PD-L1 blockade in combination with carboplatin as immune induction in metastatic lobular breast cancer: the GELATO trial.

Invasive lobular breast cancer (ILC) is the second most common histological breast cancer subtype, but ILC-specific trials are lacking. Translational research revealed an immune-related ILC subset, and in mouse ILC models, synergy between immune checkpoint blockade and platinum was observed. In the phase II GELATO trial ( NCT03147040 ), patients with metastatic ILC were treated with weekly carboplatin (area under the curve 1.5 mg ml-1 min-1) as immune induction for 12 weeks and atezolizumab (PD-L1 blockade; triweekly) from the third week until progression. Four of 23 evaluable patients had a partial response (17%), and 2 had stable disease, resulting in a clinical benefit rate of 26%. From these six patients, four had triple-negative ILC (TN-ILC). We observed higher CD8+ T cell infiltration, immune checkpoint expression and exhausted T cells after treatment. With this GELATO trial, we show that ILC-specific clinical trials are feasible and demonstrate promising antitumor activity of atezolizumab with carboplatin, particularly for TN-ILC, and provide insights for the design of highly needed ILC-specific trials.

Efficacy and safety of pembrolizumab for patients with previously treated advanced vulvar squamous cell carcinoma: Results from the phase 2 KEYNOTE-158 study.

OBJECTIVE: Treatment options for advanced vulvar cancer are limited. We evaluated pembrolizumab monotherapy in patients with advanced vulvar squamous cell carcinoma (SCC) enrolled in the phase 2 multicohort, open-label KEYNOTE-158 study (NCT02628067). METHODS: Eligible patients had histologically or cytologically documented advanced vulvar SCC with prior treatment failure, measurable disease per RECIST v1.1, ECOG performance status 0-1, and a tumor sample available for biomarker analysis. Pembrolizumab 200 mg was administered intravenously Q3W for up to 35 cycles (approximately 2 years). The primary endpoint was objective response rate (ORR) per RECIST v1.1 by independent central radiologic review in all patients and subgroups based on PD-L1 combined positive score (≥1 [PD-L1-positive] versus <1 [PD-L1-negative]). RESULTS: 101 patients were enrolled. Median time from first dose to data cutoff was 36.0 months. The ORR (95% CI) was 10.9% (5.6%-18.7%) among all patients, 9.5% (4.2%-17.9%) among the 84 patients with PD-L1-positive tumors, and 28.6% (3.7%-71.0%) among the 7 patients with PD-L1-negative tumors. Among patients with a response, median DOR was 20.4 (range, 2.1+ to 28.0) months. Median (95% CI) PFS and OS were 2.1 (2.0-2.1) and 6.2 (4.9-9.4) months, respectively. Treatment-related AEs occurred in 50.5% of patients (grade 3-5, 11.9%) and led to discontinuation of treatment in 5.0% of patients. Two deaths were considered treatment-related (hepatitis, n = 2). CONCLUSIONS: Pembrolizumab monotherapy was associated with durable responses in a subset of patients with vulvar SCC. Responses occurred regardless of tumor PD-L1 status. No new safety signals emerged; overall, pembrolizumab was well tolerated.

Pembrolizumab for previously treated advanced anal squamous cell carcinoma: results from the non-randomised, multicohort, multicentre, phase 2 KEYNOTE-158 study.

BACKGROUND: Outcomes in advanced anal squamous cell carcinoma are poor, with few treatment options and controlled clinical trials. We evaluated the efficacy and safety of pembrolizumab in patients with advanced anal squamous cell carcinoma (cohort A) from the phase 2 KEYNOTE-158 study. METHODS: Eligible patients enrolled in the ongoing non-randomised, multicohort, multicentre, phase 2 KEYNOTE-158 study, which was done across 38 centres worldwide, were aged 18 years or older; had histologically or cytologically confirmed advanced or metastatic anal squamous cell carcinoma; had previous failure of or intolerance to standard therapy or no standard therapy options; and had a PD-L1-evaluable tissue sample. Patients received pembrolizumab 200 mg intravenously every 3 weeks for 2 years, or until disease progression, unacceptable toxicity, investigator's decision to withdraw the patient from the study, or withdrawal of patient consent. The primary endpoint was objective response, as assessed by Response Evaluation Criteria in Solid Tumors version 1.1. Efficacy and safety analyses included all patients who received at least one dose of pembrolizumab. The trial is registered with ClinicalTrials.gov, NCT02628067. FINDINGS: Between March 3, 2016, and July 23, 2018, 163 patients were screened, of whom 112 were enrolled and treated in the anal cancer cohort. 91 (81%) patients were female, 104 (93%) had M1 disease, and 75 (67%) had PD-L1-positive tumours. The median time from first dose to data cutoff (June 27, 2019) was 34·7 months (IQR 32·5-36·4). 12 (11%, 95% CI 6-18) patients had an objective response, including 11 (15%, 8-25) of 75 patients with PD-L1-positive tumours and one (3%; 0-17) of 30 patients with PD-L1-negative tumours. 68 (61%) patients had treatment-related adverse events (20 [18%] patients had grade 3-4 adverse events), the most common of which were fatigue (17 patients), diarrhoea (13), hypothyroidism (13), and nausea (13). Serious treatment-related adverse events occurred in 12 (11%) patients. 25 (22%) patients had immune-mediated adverse events, and one (1%) had an infusion reaction. There were no treatment-related deaths. INTERPRETATION: Pembrolizumab monotherapy is a possible treatment option with a favourable benefit-risk ratio for patients with previously treated advanced anal squamous cell carcinoma who have no alternative satisfactory treatment options. FUNDING: Merck Sharp & Dohme.

