Application of an Environmental Monitoring to Assess the Practices and Control the Risk of Occupational Exposure to Cyclophosphamide in Two Sites of a French Comprehensive Cancer Center

OBJECTIVES

The risk of chronic exposure to antineoplastic agents in hospitals, mainly by skin contact with contaminated surfaces, is well established. The aim of this study was to assess indirectly the risk of occupational exposure to antineoplastics drugs at two hospitals by using an environmental monitoring, and to suggest ways of improving the exposure to healthcare workers.

METHODS

An observational study of care practices on both sites was carried out. A wipe sampling campaign was then designed to study environmental contamination throughout the chemotherapy process: receipt, storage, compounding, transport, administration, and elimination areas. Samples were analyzed by a validated LC-MS/MS method allowing trace quantification of cyclophosphamide. A guidance 'safe value' of 0.10 ng/cm2 was considered.

RESULTS

A total of 293 samples were analyzed, of which 58% were found to be positive. In the compounding units, the drug vials were contaminated before [range = (non-quantifiable [NQ]-0.71) ng/cm2] and after cleaning procedure [(NQ-0.62) ng/cm2], particularly when the flip-off lid was removed during cleaning. The contamination found on manual preparations was operator-dependent: [non-detectable (ND)-3.51] ng/cm2 on infusion bag surfaces; (780.61-24 698.98) ng/cm2 on medication ports. In the case of automated preparations, the average contamination was higher on infusion bag surfaces [(2.43-36.86) ng/cm2] and lower on medication ports [(0.43-7.65) ng/cm2] than manual preparations. Contamination of the analytical control area was also highlighted. In the daily care unit, the contamination was located near the infusion area (armchairs, infusion stands, floor, and patient toilets), and varied somewhat between the two sites, especially on the floor with (0.46-27.32) compared to (ND-0.18) ng/cm2. We did not detect contamination on the transport boxes, on the door handles or in the disposal areas.

CONCLUSIONS

The variability of contamination observed between the two sites can be explained in part by the difference in routine practices, especially training of the staff, and cleaning procedures. Findings were communicated to healthcare workers, and news interventions were implemented based on wipe sampling results. This study demonstrated a method for routine environmental monitoring and worker education as a strategy to reduce occupational exposure.

Abstract 2569: Development of potent dual PDK1/AurA kinase inhibitors for Ewing sarcoma therapy

Background. It has been estimated that more than 50% of cancers are related to the dysregulation of the PI3K-PDK1-Akt signaling axis. Within this pathway, phosphoinositide-dependent kinase-1 (PDK1) and Aurora kinase A (AurA) have key roles. PDK1 is a phosphorylation-mediated activator of Akt, the main apoptotic regulator, thereby acting at the crossroads of several oncogenic pathways. Overexpression and/or aberrant activation of AurA have been functionally linked to neoplastic transformation principally through the development of centrosome amplification and chromosomal instability. In this study, the molecular mechanisms involved in the dual inhibitory capacity of PDK1- and AurA-targeting OXID-pyridonyl compounds were explored in a panel of tumor cell lines carrying PI3KCA, K-RAS, PTEN, RB-1, EGFR and/or TP53 mutations

Materials and Methods. To evaluate the enzymatic inhibitory activity, the oxindole-based derivatives were subjected to FRET-based Z′-Lyte assay (Invitrogen™) against PDK1 and AurA. All in vitro assays for ADME-Tox profiling were performed as published previously[1]. Anti-proliferative effects of OXID-pyridonyl compounds (SA16, IB35, VI8, VI18) were assessed by soft agar clonogenic formation and MTT assays after 72-h exposures with increasing concentrations (from 0.014 to 30 µM) in a panel of 15 cell lines. Protein levels were analyzed by Western Blot using commercial antibodies. OSU-03012 (PDK-1 inhibitor) and MK-5108 (AurA inhibitor) were used as reference compounds.

Results. Among the four evaluated compounds, SA16 displayed nanomolar inhibitory potency against both PDK1 and AurA. In vitro, drugs SA16 and VI8 showed to exert anti-tumor activity in the 6647, TC71, SKNMC Ewing sarcoma (ES) cells lines and in the HCT116 colon carcinoma-derived cells (IC50s values between 2.6 and 25 µM after 72-h exposures), when tested in a panel of 15 cancer cell lines. These results were confirmed by the evaluation of 3D-clonogenic capacity in soft agar. The effect of 1 µM SA16 at the protein level was evaluated after 5 to 120 min exposure in the ES cell line SKNMC. No modulation of Aur-A protein or PDK-1 phosphorylation (Ser241) were observed in SKNMC cells, whereas a decrease of downstream PDK1 targets such as p-AKT, p-RSK2, and p-p44/42 MAPK was observed after 30 min of exposure. In addition, SA16 displayed acceptable in vitro ADME-Tox properties. Our results on structural insights into the mode of binding[2], in vitro drug-intake kinetics and in vivo PK appear to indicate that SA16 presents adequate features as a scaffold for the design of PDK1/AurA dual-target molecules.

Conclusion. We report the synthesis of novel first-in-class 2-oxindole-based derivatives as dual PDK1-AurA kinase inhibitors as a novel scaffold for the design and synthesis of a new multitarget strategy for Ewing sarcoma.[1] Runfola M. et al. Data Brief 29 (2020) 105206.[2] Sistito S. et al. Eu J Med Chem 226 (2021) 11389.

Citation Format: Maria Eugenia Riveiro, Samuel Huguet, Ramiro Vazquez, Roberta Frapolli, Guido Puricelli, Simona Sestito, Olivier Madar, Keyvan Rezai, Gianpiero Garau, Simona Rapposelli. Development of potent dual PDK1/AurA kinase inhibitors for Ewing sarcoma therapy [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 2569.

Development of potent dual PDK1/AurA kinase inhibitors for cancer therapy: Lead-optimization, structural insights, and ADME-Tox profile

We report the synthesis of novel first-in-class 2-oxindole-based derivatives as dual PDK1-AurA kinase inhibitors as a novel strategy to treat Ewing sarcoma. The most potent compound 12 is suitable for progression to in vivo studies. The specific attributes of 12 included nanomolar inhibitory potency against both phosphoinositide-dependent kinase-1 (PDK1) and Aurora A (AurA) kinase, with acceptable in vitro ADME-Tox properties (cytotoxicity in 2 healthy and 14 hematological and solid cancer cell-lines; inhibition of PDE4C1, SIRT7, HDAC4, HDAC6, HDAC8, HDAC9, AurB, CYP1A2, CYP2C9, CYP2C19, CYP2D6, and hERG). X-ray crystallography and docking studies led to the identification of the key AurA and PDK1/12 interactions. Finally, in vitro drug-intake kinetics and in vivo PK appear to indicate that these compounds are attractive lead-structures for the design and synthesis of PDK1/AurA dual-target molecules to further investigate the in vivo efficacy against Ewing Sarcoma.

Phase I or II Study of Ribociclib in Combination With Topotecan-Temozolomide or Everolimus in Children With Advanced Malignancies: Arms A and B of the AcSé-ESMART Trial

PURPOSE

AcSé-ESMART is a proof-of-concept, phase I or II, platform trial, designed to explore targeted agents in a molecularly enriched cancer population. Arms A and B aimed to define the recommended phase II dose and activity of the CDK4/6 inhibitor ribociclib with topotecan and temozolomide (TOTEM) or everolimus, respectively, in children with recurrent or refractory malignancies.

PATIENTS AND METHODS

Ribociclib was administered orally once daily for 16 days after TOTEM for 5 days (arm A) or for 21 days with everolimus orally once daily continuously in a 28-day cycle (arm B). Dose escalation followed the continuous reassessment method, and activity assessment the Ensign design. Arms were enriched on the basis of molecular alterations in the cell cycle or PI3K/AKT/mTOR pathways.

RESULTS

Thirty-two patients were included, 14 in arm A and 18 in arm B, and 31 were treated. Fourteen patients had sarcomas (43.8%), and 13 brain tumors (40.6%). Main toxicities were leukopenia, neutropenia, and lymphopenia. The recommended phase II dose was ribociclib 260 mg/m2 once a day, temozolomide 100 mg/m2 once a day, and topotecan 0.5 mg/m2 once a day (arm A) and ribociclib 175 mg/m2 once a day and everolimus 2.5 mg/m2 once a day (arm B). Pharmacokinetic analyses confirmed the drug-drug interaction of ribociclib on everolimus exposure. Two patients (14.3%) had stable disease as best response in arm A, and seven (41.2%) in arm B, including one patient with T-acute lymphoblastic leukemia with significant blast count reduction. Alterations considered for enrichment were present in 25 patients (81%) and in eight of nine patients with stable disease; the leukemia exhibited CDKN2A/B and PTEN deficiency.

CONCLUSION

Ribociclib in combination with TOTEM or everolimus was well-tolerated. The observed activity signals initiated a follow-up study of the ribociclib-everolimus combination in a population enriched with molecular alterations within both pathways.

A phase II randomised study of preoperative trastuzumab alone or combined with everolimus in patients with early HER2-positive breast cancer and predictive biomarkers (RADHER trial)

INTRODUCTION

Resistance to trastuzumab in breast cancer is an ongoing challenge. Clinical and biological effects of co-targeting HER2 and mammalian target of rapamycin (mTOR) in patients with HER2-positive early operable breast cancer via the addition of everolimus to preoperative trastuzumab were evaluated in a phase II randomised study.

