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.

Abstract 3365: Transcriptomics-based stratification of response to MAPK inhibition in vitro better predicts sensitivity to single agent and combination treatment than MAPK genomic alteration status alone

Overactivation of mitogen-activated protein kinase (MAPK) signaling is a frequently observed driver of many cancers. Targeted MAPK pathway inhibitors have been approved as therapies in patient populations with genomic alterations to MAPK pathway genes (e.g. dabrafenib in BRAF-mutant melanoma), with multiple other MAPK-targeted therapies in development. We have previously demonstrated that cell lines with MAPK pathway genomic alterations show increased sensitivity to ASTX029, our potent and selective dual-mechanism ERK inhibitor which is currently undergoing clinical development. However, MAPK oncogene status alone is not a universal indicator of sensitivity, nor is it clear that genomic markers of sensitivity to single agent inhibition represent the optimal approach to predicting response to MAPK targeted agents in the combination setting (e.g. sotorasib + trametinib). We therefore analysed MAPK pathway related transcriptional signatures to assess predictability for response to ASTX029 in combination with a SHP2 inhibitor.

We previously presented data from large-scale viability screens assessing the response to ASTX029 as a single agent treatment (437 cell lines), as well as in combination with an inhibitor of SHP2 (491 cell lines), an upstream adaptor protein in the MAPK pathway. Using these data, several published transcriptional signatures related to the MAPK pathway were assessed for their ability to stratify sensitive vs resistant cell lines when benchmarked against MAPK oncogene genomic status alone.

All assessed transcriptomics-based scores had a significant positive correlation with growth inhibition for ERK inhibitor single agent treatment as well as in combination with a SHP2 inhibitor. Transcriptomics-based scores were shown to be more sensitive than the use of mutant MAPK oncogene status alone based on assessment of binomial regression models. The significant increase in sensitivity enables the identification of additional cell lines responsive to MAPK pathway inhibition. The sensitivity was further increased when considering response to the combination of an ERK and SHP2 inhibitor compared to the ERK inhibitor as a single agent.

This analysis demonstrates the potential use of MAPK pathway-related transcriptomics-based scores for the stratification of MAPK pathway inhibitor response. ASTX029 is currently undergoing clinical development in advanced solid tumours (NCT03520075) and transcriptomics-based methods may provide utility in refining patient selection in the clinic for single agent or combination approaches.

Citation Format: Jessica Brothwood, Andrea Biondo, Kim-Hien Dao, Keisha Hearn, Chris Hindley, Navrohit Kandola, Harold Keer, John Lyons, Yoko Nakatsuru, Marc O'Reilly, Nicola Wallis, Harpreet Saini. Transcriptomics-based stratification of response to MAPK inhibition in vitro better predicts sensitivity to single agent and combination treatment than MAPK genomic alteration status alone [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3365.

Abstract P112: Treatment with the dual-mechanism ERK inhibitor, ASTX029, alters myeloid cell differentiation

The inhibition of aberrant MAPK pathway activity is a clinically validated approach which has resulted in the approval of agents targeting tumors driven by activating mutations in BRAF and KRAS. Although the overall response rate to MAPK-targeting agents is high, duration of response is often limited by the emergence of acquired resistance. In contrast, immune checkpoint inhibitors (ICI) such as the anti-PD1 therapy, pembrolizumab, have a lower response rate but induce more durable responses. It has been demonstrated that inhibition of aberrant MAPK pathway activity enhances immune activation. For example, preclinical studies show that treatment with the BRAFV600E inhibitor dabrafenib or the KRASG12C inhibitor sotorasib induces a pro-inflammatory tumor microenvironment (TME), which is associated with increased anti-tumor immunity. Further, studies using syngeneic, MAPK-activated in vivo models have demonstrated that the combination of MAPK-targeting agents and ICI results in synergistic inhibition of tumor growth. ASTX029 is a dual-mechanism ERK1/2 (ERK) inhibitor, inhibiting both the catalytic activity and phosphorylation of ERK, which is currently undergoing clinical development as part of a Phase 1/2 trial in advanced solid tumors (NCT03520075). ASTX029 has good oral bioavailability and shows potent inhibition of tumor growth in preclinical models bearing activating mutations in the MAPK pathway. We have previously investigated the immunomodulatory effects of ASTX029 using an in vivo syngeneic tumor model and observed that treatment with ASTX029 resulted in a pro-inflammatory TME, with increased interferon signaling consistent with published data describing the effects of treatment with dual-mechanism ERK inhibitors (Kidger et al., Mol Cancer Ther, 2020). We also observed an increased expression of antigen presentation genes. Using digital spatial profiling, we evaluated the expression of 31 proteins in immune infiltrates and observed a significant decrease in CD14 and a significant increase in MHC class II in ASTX029-treated tumors compared to untreated tumors. We therefore investigated the immunomodulatory effects of ASTX029 using primary human monocytes under conditions that induce macrophage differentiation and polarisation. Treatment with ASTX029 induced a decrease in CD14 and an increase in MHC class II cell surface expression, consistent with our previous in vivo mouse model data. In addition, we observed changes in cell surface expression of phenotypic markers, such as CD206, following treatment with ASTX029. These data support our previous observations and demonstrate that ERK inhibition by ASTX029 leads to phenotypic changes during monocyte to macrophage differentiation. Our data provide a strong rationale for the combination of ASTX029 with agents which aim to modulate the myeloid compartment or response to myeloid signaling.

