2018 EBF: Development and validation of an LC-MS/MS method for the simultaneous quantitation of cedazuridine (E7727), epimer of cedazuridine and decitabine in THU-stabilized K2EDTA human Plasma

Summary

Abstract:

Cedazuridine is a novel cytidine deaminase inhibitor that inhibits the in vivo metabolic degradation of decitabine when administered orally in combination with decitabine (known as ASTX727) in clinical trials. Cedazuridine inhibits degradation of decitabine by inhibiting cytidine deaminase in the gut and liver thereby increasing oral bioavailability of decitabine. To support clinical trial pharmacokinetic studies for ASTX727, a sensitive LC-MS/MS method for the simultaneous quantitation of decitabine and cedazuridine, as well as the epimer of cedazuridine, in human plasma was developed and validated. Decitabine is known for its instability in human plasma over time as well as a previously observed chromatographic interference in certain subjects that was inseparable using reverse-phase chromatography. To stabilize decitabine, tetrahydrouridine (THU) was mixed with the human plasma samples. Chromatographic interference was resolved using normal phase chromatography. In-house synthesized stable-label internal standards for all three analytes were employed to ensure assay robustness. Stability of cedazuridine and cedazuridine-epimer were carefully evaluated and extensive experiments were conducted to ensure no inter-conversion occurs. As a result, a 3-in-1 method (single sample extraction) for the quantitation of cedazuridine, cedazuridine epimer and decitabine has been developed and fully validated. Protein precipitation (PPT) was used to extract all analytes from THU-stabilized human plasma samples. The analytes were separated on two different HPLC columns (reverse phase for cedazuridine and cedazuridine epimer and normal phase for decitabine). The method has been applied for clinical studies to evaluate the pharmacokinetics of cedazuridine, cedazuridine-epimer and decitabine in human.

 

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2018 SGI-110 Poster presented at EBF

2019 MDSF: Development of an oral hypomethylating agent (HMA) as a fixed dose combination (FDC) of decitabine and CDA inhibitor cedazuridine

Summary:

Background: Hypomethylating agents azacitidine and decitabine are not readily bioavailable orally due to their degradation in the gut and liver by CDA. We developed a selective, potent, and safe CDA inhibitor cedazuridine. The combination of cedazuridine with decitabine delivered orally as an FDC tablet is developed to achieve an equivalent AUC exposure to IV decitabine.

Methods: A phase 1-2 study was conducted in 124 patients eligible to receive IV decitabine. The phase 1 dose escalation (n=44 patients) established a recommended dose for both oral decitabine (35 mg), and cedazuridine (100 mg) likely to achieve a decitabine AUC exposure equivalent to decitabine IV at 20 mg/m2. The phase 2 (n=80 patients) was conducted using a randomized cross-over design comparing IV decitabine to oral ASTX727 to confirm intra-patient decitabine AUC exposure equivalence between standard IV decitabine and the selected ASTX727 FDC doses (35/100 mg decitabine/cedazuridine).

Results: In the phase 2 patients were randomized to either decitabine IV 20 mg/m2/d x5 or oral ASTX727 (decitabine/cedazuridine 35/100 mg/d) x5 Q 28 days in Cycle 1 and crossed over to the other arm in Cycle 2. All patients continued to receive oral ASTX727 from Cycle 3 onwards until progression or treatment discontinuation for other reasons. The median age was 69.7 years, median weight was 82.7 Kg (range 40-122), and median BSA was 1.99 m2 (range 1.3-2.4). The MDS-IPSS status of the patients was Int-1 in 44%, Int-2 in 24%, and HR in 11%, with 21% having CMML. No differences were observed between the 2 randomized arms. The decitabine AUC0-t (h*ng/mL) 5-Day geometric mean estimate was 745 from decitabine IV and 727 from the oral FDC tablet resulting in an oral/IV AUC ratio of 97.6% (80% CI of 80, 118%). Hypomethylating activity as measured by LINE-1 demethylation, and safety were comparable between decitabine IV and oral ASTX727 in the first 2 randomized cycles. Of note is the absence of grade 3 or higher GI AEs related to ASTX727. Overall response rate in the phase 2 population was 65% including 18% CR by the IWG 2006 MDS response criteria