METHODS

Patients were randomised 1:1 to receive trastuzumab (4 mg/kg initial dose then 2 mg/kg weekly for 5 weeks) alone or combined with everolimus (10 mg/day for 6 weeks) and then underwent surgery. Tumours were assessed by clinical examination and echography at the baseline and on treatment. The primary end-point was the clinical response rate at 6 weeks. Pathological response and safety were also evaluated. Baseline and surgery tumour samples were assessed by immunohistochemistry and multiplex immunoanalysis for predictive downstream effectors of the PI3K/AKT/mTOR and MAP kinase (MAPK) pathways.

RESULTS

Eighty-two patients were enrolled, 41 per arm. The clinical response rates were 34.1% and 43.9% with trastuzumab alone and combined with everolimus, respectively. Pathological response rates were 43.6% and 47.5%, respectively. Addition of everolimus increased toxicity, notably mucositis (82.5% versus 5.0%) and rash (57.5% versus 10.0%), but grade III/IV events were rare. No correlation between response to treatments and baseline candidate biomarkers was identified, except for PIK3CA mutations which were found to predict trastuzumab resistance. Significant changes were seen in several MAPK pathway effectors after combination therapy.

CONCLUSIONS

The addition of everolimus did not improve the efficacy, but induced MAPK signalling. Combination therapy to overcome pathway cross-talk should be considered to maximise the effectiveness of trastuzumab in this setting. ClinicalTrial.gov Identifier NCT00674414.

Single radio UHPLC analysis for the quality control of technetium-99m radiolabelled radiopharmaceuticals

The radiochemical purity (RCP) determination of radiopharmaceuticals is routinely done with radio-thin layer chromatography (r-TLC). These methods are usually transposed and adjusted from the summary product characteristics without any analytical validation. The r-TLC method is simple but manually-performed steps could lead to RCP misinterpretation. To increase the sensitivity, radio ultra-high performance liquid chromatography (r-UHPLC) can be used. In this study, an r-UHPLC method had been validated and compared to the r-TLC method. Hydrolyzed-reduced technetium had also been studied.

Abstract 916: A novel LAP-IL2 fusion protein elicits efficacy as single agent in syngeneic renal and melanoma mouse models

Background. Recombinant IL-2 (rIL-2; aldesleukin) has consistently shown single agent responses and survival benefits in metastatic melanoma and renal cell carcinoma. However, severe toxic side effects associated with high doses, as well as the poor PK profile of rIL-2, have limited its clinical usage. Stealthyx generated a new compound linking the Latency Associated Peptide (LAP) of TGF-β precursor to IL-2 via a metalloproteinase (MMP) cleavage site, providing a protective shell-like structure around IL-2. This structure increases its half-life and warrants release of IL-2 at sites of high MMP activity thus avoiding systemic side effects. Here we have evaluated the efficacy and tolerability of the novel construct LAP (mut) IL-2 T pep in mice bearing subcutaneous melanoma (B16-BL6) or renal carcinoma (RENCA) compared to equimolar rIL-2 doses.

Materials and Methods. B16-BL6 cells were injected s.c. in the flank of C57BL/6 mice and RENCA cells were injected s.c in BALB/c mice. Once tumor masses reached about 50 mg mice were randomized to receive LAP (mut) IL-2 T (2.7-0.54 mg/kg i.p.), rIL-2 (300000 UI/mouse), their combination with anti-PD1 antibody (250 μg/mouse) or the irrelevant (250 μg/mouse). Four hours after the 9th dose of construct, mice were sacrificed to collect plasma and tumors. Tumor CD3 infiltration was evaluated by IHC. Plasma cytokines were measured with Luminex technology Milliplex MCYTOMAG-70K with Bio-Plex Multiplex (BioRad).

Results. LAP (mut) IL-2 T pep at 2.7 mg/kg displayed anti-tumor activity (best T/C = 57% at day 16 after inoculum, p<0.01) against the B16-BL6 melanoma. A non-significant reduction in tumor growth was observed with rIL-2. The combination of LAP (mut) IL-2 T pep with the anti-PD1 antibody exerted a deleterious effect. A good tolerability of the LAP (mut) IL-2 T pep construct and rIL-2 - treatment was observed in mice bearing B16-BL6 and RENCA tumors. LAP (mut) IL-2 T pep treatment did not cause relevant changes in the plasma levels of a panel of selected murine cytokines IFN -γ, IL-10, IL-12p70, IL-1β, IL-2, IL-4, IL-5, IL-6, KC/GRO and TNF-α in B16-BL6-bearing mice. However, tumor CD3 positive cells infiltration significantly increased after treatment with 2.7 mg/kg LAP (mut) IL-2 T pep and rIL-2. A non-significant reduction in tumor growth was observed with LAP (mut) IL-2 T pep or rIL-2 in RENCA tumors. However, we observed a dose-dependent increase in the plasma levels of the anti-inflammatory cytokines: IL-10, IL-4, and IL-5, whereas plasma IFN-γ, IL-12p70, IL-1β, IL-6, KC/GRO and TNF-α were not affected by the treatment with LAP(mut)-IL2 T pep in RENCA-bearing mice. In mice treated with rIL-2, it was observed only an increase in plasmatic IFN-γ.

Conclusion. These results show that LAP(mut) IL-2 T pep is well tolerated and has anti-tumor efficacy against the B16-BL6 preclinical model, with a different profile of systemic activity on cytokines compared to rIL-2.

Citation Format: Maria Eugenia Riveiro, Roberta Frapolli, Giulia Taraboletti Giulia Taraboletti, Keyvan Rezai, Marina Meroni, Massimo Russo, Patrizia Borsotti, Chris Schultz, David Gould, Yuti Chernajovsky. A novel LAP-IL2 fusion protein elicits efficacy as single agent in syngeneic renal and melanoma mouse 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 916.

Phase I-II Open-Label Multicenter Study of Palbociclib + Vemurafenib in BRAF V600MUT Metastatic Melanoma Patients: Uncovering CHEK2 as a Major Response Mechanism

PURPOSE

In BRAF ^V600MUT metastatic melanoma, cyclin D-CDK4/6-INK4-Rb pathway alterations are involved in resistance to MAPK inhibitors, suggesting a clinical benefit of cyclin-dependent kinase 4 (CDK4) inhibitors. In this phase I-II study, we aimed to establish the MTD of palbociclib when added to vemurafenib.

PATIENTS AND METHODS

Patients with BRAF ^V600E/KMUT metastatic melanoma harboring CDKN2A loss and RB1 expression were included and stratified into two groups according to previous BRAF inhibitor treatment (no:strata 1; yes:strata 2). Treatment comprised palbociclib once daily for 14 days followed by a 7-day break + continuous dosing of vemurafenib. The primary endpoint was the occurrence of dose-limiting toxicity (DLT), and the secondary endpoints included the best response, survival, pharmacokinetics, and tumor molecular profiling.

RESULTS

Eighteen patients were enrolled, with 15 in strata 2. Characteristics at inclusion were American Joint Committee on Cancer stage IVM1c (N = 16; 88.9%), high lactate dehydrogenase (N = 9; 50.0%), and median number of previous treatments of 2. One and 5 patients experienced DLT in strata 1 and 2, respectively, defining the MTD at palbociclib 25 mg and vemurafenib 960 mg in strata 2. No significant evidence for drug-drug interactions was highlighted. The median progression-free survival was 2.8 months, and 5 (27.8%) patients showed a clinical response. The baseline differential mRNA expression analysis and in vitro data revealed the role of CHEK2 in the response to palbociclib.

CONCLUSIONS

Although the combination of palbociclib + fixed-dose vemurafenib did not allow an increased palbociclib dosage above 25 mg, a significant clinical benefit was achieved in pretreated patients with melanoma. An association between the transcriptomic data and clinical response was highlighted.

Targeting Adrenomedullin in Oncology: A Feasible Strategy With Potential as Much More Than an Alternative Anti-Angiogenic Therapy

The development, maintenance and metastasis of solid tumors are highly dependent on the formation of blood and lymphatic vessels from pre-existing ones through a series of processes that are respectively known as angiogenesis and lymphangiogenesis. Both are mediated by specific growth-stimulating molecules, such as the vascular endothelial growth factor (VEGF) and adrenomedullin (AM), secreted by diverse cell types which involve not only the cancerogenic ones, but also those constituting the tumor stroma (i.e., macrophages, pericytes, fibroblasts, and endothelial cells). In this sense, anti-angiogenic therapy represents a clinically-validated strategy in oncology. Current therapeutic approaches are mainly based on VEGF-targeting agents, which, unfortunately, are usually limited by toxicity and/or tumor-acquired resistance. AM is a ubiquitous peptide hormone mainly secreted in the endothelium with an important involvement in blood vessel development and cardiovascular homeostasis. In this review, we will introduce the state-of-the-art in terms of AM physiology, while putting a special focus on its pro-tumorigenic role, and discuss its potential as a therapeutic target in oncology. A large amount of research has evidenced AM overexpression in a vast majority of solid tumors and a correlation between AM levels and disease stage, progression and/or vascular density has been observed. The analysis presented here indicates that the involvement of AM in the pathogenesis of cancer arises from: 1) direct promotion of cell proliferation and survival; 2) increased vascularization and the subsequent supply of nutrients and oxygen to the tumor; 3) and/or alteration of the cell phenotype into a more aggressive one. Furthermore, we have performed a deep scrutiny of the pathophysiological prominence of each of the AM receptors (AM₁ and AM₂) in different cancers, highlighting their differential locations and functions, as well as regulatory mechanisms. From the therapeutic point of view, we summarize here an exhaustive series of preclinical studies showing a reduction of tumor angiogenesis, metastasis and growth following treatment with AM-neutralizing antibodies, AM receptor antagonists, or AM receptor interference. Anti-AM therapy is a promising strategy to be explored in oncology, not only as an anti-angiogenic alternative in the context of acquired resistance to VEGF treatment, but also as a potential anti-metastatic approach.