Citation Format: Christopher Hindley, Andrea Biondo, Kim-Hien Dao, Lynsey Fazal, Alpesh Shah, Martin Sims, Nicola Wilsher, Harold Keer, John Lyons. Treatment with the dual-mechanism ERK inhibitor, ASTX029, alters myeloid cell differentiation [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P112.

Abstract 1661: Immune modulation by the dual-mechanism ERK inhibitor, ASTX029, in MAPK-activated tumor models

Whilst mitogen-activated protein kinase (MAPK) pathway inhibitors are approved therapies in mutant-BRAF driven cancers and have demonstrated a high response rate in the clinic, the duration of response is often short-lived. Approaches targeting the immune system have elicited durable responses and led to the approval of checkpoint inhibitors such as the anti-PD1 therapy, pembrolizumab, in indications where MAPK pathway activation is often observed, such as melanoma. Activation of the MAPK pathway has been associated with an immunosuppressive tumor microenvironment (TME). Further, preclinical studies have demonstrated that in addition to inhibiting MAPK activity in tumor cells, MAPK pathway inhibitors such as the BRAFV600E inhibitor dabrafenib or MEK inhibitor trametinib have promoted a more proinflammatory TME leading to upregulated antigen presentation on tumor cells, increased CD8+ T cell infiltration and tumor cell killing. Similar preclinical results were recently reported for a KRASG12C inhibitor, AMG 510, where treatment of in vivo models led to an increase in tumor infiltrating lymphocytes, macrophages, dendritic cells and an increase in active immune gene signatures leading to tumor immunity. We have recently described the discovery of ASTX029, which is currently undergoing clinical development in advanced solid tumors (NCT03520075). ASTX029 is a dual-mechanism ERK1/2 (ERK) inhibitor, inhibiting both the catalytic activity and phosphorylation of ERK, and shows potent inhibition of MAPK-activated tumor growth in preclinical models. Previous studies have demonstrated a difference in regulation of genes involved in response to type I interferon following treatment with dual-mechanism compared to catalytic ERK inhibitors. We investigated whether treatment with ASTX029 modulates antigen presentation and the TME in MAPK-activated tumors. Following treatment of cell lines in vitro, we observed ASTX029-dependent changes consistent with increased antigen presentation, including an increase in cell surface expression of MHC class I and the increase in gene expression of tumor-specific antigens gp100 and MART-1 following treatment of melanoma cells. We have previously demonstrated that ASTX029 has good bioavailability following oral dosing in mice. To further investigate the effect of ASTX029 on the TME, syngeneic tumors grown in immunocompetent mice dosed with ASTX029 were characterized in terms of immune cell composition of the TME and gene expression. Our results were consistent with increased immune activation, including increased interferon signaling and a change in the immune cell composition of the TME. These data demonstrate that treatment with ASTX029 leads to modulation of the TME and we hypothesize that to optimize therapeutic activity, ASTX029 could be partnered either with an immunomodulatory or tumor-directed agent.

Citation Format: Chris Hindley, Andrea Biondo, Kim-Hien Dao, Matthew Davis, Lynsey Fazal, Roberta Ferraldeschi, Keisha Hearn, Vanessa Martins, Harpreet Saini, Martin Sims, Nicola Wallis, Nicola Wilsher, Harold Keer, John Lyons, Joanne Munck. Immune modulation by the dual-mechanism ERK inhibitor, ASTX029, in MAPK-activated tumor models [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 1661.

Abstract CT108: A first-in-human, Phase 1 study of ASTX029, a dual-mechanism inhibitor of ERK1/2, in relapsed/refractory solid tumors

