Epigenetic priming by hypomethylation enhances the immunogenic potential of tolinapant in T-cell lymphoma.

Programmed cell death mechanisms are important for the regulation of tumor development and progression. Evasion of and resistance to apoptosis are significant factors in tumorigenesis and drug resistance. Bypassing apoptotic pathways and eliciting another form of regulated cell death, namely necroptosis, an immunogenic cell death (ICD), may override apoptotic resistance. Here, we present the mechanistic rationale for combining tolinapant, an antagonist of the inhibitor of apoptosis proteins (IAP), with decitabine, a hypomethylating agent (HMA), in T-cell lymphoma (TCL). Tolinapant treatment alone of TCL cells in vitro and in syngeneic in vivo models demonstrated that ICD markers can be upregulated, and we have shown that epigenetic priming with decitabine further enhances this effect. The clinical relevance of ICD markers was confirmed by the direct measurement of plasma proteins from peripheral TCL patients treated with tolinapant. We showed increased levels of necroptosis in TCL lines, along with the expression of cancer-specific antigens (such as cancer testis antigens) and increases in genes involved in interferon signaling induced by HMA treatment, together deliver a strong adaptive immune response to the tumor. These results highlight the potential of a decitabine and tolinapant combination for TCL and could lead to clinical evaluation.

Guadecitabine vs TC in relapsed/refractory AML after intensive chemotherapy: a randomized phase 3 ASTRAL-2 trial.

ABSTRACT: Guadecitabine is a novel hypomethylating agent (HMA) resistant to deamination by cytidine deaminase. Patients with relapsed/refractory acute myeloid leukemia (AML) were randomly assigned to guadecitabine or a preselected treatment choice (TC) of high-intensity chemotherapy, low-intensity treatment with HMAs or low-dose cytarabine, or best supportive care (BSC). The primary end point was overall survival (OS). A total of 302 patients were randomly assigned to guadecitabine (n = 148) or TC (n = 154). Preselected TCs were low-intensity treatment (n = 233 [77%; mainly HMAs]), high-intensity chemotherapy (n = 63 [21%]), and BSC (n = 6 [2%]). The median OS were 6.4 and 5.4 months for guadecitabine and TC, respectively (hazard ratio 0.88 [95% confidence interval, 0.67-1.14]; log-rank P = .33). Survival benefit for guadecitabine was suggested in several prospective subgroups, including age <65 years, Eastern Cooperative Oncology Group performance status 0 to 1, refractory AML, and lower peripheral blood blasts ≤30%. Complete response (CR) + CR with partial hematologic recovery rates were 17% for guadecitabine vs 8% for TC (P < .01); CR+CR with incomplete count recovery rates were 27% for guadecitabine vs 14% for TC (P < .01). Safety was comparable for the 2 arms, but guadecitabine had a higher rate of grade ≥3 neutropenia (32% vs 17%; P < .01). This study did not demonstrate an OS benefit for guadecitabine. Clinical response rates were higher for guadecitabine, with comparable safety to TC. There was an OS benefit for guadecitabine in several prespecified subgroups. This study was registered at www.clinicaltrials.gov as #NCT02920008.

Oral decitabine-cedazuridine versus intravenous decitabine for myelodysplastic syndromes and chronic myelomonocytic leukaemia (ASCERTAIN): a registrational, randomised, crossover, pharmacokinetics, phase 3 study.