Conclusions: ASTX727 FDC oral tablet at the selected doses (35/100 mg decitabine/cedazuridine) with no body weight or BSA adjustment achieved an equivalent decitabine AUC exposure to IV decitabine 20 mg/m2 over the 5-day cycle. LINE-1 demethylation and safety in the 2 randomized cycles were comparable and overall response rate was consistent with expected decitabine IV clinical response

 

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2019 ASTX727 Poster MDSF abst-MDSF19-0166

Savona et al., An oral fixed-dose combination of decitabine and cedazuridine in myelodysplastic syndromes: a multicentre, open-label, dose-escalation, phase 1 study

Abstract

BACKGROUND:

Decitabine, a DNA methyltransferase 1 inhibitor or DNA hypomethylating compound, is not readily orally bioavailable because of rapid clearance by cytidine deaminase (CDA) in the gut and liver. This dose-escalation study, guided by pharmacokinetic and pharmacodynamic observations, evaluated whether simultaneous oral administration with the novel CDA inhibitor cedazuridine increases decitabine bioavailability for the treatment of myelodysplastic syndromes.METHODS:

In this phase 1 study, we enrolled patients aged 18 years or older with myelodysplastic syndromes or chronic myelomonocytic leukaemia. Eligible patients were assigned to cohorts to receive escalating oral doses of decitabine and cedazuridine. The starting dose was decitabine 20 mg and cedazuridine 40 mg. Treatment cycles lasted 28 days, with 5 days of drug administration. In cycle 1, each patient received a cohort-defined dose of oral decitabine on day -3, a 1-h intravenous infusion of decitabine 20 mg/m2 on day 1, and cohort-defined doses of oral decitabine plus cedazuridine on days 2-5. In cycles 2 and beyond, the oral decitabine and cedazuridine were given on days 1-5. The dose of cedazuridine was escalated first and decitabine was escalated once CDA inhibition by cedazuridine approached the maximum effect. The drug dose was escalated if mean decitabine area under the curve (AUC) of the oral drug was less than 90% of that for intravenous decitabine in the cohort and if no dose-limiting toxicity was observed. Dose-limiting toxicity was defined as a grade 3 or greater non-haematologic toxicity or grade 4 haematologic toxicity lasting more than 14 days and unrelated to the underlying disease. Once the decitabine AUC target range set as the primary endpoint, and established with intravenous decitabine, was reached at a dose deemed to be safe, the cohort that most closely approximated intravenous decitabine exposure was expanded to 18 evaluable patients. The primary objectives were to assess the safety of decitabine plus cedazuridine, and to determine the dose of each drug needed to achieve a mean AUC for decitabine exposure similar to that for intravenous decitabine exposure. This study is registered with ClinicalTrials.gov, number NCT02103478.

FINDINGS:

Between Oct 28, 2014, and Nov 13, 2015, we enrolled 44 eligible patients (of 75 screened) with previously treated or newly diagnosed myelodysplastic syndromes or chronic myelomonocytic leukaemia; 43 of the enrolled patients were evaluable. Participants were treated in five cohorts: cohorts 1-4 included six evaluable patients each; cohort 5 included 19 patients in a 13-patient expansion. Dose-dependent increases in decitabine AUC and peak plasma concentration occurred with each cohort dose escalation. There was no evident increase in toxicity compared with that reported for intravenous decitabine. Decitabine 30 mg and 40 mg plus cedazuridine 100 mg produced mean day-5 decitabine AUCs (146 ng × h/mL for decitabine 30 mg, and 221 ng × h/mL for decitabine 40 mg) closest to the mean intravenous-decitabine AUC (164 ng × h/mL). The most common grade 3 or more adverse events were thrombocytopenia (18 [41%] of 44 patients), neutropenia (13 [30%]), anaemia (11 [25%]), leukopenia (seven [16%]), febrile neutropenia (seven [16%]), and pneumonia (seven [16%]). Four (9%) patients died because of adverse events, none of which was considered drug related, and three (7%) patients died more than 30 days after discontinuing treatment because of progressive disease (two [5%]) and respiratory failure (one [2%]).

INTERPRETATION:

Oral decitabine plus cedazuridine emulated the pharmacokinetics of intravenous decitabine, with a similar safety profile and dose-dependent demethylation. Clinical responses were similar to intravenous decitabine treatment for 5 days. Further study of decitabine plus cedazuridine as an alternative to parenteral therapy or in combination with other new oral agents for myeloid disorders is warranted.