Background: The RAS-RAF-MEK-ERK pathway is commonly upregulated in human cancers. This is an open-label Phase 1 study of ASTX029, a dual-mechanism extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor, in subjects with relapsed/refractory solid tumors (NCT03520075). Methods: The primary objectives are to identify a maximum tolerated dose and/or recommended Phase 2 dose. ASTX029 was administered orally daily of 21-day cycles as powder-in-bottle (PiB, Cohort 1/10mg) and tablet formulation (beginning with Cohort 6/80 mg) under fed conditions, and as tablet formulation under fasting conditions (beginning with Cohort 8/40 mg). Dose escalation occurred according to a “3+3 design” based on dose-limiting toxicity (DLT) events. Disease response was evaluated according to RECIST v1.1 and exploratory indicators, including tumor variant allele frequency changes detected by cell-free DNA (cfDNA) quantitation. Results: 56 subjects were treated with at least one dose of ASTX029 in Phase 1A (dose escalation). Of 46 subjects with data, 35 (76%) had any RAS mutations and 4 (9%) had BRAF mutations; 1 subject had both. At the 200 mg dose level (Cohort 5, PiB/fed), one of six evaluable subjects developed a DLT (grade 3 maculopapular rash). At the 280 mg dose level (Cohort 12, tablet/fasting), two subjects experienced grade 2 central serous retinopathy adverse events (CSR AEs) within a few days of dosing. These were the only CSR AEs noted and one event was declared a DLT. Both subjects recovered to baseline within days of dose interruption. One cohort level below this dose was expanded (Cohort 11/200 mg, tablet/fasting); this dose level was deemed safe (without a DLT or grade ≥2 visual AE in 7 subjects) and was selected for Phase 1B dose expansion. Mean pharmacokinetic (PK) exposure was 151% of target exposure, which is defined as the level expected to have biological activity based on animal studies. The most frequent grade ≥2 AEs assessed as drug-related included nausea (4 subjects, grade 2) and transaminitis (4 subjects: 3 grade 2, 1 grade 3). The grade 3 transaminitis occurred in a subject with metastatic sarcoma involving the liver. There was one serious AE of malaise considered related to study drug. Two subjects, one with KRAS-G12A and BRAF-D549N non-small cell lung cancer (120 mg) and one with KRAS-G12D metastatic pancreatic cancer (200 mg), achieved partial responses (cycle 15/ongoing and cycle 3/ongoing, respectively). In 2 subjects with stable disease as the best response, longitudinal cfDNA sequencing showed a decrease of tumor variant allele frequencies after 2 cycles of ASTX029, followed by a return to baseline levels before disease progression. The most common reason for ASTX029 discontinuation was disease progression. Conclusions: This Phase 1A study of the ERK1/2 inhibitor ASTX029 has identified a dose level of 200 mg daily of a 21-day cycle for investigation in the Phase 1B portion of the study. Pharmacokinetic and pharmacodynamic data suggest target exposures are achieved with preliminary clinical activity.

Citation Format: Patricia LoRusso, Drew Rasco, Geoffrey Shapiro, Filip Janku, Alain Mita, Nilofer Azad, Marcia Toguchi, Chris Hindley, Shannon Bradley, Danna Chan, Harold Keer, Kim-Hien Dao, Ryan J. Sullivan, Alexander Spira. A first-in-human, Phase 1 study of ASTX029, a dual-mechanism inhibitor of ERK1/2, in relapsed/refractory solid tumors [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 CT108.

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 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.

Abstract CT270: A randomized, multi-center, phase II study of nivolumab combined with ipilimumab and guadecitabine or nivolumab combined with ipilimumab in melanoma and NSCLC patients resistant to anti-PD-1/-PD-L1: The NIBIT-ML1 Study

Background: Therapeutic targeting of the PD-1/PDL-1 axis significantly increases the survival of melanoma (MM) and non-small cell lung cancer (NSCLC) patients. Despite this unprecedented efficacy, a sizeable proportion of MM and NSCLC patients fails to benefit from therapy due to primary or secondary resistance to treatment. In this scenario, deepening the knowledge on mechanism(s) underlying treatment failure allows to design novel, mechanism-based, therapeutic approaches to overcome resistance to anti-PD-1/PDL-1 therapy. Along this line, we have extensively characterized the immunomodulatory properties of DNA hypomethylating agents (DHA) in different human malignances. Exposure of neoplastic cells to DHA efficiently improved antigen-restricted and -unrestricted T cell recognition of cancer cells in vitro through the upregulation/induction of the expression of epigenetically regulated tumor associated antigens, HLA class I and/or accessory/co-stimulatory molecules by neoplastic cells. Supporting these ex vivo data, combining the systemic administration of DHA (ie, decitabine or guadecitabine) with antibodies to different immune checkpoints significantly reduced tumor growth of murine syngeneic grafts, compared to single-agent therapy. Supporting these pre-clinical findings, our phase Ib NIBIT-M4 study has been the first clinical trial demonstrating that systemic administration of guadecitabine followed by CTLA-4 blockade with ipilimumab is safe and tolerable in MM patients, shows a promising anti-tumor, and induces a significant modulation of immune related pathways in tumor samples (Di Giacomo AM, Clin Cancer Res 2019). Prompted by these results and to further explore the efficacy of DHA combined with immune-checkpoints blockade we have designed and activated the NIBIT-ML1 trial. This study aims at investigating the efficacy of guadecitabine combined with ipilimumab and nivolumab in reverting the resistance to PD-1/PDL-1 therapy of MM and NSCLC patients. Methods: The NIBIT-ML1 is a randomized, phase II study designed according to the two stages optimal design by Simon, in unresectable Stage III or Stage IV MM (Cohort A) or NSCLC (Cohort B) patients who failed therapy with anti-PD-1/PDL-1 as last treatment. Primary objective of the study is immune (i)-ORR according to iRECIST criteria. Secondary objectives include safety, DCR, PFS, median OS, and survival rate at 1 and 2-years. Extensive cellular and molecular immune correlates will also be explored. Following a safety run-in phase in 6 subjects per Cohort, eligible patients will be randomized to receive: guadecitabine plus ipilimumab and nivolumab (ARM A) or ipilimumab and nivolumab (ARM B). Sample size will range from 6 to 92 patients per Cohort. The first patient first visit is foreseen by March 2020 (NCT04250246)

