Evaluation of the Pharmacokinetic-Pharmacodynamic relationship, Metabolism and Plasma Protein Binding of the novel antitumor agent, 2-Methoxyestradiol (2ME2), following oral administration in patients with solid tumors.

The goal of this study was to determine safety, tolerability and pharmacokinetics of 2ME2 in patients with solid tumors and determine maximum tolerated dose (MTD). The following hypotheses were tested: 1) 2ME2 will be well tolerated in clinic when given orally and will have quantifiable effects on the ex vivo markers of angiogenesis and apoptosis; 2) 2ME2 will exhibit linear pharmacokinetics; 3) Plasma protein binding will be extensive and linear; 4) Sulfation will be the major metabolic pathway for 2ME2.This was a phase I dose escalation study. Twenty patients with refractory solid tumors were enrolled. 2ME2 was administered orally starting at 400 mg bid with dose escalation upto 3000 mg bid. Pharmacokinetic sampling was done up to 50 hours after single oral dose for characterization of pharmacokinetics and plasma drug concentrations which were determined by liquid chromatography tandem mass-spectrometry [LC/MS/MS, LOQ: 1ng/mL]. Circulating plasma concentrations were very low at all dose levels with high interindividual pharmacokinetic variability. Median plasma half-life was about 1-2 days. The unphysiologically high oral CL/F and Vd/F reflect low oral bioavailability of 2ME2. There was no dose proportional increase in Cmax or AUClast. There were no dose limiting toxicities at highest dose level, therefore MTD was not defined. The trial was closed due to extremely low plasma concentrations of 2ME2 achieved. Hepatic in vitro metabolism studies showed that 2ME2 was metabolized by CYP 450 enzymes (CYP 1A1, 1A2, 3A4, 3A5 and 2E1) to four major metabolites. Hepatic phase II metabolism studies revealed two major glucuronide metabolites of 2ME2. Sulfation did not play a major role in metabolism of 2ME2. Total in-vivo hepatic clearance was estimated as 862 mL/min, primarily due to glucuronidation. Less than 0.01 % of total administered dose of 2ME2 was excreted unchanged in urine, and about 1% was excreted as glucuronides. Plasma protein binding of 2ME2 was studied using equilibrium dialysis. Mean unbound fraction of 2ME2 (fu) in plasma of patients and healthy human volunteers was 0.019 ± 0.0043 and 0.027 ± 0.0019 respectively. Binding was concentration-independent and unaffected by presence of 2-methoxyestrone. 2ME2 binds to albumin, a1-acid glycoprotein (AAG) and sex-hormone binding globulin (SHBG)

A first-in-human study of the anti-LAG-3 antibody favezelimab plus pembrolizumab in previously treated, advanced microsatellite stable colorectal cancer

Advanced; Colorectal cancerAvanzado; Cáncer colorrectalAvançat; Càncer colorrectalBackground Treatment options are limited for participants with microsatellite stable (MSS) metastatic colorectal cancer (mCRC) that progressed after two or more prior therapies. Studies have shown that blockade of both lymphocyte-activation gene 3 (LAG-3) and programmed cell death protein 1 (PD-1) can improve antitumor activity. Here, we evaluate the antitumor activity of the LAG-3 antibody favezelimab alone or in combination with pembrolizumab in participants with MSS mCRC. Patients and methods Eligible participants with MSS PD-1/programmed death-ligand 1 (PD-L1) treatment-naive mCRC that progressed on two or more prior therapies received 800 mg favezelimab, 800 mg favezelimab plus 200 mg pembrolizumab, or 800 mg favezelimab/200 mg pembrolizumab co-formulation, every 3 weeks. The primary endpoint was safety, the secondary endpoint was objective response rate (ORR), and exploratory endpoints included duration of response, progression-free survival (PFS), and overall survival (OS). Results At the data cut-off date of 23 October 2020, a total of 20 participants received favezelimab alone, 89 received favezelimab plus pembrolizumab (including as favezelimab/pembrolizumab co-formulation); 48 had PD-L1 combined positive score (CPS) ≥1 tumors. At this interim analysis median follow-up was 5.8 months with favezelimab and 6.2 with favezelimab plus pembrolizumab. Treatment-related adverse events (TRAEs) were 65% with favezelimab and 65.2% with favezelimab plus pembrolizumab. Grade ≥3 TRAEs were 15% with favezelimab and 20% with favezelimab plus pembrolizumab. No grade 5 TRAEs occurred. Common TRAEs (≥15%) included fatigue (20.0%), nausea (15.0%) with favezelimab, and fatigue (16.9%) with favezelimab plus pembrolizumab. Confirmed ORR was 6.3% with favezelimab plus pembrolizumab, with median duration of response of 10.6 months (range 5.6-12.7 months), median OS of 8.3 months (95% confidence interval 5.5-12.9 months), and median PFS of 2.1 months (1.9-2.2 months). In an exploratory analysis of PD-L1 CPS ≥1 tumors, the confirmed ORR was 11.1%, median OS was 12.7 months (4.5 to not reached), and median PFS was 2.2 months (1.8-4.2 months) with favezelimab plus pembrolizumab. Conclusions Favezelimab with or without pembrolizumab had a manageable safety profile, with no treatment-related deaths. Promising antitumor activity was observed with combination therapy, particularly in participants with PD-L1 CPS ≥1 tumors.This work was supported by Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA (no grant number)