Input of serum haptoglobin fucosylation profile in the diagnosis of hepatocellular carcinoma in patients with non-cirrhotic liver disease

BACKGROUND

Haptoglobin bifucosylated tetra-antennary glycan have been identified in patients with early stage hepatocellular carcinoma, but its specificity according to the presence or not of cirrhosis has never been assessed. The aims of this study were to determine if haptoglobin bifucosylated tetra-antennary glycan (1) could be a marker of HCC in patients without cirrhosis; (2) could increase the performance of standard alpha-fetoprotein (AFP) or recent blood tests for HCC detection, i.e., lectin-reactive alpha-fetoprotein (AFP-L3), des-gamma-carboxy prothrombin (DCP) and Liver-Cancer-Risk-test (LCR1-test).

METHODS

We retrospectively selected patients, 102 with HCC (21 without cirrhosis), matched by stages with 140 controls without HCC (81 without cirrhosis). Haptoglobin fucosylation was assessed by MALDI-TOF. LCR-glycan algorithm was constructed combining components of the LCR-1 test (haptoglobin, gammaglutamyl-transpeptidase, apolipoproteinA1, alpha-2-macroglobulin) with AFP, AFP-L3, DCP and haptoglobin bifucosylated tetra-antennary glycan.

RESULTS

In 102 patients without cirrhosis (21 HCC and 81 controls), the intention-to-diagnose analyses showed that haptoglobin bifucosylated tetra-antennary glycan alone had a sensitivity of 71% (15/21;95%CI 50-86), significantly better (P=0.02) than standard AFP (43%;9/21;95%CI 24-63), and a specificity of 96% (78/81;95% 90-99). The sensitivity of LCR-glycan, in patients without cirrhosis, was 86% (18/21; 95%CI 63-95) significantly better (P=0.001) than standard AFP (43%; 9/21; 95%CI 24-63), with an AUROC of 0.943 (95%CI 0.806-0.98) compared to 0.811 (95%CI 0.630-0.908) for AFP (P=0.06).

CONCLUSION

Haptoglobin bifucosylated tetra-antennary glycan is associated with the presence of HCC in patients with chronic liver disease including those without cirrhosis. Its combination with existing HCC biomarkers could improve the performance of standard AFP for HCC detection.

Epigenetic Control of Mitochondrial Fission Enables Self-Renewal of Stem-like Tumor Cells in Human Prostate Cancer

Cancer stem cells (CSCs) contribute to disease progression and treatment failure in human cancers. The balance among self-renewal, differentiation, and senescence determines the expansion or progressive exhaustion of CSCs. Targeting these processes might lead to novel anticancer therapies. Here, we uncover a novel link between BRD4, mitochondrial dynamics, and self-renewal of prostate CSCs. Targeting BRD4 by genetic knockdown or chemical inhibitors blocked mitochondrial fission and caused CSC exhaustion and loss of tumorigenic capability. Depletion of CSCs occurred in multiple prostate cancer models, indicating a common vulnerability and dependency on mitochondrial dynamics. These effects depended on rewiring of the BRD4-driven transcription and repression of mitochondrial fission factor (Mff). Knockdown of Mff reproduced the effects of BRD4 inhibition, whereas ectopic Mff expression rescued prostate CSCs from exhaustion. This novel concept of targeting mitochondrial plasticity in CSCs through BRD4 inhibition provides a new paradigm for developing more effective treatment strategies for prostate cancer.

Ibrutinib monotherapy for relapse or refractory primary CNS lymphoma and primary vitreoretinal lymphoma: Final analysis of the phase II 'proof-of-concept' iLOC study by the Lymphoma study association (LYSA) and the French oculo-cerebral lymphoma (LOC) network

BACKGROUND

Primary central nervous system lymphomas (PCNSLs) are mainly diffuse large B-cell lymphomas (DLBCLs) of the non-germinal centre B-cell subtype, with unmet medical needs. This study aimed to evaluate the efficacy and toxicity of ibrutinib in DLBCL-PCNSL PATIENTS AND METHODS: This prospective, multicentre, phase II study involved patients with relapse or refractory(R/R) DLBCL-PCNSL or primary vitreoretinal lymphoma. The treatment consisted of ibrutinib (560 mg/day) until disease progression or unacceptable toxicity occurred. The primary outcome was the disease control (DC) rate after two months of treatment (P0 < 10%; P1 > 30%).

RESULTS

Fifty-two patients were recruited. Forty-four patients were evaluable for response. After 2 months of treatment, the DC was 70% in evaluable patients and 62% in the intent-to-treat analysis, including 10 complete responses (19%), 17 partial responses (33%) and 5 stable diseases (10%). With a median follow-up of 25.7 months (range, 0.7-30.5), the median progression-free and overall survivals were 4.8 months (95% confidence interval [CI]; 2.8-12.7) and 19.2 months (95% CI; 7.2-NR), respectively. Thirteen patients received ibrutinib for more than 12 months. Two patients experienced pulmonary aspergillosis with a favourable (n = 1) or fatal outcome (n = 1). Ibrutinib was detectable in the cerebrospinal fluid (CSF). The clinical response to ibrutinib seemed independent of the gene mutations in the BCR pathway.

CONCLUSION

Ibrutinib showed clinical activity in the brain, the CSF and the intraocular compartment and was tolerated in R/R PCNSL. The addition of ibrutinib to standard methotrexate-base induction chemotherapy will be further evaluated in the first-line treatment.

CLINICAL TRIAL NUMBER

NCT02542514.

Abstract 3895: A phase I-II pharmacokinetic drug-drug interaction evaluation of oral palbociclib in combination with vemurafenib in patients suffering metastatic melanoma with BRAF V600 mutated and CDKN2A loss & expression of Rb

Background: A novel combination of vemurafenib (VM), a selectif inhibitor of BRAF V600 mutated protein + oral palbociclib (Palbo) a highly selective reversible oral inhibitor of cyclin-dependent kinases (CDK) 4 and 6, could provide a synergistic antitumor activity in patients with metastatic melanoma harbouring BRAF V600 mutation and CDKN2A loss. VM has been shown to be an inductor of CYP3A4 which is also mainly involved in Palbo metabolism.

In this study we investigated the potential pharmacokinetic (PK) drug-drug interactions (DDI) related to the association of VM and Palbo.

Methods: metastatic melanoma harbouring BRAF V600 mutation and CDKN2A loss patients were treated with a 14 days on followed by 7 days off dosing schedule of Palbo + continuous bid dosing of VM. Dose levels [DL, Palbo (mg/day)/VM (mg/bid)] ranged from 25/720 to 200/960. For PK analysis, 7 time point samples were collected on D1C1, D21C1, and D7C2, for Palbo and VM assays. Plasma concentrations of Palbo and VM, were measured using ultra high performance liquid chromatography (UHPLC) coupled with tandem mass spectrometry validated methods.

Population PK (PPK) was modeled using a non linear mixed effect model program (Monolix version 2018r) by computing the maximum likelihood estimator of the parameters without any approximation of the model (no linearization). The following parameters were calculated absorption constant (Ka); apparent distribution volume (V/F); apparent clearance (CL/F)

Results: A total of 18 patients were treated by the combination of Palbo + VM. VM and palbo plasma concentrations were measured in 236 and 275 blood samples respectively. A one-compartment open model with linear elimination adequately described Palbo concentration-time courses. The inter-individual variabilities (ISV) could be well estimated for all stuctural parameters. The PPK parameters obtained for the structural model were: Ka = 0.791 h-1, CL/F=76.0L/h, V1/F=2830 L. Albuminemia had a significant impact on palbo CL. A one-compartment model adequately fitted the VM plasma concentration-time data. The PPK parameters were CL/F=0.133 L/h, V/F=83.6 L and Ka has been fixed at 0.2 h-1. Body weight (BW) was the best size descriptor when VM CL and V terms were normalized to a mean BW of 70 Kg according to an allometric scaling rule.

Conclusions: The PPK modeling satisfactorily described the plasma Plabo and VM time-concentration curves in patients. The main covariate effect was related to BW and albuminemia. There is no significant evidence for drug-drug PK interaction between Palbo and VM. PK-PD modeling will be performed.

Citation Format: Samuel Huguet, Thierry Lesimple, Arthur Geraud, Mouna Amini-Adle, Caroline Dutriaux, Laetitia Da Meda, Florence Capelle, Zineb Ghrieb, Samia Mourah, Olivier Madar, Didier Bouton, Mathieu Resche-Rigon, Celest Lebbe, Keyvan Rezai. A phase I-II pharmacokinetic drug-drug interaction evaluation of oral palbociclib in combination with vemurafenib in patients suffering metastatic melanoma with BRAF V600 mutated and CDKN2A loss & expression of Rb [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3895.