Citation Format: Anna Maria Di Giacomo, Luana Calabrò, Riccardo Danielli, Monica Valente, Elisabetta Gambale, Sandra Coral, Giovanni Amato, Harold Keer, Diana Giannarelli, Mohammad Azab, Andrea Anichini, Alessia Covre, Michele Maio. A randomized, multi-center, phase II study of nivolumab combined with ipilimumab and guadecitabine or nivolumab combined with ipilimumab in melanoma and NSCLC patients resistant to anti-PD-1/-PD-L1: The NIBIT-ML1 Study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT270.

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.

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.

Epigenetic Targeting of Adipocytes Inhibits High-Grade Serous Ovarian Cancer Cell Migration and Invasion

Ovarian cancer (OC) cells frequently metastasize to the omentum, and adipocytes play a significant role in ovarian tumor progression. Therapeutic interventions targeting aberrant DNA methylation in ovarian tumors have shown promise in the clinic, but the effects of epigenetic therapy on the tumor microenvironment are understudied. Here, we examined the effect of adipocytes on OC cell behavior in culture and impact of targeting DNA methylation in adipocytes on OC metastasis. The presence of adipocytes increased OC cell migration and invasion, and proximal and direct coculture of adipocytes increased OC proliferation alone or after treatment with carboplatin. Treatment of adipocytes with hypomethylating agent guadecitabine decreased migration and invasion of OC cells toward adipocytes. Subcellular protein fractionation of adipocytes treated with guadecitabine revealed decreased DNA methyltransferase 1 (DNMT1) levels even in the presence of DNA synthesis inhibitor, aphidicolin. Methyl-Capture- and RNA-sequencing analysis of guadecitabine-treated adipocytes revealed derepression of tumor-suppressor genes and epithelial-mesenchymal transition inhibitors. SUSD2, a secreted tumor suppressor downregulated by promoter CpG island methylation in adipocytes, was upregulated after guadecitabine treatment, and recombinant SUSD2 decreased OC cell migration and invasion. Integrated analysis of the methylomic and transcriptomic data identified pathways associated with inhibition of matrix metalloproteases and fatty acid α-oxidation, suggesting a possible mechanism of how epigenetic therapy of adipocytes decreases metastasis. In conclusion, the effect of DNMT inhibitor on fully differentiated adipocytes suggests that hypomethylating agents may affect the tumor microenvironment to decrease cancer cell metastasis.Implications: Epigenetic targeting of tumor microenvironment can affect metastatic behavior of ovarian cancer cells. Mol Cancer Res; 16(8); 1226-40. ©2018 AACR.

Treatment with epigenetic agents profoundly inhibits tumor growth in leiomyosarcoma

Leiomyosarcomas are rare mesenchymal neoplasms characterized by a smooth muscle differentiation pattern. Due to the extremely poor prognosis in patients, the development of novel chemotherapeutic regimens remains critically important. In this study, multiple leiomyosarcoma cell lines, SK-UT1, SK-LMS1, and MES-SA were treated with varying doses of the DNA Methyltransferase Inhibitors (DNMTi) 5-azacitidine (Aza), 5-aza-2-deoxycytidine (DAC), and guadecitabine (SGI-110). The effect of these epigenetic modulators was measured using both in-vitro and in-vivo models.

Of the three epigenetic modulators, Guadecitabine was the most effective at decreasing cell survival in LMS cell lines. SK-UT1 was found to be the more sensitive to all three epigenetic modulators, while SK-LMS1 and MES-SA were more resistant. The contrast in sensitivity seen was also represented by the increase in apoptosis in Aza and guadecitabine. In parallel with Aza, guadecitabine was observed to also arrest the cell cycle.

Treatment with guadecitabine led to a decrease in growth across the spectrum of sensitivity in LMS cell lines, both in a delayed in vitro and in vivo model; in parallel experiments, apoptotic pathways were activated in sensitive and less sensitive lines. Additional studies are required to explore potential therapeutic applications and mechanisms for leiomyosarcoma treatment.