Effects of the Moderate CYP3A4 Inhibitor Erythromycin on the Pharmacokinetics of Palbociclib: A Randomized Crossover Trial in Patients With Breast Cancer.

Palbociclib is an oral inhibitor of cyclin-dependent kinases 4 and 6 used in the treatment of locally advanced and metastatic breast cancer, and is extensively metabolized by cytochrome P450 enzyme 3A4 (CYP3A4). A pharmacokinetic/pharmacodynamic relationship between palbociclib exposure and neutropenia is well known. This study aimed to investigate the effects of the moderate CYP3A4 inhibitor erythromycin on the pharmacokinetics of palbociclib. We performed a randomized crossover trial comparing the pharmacokinetics of palbociclib monotherapy 125 mg once daily (q.d.) with palbociclib 125 mg q.d. plus oral erythromycin 500 mg three times daily for seven days. Pharmacokinetic sampling was performed at steady-state for both dosing schedules. Eleven evaluable patients have been enrolled. For palbociclib monotherapy, geometric mean area under the plasma concentration-time curve from zero to infinity (AUC0-24h ), maximum plasma concentration (Cmax ), and minimum plasma concentration (Cmin ) were 1.46 × 103  ng•h/mL (coefficient of variation (CV) 45.0%), 80.5 ng/mL (CV 48.5%), and 48.4 ng/mL (CV 38.8%), respectively, compared with 2.09 × 103  ng•h/mL (CV 49.3%, P = 0.000977), 115 ng/mL (CV 53.7%, P = 0.00562), and 70.7 ng/mL (CV 47.5%, P = 0.000488) when palbociclib was administered concomitantly with erythromycin. Geometric mean ratios (90% confidence intervals) of AUC0-24h , Cmax , and Cmin for palbociclib plus erythromycin vs. palbociclib monotherapy were 1.43 (1.24-1.66), 1.43 (1.20-1.69), and 1.46 (1.30-1.63). Minor differences in adverse events were observed, and only one grade ≥ 3 toxicity was observed in this short period of time. To conclude, concomitant intake of palbociclib with the moderate CYP3A4 inhibitor erythromycin resulted in an increase in palbociclib AUC0-24h and Cmax of both 43%. Therefore, a dose reduction of palbociclib to 75 mg q.d. is rational, when palbociclib and moderate CYP3A4 inhibitors are used concomitantly.

Clinical Pharmacokinetics and Pharmacodynamics of the Cyclin-Dependent Kinase 4 and 6 Inhibitors Palbociclib, Ribociclib, and Abemaciclib.

Palbociclib, ribociclib, and abemaciclib are inhibitors of the cyclin-dependent kinases 4 and 6 approved for the treatment of locally advanced or metastatic breast cancer. In this review, we provide an overview of the available clinical pharmacokinetic and pharmacodynamic characteristics of these novel drugs, summarize the results of food-effect and drug-drug interaction studies, and highlight exposure-response and exposure-toxicity relationships. All three drugs exhibit a large inter-individual variability in exposure (coefficient of variation range 40-95% for minimum plasma concentration), are extensively metabolized by cytochrome P450 3A4, and have their brain penetration limited by efflux transporters. Abemaciclib has three active metabolites with similar potency that are clinically relevant (i.e., M2, M20, M18), whereas the metabolites of palbociclib and ribociclib are not of clinical significance. Pharmacokinetic exposure increases in a dose-proportional manner for palbociclib, whereas exposure increases under- and over-proportionally with an increasing dose for abemaciclib and ribociclib, respectively. High exposure is associated with an increased risk of neutropenia, and for ribociclib also to corrected QT prolongation. For abemaciclib, a clear exposure-efficacy relationship has been described, while for palbociclib and ribociclib exposure-response analyses remain inconclusive. Future studies are needed to address exposure-efficacy relationships to further improve dosing.

Mass balance and metabolite profiling of 14C-guadecitabine in patients with advanced cancer.