Phase I-II open label multicenter study of PD0332991 in BRAFV600mut metastatic melanoma patients harboring CDKN2A loss and RB1 expression and treated with vemurafenib

9545

Background: Among mechanisms of resistance to BRAF inhibitors (BRAFi), cell cycle effectors including CDK4 have been involved in ERK reactivation. In this phase I-II open label study, we aimed to establish the Maximum Tolerated Dose (MTD) of PD0332991, an inhibitor of CDK4/6, when added to vemurafenib (VM) in metastatic melanoma patients. Methods: Patients with BRAFV600E/K mutated metastatic melanoma harbouring CDKN2A loss and RB1 expression were included. Patients were treated with a 14 days followed by 7 days rest daily dosing schedule of PD0332991 + continuous BID dosing of VM, and stratified into 2 groups according to previous BRAFi treatment (no group 1, yes group 2). Dose levels (PD0332991 (mg/QD)/VM (mg/BID) ranged from 25/720 to 200/960. The primary endpoint was the occurrence of a DLT within the first 2 cycles of therapy. Secondary endpoints included best response (RECIST), OS, PFS, pharmacokinetics parameters, tumour molecular profiling on baseline lesions using transcriptomic and NGS analysis. Results: Nineteen patients were enrolled, among them 16 (84%) in group 2, with 18.5 months median follow-up. Characteristics at baseline were: male 11 (58%), median age 54.4 years, unresectable stage IIIC 2 (11%), stage IV 17 (89%), M1C 12 (67%), high LDH 9 (47%), median time from advanced melanoma diagnosis to inclusion 26.8 months, ≥ 2 lines therapy 13 (68%). A DLT was observed for 1 and 5 patients in group 1 and 2 respectively, defining the MTD at PD0332991 25mg and VM 960mg in group 2. No significant evidence for drug-drug interaction between PD0332991 and VM was highlighted. In group 2, ORR was estimated to 4 (25%), SD to 8 (50%), median PFS to 9.3 months and median OS to 13.2 months. Baseline transcriptomic analysis revealed high alteration rate associated with clinical response and enrichment in genes related to MAPK, cell cycle and apoptosis pathways. Conclusions: While combination of fixed dose of PD0332991 + VM did not allow us to increase PD0332991 dosage above 25mg, significant clinical benefit was achieved in heavily pretreated patients; baseline molecular analysis revealed an association between transcriptomic data and clinical response. Clinical trial information: NCT02202200.

TAKTIC: A prospective, multicenter, uncontrolled, phase IB/II study of LY2780301 (LY) in combination with weekly paclitaxel (wP) in HER2-negative locally advanced (LA) or metastatic breast cancer (MBC) patients

1091

Background: Phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR)-pathway is frequently activated in HER2-negative breast cancer and may play a role in taxane-resistance. LY is a dual inhibitor of p70 S6 kinase and AKT. TAKTIC study aimed to determine the recommended phase II dose (RP2D) of the combination of LY with wP (phase Ib) and to estimate overall response rate (ORR) of this regimen (phase II) in HER2-negative LA or MBC patients, both in the overall patient population and in patients with activation of PI3K/AKT pathway (PI3KAKT+). Methods: HER2-negative inoperable LA or MBC patients (pts), with (phase Ib) or without (phase II) previous cytotoxic treatment for advanced disease were eligible. Oral LY (400 or 500mg) was administered daily in combination with intravenous wP (70 or 80mg/m2). A modified CRM using an adaptive Bayesian model guided the dose escalation of both agents. PI3KAKT+ was defined as activating mutation of PIK3CA and/or AKT by targeted NGS or homozygous loss of PTEN by array comparative genomic hybridization (aCGH) or loss of PTEN by immunohistochemistry, as evaluated on available fresh tumor tissue. Results: A total of 12 and 35 patients (pts) were included in the phase Ib and II, respectively. In phase Ib, only 1 dose-limiting toxicity (confusion) was observed at the last dose level (LY, 500 + wP, 80), which was determined as RP2D. Main drug-related adverse events (AE) in phase Ib were skin toxicity (92% of pts, G3-4 in 33%), and paresthesia (50% of pts, G3-4 in 8%). In the phase II study, ORR was 62.9 % [44.9,78.5] including 1 CR and 21 PR in the overall population and 55.6 % [30.8,78.5] in PI3KAKT+ pts (10 PR in 18 pts). Median progression-free survival was 12.4 months [7.9,17.9] and 6-month clinical benefit rate was 82.9% [66.4,93.4]. AEs in phase II were similar to phase I part, except that 17% of pts experienced pneumonia (G3-4 in 9%). Conclusions: Combining LY and wP in HER2-negative LA or MBC was feasible with preliminary evidences of efficacy, independently of PI3K/AKT activation. Clinical trial information: NCT01980277.

Phase I study of onapristone, a type I antiprogestin, in female patients with previously treated recurrent or metastatic progesterone receptor-expressing cancers

INTRODUCTION

Onapristone is a type I progesterone receptor (PR) antagonist, which prevents PR- mediated DNA transcription. Onapristone is active in multiple preclinical models and two prior studies demonstrated promising activity in patients with breast cancer. We conducted a study of extended release (ER) Onapristone to determine a recommended dose and explore the role of transcriptionally-activated PR (APR), detected as an aggregated subnuclear distribution pattern, as a predictive biomarker.

METHODS

An open-label, multicenter, randomized, parallel-group, phase 1 study (target n = 60; NCT02052128) included female patients ≥18 years with PRpos tumors. APR analysis was performed on archival tumor tissue. Patients were randomized to five cohorts of extended release (ER) onapristone tablets 10, 20, 30, 40 or 50 mg BID, or immediate release 100 mg QD until progressive disease or intolerability. Primary endpoint was to identify the recommended phase 2 dose. Secondary endpoints included safety, clinical benefit and pharmacokinetics.

RESULTS

The phase 1 dose escalation component of the study is complete (n = 52). Tumor diagnosis included: endometrial carcinoma 12; breast cancer 20; ovarian cancer 13; other 7. Median age was 64 (36-84). No dose limiting toxicity was observed with reported liver function test elevation related only to liver metastases. The RP2D was 50 mg ER BID. Median therapy duration was 8 weeks (range 2-44), and 9 patients had clinical benefit ≥24 weeks, including 2 patients with APRpos endometrial carcinoma.

CONCLUSION

Clinical benefit with excellent tolerance was seen in heavily pretreated patients with endometrial, ovarian and breast cancer. The data support the development of Onapristone in endometrial endometrioid cancer. Onapristone should also be evaluated in ovarian and breast cancers along with APR immunohistochemistry validation.

BET bromodomain inhibitor birabresib in mantle cell lymphoma: in vivo activity and identification of novel combinations to overcome adaptive resistance

Background

The outcome of patients affected by mantle cell lymphoma (MCL) has improved in recent years, but there is still a need for novel treatment strategies for these patients. Human cancers, including MCL, present recurrent alterations in genes that encode transcription machinery proteins and of proteins involved in regulating chromatin structure, providing the rationale to pharmacologically target epigenetic proteins. The Bromodomain and Extra Terminal domain (BET) family proteins act as transcriptional regulators of key signalling pathways including those sustaining cell viability. Birabresib (MK-8628/OTX015) has shown antitumour activity in different preclinical models and has been the first BET inhibitor to successfully undergo early clinical trials.

Materials and methods

The activity of birabresib as a single agent and in combination, as well as its mechanism of action was studied in MCL cell lines.

Results

Birabresib showed in vitro and in vivo activities, which appeared mediated via downregulation of MYC targets, cell cycle and NFKB pathway genes and were independent of direct downregulation of CCND1. Additionally, the combination of birabresib with other targeted agents (especially pomalidomide, or inhibitors of BTK, mTOR and ATR) was beneficial in MCL cell lines.

Conclusion

Our data provide the rationale to evaluate birabresib in patients affected by MCL.

Abstract 801: Cellular pharmacokinetics and molecular pharmacodynamics studies of a novel BET inhibitor NHWD870 in sensitive and resistant leukemic cell lines

Background: NHWD870 (Ningbo Wenda Pharma, China) is a novel oral bromodomain and extraterminal (BET) protein family inhibitor. BET proteins are transcriptional co-activators that interact with multiple co-regulatory molecules at gene promoters and enhancers. BET inhibitors disrupt transcriptional regulatory complexes and have broad anticancer activity. The relation between the cellular pharmacokinetics (PK) and targeted-gene regulation governing the biological effects of BET inhibitors is still largely not understood. We analyzed cellular PK properties and CMYC and related genes modulation in NHWD870-sensitive and resistant leukemic cell lines.

Materials and Methods. Established human cell lines from acute and chronic myeloid leukemia (HL-60, U937, K562), acute lymphoblastic leukemia (Jurkat, MOLT-3) and SET-2 a JAK2 V617F mutated-megakaryoblastic cell line were studied. Anti-proliferative effects of NHWD870 were assessed by MTT after 72h-exposure. For cellular PK studies, cells were seeded at 2.106cells/ml and exposed to 245.5 ng/ml (500nM) NHWD870 for 0, 3, 10, 30, 60, 120 and 180 min. At each time point, NHWD870 extracellular and intracellular concentrations were analyzed in cell supernatants and pellets respectively, using Ultra Performance Liquid Chromatography with tandem Mass Spectrometry (concentration range 0.1-100 ng/mL). In cell pellets, protein modulation was analyzed by Western blot using commercial antibodies.

Results: IC50 values were between 20-600 nM in HL60, U937, SET-2 and Jurkat cells and were ≥ 1,000 nM for other cell lines. Cellular uptake of NHWD870 was rapid (3 min) in both sensitive and resistant leukemic cell lines, with a mean concentration of ~5.0 ng/106 cells (3-8.5 ng/106cells) and ~3.1 ng/106 cells (2.8-3.5 ng /106cells) for HL60 and K562 cell line respectively, whereas extracellular levels of NHWD870 were stable with up to 3h exposure. In the resistant cell line, K562, we observed CMYC mRNA downregulation after 2h exposure, even though NHWD870 intracellular levels were detected after 5 min exposure. A rapid downregulation of CMYC and P21 proteins were observed in the sensitive cell lines, HL60, U937, SET-2 and Jurkat, whereas other BET-targeted genes, such as HEXIM and BCL2 levels were modulated after longer exposure time points in sensitive cell lines.