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Savona et al, “Savona et al., An oral fixed-dose combination of decitabine and cedazuridine in myelodysplastic syndromes: a multicentre, open-label, dose-escalation, phase 1 study”, The Lancet Haematology, Volume 6, Issue 4, e194 – e203  DOI:10.1016/S2352-3026(19)30030-4

 

Ferraris et al., “Design, Synthesis, and Pharmacological Evaluation of Fluorinated Tetrahydrouridine Derivatives as Inhibitors of Cytidine Deaminase.” Journal of Medicinal Chemistry, 2014

Abstract:

Several 2′-fluorinated tetrahydrouridine derivatives were synthesized as inhibitors of cytidine deaminase (CDA). (4R)-2′-Deoxy-2′,2′-difluoro-3,4,5,6-tetrahydrouridine (7a) showed enhanced acid stability over tetrahydrouridine (THU) 5 at its N-glycosyl bond. As a result, compound 7a showed an improved oral pharmacokinetic profile with a higher and more reproducible plasma exposure in rhesus monkeys compared to 5. Co-administration of 7a with decitabine, a CDA substrate, boosted the plasma levels of decitabine in rhesus monkeys. These results demonstrate that compound 7a can serve as an acid-stable alternative to 5 as a pharmacoenhancer of drugs subject to CDA-mediated metabolism.

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Ferraris et al., “Design, Synthesis, and Pharmacological Evaluation of Fluorinated Tetrahydrouridine Derivatives as Inhibitors of Cytidine Deaminase.” J.MedChem. ,2014, 57 (6), pp 2582–2588 DOI: 10.1021/jm401856k

 

 

2018: ASTX660, a Novel Non-peptidomimetic Antagonist of cIAP1/2 and XIAP, Potently Induces TNFα-Dependent Apoptosis in Cancer Cell Lines and Inhibits Tumor Growth.

Abstract

Because of their roles in the evasion of apoptosis, inhibitor of apoptosis proteins (IAP) are considered attractive targets for anticancer therapy. Antagonists of these proteins have the potential to switch prosurvival signaling pathways in cancer cells toward cell death. Various SMAC-peptidomimetics with inherent cIAP selectivity have been tested clinically and demonstrated minimal single-agent efficacy. ASTX660 is a potent, non-peptidomimetic antagonist of cIAP1/2 and XIAP, discovered using fragment-based drug design. The antagonism of XIAP and cIAP1 by ASTX660 was demonstrated on purified proteins, cells, and in vivo in xenograft models. The compound binds to the isolated BIR3 domains of both XIAP and cIAP1 with nanomolar potencies. In cells and xenograft tissue, direct antagonism of XIAP was demonstrated by measuring its displacement from caspase-9 or SMAC. Compound-induced proteasomal degradation of cIAP1 and 2, resulting in downstream effects of NIK stabilization and activation of noncanonical NF-κB signaling, demonstrated cIAP1/2 antagonism. Treatment with ASTX660 led to TNFα-dependent induction of apoptosis in various cancer cell lines in vitro, whereas dosing in mice bearing breast and melanoma tumor xenografts inhibited tumor growth. ASTX660 is currently being tested in a phase I–II clinical trial (NCT02503423), and we propose that its antagonism of cIAP1/2 and XIAP may offer improved efficacy over first-generation antagonists that are more cIAP1/2 selective. Mol Cancer Ther; 17(7); 1–11. ©2018 AACR.

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Ward et al. “ASTX660, a Novel Non-peptidomimetic Antagonist of cIAP1/2 and XIAP, Potently Induces TNFα-Dependent Apoptosis in Cancer Cell Lines and Inhibits Tumor Growth.” Mol Cancer Ther. June 14, 2018, doi: 10.1158/1535-7163.MCT-17-0848

2017 ASH: Predictors of Response and Survival in 206 AML Patients Treated with Guadecitabine in a Phase 2 Study

Summary
Background: Guadecitabine is a next generation hypomethylating agent (HMA) resistant to degradation by cytidine deaminase which results in prolonged in vivo exposure to the active metabolite decitabine. We conducted a prospective phase 2 study testing different schedules of guadecitabine in 206 AML patients. We present here the results of multiple logistic regression, and Cox regression analyses of predictors of composite Complete Response or CRc (CR+CRp+CRi) and overall survival (OS).

