: This study involves a step 1 dose escalation to determine the dose-limiting toxicities (DLT) and maximum tolerated dose (MTD), then a step 2 dose-confirmation expansion at recommended phase 2 dose. In Step 1, BI 765063 ascending doses, given IV every 3 weeks, were tested using a Bayesian Logistic Regression Model (BLRM) approach with overdose control. The endpoints were safety, pharmacokinetics, receptor occupancy (RO) in peripheral CD14+ monocytes and efficacy (RECIST 1.1). Results: Fifty patients (26 V1/V1, 24 V1/V2) received at least one dose of BI 765063. The most frequent tumors were ovarian (9), colorectal (8), lung (5), breast (4), melanoma (3), and kidney (3). No DLTs were reported up to the highest dose tested. MTD was not reached. The most frequent related adverse events were infusion related reaction (IRR) (46%), fatigue (12%), headache (10%), arthralgia and diarrhea (8% each). All related adverse events were mild to moderate, except one case of IRR Grade 3. No related anemia nor thrombocytopenia were observed. BI 765063 showed dose proportional exposure and full RO saturation in Cycle 1 after the fourth dose level. Clinical benefit was observed in 21/47 (45%) patients evaluable per RECIST 1.1. One patient with hepatocellular carcinoma (HCC) with liver and lung metastases and 7 prior lines of therapy showed a durable partial response maintained for 27 weeks treatment (ongoing). The baseline tumor biopsy of this patient showed high CD8 T-cell and macrophage infiltration. There was an increase in CD8 T-cell infiltration and activation on treatment. An increase in PD-L1 expression on tumor cells 2 weeks after first dosing was also observed. Analysis of paired tumor biopsies in other patients is ongoing. Conclusions: The first-in-class SIRPα inhibitor BI 765063 was well-tolerated, showed monotherapy activity, and sustained RO saturation. A durable partial response was observed in an advanced HCC patient. The on-treatment biopsy of the responder showed an increase in CD8 T-cell infiltration and activation. PD-L1 expression on tumor cells also increased. BI 765063 dose escalation in combination with ezabenlimab (anti-PD1 antibody) is ongoing. Clinical trial information: NCT03990233.

L-citrulline: A preclinical safety biomarker for the small intestine in rats and dogs in repeat dose toxicity studies

IntroductionGastrointestinal (GI) toxicity is still an issue within drug development, especially for novel oncology drugs. The identification of GI mucosal damage at an early stage with high sensitivity and specificity across preclinical species and humans remains difficult. To date, in preclinical studies, no qualified mechanistic, diagnostic or prognostic biomarkers exist for GI mucosal toxicity. l-citrulline is one of the most promising biomarker candidates used in clinical settings to quantify enterocyte integrity in various small intestinal diseases. l-citrulline is an intermediate metabolic amino acid produced mainly by functional enterocytes of the small intestine, whereby enterocyte loss will cause a drop in circulating l-citrulline. MethodsIn several repeat-dose toxicity studies, plasma l-citrulline has been evaluated as a potential safety biomarker for intestinal toxicity in beagle dogs and Wistar (Han) rats treated with different oncological drug candidates in drug development. Clinical observations and body weight determinations were performed during the pretreatment, treatment and treatment-free recovery period as well as toxicokinetic, gross and histopathology examinations. The quantitative determination of plasma l-citrulline levels during the pretreatment (only dogs), treatment and treatment-free recovery period were performed using an HPLC MS/MS assay. In cynomolgus monkeys, the first investigations on baseline l-citrulline levels were performed. ResultsIn dogs, a dose- and exposure-dependent decrease of up to 50% in plasma l-citrulline was seen without histopathological alterations. However, a decrease of more than 50% in comparison to the individual animal pretreatment value of l-citrulline correlated very well with histopathological findings (intestinal crypt necrosis, villus atrophy, enterocyte loss) and clinical signs (bloody faeces and diarrhoea). During a treatment-free recovery period, a trend of increasing levels was observed in dogs. In rats, absolute l-citrulline plasma levels of treated animals decreased compared to the values of the concurrent control group. This decrease also correlated with the histopathological findings in the small intestine (single cell necrosis and mucosa atrophy). Because of a large physiological variation in l-citrulline plasma levels in dogs and rats, a clear cut-off value for absolute l-citrulline levels predictive of intestinal mucosal toxicity was difficult to establish. However, a > 50% decrease in l-citrulline plasma levels during the treatment period strongly correlated with histopathological findings. DiscussionBased on the performed analysis, a longitudinal investigation of l-citrulline plasma levels for individual animals in the control and treatment groups is essential and pretreatment values of l-citrulline levels in rodents would be highly informative. Overall, further cross-species comparison (Cynomolgus monkey, mouse) and implementation in clinical trials as exploratory biomarker is essential to foster the hypothesis and to understand completely the clinical relevance of l-citrulline as a small intestine biomarker.

Qualification of translational safety biomarkers.