Conclusions: NHWD870 intracellular accumulation occurred to a similar extent and timing in NHWD870 sensitive and resistant leukemic cell lines. Rapid modulation of NHWD870-target genes was observed at the protein levels only in sensitive cell lines.

Citation Format: Maria E. Riveiro, Samuel Huguet, Marie-francoise Gauzan, Mohamed Bekradda, Nenghui Wang, François Lokiec, Olivier Madar, Keyvan Rezai. Cellular pharmacokinetics and molecular pharmacodynamics studies of a novel BET inhibitor NHWD870 in sensitive and resistant leukemic cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 801.

Abstract 4921: Population pharmacokinetic modeling of ibrutinib administered in patients with relapsed or refractory B cell malignancies eligible for autologous stem cell transplantation

Background: Ibrutinib is a first-in-class selective, irreversible small molecule inhibitor of Bruton's tyrosine kinase (BTK). The present study's aim is to assess the feasibility and safety and pharmacokinetics (PK) of escalating doses of ibrutinib combined with rituximab (R), dexamethasone (D), ara-C (HA) and one of two platinum compounds (cisplatinum (P) or oxaliplatinum (Ox)) in patients with relapsed or refractory lymphoma. As part of this, Population PK (POPPK) modeling, PK parameters, and inter-individual and inter-occasion variabilities of oral ibrutinib in the presence of R-DHA(P/Ox) were assessed during the dose escalation part of this clinical trial.

Materials and methods: Dataset was obtained from an open label, multicenter, dose escalation, phase Ib study of ibrutinib in combination with R-DHA (P/Ox) in patients with B-cell malignancies. Patients received three doses (280, 420, 560 mg) of oral ibrutinib once a day D5 to D18. Blood samples were collected during cycles 1 and 2 on D5, Just before ibrutinib intake (T0) and at 1, 2 and 4 hours after ibrutinib intake and on D15 at T0 and 1 hour after ibrutinib intake. Ibrutinib plasma concentrations were measured using validated ultra-performance liquid chromatography with tandem mass spectrometry detection with a concentration range 1-400ng/mL. Analyses and POPPK modeling were performed with the nonlinear mixed effect modeling software program Monolix version 4.3.2. The following parameters were calculated Lagtime (Tlag), absorption constant (Ka); apparent distribution volumes (V1/F, V2); apparent clearances (CL/F, Q).

Results: 24 pts (18 male, 6 female), have validated PK data with 184 plasma concentrations. A 2-compartment model with linear elimination and lag time adequately described the total ibrutinib time-concentration curve. The main PK parameters (RSE%) estimated for ibrutinib were Tlag=0.6 (15), Ka=3.36 (36) h-1, CL/F= 699 (12) L/h, Q=182 (1) L/h, V1/F=5,060 (15) L, and V2=32,100 (49) L. The main covariate effect on ibrutinib CL was related to body weight (BW). The inter-individual and variabilities could be well estimated for CL and V1 and inter-occasion variabilities were well estimated for Tlag and V1.

Conclusions: The POPPK modeling satisfactorily described the plasma ibrutinib time-concentration curves in patients. Our data revealed the effect of BW on ibrutinib PK parameters. A large volume of the deep compartment suggest that ibrutinib has large tissue diffusion. The clinical data describes the toxicity and efficacy. This is an analysis of correlation between the PK and the clinical outcomes.

Citation Format: Keyvan Rezai, Olivier Madar, Christophe Bonnet, Jean Dupuis, Hervé Tilly, Thierry Lamy de la Chapelle, Steven Le Gouill, Ombeline Verite, Julie Assemat, Fanny Bret, Sophie Weill, François Lokiec, Gilles Salles. Population pharmacokinetic modeling of ibrutinib administered in patients with relapsed or refractory B cell malignancies eligible for autologous stem cell transplantation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4921.

Abstract 3213: Evaluation of porphyrin biodistribution for use in photodynamic therapy of retinoblastoma in transgenic mice

Background: Porphyrins are a group of heterocyclic macrocycle organic compounds. They have shown good efficiency in the photodynamic treatment of tumors in the last twenty years. The photodynamic therapy could be an alternative treatment for retinoblastoma using a photosensitizer with low dark toxicity and low mutagenic properties unlike the conventional chemotherapies. The objectives of this study were to develop a photosensitizer in our lab which is a diethylene glycol mannoconjugated tetraphenyl porphyrin (TPP, MW: 1413.6) and to determine the optimal interval time for photodynamic therapy using the concentration of TPP in eye and blood samples of mice. Materials and method: Transgenic mice developed bilateral retinoblastoma from the retina since 4 weeks of age to 16 weeks of age (tumors fill the ocular globe and the mice will be sacrificed for ethic purpose). The evaluation of the biodistribution of our TPP was realized to know the best drug-light interval to perform the photodynamic therapy. For this purpose, an intraperitoneal injection of 200 µl at 5.25 mg/ml in PEG 400/physiological serum (1:1, v/v) was performed on the LHbetaTag transgenic mice. At different time intervals (8h, 24h, 40h, 48h, and 72h) following injection, the mice were sacrificed and the eyes and blood were collected. TPP in eye samples were extracted in methanol and the level of TPP was measured by ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) analysis (0.5-100 ng/mL). The level of TTP in blood samples was quantified after protein precipitation by UPLC-MS/MS method (5.00-1000 ng/mL).

Results: We observed a time dependency accumulation of TPP in eyes with observed Tmax=48 hours. TPP serum concentrations decreased by the same manner up to 48 h. The determination of drug-light interval allowed us to perform the light delivery when the TPP level is highest (48 h) in the ocular tumor tissue (retinoblastoma).

Conclusions: Our TPP had a good in vitro photocytotoxicity at very low doses and showed a good efficacy in vivo with subcutaneous patient derived retinoblastoma xenografts in immunodeficient mice. The knowledge of Tmax and this interval is essential to realize the photodynamic therapy with the better efficiency, the final goal being to eradicate the retinoblastoma from the retina.

Citation Format: Florent Poyer, Samuel Hugeut, Stéphanie Lemaitre, Olivier Madar, Carole D Thomas, Philippe Maillard, Marie-Paule Teulade-Fichou, Nathalie Cassoux, François Doz, Keyvan Rezai. Evaluation of porphyrin biodistribution for use in photodynamic therapy of retinoblastoma in transgenic mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3213.

Phase Ib Trial With Birabresib, a Small-Molecule Inhibitor of Bromodomain and Extraterminal Proteins, in Patients With Selected Advanced Solid Tumors

PURPOSE

Birabresib (MK-8628/OTX015) is a first-in-class bromodomain inhibitor with activity in select hematologic tumors. Safety, efficacy, and pharmacokinetics of birabresib were evaluated in patients with castrate-resistant prostate cancer, nuclear protein in testis midline carcinoma (NMC), and non-small-cell lung cancer in this phase Ib study.

PATIENTS AND METHODS

Forty-seven patients were enrolled to receive birabresib once daily at starting doses of 80 mg continuously (cohort A) or 100 mg for 7 consecutive days (cohort B) in 21-day cycles using a parallel dose escalation 3 + 3 design. The primary objective was occurrence of dose-limiting toxicities (DLTs) and determination of the recommended phase II dose.

RESULTS

Of 46 treated patients, 26 had castrate-resistant prostate cancer, 10 NMC, and 10 non-small-cell lung cancer. For cohort A, four of 19 (21%) evaluable patients had DLTs at 80 mg once daily (grade 3 thrombocytopenia [n = 3], ALT/hyperbilirubinemia [n = 1]) and two of three had DLTs at 100 mg once daily (grade 2 anorexia and nausea with treatment delay > 7 days [n = 1], grade 4 thrombocytopenia [n = 1]). No DLTs occurred in cohort B. Of 46 patients, 38 (83%) had treatment-related adverse events (diarrhea, 17 [37%]; nausea, 17 [37%]; anorexia, 14 [30%]; vomiting, 12 [26%]; thrombocytopenia 10 [22%]). Three patients with NMC (80 mg once daily) had a partial response (Response Evaluation Criteria in Solid Tumors [RECIST] version 1.1) with duration of 1.4 to 8.4 months. Pharmacokinetic analysis indicated a dose-proportional increase in birabresib exposure and rapid absorption.

CONCLUSION

The recommended phase II dose of birabresib in patients with select solid tumors is 80 mg once daily with continuous dosing. Birabresib has dose-proportional exposure and a favorable safety profile, with clinical activity observed in NMC. Future studies of birabresib must consider intermittent scheduling to possibly mitigate the toxicities of chronic dosing.