BACKGROUND: The DNA methyltransferase inhibitors azacitidine and decitabine for individuals with myelodysplastic syndromes or chronic myelomonocytic leukaemia are available in parenteral form. Oral therapy with similar exposure for these diseases would offer potential treatment benefits. We aimed to compare the safety and pharmacokinetics of oral decitabine plus the cytidine deaminase inhibitor cedazuridine versus intravenous decitabine. METHODS: We did a registrational, multicentre, open-label, crossover, phase 3 trial of individuals with myelodysplastic syndromes or chronic myelomonocytic leukaemia and individuals with acute myeloid leukaemia, enrolled as separate cohorts; results for only participants with myelodysplastic syndromes or chronic myelomonocytic leukaemia are reported here. In 37 academic and community-based clinics in Canada and the USA, we enrolled individuals aged 18 years or older who were candidates to receive intravenous decitabine, with Eastern Cooperative Oncology Group performance status 0 or 1 and a life expectancy of at least 3 months. Participants were randomly assigned (1:1) to receive 5 days of oral decitabine-cedazuridine (one tablet once daily containing 35 mg decitabine and 100 mg cedazuridine as a fixed-dose combination) or intravenous decitabine (20 mg/m2 per day by continuous 1-h intravenous infusion) in a 28-day treatment cycle, followed by 5 days of the other formulation in the next treatment cycle. Thereafter, all participants received oral decitabine-cedazuridine from the third cycle on until treatment discontinuation. The primary endpoint was total decitabine exposure over 5 days with oral decitabine-cedazuridine versus intravenous decitabine for cycles 1 and 2, measured as area under the curve in participants who received the full treatment dose in cycles 1 and 2 and had decitabine daily AUC0-24 for both oral decitabine-cedazuridine and intravenous decitabine (ie, paired cycles). On completion of the study, all patients were rolled over to a maintenance study. This study is registered with ClinicalTrials.gov, NCT03306264. FINDINGS: Between Feb 8, 2018, and June 7, 2021, 173 individuals were screened, 138 (80%) participants were randomly assigned to a treatment sequence, and 133 (96%) participants (87 [65%] men and 46 [35%] women; 121 [91%] White, four [3%] Black or African-American, three [2%] Asian, and five [4%] not reported) received treatment. Median follow-up was 966 days (IQR 917-1050). Primary endpoint of total exposure of oral decitabine-cedazuridine versus intravenous decitabine was 98·93% (90% CI 92·66-105·60), indicating equivalent pharmacokinetic exposure on the basis of area under the curve. The safety profiles of oral decitabine-cedazuridine and intravenous decitabine were similar. The most frequent adverse events of grade 3 or worse were thrombocytopenia (81 [61%] of 133 participants), neutropenia (76 [57%] participants), and anaemia (67 [50%] participants). The incidence of serious adverse events in cycles 1-2 was 31% (40 of 130 participants) with oral decitabine-cedazuridine and 18% (24 of 132 participants) with intravenous decitabine. There were five treatment-related deaths; two deemed related to oral therapy (sepsis and pneumonia) and three to intravenous treatment (septic shock [n=2] and pneumonia [n=1]). INTERPRETATION: Oral decitabine-cedazuridine was pharmacologically and pharmacodynamically equivalent to intravenous decitabine. The results support use of oral decitabine-cedazuridine as a safe and effective alternative to intravenous decitabine for treatment of individuals with myelodysplastic syndromes or chronic myelomonocytic leukaemia. FUNDING: Astex Pharmaceuticals.

Clinical impact of the genomic landscape and leukemogenic trajectories in non-intensively treated elderly acute myeloid leukemia patients.

To characterize the genomic landscape and leukemogenic pathways of older, newly diagnosed, non-intensively treated patients with AML and to study the clinical implications, comprehensive genetics analyses were performed including targeted DNA sequencing of 263 genes in 604 patients treated in a prospective Phase III clinical trial. Leukemic trajectories were delineated using oncogenetic tree modeling and hierarchical clustering, and prognostic groups were derived from multivariable Cox regression models. Clonal hematopoiesis-related genes (ASXL1, TET2, SRSF2, DNMT3A) were most frequently mutated. The oncogenetic modeling algorithm produced a tree with five branches with ASXL1, DDX41, DNMT3A, TET2, and TP53 emanating from the root suggesting leukemia-initiating events which gave rise to further subbranches with distinct subclones. Unsupervised clustering mirrored the genetic groups identified by the tree model. Multivariable analysis identified FLT3 internal tandem duplications (ITD), SRSF2, and TP53 mutations as poor prognostic factors, while DDX41 mutations exerted an exceptionally favorable effect. Subsequent backwards elimination based on the Akaike information criterion delineated three genetic risk groups: DDX41 mutations (favorable-risk), DDX41wildtype/FLT3-ITDneg/TP53wildtype (intermediate-risk), and FLT3-ITD or TP53 mutations (high-risk). Our data identified distinct trajectories of leukemia development in older AML patients and provide a basis for a clinically meaningful genetic outcome stratification for patients receiving less intensive therapies.