Phase 1b study to assess the safety, tolerability, and clinical activity of pamiparib in combination with temozolomide in patients with locally advanced or metastatic solid tumors

BackgroundPamiparib is a potent, selective, poly (ADP-ribose) polymerase 1/2 inhibitor that demonstrates synthetic lethality in cells with breast cancer susceptibility gene mutations or other homologous recombination deficiency. This two-stage phase 1b study (NCT03150810) assessed pamiparib in combination with temozolomide (TMZ) in adult patients with histologically confirmed locally advanced and metastatic solid tumors.MethodsOral pamiparib 60 mg was administered twice daily. During the dose-escalation stage, increasing doses of TMZ (40-120 mg once daily pulsed or 20-40 mg once daily continuous) were administered to determine the recommended dose to be administered in the dose-expansion stage. The primary objectives were to determine safety and tolerability, maximum tolerated/administered dose, recommended phase 2 dose and schedule, and antitumor activity of pamiparib in combination with TMZ. Pharmacokinetics of pamiparib and TMZ and biomarkers were also assessed.ResultsAcross stages, 139 patients were treated (dose escalation, n = 66; dose expansion, n = 73). The maximum tolerated dose of TMZ, which was administered during dose expansion, was 7-day pulsed 60 mg once daily. The most common treatment-emergent adverse events (TEAEs) were anemia (dose escalation, 56.1%; dose expansion, 63.0%), nausea (dose escalation, 54.5%; dose expansion, 49.3%), and fatigue (dose escalation, 48.5%; dose expansion, 47.9%). In the dose-escalation stage, four patients experienced dose-limiting toxicities (three neutropenia and one neutrophil count decreased). No TEAEs considered to be related to study drug treatment resulted in death. Antitumor activity was modest, indicated by confirmed overall response rate (dose escalation, 13.8%; dose expansion, 11.6%), median progression-free survival (3.7 and 2.8 months), and median overall survival (10.5 and 9.2 months). Administration of combination therapy did not notably impact pamiparib or TMZ pharmacokinetics.ConclusionsPamiparib in combination with TMZ had a manageable safety profile. Further investigation of the efficacy of this combination in tumor types with specific DNA damage repair deficiencies is warranted

Non-coding RNAs underlie genetic predisposition to breast cancer

Funder: National Breast Cancer Foundation; doi: http://dx.doi.org/10.13039/501100001026Abstract: Background: Genetic variants identified through genome-wide association studies (GWAS) are predominantly non-coding and typically attributed to altered regulatory elements such as enhancers and promoters. However, the contribution of non-coding RNAs to complex traits is not clear. Results: Using targeted RNA sequencing, we systematically annotated multi-exonic non-coding RNA (mencRNA) genes transcribed from 1.5-Mb intervals surrounding 139 breast cancer GWAS signals and assessed their contribution to breast cancer risk. We identify more than 4000 mencRNA genes and show their expression distinguishes normal breast tissue from tumors and different breast cancer subtypes. Importantly, breast cancer risk variants, identified through genetic fine-mapping, are significantly enriched in mencRNA exons, but not the promoters or introns. eQTL analyses identify mencRNAs whose expression is associated with risk variants. Furthermore, chromatin interaction data identify hundreds of mencRNA promoters that loop to regions that contain breast cancer risk variants. Conclusions: We have compiled the largest catalog of breast cancer-associated mencRNAs to date and provide evidence that modulation of mencRNAs by GWAS variants may provide an alternative mechanism underlying complex traits

Characterization of In Vitro and In Vivo Metabolic Pathways of the Investigational Anticancer Agent, 2-Methoxyestradiol

The aim of this study was to characterize the metabolic pathways of 2-methoxyestradiol (2ME2), an investigational anticancer drug. In vitro metabolism studies were performed by incubation of 2ME2 with human liver microsomes under various conditions and metabolite identification was performed using liquid chromatography-tandem mass spectrometry. In microsomal mixtures, four major oxidative metabolites and two glucuronic acid conjugates were observed originating from 2ME2. Human liver S9 protein fraction was used to screen for in vitro sulfation but no prominent conjugates were observed. The total hepatic clearance as estimated using the well-stirred model was approximately 712 mL/min. In vivo metabolism, assessed using 24-h collections of urine from cancer patients treated with 2ME2 revealed tha

Plasma Protease-Mediated Metabolism of Carfilzomib and Its Implications on Clinical Effects and Side Effects