The bromodomain inhibitor OTX015 (MK-8628) exerts anti-tumor activity in triple-negative breast cancer models as single agent and in combination with everolimus

Triple-negative breast cancer (TNBC) is an aggressive and heterogeneous subgroup of breast tumors clinically defined by the lack of estrogen, progesterone and HER2 receptors, limiting the use of the targeted therapies employed in other breast malignancies. Recent evidence indicates that c-MYC is a key driver of TNBC. The BET-bromodomain inhibitor OTX015 (MK-8628) has potent antiproliferative activity accompanied by c-MYC down-regulation in several tumor types, and has demonstrated synergism with the mTOR inhibitor everolimus in different models. The aim of this study was to evaluate the anti-tumor activity of OTX015 as single agent and in combination with everolimus in TNBC models. OTX015 was assayed in three human TNBC-derived cell lines, HCC1937, MDA-MB-231 and MDA-MB-468, all showing antiproliferative activity after 72 h (GI₅₀ = 75–650 nM). This was accompanied by cell cycle arrest and decreased expression of cancer stem cells markers. However, c-MYC protein and mRNA levels were only down-regulated in MDA-MB-468 cells. Gene set enrichment analysis showed up-regulation of genes involved in epigenetic control of transcription, chromatin and the cell cycle, and down-regulation of stemness-related genes. In vitro, combination with everolimus was additive in HCC1937 and MDA-MB-231 cells, but antagonistic in MDA-MB-468 cells. In MDA-MB-231 murine xenografts, tumor mass was significantly (p < 0.05) reduced by OTX015 with respect to vehicle-treated animals (best T/C = 40.7%). Although everolimus alone was not active, the combination was more effective than OTX015 alone (best T/C = 20.7%). This work supports current clinical trials with OTX015 in TNBC (NCT02259114).

Bromodomain inhibitor OTX015 (MK-8628) combined with targeted agents shows strong in vivo antitumor activity in lymphoma

The bromodomain inhibitor OTX015 (MK-8628) has shown anti-lymphoma activity as a single agent in both the preclinical and clinical settings, as well as in vitro synergism with several anticancer agents. Here, we report in vivo data for OTX015 in combination with the histone deacetylase inhibitor vorinostat, the Bruton's tyrosine kinase inhibitor ibrutinib, the anti-CD20 monoclonal antibody rituximab, and the mTOR inhibitor everolimus in a diffuse large B cell lymphoma model. The antitumor effect of OTX015-containing combinations in SU-DHL-2 xenografts in mice was much stronger than the activity of the corresponding single agents with almost complete tumor eradication for all four combinations. Pharmacokinetic analyses showed similar OTX015 levels in plasma and tumor samples of approximately 1.5 μM, which is equivalent to the concentration showing strong in vitro activity. For all four combinations, mean terminal levels of the bromodomain inhibitor differed from those in mice exposed to single agent OTX015, indicating a need for thorough pharmacokinetic investigations in phase I combination studies. In conclusion, our results provide a strong rationale to explore OTX015-containing combinations in the clinical lymphoma setting.

PIKHER2: A phase IB study evaluating buparlisib in combination with lapatinib in trastuzumab-resistant HER2-positive advanced breast cancer

BACKGROUND

Phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin pathway is frequently activated in HER2-positive breast cancer and may play a major role in resistance to trastuzumab. Buparlisib is a pan-class-I PI3K inhibitor with potent and selective activity against wild-type and mutant PI3K p110 isoforms.

PATIENTS AND METHODS

PIKHER2 phase IB study aimed primarily to determine a maximum tolerated dose (MTD) and propose a recommended phase II dose (RP2D) for buparlisib in combination with lapatinib in HER2-positive, trastuzumab-resistant, advanced breast cancer. Oral buparlisib (40, 60 or 80 mg) and lapatinib (750, 1000 or 1250 mg) were administered daily. A modified continuous reassessment method using an adaptive Bayesian model guided the dose escalation of both agents. Secondary end-points included antitumour activity and pharmacokinetic (PK) assessments.

RESULTS

A total of 24 patients were treated across five dose levels. Dose-limiting toxicities included transaminases elevation, vomiting, stomatitis, hyperglycemia and diarrhoea. MTD was declared at buparlisib 80 mg/d + lapatinib 1250 mg/d, but toxicities and early treatment discontinuation rate beyond cycle 1 led to select buparlisib 80 mg + lapatinib 1000 mg/d as the RP2D. Main drug-related adverse events included diarrhoea, nausea, skin rash, asthenia, depression, anxiety and transaminases increase. There was no significant evidence for drug-drug PK interaction. Disease control rate was 79% [95% confidence interval [CI] 57-92%], one patient obtained a complete remission, and six additional patients experienced stable disease for ≥ 24 weeks (clinical benefit rate of 29% [95% CI 12-51%]).

CONCLUSION

Combining buparlisib and lapatinib in HER2-positive trastuzumab-resistant advanced breast cancer was feasible. Preliminary evidence of antitumour activity was observed in this heavily pre-treated population.

TRIAL REGISTRATION ID

NCT01589861.

Permeability and Release of Decontaminating Agent Used in Cytotoxic Reconstitution Units: Diffusion of Hydrogen Peroxide in IV Bags

Introduction

Oxidant agents used for top-decontamination in cytotoxic reconstitution units may spread into IV bags. The amount of hydrogen peroxide passing through the bags and its release have been evaluated using wrapped or unwrapped infusion bags made of three layers of polyolefin (Freeflex

Methods

3 experiments were carried out using 2 packages of 30 bags of polyolefin with (package A) or without (package B) overwrapping. A 43 min decontamination cycle with H

Results

A linear calibration curve over the concentration range of 0.00–2.70 ppm was used prior to each analysis. The concentration of H

Conclusion/Discussion

These results allow removing overwrapping for a lean production system, with an extemporaneous use. However, the graduate release of H

OTX015 (MK-8628), a novel BET inhibitor, displays in vitro and in vivo antitumor effects alone and in combination with conventional therapies in glioblastoma models

Bromodomain and extraterminal (BET) bromodomain (BRD) proteins are epigenetic readers that bind to acetylated lysine residues on chromatin, acting as co-activators or co-repressors of gene expression. BRD2 and BRD4, members of the BET family, are significantly increased in glioblastoma multiforme (GBM), the most common primary adult brain cancer. OTX015 (MK-8628), a novel BRD2/3/4 inhibitor, is under evaluation in dose-finding studies in solid tumors, including GBM. We investigated the pharmacologic characteristics of OTX015 as a single agent and combined with targeted therapy or conventional chemotherapies in glioblastoma cell lines. OTX015 displayed higher antiproliferative effects compared to its analog JQ1, with GI50 values of approximately 0.2 µM. In addition, C-MYC and CDKN1A mRNA levels increased transiently after 4 h-exposure to OTX015, while BRD2, SESN3, HEXIM-1, HIST2H2BE, and HIST1H2BK were rapidly upregulated and sustained after 24 h. Studies in three additional GBM cell lines supported the antiproliferative effects of OTX015. In U87MG cells, OTX015 showed synergistic to additive activity when administered concomitant to or before SN38, temozolomide or everolimus. Single agent oral OTX015 significantly increased survival in mice bearing orthotopic or heterotopic U87MG xenografts. OTX015 combined simultaneously with temozolomide improved mice survival over either single agent. The passage of OTX015 across the blood-brain barrier was demonstrated with OTX015 tumor levels 7 to 15-fold higher than in normal tissues, along with preferential binding of OTX015 to tumor tissue. The significant antitumor effects seen with OTX015 in GBM xenograft models highlight its therapeutic potential in GBM patients, alone or combined with conventional chemotherapies.

Abstract 2049: Pharmacokinetic drug-drug interaction: a phase Ib dose escalation study of LY2780301 in combination with weekly paclitaxel

Introduction: LY2780301 is an orally available small molecule dual inhibitor of p70 S6 kinase and AKT. LY2780301 is an inhibitor of CYP3A4. By the one hand, Paclitaxel (PXL) undergoes extensive metabolism via CYP450 2C8 and CYP450 3A4 pathways. By the other hand, PXL induces weakly CYP3A4 activity. In this study we investigated for the first time, the potential pharmacokinetic (PK) drug-drug interaction (DDI) related to the combination of both drugs LY2780301 and PXL.

Methods: Women with HER2- locally advanced or metastatic breast cancer, with and without PI3/AKT pathway activation, were treated with weekly administration of PXL on day1 (D1), D8 and D15. LY2780301 was administered by a daily flat dosing regimen starting at D3. Dose levels [DL, LY2780301 (mg/day)/PXL (mg/m2/week)] ranged from 400/70 to 500/80. For PK analysis, 7 time point samples were collected on D1 and D3 of cycle 1 for PXL and LY2780301 respectively. 7 samples were collected on D8 for both drugs. LY2780301 plasma concentrations were measured using Ultra Performance Liquid Chromatography (UPLC) coupled with tandem mass spectrometry validated method. PXL plasma concentrations were measured using UPLC coupled with UV validated method. A joint population PK (PK-POP) model has been developed for LY2780301 and

its main metabolite. PK-POP modelling has been performed with a non linear mixed effect model program (Monolix version 4.3.2).

Results: 12 patients, 35 to 67 years old, were treated. A total of 160 and 157 concentrations for LY2780301 and its metabolite were used respectively for PK-POP modeling. A one compartment open model adequately described LY2780301 and its metabolite concentration versus time courses respectively with the estimation of the fraction of absorbed dose (fm) of LY2780301 metabolised in that metabolite. The interindividual variabilities (ISV) could be well estimated for all structural parameters (clearance: CL, volume of distribution: V, L and the absorption constant: Ka). The population PK parameters obtained for the structural model were: Ka = 0.536 h−1, CL/F = 3.57 L/h, V/F = 85.2 L, CL/(F*fm) = 13.2 L/h, V2/(F*fm) = 13.2 L, fm = 0.747 for LY2780301 and its metabolite respectively. PXL increases LY2780301 CL from 3.57 to 4.4 L/h (p = 0.016).