Guadecitabine vs treatment choice in newly diagnosed acute myeloid leukemia: a global phase 3 randomized study.

This phase 3 study evaluated the efficacy and safety of the new hypomethylating agent guadecitabine (n = 408) vs a preselected treatment choice (TC; n = 407) of azacitidine, decitabine, or low-dose cytarabine in patients with acute myeloid leukemia unfit to receive intensive induction chemotherapy. Half of the patients (50%) had poor Eastern Cooperative Oncology Group Performance Status (2-3). The coprimary end points were complete remission (19% and 17% of patients for guadecitabine and TC, respectively [stratified P = .48]) and overall survival (median survival 7.1 and 8.5 months for guadecitabine and TC, respectively [hazard ratio, 0.97; 95% confidence interval, 0.83-1.14; stratified log-rank P = .73]). One- and 2-year survival estimates were 37% and 18% for guadecitabine and 36% and 14% for TC, respectively. A large proportion of patients (42%) received <4 cycles of treatment in both the arms. In a post hoc analysis of patients who received ≥4 treatment cycles, guadecitabine was associated with longer median survival vs TC (15.6 vs 13.0 months [hazard ratio, 0.78; 95% confidence interval, 0.64-0.96; log-rank P = .02]). There was no significant difference in the proportion of patients with grade ≥3 adverse events (AEs) between guadecitabine (92%) and TC (88%); however, grade ≥3 AEs of febrile neutropenia, neutropenia, and pneumonia were higher with guadecitabine. In conclusion, no significant difference was observed in the efficacy of guadecitabine and TC in the overall population. This trial was registered at www.clinicaltrials.gov as #NCT02348489.

Dose-escalation trial of combination dabrafenib, trametinib, and AT13387 in patients with BRAF-mutant solid tumors.

BACKGROUND: Combination BRAF and MEK inhibitor therapy is an active regimen in patients who have BRAF V600E-mutated tumors; however, the clinical efficacy of this therapy is limited by resistance. Preclinically, the addition of heat shock protein 90 (HSP90) inhibition improves the efficacy of BRAF inhibitor therapy in both BRAF inhibitor-sensitive and BRAF inhibitor-resistant mutant cell lines. METHODS: Cancer Therapy Evaluation Program study 9557 (ClinicalTrials.gov identifier NCT02097225) is a phase 1 study that was designed to assess the safety and efficacy of the small-molecule HSP90 inhibitor, AT13387, in combination with dabrafenib and trametinib in BRAF V600E/K-mutant solid tumors. Correlative analyses evaluated the expression of HSP90 client proteins and chaperones. RESULTS: Twenty-two patients with metastatic, BRAF V600E-mutant solid tumors were enrolled using a 3 + 3 design at four dose levels, and 21 patients were evaluable for efficacy assessment. The most common tumor type was colorectal cancer (N = 12). Dose-limiting toxicities occurred in one patient at dose level 3 and in one patient at dose level 4; specifically, myelosuppression and fatigue, respectively. The maximum tolerated dose was oral dabafenib 150 mg twice daily, oral trametinib 2 mg once daily, and intravenous AT13387 260 mg/m2 on days 1, 8, and 15. The best response was a partial response in two patients and stable disease in eight patients, with an overall response rate of 9.5% (90% exact confidence interval [CI], 2%-27%), a disease control rate of 47.6% (90% CI, 29%-67%), and a median overall survival of 5.1 months (90% CI, 3.4-7.6 months). There were no consistent proteomic changes associated with response or resistance, although responders did have reductions in BRAF expression, and epidermal growth factor receptor downregulation using HSP90 inhibition was observed in one patient who had colorectal cancer. CONCLUSIONS: HSP90 inhibition combined with BRAF/MEK inhibition was safe and produced evidence of modest disease control in a heavily pretreated population. Additional translational work may identify tumor types and resistance mechanisms that are most sensitive to this approach.