An Effective Epigenetic-PARP Inhibitor Combination Therapy for Breast and Ovarian Cancers Independent of BRCA Mutations

Purpose: PARP inhibitors (PARPi) are primarily effective against BRCA1/2-mutated breast and ovarian cancers, but resistance due to reversion of mutated BRCA1/2 and other mechanisms is common. Based on previous reports demonstrating a functional role for DNMT1 in DNA repair and our previous studies demonstrating an ability of DNA methyltransferase inhibitor (DNMTi) to resensitize tumors to primary therapies, we hypothesized that combining a DNMTi with PARPi would sensitize PARPi-resistant breast and ovarian cancers to PARPi therapy, independent of BRCA status.Experimental Design: Breast and ovarian cancer cell lines (BRCA-wild-type/mutant) were treated with PARPi talazoparib and DNMTi guadecitabine. Effects on cell survival, ROS accumulation, and cAMP levels were examined. In vivo, mice bearing either BRCA-proficient breast or ovarian cancer cells were treated with talazoparib and guadecitabine, alone or in combination. Tumor progression, gene expression, and overall survival were analyzed.Results: Combination of guadecitabine and talazoparib synergized to enhance PARPi efficacy, irrespective of BRCA mutation status. Coadministration of guadecitabine with talazoparib increased accumulation of ROS, promoted PARP activation, and further sensitized, in a cAMP/PKA-dependent manner, breast and ovarian cancer cells to PARPi. In addition, DNMTi enhanced PARP "trapping" by talazoparib. Guadecitabine plus talazoparib decreased xenograft tumor growth and increased overall survival in BRCA-proficient high-grade serous ovarian and triple-negative breast cancer models.Conclusions: The novel combination of the next-generation DNMTi guadecitabine and the first-in-class PARPi talazoparib inhibited breast and ovarian cancers harboring either wild-type- or mutant-BRCA, supporting further clinical exploration of this drug combination in PARPi-resistant cancers. Clin Cancer Res; 24(13); 3163-75. ©2018 AACR.

A Phase I Clinical Trial of Guadecitabine and Carboplatin in Platinum-Resistant, Recurrent Ovarian Cancer: Clinical, Pharmacokinetic, and Pharmacodynamic Analyses

Purpose: Epigenetic changes are implicated in acquired resistance to platinum. Guadecitabine is a next-generation hypomethylating agent (HMA). Here, we report the clinical results, along with pharmacokinetic (PK) and pharmacodynamic analyses of the phase I study of guadecitabine and carboplatin in patients with recurrent, platinum-resistant high-grade serous ovarian cancer, primary peritoneal carcinoma (PPC), or fallopian tube cancer (FTC).Experimental Design: Guadecitabine was administered once daily on days 1 to 5 followed by carboplatin i.v. on day 8 of a 28-day cycle. Patients had either measurable or detectable disease. Safety assessments used CTCAE v4.Results: Twenty patients were enrolled and treated. Median age was 56 years (38-72 years). The median number of prior regimens was 7 (1-14). In the first cohort (N = 6), the starting doses were guadecitabine 45 mg/m² and carboplatin AUC5. Four patients experienced dose-limiting toxicity (DLT; neutropenia and thrombocytopenia), leading to dose deescalation of guadecitabine to 30 mg/m² and of carboplatin to AUC4. No DLTs were observed in the subsequent 14 patients. Grade ≥3 adverse events ≥10% were neutropenia, leukopenia, anemia, nausea, vomiting, ascites, constipation, hypokalemia, pulmonary embolism, small-intestinal obstruction, and thrombocytopenia. Three patients had a partial response (PR), and 6 patients had stable disease (SD) >3 months, for an overall response rate (ORR) and clinical benefit rate of 15% and 45%, respectively. LINE-1 demethylation in PBMCs and promoter demethylation/gene reexpression in paired tumor biopsies/ascites were recorded.Conclusions: Guadecitabine and carboplatin were tolerated and induced clinical responses in a heavily pretreated platinum-resistant ovarian cancer population, supporting a subsequent randomized phase II trial. Clin Cancer Res; 24(10); 2285-93. ©2018 AACR.

Abstract A70: Epigenome and genome alterations in platinum resistant ovarian tumors

Purpose: Epigenetic changes, particularly in DNA methylation, have been implicated in acquired resistance to platinum in ovarian cancer (OC). The goal of the current study was to analyze and integrate global RNA expression and DNA methylation profiles of platinum resistant tumors compared to untreated, platinum-sensitive ovarian tumors, as well as to measure genomic and epigenomic changes induced by guadecitabine (SGI-110) in tumors.

Methods: An ongoing phase I/II multi-institutional clinical trial uses the novel DNA methyltransferase (DNMT) inhibitor guadecitabine to re-sensitize recurrent platinum resistant OC to carboplatin. Patients enrolled in this trial had recurrent platinum resistant OC. Tumor biopsies were collected at baseline and after two cycles of guadecitabine administered daily for 5 days at a low (30mg/m2) dose (28 days per cycle). RNA and DNA were extracted from 48 and 57 baseline tumors and analyzed for next generation sequencing approaches to interrogate transcriptomes (RNA-seq) and methylomes (Infinium Human Methylation450 (HM450) arrays), respectively. Differential gene expression and DNA methylation profiles were generated and used for Ingenuity Pathway Analysis (IPA) to identify the top altered pathways in response to guadecitabine. Expression of DNMTs was examined by real-time RT-PCR and immunohistochemistry. LINE1 methylation and promoter methylation of selected genes (MAGE-A2, MAGE-A3, MAGE-A11, NY-ESO, RASSF1, MLH1, and HOXA11) were quantified by pyrosequencing before and after guadecitabine treatment (n=12 paired samples).