Methods: Multiple logistic regression analysis of response (CRc), and Cox regression analysis of OS were conducted with inclusion of the following baseline variables: disease state (relapsed/refractory (r/r) vs. treatment naïve (TN) AML); guadecitabine schedule (10day vs. 5day); age (<75 vs. ≥75); ECOG PS (01 vs. ≥2); Cytogenetics (others vs. poor risk); baseline BM blasts (≤40% vs. >40%); baseline Peripheral blood (PB) blasts (≤30% vs. >30%); baseline WBCs count (<20,000/μL vs. ≥20,000/μL); Flt3 ITD, NPM, and TP53 mutations (each present vs. not detected). Cutoff values for blasts % for BM and PB were chosen based on the median or mean values respectively, and cutoff value for WBCs count was chosen as a common cutoff used for proliferative AML. Backward elimination method with alpha =0.05 was used to reach the final models.

Results: We treated 206 AML patients (103 patients each for TN or r/r AML); 101 with 5day schedule and 105 with 10day schedule. There were 91 patients (44%) ≥75 y; 53 (26%) with ECOG PS≥2; 85 (41%) with poor risk cytogenetics; 99 (48%) with baseline BM blasts >40%; 65 (32%) with baseline PB blasts >30%; 20 (9.7%) with WBCs ≥20,000/μL. Flt3, NPM, and TP53 mutations were present in 8%, 9%, and 4% of patients respectively. The final logistic regression model indicated that patients with ECOG PS 01 and those with baseline PB blasts ≤ 30% have twofold higher odds of response than those with ECOG PS ≥2 and PB blasts >30% (Odds ratio 2.18; and 2.03 respectively; p<0.05 for both). Patients with TN AML had fivefold higher odds of response to guadecitabine than r/r AML (Odds ratio of response for r/r AML 0.22; p <0.0001). The final Cox regression model showed that both ECOG PS 01 and PB blasts ≤30% retained their significance for OS (HR 0.69 with p=0.03; and 0.61 with p=0.004 respectively). However disease state (r/r AML vs TN AML) lost significance for OS while cytogenetics risk level (others vs poor risk) became significant with a HR for OS of 0.68, p=0.016.

Summary/Conclusions: In a prospective series of AML patients treated with guadecitabine in a phase 2 study, better ECOG PS 01 and lower baseline PB blasts ≤30% were associated with a significantly higher likelihood of response and a longer OS. Patients with TN AML had significantly higher likelihood of response than those with r/r AML but this was not a significant factor for OS when other factors are present in the model such as ECOG PS, cytogenetics risk and PB blasts. On the other hand, the presence of poor risk cytogenetics did not alter the likelihood of response to guadecitabine but still had shorter survival compared to patients with other cytogenetics risk levels. Other variables such as age, baseline BM blasts %, and baseline WBCs count did not significantly impact response or OS in AML patients treated with guadecitabine when all other factors are present in the models. The analysis of genetic mutations was limited by the small number of patients where these mutations were present. The analysis of the treatment schedule is limited by the different effect of the schedule on r/r AML compared to TN AML where the 10day schedule did better than the 5day schedule in r/r AML but not in TN AML patients.

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Predictors of Response and Survival in 206 AML Patients Treated with Guadecitabine in a Phase 2 Study

2017 ASH: A Phase 2 Dose-Confirmation Study of Oral ASTX727, a Combination of Oral Decitabine with a Cytidine Deaminase Inhibitor (CDAi) Cedazuridine (E7727), in Subjects with Myelodysplastic Syndromes (MDS)

Summary

An oral hypomethylating agent which could be administered at a dose which would emulate parenteral pharmacokinetics would be more convenient and potentially enhance adherence to treatment. Heretofore, rapid clearance by cytidine deaminase (CDA) during first pass has prevented good oral bioavailability for decitabine (DAC). Cedazuridine (E7727), a novel CDAi, is orally bioavailable with a large safety margin and reproducible effectiveness in preclinical models. A phase I dose finding study found that a fixed oral combination of 35 mg of decitabine and 100 mg of E7727 (ASTX727 with 35 mg decitabine/100 mg cedazuridine (ASTX727 35/100 mg) should produce similar PK to decitabine administered intravenously at 20 mg/m2 as a 1-hour infusion.3 We tested this hypothesis in a phase 2 cross-over study, and report the preliminary results here.