Correction: Phase II Study Evaluating 2 Dosing Schedules of Oral Foretinib (GSK1363089), cMET/VEGFR2 Inhibitor, in Patients with Metastatic Gastric Cancer.

[This corrects the article DOI: 10.1371/journal.pone.0054014.].

Correction: Phase II Study Evaluating 2 Dosing Schedules of Oral Foretinib (GSK1363089), cMET/VEGFR2 Inhibitor, in Patients with Metastatic Gastric Cancer.

[This corrects the article DOI: 10.1371/journal.pone.0054014.].

Antagonism of inhibitors of apoptosis proteins reveals a novel, immune response-based therapeutic approach for T-cell lymphoma.

Tolinapant (ASTX660) is a potent, nonpeptidomimetic antagonist of cellular inhibitor of apoptosis proteins 1 and 2 (cIAP1/2) and X-linked IAP, which is currently being evaluated in a phase 2 study in T-cell lymphoma (TCL) patients. Tolinapant has demonstrated evidence of single-agent clinical activity in relapsed/refractory peripheral TCL and cutaneous TCL. To investigate the mechanism of action underlying the single-agent activity observed in the clinic, we have used a comprehensive translational approach integrating in vitro and in vivo models of TCL confirmed by data from human tumor biopsies. Here, we show that tolinapant acts as an efficacious immunomodulatory molecule capable of inducing complete tumor regression in a syngeneic model of TCL exclusively in the presence of an intact immune system. These findings were confirmed in samples from our ongoing clinical study showing that tolinapant treatment can induce changes in gene expression and cytokine profile consistent with immune modulation. Mechanistically, we show that tolinapant can activate both the adaptive and the innate arms of the immune system through the induction of immunogenic forms of cell death. In summary, we describe a novel role for IAP antagonists as immunomodulatory molecules capable of promoting a robust antitumor immune response in TCL.

Erlotinib and Onalespib Lactate Focused on EGFR Exon 20 Insertion Non-Small Cell Lung Cancer (NSCLC): A California Cancer Consortium Phase I/II Trial (NCI 9878).

BACKGROUND: Onalespib is a novel heat shock protein 90 inhibitor (HSP90i). Previous preclinical and clinical studies with HSP90i have demonstrated activity in EGFR-mutant non-small cell lung cancer (NSCLC). This study sought to determine the safety and tolerability of onalespib plus erlotinib in EGFR-mutant NSCLC and to evaluate the preliminary efficacy of the combination in epidermal growth factor receptor exon 20 insertion (EGFRex20ins) NSCLC. PATIENTS AND METHODS: Standard 3+3 dose escalation was followed by a phase II expansion in EGFRex20ins. The phase II component targeted a response rate of 25% versus a background rate of 5%. Prospective next-generation sequencing (NGS) of 70 cancer-related genes, including EGFR, via plasma circulating tumor DNA (ctDNA) was performed. Toxicity was graded by Common Terminology Criteria for Adverse Events (CTCAE), version 4, and response was determined by Response Evaluation Criteria in Solid Tumours (RECIST) 1.1. RESULTS: Eleven patients were treated (nine dose escalation, two dose expansion). Two dose-limiting toxicities (DLTs) occurred in dose level (DL) 0 and zero in DL -1 (minus). In 10 EGFRex20ins patients, no responses were observed, median progression-free survival was 5.4 months (95% confidence interval, 0.9-5.7), and the disease control rate (DCR) was 40% (median, 3.5 months). EGFRex20ins was detected in nine of 10 ctDNA samples at baseline; on-treatment ctDNA clearance was not observed. Grade 3 diarrhea was the predominant toxicity in 45% of patients. The recommended phase II dose is DL -1 (minus): erlotinib 150 mg orally every morning and onalespib 120 mg/m2 intravenously on days 1, 8, and 15 every 28 days. CONCLUSION: Overlapping toxicities of erlotinib and onalespib, mainly diarrhea, limited the tolerability of this combination, and limited clinical activity was observed, so the trial was closed early. Plasma EGFRex20ins ctDNA was detected in the majority of patients; failure to clear ctDNA was consistent with lack of tumor response (NCT02535338).