Abstract Introduction: Similar to most other anti-cancer drugs, carfilzomib is administered at a defined dose per m2. Inspired by preclinical data showing that extrahepatic peptidases play an important role in the metabolism of carfilzomib, using samples from a prospective clinical trial, we conducted an investigation focusing on concentrations of albumin in peripheral blood and its effects on plasma protease-mediated metabolism of carfilzomib. Methods: Baseline laboratory values, pharmacokinetics data, and response data were collected from the clinical trial. Minimal residual disease was determined by multi-parametric flow cytometry utilizing, 8-color flow panel and analyzes ≥ 3 x 106 events (sensitivity 1 x 10-5). To study the rate of metabolism in plasma, apheresis samples were obtained from the NIH blood bank, lyophilized albumin was added to plasma with and without a non-specific protease inhibitor cocktail (1X). Carfilzomib concentrations were obtained at several time points over the course of 24 hours by mass spectrometry via previously published methods. Results: Patients with baseline serum albumin >4.0 g/dL had a near 4-fold greater clearance (1576 L/h vs 401.1 L/h; n=9 vs n=34) that was further increased in patients with normal white blood cell count. Consistent with the increase in clearance, 80% of patients (29/33) with albumin 4.0 g/dL had a similar outcome. Therefore, individuals with baseline albumin >4.0 g/dL are at significantly greater risk for not responding to the combination of carfilzomib, lenalidomide, and dexamethasone [OR (95%CI) = 7.3 (1.4-36.7); P=0.0049]. Median progression-free survival was also longer in patients with albumin 4.0 g/dL (unreached vs. 18.8 months; P=0.0002). A trend between albumin and lymphopenia was also detected (P=0.17). The addition of 1.0 g/dL albumin increased the ex vivo proteolytic rate of carfilzomib in apheresis plasma from healthy individuals (74% vs 57.2% unreacted carfilzomib after 24 hours at 37°C), and the addition of a non-specific protease inhibitor reduced carfilzomib metabolism in plasma Conclusions: Although they have lower grade myeloma, patients with albumin >4.0 g/dL, surprisingly, are at greater risk at having worse clinical outcomes to carfilzomib therapy; this finding appears to depend upon the ability of albumin to directly potentiate plasma protease-mediated metabolism of carfilzomib. Therefore, dose adjustments or concomitant therapy with protease inhibitors may be warranted in such patients. Efforts are underway to identify specific proteases that metabolize carfilzomib and determine potential inhibitors that may be clinically useful. Disclosures No relevant conflicts of interest to declare

CX-2029, a PROBODY drug conjugate targeting CD71 (transferrin receptor): Results from a first-in-human study (PROCLAIM-CX-2029) in patients (Pts) with advanced cancer.

3502 Background: CX-2029 is a PROBODY drug conjugate (PDC) of MMAE, a potent microtubule inhibitor, directed against CD71 (transferrin receptor 1). In addition to being an abundant tumor antigen, CD71 is highly expressed on normal cells, precluding targeting by a traditional antibody drug conjugate (ADC). PDCs are masked ADCs, unmasked predominantly by tumor-associated proteases, thereby restricting target engagement to tumors. Both a CD71 PDC and ADC displayed broad activity in multiple xenograft tumor models; in toxicology studies, the PDC was tolerable at doses consistent with efficacy in non-clinical tumor models while the ADC was not. Methods: In a phase 1/2 first-in-human study of PDC CX-2029 in advanced solid tumors (NCT03543813), pts with ECOG 0–1 and ≥1 prior systemic therapy were enrolled into escalating dose cohorts of the PDC CX-2029 given IV every 21 days. Endpoints included evaluation of MTD, safety, antitumor activity, and potential biomarkers; plasma and tissue samples were collected for PK/PD analyses. Preliminary results are reported. Results: As of 30 November 2019, 34 pts were enrolled (median age 59 y; 59% male; 71% ECOG 1; median [range] of 3 [1–16] prior therapies). Pts received a median of 3 (1–12) CX-2029 doses. Starting dose for escalation was 0.1 mg/kg. Following a single CX-2029 dose, median molar ratio of masked CX-2029 to total CX-2029 for AUCtau was 0.938 (0.864–0.942); the ratio of free MMAE to total CX-2029 was \u3c0.03. Infusion-related reactions were the most common treatment-related AE (TRAE) of any grade (88%; primarily low grade and with first infusion), followed by anemia (56%), fatigue and nausea (24% each), neutropenia (21%), and leukopenia (12%). Grade 3+ TRAEs in ≥10% pts were anemia (35%) and neutropenia (18%). In 32 response-evaluable pts, 1 pt had a confirmed partial response (squamous NSCLC); 9 had stable disease including 1 pt with ocular melanoma treated for 36 weeks. Conclusions: The observed safety profile for CX-2029 effectively reduces on-target toxicity for this previously undruggable target, supporting the PROBODY platform. Evidence of anti-tumor activity was observed. Dose escalation continues. Clinical trial information: NCT03543813