Conclusions: We have demonstrated a PK DDI between LY2780301 and PXL. PXL increases LY2780301 CL and decreases LY2780301 AUC. PXL PK modeling is ongoing in order to verify the effect of LY2780301 on PXL PK.

Citation Format: Keyvan Rezai, Samuel Huguet, Olivier Madar, Jean-Marc Extra, Magali Provansal, Carole Tarpin, Nicolas Isambert, Jihane Pakradouni, Anthony Goncalves, François Lokiec. Pharmacokinetic drug-drug interaction: a phase Ib dose escalation study of LY2780301 in combination with weekly paclitaxel. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2049.

Abstract 2036: A phase Ib pharmacokinetic drug-drug interaction evaluation of oral buparlisib in combination with lapatinib in HER2+/PI3K-activated, trastuzumab-resistant locally advanced, recurrent and metastatic breast cancer (MBC)

Background: A novel combination of oral lapatinib (LPT), a selective dual ErbB1/ErbB2 targeted drug, + oral buparlisib (B) a pan-class I PI3K inhibitor, could provide a synergestic antitumor activity in trastuzumab resistant disease. LPT has been shown to be a potent CYP3A4 inhibitor which is also mainly involved in BKM120 metabolism. In this study we investigated the potential pharmacokinetic (PK) drug-drug interactions (DDI) related to the association of B and LPT. Methods: Trastuzumab-resistant HER2 + metastatic breast cancer (MBC) patients were treated with a continuous once daily dosing schedule of LPT + B. Dose levels [DL, LPT (mg)/B (mg)] ranged from 750/40 to 1,250/80. For PK analysis, 2 time point samples were collected on D1 and D8 and 10 time point samples were collected on D15 of cycle 1 for LPT and B assays. Plasma concentrations of B and LPT, were measured using UPLC coupled with tandem mass spectrometry validated methods. Population PK was modeled using a non linear mixed effect model program (Monolix version 4.3s) by computing the maximum likelihood estimator of the parameters without any approximation of the model (no linearization). Results: 343 and 322 plasma concentrations were available for PK analysis of LPT and B respectively. A two-compartment open model adequately described B concentration versus time courses. The inter-individual variabilities (ISV) could be well estimated for all stuctural parameters (clearance: CL, volume of distribution: V, inter-compartmental clearance: Q) except for absorption constant: Ka. The population PK parameters obtained for the structural model were: Ka = 0.985 h−1, CL/F = 10.5L/h, V1/F = 54.8 L, Q/F = 46.3 L/h, V2/F = 582 L. Mean AUC0-24h(CV%) values for B were 10130 (34%), 15450 (29%), and 20560 (38%) ng*hr/mL for 40 mg, 60 mg and 80 mg dose level respectively. A one-compartment model adequately fitted the LPT plasma concentration-time data. The population PK parameters were CL/F = 25.7 L/h, V/F = 291 L and the absorption constant, Ka = 0.214 h−1. B has no significant effect on the PK of LPT and vice versa. Conclusions: B AUC increased proportionally with increasing dose. LPT PK parameters are consistent with those already published. There is no significant evidence for drug-drug PK interaction between LPT and B. Intra-occasion variabilities will be discussed.

Citation Format: François Lokiec, Anthony Goncalves, Fanny Bret, Jihane Pakradouni, Magali Provansal, Renaud Sabatier, Jean-Marc Extra, Carole Tarpin, Nicolas Isambert, Mario Campone, Keyvan Rezai. A phase Ib pharmacokinetic drug-drug interaction evaluation of oral buparlisib in combination with lapatinib in HER2+/PI3K-activated, trastuzumab-resistant locally advanced, recurrent and metastatic breast cancer (MBC). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2036.

Influence of tumour burden on trastuzumab pharmacokinetics in HER2 positive non-metastatic breast cancer

AIMS

Trastuzumab, an antibody binding to epidermal growth factor receptor-2 (HER2), has been approved to treat HER2-positive breast cancer in different settings. This study aimed at evaluating the influence of tumour size on trastuzumab pharmacokinetics (PK) in non-metastatic breast cancer patients treated with short term pre-operative trastuzumab.

METHODS

Trastuzumab PK data were obtained from a multicentre, randomized and comparative study. This antibody was administered pre-operatively to patients with localized HER2-positive breast cancer as a single 4 mg kg(-1) loading dose followed by 5 weekly 2 mg kg(-1) doses. Trastuzumab concentrations were measured repeatedly using an ELISA technique. Tumour size was evaluated at baseline using breast echography. Trastuzumab pharmacokinetics were studied using a population approach and a two compartment model. The influence of tumour burden on trastuzumab pharmacokinetics was quantified as a covariate.

RESULTS

A total of 784 trastuzumab concentrations were available from the 79 eligible patients. Estimated parameters (interindiviual standard deviation) were central volume of distribution =2.1 l (23%), peripheral volume of distribution =1.3 l (38%), intercompartment clearance =0.36 l day(-1) , with an elimination half-life of 11.8 days. Typical clearance was 0.22 l day(-1) (19%) and its value was increased with tumour size. In patients with the highest tumour size, trastuzumab clearance was 50% [18%-92%] higher than in patients with the lowest tumour size.

CONCLUSIONS

In non-metastatic breast cancer patients, trastuzumab clearance increases with tumour size. The elimination half-life of trastuzumab was shorter in the present population of patients than in metastatic breast cancer patients previously studied.

Abstract 4523: Population pharmacokinetic (PPK) modeling of onapristone in patients (pts) with progesterone receptor (PR)-expressing cancers

Background: Onapristone is a type I PR antagonist, which prevents PR-induced DNA transcription. Onapristone anti-cancer activity is well documented. An extended-release (ER) tablet formulation of onapristone was designed to address the liver function test (LFT) elevations seen with immediate-release (IR) onapristone. A phase 1 study with onapristone in patients with tumors expressing PR is underway. Objectives included determining the PK profile of ER onapristone using a PPK approach.

Materials and methods: This is an ongoing multi-center, open-label, randomized, parallel-group, 2-stage ph1 study. Female pts ≥18 yrs with tumors expressing PR are eligible. The Stage 1 primary endpoint is the recommended ph2 dose of ER onapristone; secondary endpoints include: safety, efficacy, and PK. Pts received onapristone ER 10, 20, 30, 40 or 50 mg BID, or onapristone IR tablets 100 mg QD until progressive disease or intolerability. PK blood samples from 8 time points were collected over 12 h post-dose Day 1 for the ER and 9 blood samples over 24 h post-dose for the IR formulation. Onapristone plasma concentrations were measured using validated UPLC with tandem mass spectrometry detection (range 1-250 ng/mL). Monolix V4.1 was used to calculate absorption constant (Ka); apparent clearance (CL/F); inter-compartmental clearance (Q); apparent distribution volume (V1/F), 2nd compartment distribution volume (V2) and bioavailability (F) of ER vs IR.

Results: Stage 1 is complete. 42 pts have validated PK data. A 2-compartment open model adequately described the total onapristone time-concentration curve with linear elimination. Results are in Table 1.

Table 1.Estimated PK parameters for onapristone in pts with PR-expressing cancers (n = 42)ParameterValueRelative standard error (%)Ka0.191 h-114CL/F1.51 L/h20Q3.11 L/h25V1/F5.41 L25V241.1 L45F60%20

Conclusions: The PPK modeling described the plasma onapristone time-concentration curves well. A central volume equivalent to the circulating blood volume and a large volume of the deep compartment suggest a large tissue diffusion. PPK/PD modeling to explore safety and efficacy is ongoing, with no overt PK/safety relationship detected.

Citation Format: Keyvan Rezai, Paul Cottu, Samuel Huguet, Mario Campone, Antoine Italiano, Andrea Varga, Jacques Bonneterre, Alexandra Leary, Marie-Paule Sablin, Stefan Proniuk, Alice Bexon, Erard Gilles, Joseph Bisaha, Alexander Zukiwski, Francois Lokiec. Population pharmacokinetic (PPK) modeling of onapristone in patients (pts) with progesterone receptor (PR)-expressing cancers. [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 4523. doi:10.1158/1538-7445.AM2015-4523

Abstract 4512: Onapristone in patients (pts) with progesterone receptor (PR)-expressing cancers: PK results from part 1 of a randomized, parallel-dose phase 1 study

Background:  Onapristone is a type I PR antagonist, which prevents PR-induced DNA transcription; its anti-cancer activity is well-documented. The reported T1/2 is 2-4h, so an extended-release (ER) tablet was designed to mitigate Cmax spikes, which may be involved in the liver function test (LFT) elevations seen with an immediate-release (IR) onapristone.

Materials and methods:   The expansion cohort of this multi-center, open-label, randomized, parallel-group, 2-stage Ph1 study (NCT02052128) is ongoing in endometrioid cancers. Female pts ≥18 years with PR-expressing tumors (including endometrial, ovarian, breast) were eligible. The primary endpoint was to recommend a Ph2 dose of ER onapristone (RP2D), with a 57-day DLT observation period; secondary endpoints include: safety, efficacy, and real-time PK. Pts received onapristone ER 10, 20, 30, 40 or 50 mg BID, or IR tablets 100 mg QD until progressive disease or intolerability in Stage 1.

Results: 52 pts are enrolled (by 2 December 2014). Validated PK data are available for 35 pts. Onapristone AUC and Cmax are dose-proportional across all dose levels including 100mg IR (Table 1), with coefficients of determination (r2) of 0.76 and 0.79, respectively. The bioavailability of onapristone ER vs IR is high. Steady state is consistently attained at approximately 8 days (200 h), with T1/2 at 8-12 h, longer than previously published, with no evidence of onapristone accumulation through day 57.