A phase 1 study of combined guadecitabine and cisplatin in platinum refractory germ cell cancer.

PURPOSE: Germ cell tumors (GCTs) are cured with therapy based on cisplatin, although a clinically significant number of patients are refractory and die of progressive disease. Based on preclinical studies indicating that refractory testicular GCTs are hypersensitive to hypomethylating agents (HMAs), we conducted a phase I trial combining the next-generation HMA guadecitabine (SGI-110) with cisplatin in recurrent, cisplatin-resistant GCT patients. METHODS: Patients with metastatic GCTs were treated for five consecutive days with guadecitabine followed by cisplatin on day 8, for a 28-day cycle for up to six cycles. The primary endpoint was safety and toxicity including dose-limiting toxicity (DLT) and maximum tolerated dose (MTD). RESULTS: The number of patients enrolled was 14. The majority of patients were heavily pretreated. MTD was determined to be 30 mg/m2 guadecitabine followed by 100 mg/m2 cisplatin. The major DLTs were neutropenia and thrombocytopenia. Three patients had partial responses by RECIST criteria, two of these patients, including one with primary mediastinal disease, completed the study and qualified as complete responses by serum tumor marker criteria with sustained remissions of 5 and 13 months and survival of 16 and 26 months, respectively. The overall response rate was 23%. Three patients also had stable disease indicating a clinical benefit rate of 46%. CONCLUSIONS: The combination of guadecitabine and cisplatin was tolerable and demonstrated activity in patients with platinum refractory germ cell cancer.

Methylomic Signatures of High Grade Serous Ovarian Cancer.

High-grade serous ovarian cancer (HGSOC) harbours aberrant epigenetic features, including DNA methylation. In this study we delineate pathways and networks altered by DNA methylation and associated with HGSOC initiation and progression to a platinum-resistant state. By including tumours from patients who had been treated with the hypomethylating agent (HMA) guadecitabine, we also addressed the role of HMAs in treatment of HGSOC. Tumours from patients with primary (platinum-naïve) HGSOC (n = 20) were compared to patients with recurrent platinum-resistant HGSOC and enrolled in a recently completed clinical trial (NCT01696032). Human ovarian surface epithelial cells (HOSE; n = 5 samples) served as normal controls. Genome-wide methylation profiles were determined. DNA methyltransferase (DNMT) expression levels were examined by immunohistochemistry and correlated with clinical outcomes. Cancer-related and tumorigenesis networks were enriched among differentially methylated genes (DMGs) in primary OC vs. HOSE. When comparing platinum-resistant and primary tumours, 452 CpG island (CGI)-containing gene promoters acquired DNA methylation; of those loci, decreased (P < 0.01) methylation after HMA treatment was observed in 42% (n = 189 CGI). Stem cell pluripotency and cytokine networks were enriched in recurrent platinum-resistant OC tumours, while drug metabolism and transport-related networks were downregulated in tumours from HMA-treated patients compared to HOSE. Lower DNMT1 and 3B protein levels in pre-treatment tumours were associated with improved progression-free survival. The findings provide important insight into the DNA methylation landscape of HGSOC tumorigenesis, platinum resistance and epigenetic resensitization. Epigenetic reprogramming plays an important role in HGSOC aetiology and contributes to clinical outcomes.