Safety biomarkers are important drug development tools, both preclinically and clinically. It is a straightforward process to correlate the performance of nonclinical safety biomarkers with histopathology, and ideally, the biomarker is useful in all species commonly used in safety assessment. In clinical validation studies, where histopathology is not feasible, safety biomarkers are compared to the response of standard biomarkers and/or to clinical adjudication. Worldwide, regulatory agencies have put in place processes to qualify biomarkers to provide confidence in the manner of use and interpretation of biomarker data in drug development studies. This paper describes currently qualified safety biomarkers which can be utilized to monitor for nephrotoxicity and cardiotoxicity and ongoing projects to qualify safety biomarkers for liver, skeletal muscle, and vascular injury. In many cases, the development and use of these critical drug development tools is dependent upon partnerships and the precompetitive sharing of data to support qualification efforts.

A randomized, placebo-controlled experimental medicine study of RIPK1 inhibitor GSK2982772 in patients with moderate to severe rheumatoid arthritis

BackgroundReceptor-interacting protein kinase 1 (RIPK1) is a key mediator of inflammation through cell death and proinflammatory cytokine production. This multicenter, randomized, double-blind (sponsor-unblinded), placebo-controlled, experimental medicine study evaluated the safety, pharmacokinetics (PK), and preliminary efficacy of GSK2982772, a RIPK1 inhibitor, in moderate to severe rheumatoid arthritis (RA).MethodsPatients with moderate to severe RA who had received ≥12 weeks’ stable-dose conventional synthetic disease-modifying antirheumatic drug (csDMARD) therapy were randomized (2:1) to GSK2982772 60 mg or placebo orally 2 or 3 times daily for 84 days. Safety, PK, disease activity, joint damage, and pharmacodynamic (PD) biomarkers were assessed at days 43 and 85.ResultsA total of 52 patients were randomized (placebo, 18; GSK2982772, 34). Adverse events (AEs) were reported in 13 (72%) in patients in the placebo group (n = 3 b.i.d; n = 10 t.i.d.) and 20 (61%) in the GSK2982772 group (n = 3 b.i.d; n = 17 t.i.d.). All treatment-related AEs were mild/moderate, except one severe case of alopecia areata at day 49 and retinal vein thrombosis at day 66 (which led to withdrawal from the study) in patients receiving GSK2982772 t.i.d. Disease Activity Score in 28 Joints–C-reactive protein (DAS28-CRP) scores, ACR20/50/70 response, and rates of low disease activity and remission were similar between placebo and GSK2982772 arms.ConclusionsThese results suggest that inhibition of RIPK1 activity at the GSK2982772 exposure levels evaluated do not translate into meaningful clinical improvement of RA.Trial registrationClinicalTrials.gov Identifier: NCT02858492. Registered 8 August 2016.

A pilot study evaluating GSK1070806 inhibition of interleukin-18 in renal transplant delayed graft function

IntroductionDelayed graft function (DGF) following renal transplantation is a manifestation of acute kidney injury (AKI) leading to poor long-term outcome. Current treatments have limited effectiveness in preventing DGF. Interleukin-18 (IL18), a biomarker of AKI, induces interferon-γ expression and immune activation. GSK1070806, an anti-IL18 monoclonal antibody, neutralizes activated (mature) IL18 released from damaged cells following inflammasome activation. This phase IIa, single-arm trial assessed the effect of a single dose of GSK1070806 on DGF occurrence post donation after circulatory death (DCD) kidney transplantation.MethodsThe 3 mg/kg intravenous dose was selected based on prior studies and physiologically based pharmacokinetic (PBPK) modeling, indicating the high likelihood of a rapid and high level of IL18 target engagement when administered prior to kidney allograft reperfusion. Utilization of a Bayesian sequential design with a background standard-of-care DGF rate of 50% based on literature, and confirmed via extensive registry data analyses, enabled a statistical efficacy assessment with a minimal sample size. The primary endpoint was DGF frequency, defined as dialysis requirement ≤7 days post transplantation (except for hyperkalemia). Secondary endpoints included safety, pharmacokinetics and pharmacodynamic biomarkers.ResultsGSK1070806 administration was associated with IL18-GSK1070806 complex detection and increased total serum IL18 levels due to IL18 half-life prolongation induced by GSK1070806 binding. Interferon-γ−induced chemokine levels declined or remained unchanged in most patients. Although the study was concluded prior to the Bayesian-defined stopping point, 4/7 enrolled patients (57%) had DGF, exceeding the 50% standard-of-care rate, and an additional two patients, although not reaching the protocol-defined DGF definition, demonstrated poor graft function. Six of seven patients experienced serious adverse events (SAEs), including two treatment-related SAEs.ConclusionOverall, using a Bayesian design and extensive PBPK dose modeling with only a small sample size, it was deemed unlikely that GSK1070806 would be efficacious in preventing DGF in the enrolled DCD transplant population.Trial registrationNCT02723786.