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A Phase 2 Dose-Confirmation Study of Oral ASTX727, a Combination of Oral Decitabine with a Cytidine Deaminase Inhibitor (CDAi) Cedazuridine (E7727), in Subjects with Myelodysplastic Syndromes (MDS)

2017 EORTC: Phase 1 study of the IAP inhibitor ASTX660 in adults with advanced cancers and lymphomas

Summary
Due to their roles in the evasion of apoptosis, Inhibitor of Apoptosis Proteins (IAPs) are considered attractive targets for anti-cancer therapy. ASTX660 is a potent, next generation, non-peptidomimetic, dual antagonist of both XIAP and cIAP1, discovered using fragment-based drug design (1-3). We report here the results of the first-in-human phase 1 dose escalation and dose expansion study of ASTX660 administered orally to adults with advanced solid tumors and lymphoma.

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Phase 1 study of the IAP inhibitor ASTX660 in adults with advanced cancers and lymphomas

2017 ESH-AML: LINE-1 and P15 Demethylation May Predict Response to Guadecitabine

Summary
Guadecitabine (formerly known as SGI-110) is a next-generation hypomethylating agent (HMA) composed of a dinucleotide of decitabine and deoxyguanosine (Figure 1). Guadecitabine is a dinucleotide resistant to degradation by cytidine deaminase (CDA) resulting in longer in vivo exposure to its active metabolite, decitabine, after a small volume ( ~ 1 mL) subcutaneous (SC) administration. A prospective phase 2 trial in 103 patients with relapsed or refractory AML (r/r AML) investigated 60 mg/m2 and 90mg/m2 doses in a 5-day regimen, and 60 mg/m2 in a 10-day regimen given every 28 days. In that trial, LINE-1 was used to measure general DNA demethylation and P15 gene promotor methylation was used to measure a specific tumor suppressor gene demethylation during Cycle 1 as potential markers of biological activity that may predict clinical response (See Trial Design in Figure 2).

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2017 ESH-AML: LINE-1 and P15 Demethylation May Predict Response to Guadecitabine

2017 ACCP: Population Pharmacokinetics Analysis for Guadecitabine (SGI-110) and Decitabine after Subcutaneous Dosing with SGI-110 in Patients with Relapsed/Refractory AML and MDS

Summary
Guadecitabine is next-generation HMA formulated as a dinucleotide of decitabine and deoxyguanosine delivered as a low volume and pharmaceutically stable subcutaneous (SC) injection. In vivo conversion to active metabolite decitabine results in longer effective half-life and more extended decitabine exposure window than decitabine IV infusion. The differentiated PK profile may lead to improved biological and clinical activity and safety over currently available HMAs (Issa et al. Lancet Oncology 2015).
SGI-110-01 (NCT01261312) was a phase 1-2, dose escalation, multicenter study of subcutaneous regimens of SGI-110 in subjects with intermediate or high-risk myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML). Several dosing regimens were tested. In regimen 1 and its phase 2 expansion, guadecitabine was administered daily for 5 days of a 28-day cycle. In regimens 2a and 2b, it was administered weekly or twice-weekly, respectively, for 3 weeks of a 28-day cycle. In another part of the phase 2 expansion, it was administered daily for 10 days (1-5 and 8-12) of a 28-day cycle.
The PK data included full concentration-time profiles of parent SGI-110 and its active metabolite, decitabine obtained after the first dose and after dose on day 5 (for regimen 1 and expansion), day 8 (for regimen 2a) or day 12 (for expansion 10-day regimen) of cycle 1.
The abstract reported results of the population PK analysis of data from 98 patients. Since the time the abstract was submitted, more data became available, and the model was updated. This poster describes the population PK modeling of data using an updated dataset from 124 patients.

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2017 ACCP: Population Pharmacokinetics Analysis for Guadecitabine (SGI-110) and Decitabine after Subcutaneous Dosing with SGI-110 in Patients with Relapsed/Refractory AML and MDS