Correction: A novel epigenetic modulating agent sensitizes pancreatic cells to a chemotherapy agent.

[This corrects the article DOI: 10.1371/journal.pone.0199130.].

Oral Azacitidine and Cedazuridine Approximate Parenteral Azacitidine Efficacy in Murine Model.

BACKGROUND: DNA methyltransferase inhibitors (DNMTis) improve survival for patients with myelodysplastic syndromes (MDS) and those with acute myeloid leukemia (AML) unable to receive standard cytotoxic chemotherapy and are, accordingly, the backbone of standard-of-care treatment for these conditions. Standard regimens with DNMTIs, decitabine (DEC) or azacitidine (AZA) include daily subcutaneous (s.c.) or intravenous (i.v.) administration for 5-7 consecutive days. Attempts to provide the therapy orally have been limited given rapid clearance of the agents by the enzyme cytidine deaminase (CDA), which is ubiquitous in the gut and liver as part of first-pass metabolism. Recently, cedazuridine (CDZ), an oral inhibitor of CDA, was successfully combined with DEC to approximate the pharmacokinetics of i.v. DEC in patients. OBJECTIVE: To determine if an oral dosing strategy might be feasible in the clinic with AZA, we attempted to increase the bioavailability of oral AZA through the use of CDZ, in a murine model. METHODS: Following pharmacokinetic and pharmacodynamic assessment of oral AZA dosed with CDZ in murine and monkey models, we tested this regimen in vivo with a human cell line-derived xenograft transplantation experiment (CDX). Following this we combined the regimen with venetoclax (VEN) to test the efficacy of an all-oral regimen in a patient-derived xenograft (PDX) model. RESULTS: Parenteral AZA and oral AZA + CDZ exhibited similar pharmacokinetic profiles, and efficacy against human AML cells. Tumor regression was seen with AZA + CDZ in MOLM-13 CDX and PDX models. CONCLUSIONS: We conclude that oral AZA when combined with CDZ achieves successful tumor regression in both CDX and PDX models. Furthermore, the combination of AZA + CDZ with VEN in a PDX model emulated responses seen with VEN + AZA in the clinic, implying a potential all-oral VEN-based therapy opportunity in myeloid diseases.

A Phase I Study of ASTX660, an Antagonist of Inhibitors of Apoptosis Proteins, in Adults with Advanced Cancers or Lymphoma.

PURPOSE: This first-in-human, phase I study evaluated ASTX660, an oral, small-molecule antagonist of cellular/X-linked inhibitors of apoptosis proteins in patients with advanced solid tumors or lymphoma. PATIENTS AND METHODS: ASTX660 was administered orally once daily on a 7-day-on/7-day-off schedule in a 28-day cycle. Dose escalation followed a standard 3+3 design to determine the MTD and recommended phase II dose (RP2D). Dose expansion was conducted at the RP2D. RESULTS: Forty-five patients received ASTX660 (range 15-270 mg/day). Dose-limiting toxicity of grade 3 increased lipase with or without increased amylase occurred in 3 patients at 270 mg/day and 1 patient at 210 mg/day. The MTD was determined to be 210 mg/day and the RP2D 180 mg/day. Common treatment-related adverse events included fatigue (33%), vomiting (31%), and nausea (27%). Grade ≥3 treatment-related adverse events occurred in 7 patients, most commonly anemia (13%), increased lipase (11%), and lymphopenia (9%). ASTX660 was rapidly absorbed, with maximum concentration achieved at approximately 0.5-1.0 hour. An approximately 2-fold accumulation in AUC exposures was observed on day 7 versus 1. ASTX660 suppressed cellular inhibitor of apoptosis protein-1 in peripheral blood mononuclear cells, which was maintained into the second cycle beyond the off-therapy week at the 180-mg/day RP2D and above. Clinical activity was seen in a patient with cutaneous T-cell lymphoma. CONCLUSIONS: ASTX660 demonstrated a manageable safety profile and exhibited evidence of pharmacodynamic and preliminary clinical activity at the 180-mg/day RP2D. The phase II part of the study is ongoing.