Table 1.Onapristone PK parameters following first doseOnapristone formERERERERERIRDose (mg)10 bid20 bid30 bid40 bid50 bid100 qdn666566Mean AUC (μg/L*h)51761765015450174403161067980CV%47.7202.722.943.070.555.1Min348029411200038091515033330Median4654860815040207302593062270Max952440000214302667062500125000Mean Cmax (μg/L)226.8676.3767.3641.614594296CV%46.0140.115.693.646.862.8Min922206762914591556Median218403732.547414953726Max4031466988134424927507

Conclusions: This study reveals a longer than anticipated onapristone T1/2, which nevertheless supports using an ER formulation. AUC and Cmax data are dose proportional and allow dosing flexibility. Protracted exposure minimizing Cmax spikes is best achieved with a twice-daily, ER formulation. There were no LFT elevations in the absence of liver metastases in 30 patients exposed to the ER formulation. The RP2D is 50 mg bid based on safety and PK, to be further explored in the endometrioid cohort.

Citation Format: Francois Lokiec, Antoine Italiano, Andrea Varga, Jacques Bonneterre, Mario Campone, Alexandra Leary, Keyvan Rezai, Marie-Paule Sablin, Alice Bexon, Stefan Proniuk, Erard Gilles, Joseph Bisaha, Alexander Zukiwski, Paul Cottu. Onapristone in patients (pts) with progesterone receptor (PR)-expressing cancers: PK results from part 1 of a randomized, parallel-dose phase 1 study. [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 4512. doi:10.1158/1538-7445.AM2015-4512

A single-dose PK study of onapristone including the effect of food on absorption

PURPOSE

Onapristone is an antiprogestin with activity in breast cancer and is under investigation for use in endometrial, ovarian and prostate cancers. Megestrol acetate and abiraterone generally show variability in absorption and, depending on the formulation, food effect. This study was conducted to determine the effect of food on 10 mg oral immediate-release (IR) onapristone and to help identify a formulation to minimize variability.

METHODS

This is an open-label, randomized, crossover study to determine the pharmacokinetic profile of onapristone and its main metabolite, N-mono-desmethyl onapristone. Twelve healthy female subjects received 10 mg of oral IR onapristone after an overnight fast, or within 30 min of a high-fat, high-calorie meal with a 2-week washout between dosing periods.

RESULTS

Onapristone plasma t1/2 (mean ± SD) was 4.36 ± 0.81 h for the fasted state and 3.76 ± 0.36 h for the fed state. Following food, onapristone tmax was delayed from 1 to 4 h. Food intake was also associated with a small increase in AUC0-∞ of approximately 13 % and a statistically significant decrease in Cmax of approximately 18 %. One subject experienced a 23-day delay in menses after one 10 mg onapristone dose, while another subject experienced transient grade 2 NCI-CTCAE liver enzyme elevation 3 weeks post dose.

CONCLUSION

The results are consistent with previous observations, indicating that there is a small increase in onapristone exposure and a significant decrease in Cmax when taken with food. These changes are within acceptable limits set out by the FDA. Thus, our findings indicate that onapristone could be administered without regard to food.

Abstract 4630: Population pharmacokinetic-pharmacodynamic (PPD) modeling of masitinib administered in combination with gemcitabine to pancreatic cancer patients

Background: Masitinib is a tyrosine kinase inhibitor that targets wild-type and mutant forms of c-Kit, as well as PDGFR, Lyn, and Fyn kinases. Masitinib in combination with gemcitabine has been shown to produce a clinically relevant survival benefit in first-line treatment of advanced pancreatic cancer. This efficacy is most likely due to its inhibition of mast cell activity and the stimulation of an anti-tumoral immune response via macrophages. The objectives of this study were to assess masitinib pharmacokinetics (PK) and pharmacodynamics (PD), and to perform a POP-PK/PD modeling of masitinib in patients with advanced pancreatic cancer.

Materials and Methods: Treatment naïve pancreatic cancer patients received oral masitinib at 9 mg/kg/day b.i.d. in combination with standard gemcitabine treatment. For PK analysis, 6 time-point blood samples were collected on D1 and D14 of the first cycle. POP-PK analyses were carried out using the nonlinear mixed effect modeling software program Monolix. Constant residual variability and exponential between subject variabilities (BSVs) were used. Different covariates including body weight (BW) and sex were investigated. PK parameters were allometrically normalized for BW to a 70 kg individual. A PPD analysis was performed to adequately describe myelosuppression time courses in terms of masitinib PK. The individual PK parameters were used to generate individual masitinib concentrations and served to model the inhibitory effect of masitinib on absolute neutrophil count (ANC).

Results: For 22 patients (9 male and 13 female), 264 time-plasma concentrations and 89 ANC were available for analysis. A 2-compartment open model with linear elimination adequately described the masitinib PK. The BSVs could be well estimated for all structural parameters (i.e. absorption constant, Ka; clearance, CL; volume of distribution, V1; and inter-compartmental clearances, Q) with the exception of peripheral volume V2. The main PK parameters (RSE%) estimated for masitinib were: Ka=0.179 (20%) h-1, CL=66.4 (16%) L/h, Q=52.7 (25%) L/h, V1=179 (24%) L, and V2=928 (22%) L. The main covariate effects were related to BW, which influenced all PK parameters, and to albumin, which influenced CL. The mean IC50 estimated for an inhibitory effect of masitinib on ANC was very high at 2210 µg/L.

Conclusions: The POP-PK modeling satisfactorily described the plasma masitinib time-concentration curves in pancreatic cancer patients. Clearance of masitinib increased with increasing total BW and albumin. A central volume higher than the circulating blood volume and a large volume of the deep compartment suggest that masitinib has large tissue diffusion. PPD modeling demonstrates that the hematotoxic effect of masitinib for ANC is very small and the feedback for the stimulation of ANC in response to masitinib plus gemcitabine treatment is strong.

Citation Format: Keyvan Rezai, Saik Urien, Sophie Weill, Lise Barbin, Alain Moussy, François Lokiec. Population pharmacokinetic-pharmacodynamic (PPD) modeling of masitinib administered in combination with gemcitabine to pancreatic cancer patients. [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 4630. doi:10.1158/1538-7445.AM2014-4630

Abstract 4636: Pharmacokinetic (PK) food effect study of immediate-release onapristone and its primary metabolite (M1) in healthy female subjects: implications for design of a new formulation

Introduction: Onapristone is an antiprogestin with demonstrated clinical activity in breast cancer, reported to have a t1/2 between 2 and 4 hours. Drugs such as megestrol acetate and abiraterone generally show variability in absorption and, depending on the formulation, food effect (≥10 x Cmax variation; ≥5 x AUC variation). A study was conducted to determine the best formulation of onapristone to minimize this variability.

Methods: The aim of this study was to determine the pharmacokinetic profile of onapristone and mono-desmethyl onapristone (M1), with and without food. Using a two-period, two-sequence, random assignment cross-over design, twelve healthy female subjects were given 10 mg of an oral immediate release formulation of onapristone either after an overnight fast, or within 30 minutes after a high-fat high-calorie meal, with a 2 week washout between dosing periods. PK sampling was performed following each oral administration at: 0, 15, 30, 45 and 60 minutes, 2, 4, 6, 8, 12, 16 and 24 hours (h). Parameters were calculated using the linear trapezoidal method. Population PK modeling was conducted using the nonlinear mixed effect model.

Results: Onapristone plasma t1/2 (mean ± SD) was 4.36 ±0.81 h for the fasted and 3.76 ±0.36 h for the fed state. The absorption phase appeared linear. Onapristone tmax was delayed from 1 to 4 h after food intake. A small effect on the single dose onapristone pharmacokinetic profile was also observed, with a slightly decreased mean Cmax (18%) and increased AUC0-last (11%). Mean population CL of onapristone was 5.02 ±0.67 L/h and 6.63 ±0.87 L/h for fasted and fed states respectively. There was no food effect on M1 exposure but a decrease in M1 plasma peaks (∼35%) after food intake. The onapristone time-concentration curve was adequately described by a 2-compartment open model with linear elimination using a population PK approach. A significant food effect (p&lt;0.0001) was observed on CL of onapristone but not M1. Modeling confirmed that food increased onapristone AUC. One subject aged 27 experienced a 23-day delay in menses after one 10mg onapristone dose and 1 subject experienced transient G2 liver enzyme elevation 3 weeks post-dose.

Conclusion: Clinically meaningful Cmax can be reached with a 10 mg onapristone dose. The results are consistent with prior observations, indicating that food delayed absorption and increased AUC when taken concomitantly. Food effect is minimal compared to other drugs in class, but onapristone should preferably be administered 2 hours before or 1 hour after meals. This food effect is unlikely to have clinical consequences. As absorption is linear, a sustained release formulation would probably reduce Cmax by ∼25% while not substantially modifying AUC. Given the estimated t1/2 of 2-4 hours, adequate concentrations should be maintained with twice a day dosing.

Citation Format: Keyvan Rezai, Stefan Proniuk, Alex Zukiwski, Erard Gilles, Didier Chassard, Caroline Denot, Haydee L. Ramos, Alice S. Bexon, François Lokiec. Pharmacokinetic (PK) food effect study of immediate-release onapristone and its primary metabolite (M1) in healthy female subjects: implications for design of a new formulation. [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 4636. doi:10.1158/1538-7445.AM2014-4636