Results: Analysis of a limited number of paired samples before and after treatment (n=8) revealed significant changes in global gene expression profiles induced by guadecitabine, with 960 altered genes representing immunopathway enrichment including cytokine production in macrophages and T helper cells by IL-17A and IL-17F, granulocyte /agranulocyte adhesion and inflammation, IL-8 signaling, p38 MAPK signaling, cAMP-mediated signaling, and innate immunity. Epigenetic profiling using HM450 revealed extensive methylation changes when comparing recurrent platinum resistant ovarian tumors (n=42) to primary, untreated ovarian cancer specimens analyzed as part of the TCGA project (n=10). Six hundred and four promoters were significantly differentially methylated (adjusted p&lt;0.05, absolute methylation changes β&gt;0.2), among which, 498 and 106 were hypermethylated or hypomethylated respectively in recurrent platinum resistant ovarian tumors. IPA analysis of baseline tumor transcriptome and methylome demonstrated significant enrichment in a wide range of pathways associated with cancer, stem cells, inflammation and the immune system. DNMT1, 3A, and 3B mRNA levels in the tumors were highly variable (n=19). Analysis of a limited number of paired samples (n=7) revealed no significant changes in global methylation or in DNMT expression levels induced by treatment with guadecitabine (adjusted p&gt;0.05). However, the DNMT inhibitor induced significant methylome alterations in selected patients. Significant hypomethylation of MAGE-A3 and MAGE–A11 promoters (p&lt;0.05) was detected. Correlations between methylation changes and clinical outcomes are being explored.

Conclusions: These data suggest that treatment with the DNMT inhibitor guadecitabine induces a reactivation of immune responses in human OC. Correlations between methylation changes and expression profiles are being explored.

Citation Format: Fang Fang, Horacio Cardenas, Dave Miller, Aaron Buechlein, Qing Yu, Yunlong Liu, Guanglong Jiang, Pietro Taverna, Harold Keer, Doug Rusch, Daniela Matei, Kenneth P. Nephew. Epigenome and genome alterations in platinum resistant ovarian tumors. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr A70.

Abstract 2947: Pharmacodynamic (PD) and pharmacokinetic (PK) results of the second-generation hypomethylating agent, SGI-110, in patients with hepatocellular carcinoma (HCC) after progression on sorafenib

Background:

HCC is the sixth most common cancer and the third most common cause of cancer death worldwide. Sorafenib treatment improves survival in advanced disease, but no therapy has demonstrated significant activity after progression on sorafenib. Increased methylation of genes implicated in tumorigenesis has been described in HCC and has been associated with outcome and etiology. We evaluated the therapeutic and biologic effects of SGI-110, a hypomethylating agent in patients with HCC. SGI-110, a dinucleotide of decitabine and deoxyguanosine, increases decitabine exposure by protecting it from deamination due to slow release on subcutaneous (SC) injection. PK and PD results of an open-label, phase 2 study in patients with HCC are presented here.

Methods:

Adults with histologically confirmed, advanced-stage HCC who had received sorafenib, had evidence of disease progression, and ECOG PS 0-1 were enrolled. SGI-110 (SC) was given on D1-5 of a 28-day cycle. Blood samples were taken for PK/PD analysis and, when possible, paired tumor biopsies were taken for analysis of global DNA (LINE-1) and gene-specific methylation and gene expression. Patients were imaged every 8 weeks and allowed to continue treatment after radiologic but not clinical progression. End points include disease control rate (DCR) at 16 weeks, overall response rate, progression-free survival, and overall survival.

Results:

50 HCC patients (43M/7F; median age 60 years [range 32-82]; ECOG PS 0/1: 21/29) were enrolled. The initial dose of SGI-110 was 60 mg/m2 (4 patients treated), but due to grade 4 neutropenia, the dose was decreased to 45 mg/m2 for subsequent patients. SGI 110 was well tolerated at 45 mg/m2; myelosuppression was the major adverse event. Full PK was available from 16 patients (3F/13M). The PK profile for SGI-110 after 45 mg/m2 showed protracted conversion to deliver active metabolite decitabine with exposure window lasting beyond 8-hr and mean(SD) decitabine AUC exposures of 94(22) ng*hr/mL that were comparable to those achieved in AML/MDS after 60 mg/m2. Potent LINE-1 demethylation was observed in blood (-35.6%, n = 27) and in tumor (-12.9%, n = 10) DNA; significant demethylation (-27.4%, n = 6) was also observed on promoter of tumor suppressor gene MZB1 which is frequently hypermethylated and silenced in HCC.