A Randomized Phase II Trial of Epigenetic Priming with Guadecitabine and Carboplatin in Platinum-resistant, Recurrent Ovarian Cancer.

PURPOSE: Platinum resistance in ovarian cancer is associated with epigenetic modifications. Hypomethylating agents (HMA) have been studied as carboplatin resensitizing agents in ovarian cancer. This randomized phase II trial compared guadecitabine, a second-generation HMA, and carboplatin (G+C) against second-line chemotherapy in women with measurable or detectable platinum-resistant ovarian cancer. PATIENTS AND METHODS: Patients received either G+C (guadecitabine 30 mg/m2 s.c. once-daily for 5 days and carboplatin) or treatment of choice (TC; topotecan, pegylated liposomal doxorubicin, paclitaxel, or gemcitabine) in 28-day cycles until progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS); secondary endpoints were RECIST v1.1 and CA-125 response rate, 6-month PFS, and overall survival (OS). RESULTS: Of 100 patients treated, 51 received G+C and 49 received TC, of which 27 crossed over to G+C. The study did not meet its primary endpoint as the median PFS was not statistically different between arms (16.3 weeks vs. 9.1 weeks in the G+C and TC groups, respectively; P = 0.07). However, the 6-month PFS rate was significantly higher in the G+C group (37% vs. 11% in TC group; P = 0.003). The incidence of grade 3 or higher toxicity was similar in G+C and TC groups (51% and 49%, respectively), with neutropenia and leukopenia being more frequent in the G+C group. CONCLUSIONS: Although this trial did not show superiority for PFS of G+C versus TC, the 6-month PFS increased in G+C treated patients. Further refinement of this strategy should focus on identification of predictive markers for patient selection.

Guadecitabine (SGI-110) in patients with intermediate or high-risk myelodysplastic syndromes: phase 2 results from a multicentre, open-label, randomised, phase 1/2 trial.