Purpose The objective of this mass balance trial was to determine the excretory pathways and metabolic profile of the novel anticancer agent guadecitabine in humans after administration of a 14C-radiolabeled dose of guadecitabine. Experimental design Included patients received at least one cycle of 45 mg/m2 guadecitabine subcutaneously as once-daily doses on Days 1 to 5 of a 28-day cycle, of which the 5th (last) dose in the first cycle was spiked with 14C-radiolabeled guadecitabine. Using different mass spectrometric techniques in combination with off-line liquid scintillation counting, the exposure and excretion of 14C-guadecitabine and metabolites in the systemic circulation, excreta, and intracellular target site were established. Results Five patients were enrolled in the mass balance trial. 14C-guadecitabine radioactivity was rapidly and almost exclusively excreted in urine, with an average amount of radioactivity recovered of 90.2%. After uptake in the systemic circulation, guadecitabine was converted into ß-decitabine (active anomer), and from ß-decitabine into the presumably inactive metabolites M1-M5. All identified metabolites in plasma and urine were ß-decitabine related products, suggesting almost complete conversion via cleavage of the phosphodiester bond between ß-decitabine and deoxyguanosine prior to further elimination. ß-decitabine enters the intracellular activation pathway, leading to detectable ß-decitabine-triphosphate and DNA incorporated ß-decitabine levels in peripheral blood mononuclear cells, providing confirmation that the drug reaches its DNA target site. Conclusion The metabolic and excretory pathways of guadecitabine and its metabolites were successfully characterized after subcutaneous guadecitabine administration in cancer patients. These data support the clinical evaluation of safety and efficacy of the subcutaneous guadecitabine drug product.

Mathematical modeling of the glucagon challenge test.

A model for the homeostasis of glucose through the regulating hormones glucagon and insulin is described. It contains a subsystem that models the internalization of the glucagon receptor. Internalization is a mechanism in cell signaling, through which G-protein coupled receptors are taken from the surface of the cell to the endosome. The model is used to interpret data from a glucagon challenge test in which subjects have been under treatment with a novel glucagon receptor anti-sense drug which is aimed at reducing the number of receptors in the liver. It is shown how the receptor internalization results in tolerance of the blood glucose concentration to glucagon-induced hyperglycemia. We quantify the reduction of the number of receptors using the model and the data before and after treatment.

First proof of pharmacology in humans of a novel glucagon receptor antisense drug.

Fasting and postprandial hyperglucagonemia in type 2 diabetes mellitus (T2DM) patients cause excessive hepatic glucose production (HGP), suggesting that attenuation of hepatic glucagon action could be a therapeutic strategy for T2DM. In this study we evaluated the safety, tolerability, PK, and pharmacodynamics in healthy human volunteers of single and multiple doses (50-400 mg) ISIS 325568, a 2'-O-MOE antisense (ASO) developed to reduce hepatic glucagon receptor (GCGR) mRNA expression. In the multiple dose cohorts, treatment consisted of eight doses of ISIS 325568 or placebo over 6-weeks. Drug effects were assessed using serial fasting glucagon measurements and the glycemic response to a glucagon challenge at baseline and at the end of 6-week treatment. ISIS 325568 was not associated with clinically relevant changes. Dose-dependent predominantly mild injection site reactions were the most common side-effect. Active treatment caused a gradual increase in fasting glucagon levels and, compared to placebo, a significantly blunted glucagon-induced increase in plasma glucose AUC (24%, P < 0.0001) and HGP (13%, P = 0.007) at the 400 mg/week dose. Six weeks treatment with ISIS 325568 in healthy volunteers attenuated glucagon-stimulated HGP and glucose excursions, supporting further evaluation of the GCGR antisense approach in patients with T2DM.

Hydrolyzed casein decreases postprandial glucose concentrations in T2DM patients irrespective of leucine content.

Lifestyle modifications, including diet, are important in the prevention and management of type 2 diabetes mellitus (T2DM). However, limited information is available on the effects of single doses of meal replacements, particularly with regard to their effect on postprandial glucose. Therefore, a study was performed comparing the effects of a single meal replacement in T2DM patients on postprandial serum glucose, insulin, and glucagon. This randomized, double-blind, partial cross-over study was performed in 36 T2DM patients who continued their oral anti-diabetic medication. Each patient received three out of four treatments separated by 7 days. The treatments were a proprietary casein hydrolysate (insuVida™) alone or with additional leucine, unhydrolyzed casein, or placebo. Blood sampling was done for 4 hr. Treatments were compared using repeated measures ANOVA. Results are given as an estimate of the difference (%) for the 4-hr epoch. Glucose concentrations were lowered by -4.7% by insuVida and insuVida plus added leucine compared to placebo (95% CI: -1.6 to -7.7%), while the effect of unhydrolyzed casein was -1.7% (-4.8 to 1.5%). Addition of leucine to insuVida induced the greatest increase in insulin (i.e., 51.8%; 41.1 to 63.4%). All three treatments increased glucagon concentrations by 14% (8 to 20%) compared to placebo. A single dose of insuVida™ with or without addition of leucine significantly lowered plasma glucose compared to placebo and intact casein in T2DM patients. This is most likely due to an insulinotropic effect of insuVida. The data suggest that this type of intervention may be a viable treatment strategy in T2DM.