Conclusions:

SGI-110 was well tolerated at a dose of 45 mg/m2 administered SC on D1-5 of a 28-day cycle. PK was consistent with that seen in another solid tumor study and provided more persistent decitabine exposures compared with PK in hematologic malignancies. The PD changes in blood and tumor LINE-1 and MZB-1 methylation are promising and consistent with the desired biologic effect of SGI-110. Analysis for clinical efficacy is ongoing.

Citation Format: Anthony El-Khoueiry, Mary F. Mulcahy, Tanios Bekaii-Saab, Richard Kim, Crystal Denlinger, Rakesh Goel, Shweta Gupta, Simone Jueliger, Aram Oganesian, Harold Keer, John Nemunaitis. Pharmacodynamic (PD) and pharmacokinetic (PK) results of the second-generation hypomethylating agent, SGI-110, in patients with hepatocellular carcinoma (HCC) after progression on sorafenib. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2947. doi:10.1158/1538-7445.AM2015-2947

Abstract 2320: Clinical epigenetic resensitization of platinum-resistant, recurrent ovarian cancer patients with SGI-110, a novel, second-generation, subcutaneously administered hypomethylating agent (HMA)

Background: Epigenetic changes have been implicated in acquired resistance to platinum. SGI-110 is a second generation SQ HMA with improved pharmaceutical properties compared to decitabine. Here we report the clinical results and pharmacodynamic analyses of the phase 1 study of SGI-110 in combination with carboplatin in patients with recurrent platinum resistant high-grade serous, epithelial ovarian cancer (EOC), primary peritoneal carcinoma (PPC) or fallopian tube (FT) cancer.

Methods: SGI-110 was administered SQ QD x 5 followed by carboplatin IV on Day 8 of a 28-day cycle. Patients were required to have either measurable disease according to RECIST v1.1 or detectable disease (modified Rustin) with clinical response assessed using the applicable criteria. Safety assessments were graded using CTCAE v4.

Results: Twenty patients (18 EOC, 1 PPC, 1 FT) were enrolled and treated in the phase 1 portion of the trial. Median age was 55.8 years (38-72); ECOG PS of 0/1/2 was 10/10/0, respectively. Median number of prior regimens was 7 (1-9). The starting doses were SGI-110 45 mg/m2 SQ QD x 5 and carboplatin AUC5 in the first cohort of 6 patients. Four DLTs of myelosuppression (neutropenia and thrombocytopenia) in the first cohort led to dose reduction to SGI-110 30 mg/m2 and carboplatin AUC4 with granulocyte-CSF permitted at the discretion of the physician. No DLTS were observed in 14 patients and this dose was recommended for the subsequent phase 2 study. Grade 3/4 AEs regardless of relationship to the combination ≥ 10% included anemia, leukopenia, neutropenia, thrombocytopenia, nausea, vomiting, constipation, small intestinal obstruction, infusion related reaction and pulmonary embolism. Three PRs and 9 SDs as best response were observed in 20 patients for an overall response rate and clinical benefit rate of 15% and 60%, respectively. All PRs and 3 SDs were accompanied by CA-125 decrease. LINE-1 hypomethylation, a marker of global DNA methylation, was recorded in PBMCs with SGI-110 30 mg/m2 (avg: -19.5%, n=14) and 45 mg/m2 (avg: -17.4%, n=6). Gene specific methylation of RASSF1A and BRCA-1 measured by pyrosequencing was significantly decreased at C2D8 compared to baseline in paired tumor biopsies/ascites (n=9). Gene re-expression measured by quantitative RT-PCR was observed in tumor biopsies.

Conclusions: Priming treatment with SGI-110 prior to carboplatin induced clinical responses in a heavily-pretreated platinum resistant ovarian cancer population with expected and manageable safety profile. Potent LINE-1 demethylation and demethylation and re-expression of silenced tumor genes were recorded. The phase 2 portion of the trial is currently ongoing with patients randomized to either the RP2D dose combination or a physician choice of 1 of 4 treatment options (topotecan; liposomal doxorubicin; weekly paclitaxel; or weekly gemcitabine).

Citation Format: Gini Fleming, Sharad Ghamande, Yvonne Lin, Angeles Alvarez Secord, John Nemunaitis, Merry-Jennifer Markham, Kenneth Nephew, Fang Fang, Shweta Gupta, Sue Naim, Gavin Choy, Simone Jueliger, Pietro Taverna, Yong Hao, Harold Keer, Mohammad Azab, Daniela Matei. Clinical epigenetic resensitization of platinum-resistant, recurrent ovarian cancer patients with SGI-110, a novel, second-generation, subcutaneously administered hypomethylating agent (HMA). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2320. doi:10.1158/1538-7445.AM2014-2320

Phase II study evaluating 2 dosing schedules of oral foretinib (GSK1363089), cMET/VEGFR2 inhibitor, in patients with metastatic gastric cancer

PURPOSE

The receptors for hepatocyte and vascular endothelial cell growth factors (MET and VEGFR2, respectively) are critical oncogenic mediators in gastric adenocarcinoma. The purpose is to examine the safety and efficacy of foretinib, an oral multikinase inhibitor targeting MET, RON, AXL, TIE-2, and VEGFR2 receptors, for the treatment of metastatic gastric adenocarcinoma.