BACKGROUND: Guadecitabine is a next-generation hypomethylating agent whose active metabolite decitabine has a longer in-vivo exposure time than intravenous decitabine. More effective hypomethylating agents are needed for the treatment of myelodysplastic syndromes. In the present study, we aimed to compare the activity and safety of two doses of guadecitabine in hypomethylating agent treatment-naive or relapsed or refractory patients with intermediate-risk or high-risk myelodysplastic syndromes. METHODS: This phase 2 part of the phase 1/2, randomised, open-label study enrolled patients aged 18 years or older from 14 North American medical centres with International Prognostic Scoring System intermediate-1-risk, intermediate-2-risk, or high-risk myelodysplastic syndromes, or chronic myelomonocytic leukaemia. They were either hypomethylating agent treatment-naive or had relapsed or refractory disease after previous hypomethylating agent treatment as determined by the investigators' judgment. Eligible patients had Eastern Cooperative Oncology Group performance status of 0-2. Patients were randomly assigned (1:1) using a computer algorithm for dynamic randomisation to subcutaneous guadecitabine 60 or 90 mg/m2 on days 1-5 of a 28-day treatment cycle. Treatment was stratified by previous treatment with hypomethylating agents and neither patients nor investigators were masked. The primary endpoint was overall response (a composite of complete response, partial response, marrow complete response, and haematological improvement) assessed in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT01261312. FINDINGS: Between July 9, 2012, and April 7, 2014, 105 patients were enrolled: 55 (52%) were allocated to guadecitabine 60 mg/m2 (28 patients were treatment-naive and 27 had relapsed or refractory disease after previous hypomethylating agent treatment) and 50 (48%) patients to 90 mg/m2 (23 patients were treatment-naive and 27 had relapsed or refractory disease). Three (3%) patients of 105 did not receive study treatment and were excluded from analyses. Median follow-up was 3·2 years (IQR 2·8-3·5). The proportion of patients achieving an overall response did not significantly differ between dose groups (21 of 53 [40%, 95% CI 27-54] with 60 mg/m2 and 27 of 49 [55%, 95% CI 40-69] with 90 mg/m2; p=0·16). 25 of 49 (51%, 95% CI 36-66) patients who were treatment-naive and 23 of 53 (43%, 30-58) patients with relapsed or refractory disease achieved an overall response. The most common grade 3 or worse adverse events in both groups, regardless of relationship to treatment, were thrombocytopenia (22 [41%] of 53 patients in the 60 mg/m2 group and 28 [57%] of 49 in the 90 mg/m2 group), neutropaenia (21 [40%] and 25 [51%]), anaemia (25 [47%] and 24 [49%]), febrile neutropaenia (17 [32%] and 21 [43%]), and pneumonia (13 [25%] and 15 [31%]). Seven (7%) of 102 patients died due to adverse events (three with 90 mg/m2 and four with 60 mg/m2), and all except one were in the relapsed or refractory cohort. Two deaths were deemed treatment related (septic shock with 60 mg/m2; pneumonia with 90 mg/m2). INTERPRETATION: Guadecitabine was clinically active with acceptable tolerability in patients with intermediate-risk and high-risk myelodysplastic syndromes. Responses and overall survival in the relapsed or refractory cohort offer the potential of a new therapeutic option for patients for whom currently available hypomethylating agents are not successful. We therefore recommend guadecitabine at a dose of 60 mg/m2 on a 5-day schedule for these patients. FUNDING: Astex Pharmaceuticals and Stand Up To Cancer.

Pharmacodynamic and Clinical Results from a Phase I/II Study of the HSP90 Inhibitor Onalespib in Combination with Abiraterone Acetate in Prostate Cancer.

PURPOSE: Onalespib is a potent, fragment-derived second-generation HSP90 inhibitor with preclinical activity in castration-resistant prostate cancer (CPRC) models. This phase I/II trial evaluated onalespib in combination with abiraterone acetate (AA) and either prednisone or prednisolone (P) in men with CRPC progressing on AA/P. PATIENTS AND METHODS: Patients with progressing CRPC were randomly assigned to receive 1 of 2 regimens of onalespib combined with AA/P. Onalespib was administered as intravenous infusion starting at 220 mg/m2 once weekly for 3 of 4 weeks (regimen 1); or at 120 mg/m2 on day 1 and day 2 weekly for 3 of 4 weeks (regimen 2). Primary endpoints were response rate and safety. Secondary endpoints included evaluation of androgen receptor (AR) depletion in circulating tumor cells (CTC) and in fresh tumor tissue biopsies. RESULTS: Forty-eight patients were treated with onalespib in combination with AA/P. The most common ≥grade 3 toxicities related to onalespib included diarrhea (21%) and fatigue (13%). Diarrhea was dose limiting at 260 and 160 mg/m2 for regimens 1 and 2, respectively. Transient decreases in CTC counts and AR expression in CTC were observed in both regimens. HSP72 was significantly upregulated following onalespib treatment, but only a modest decrease in AR and GR was shown in paired pre- and posttreatment tumor biopsy samples. No patients showed an objective or PSA response. CONCLUSIONS: Onalespib in combination with AA/P showed mild evidence of some biological effect; however, this effect did not translate into clinical activity, hence further exploration of this combination was not justified.