PATIENTS AND METHODS

Foretinib safety and tolerability, and objective response rate (ORR) were evaluated in patients using intermittent (240 mg/day, for 5 days every 2 weeks) or daily (80 mg/day) dosing schedules. Thirty evaluable patients were required to achieve alpha = 0.10 and beta = 0.2 to test the alternative hypothesis that single-agent foretinib would result in an ORR of ≥ 25%. Up to 10 additional patients could be enrolled to ensure at least eight with MET amplification. Correlative studies included tumor MET amplification, MET signaling, pharmacokinetics and plasma biomarkers of foretinib activity.

RESULTS

From March 2007 until October 2009, 74 patients were enrolled; 74% male; median age, 61 years (range, 25-88); 93% had received prior therapy. Best response was stable disease (SD) in 10 (23%) patients receiving intermittent dosing and five (20%) receiving daily dosing; SD duration was 1.9-7.2 months (median 3.2 months). Of 67 patients with tumor samples, 3 had MET amplification, one of whom had SD. Treatment-related adverse events occurred in 91% of patients. Rates of hypertension (35% vs. 15%) and elevated aspartate aminotransferase (23% vs. 8%) were higher with intermittent dosing. In both patients with high baseline tumor phospho-MET (pMET), the pMET:total MET protein ratio decreased with foretinib treatment.

CONCLUSION

These results indicate that few gastric carcinomas are driven solely by MET and VEGFR2, and underscore the diverse molecular oncogenesis of this disease. Despite evidence of MET inhibition by foretinib, single-agent foretinib lacked efficacy in unselected patients with metastatic gastric cancer.

A phase I study of foretinib, a multi-targeted inhibitor of c-Met and vascular endothelial growth factor receptor 2

PURPOSE

Foretinib is an oral multikinase inhibitor targeting Met, RON, Axl, and vascular endothelial growth factor receptor. We conducted a phase I, first-time-in-human, clinical trial using escalating doses of oral foretinib. The primary objectives are to identify a maximum tolerated dose and determine the safety profile of foretinib. Secondary objectives included evaluation of plasma pharmacokinetics, long-term safety after repeated administration, preliminary antitumor activity, and pharmacodynamic activity.

EXPERIMENTAL DESIGN

Patients had histologically confirmed metastatic or unresectable solid tumors for which no standard measures exist. All patients received foretinib orally for 5 consecutive days every 14 days. Dose escalation followed a conventional "3+3" design.

RESULTS

Forty patients were treated in eight dose cohorts. The maximum tolerated dose was defined as 3.6 mg/kg, with a maximum administered dose of 4.5 mg/kg. Dose-limiting toxicities included grade 3 elevations in aspartate aminotransferase and lipase. Additional non-dose-limiting adverse events included hypertension, fatigue, diarrhea, vomiting, proteinuria, and hematuria. Responses were observed in two patients with papillary renal cell cancer and one patient with medullary thyroid cancer. Stable disease was identified in 22 patients. Foretinib pharmacokinetics increased linearly with dose. Pharmacodynamic evaluation indicated inhibition of MET phosphorylation and decreased proliferation in select tumor biopsies at submaximal doses.

CONCLUSIONS

The recommended dose of foretinib was determined to be 240 mg, given on the first 5 days of a 14-day cycle. This dose and schedule were identified as having acceptable safety and pharmacokinetics, and will be the dose used in subsequent phase II trials.

Phase II trial of the histone deacetylase inhibitor pivaloyloxymethyl butyrate (Pivanex, AN-9) in advanced non-small cell lung cancer

This multicenter phase II trial evaluated the therapeutic activity and safety profile of pivaloyloxymethyl butyrate (Pivanex, AN-9) as a single agent in refractory non-small cell lung cancer (NSCLC). Pivanex (2.34 g/m2 per day) was administered as a 6-h continuous intravenous infusion, daily for 3 days, and repeated every 21 days until disease progression. Forty-seven patients were treated. More than 90% of patients had received both a platinum compound and a taxane and 32% had received three or more prior chemotherapy regimens. The most common toxicities were transient grade 1-2 fatigue (34%), nausea (17%), and dysgeusia (11%). Three patients had partial responses (6.4 and 95%; CI 1.4-18.7%) and 14 patients had stable disease for > or =12 weeks (30%). Median survival for all patients was 6.2 months with 1-year survival of 26%. For patients who received fewer than three prior chemotherapy regimens, median survival was 7.8 months and 1-year survival was 31%. Pivanex is well tolerated and appears to be active as a single agent in patients with advanced NSCLC refractory to previous chemotherapy. Based on its therapeutic activity and favorable safety profile, further studies of Pivanex in NSCLC, particularly in combination with current chemotherapeutic agents, are warranted.