A first-in-human phase 1 study of cavrotolimod, a TLR9 agonist spherical nucleic acid, in healthy participants: Evidence of immune activation

Introduction

Tumor immunotherapy is designed to control malignancies through the host immune response but requires circumventing tumor-dysregulated immunomodulation through immunostimulation, relieving immunorepression, or a combination of both approaches. Here we designed and characterized cavrotolimod (formerly AST-008), an immunostimulatory spherical nucleic acid (SNA) compound targeting Toll-like receptor 9 (TLR9). We assessed the safety and pharmacodynamic (PD) properties of cavrotolimod in healthy participants in a first-in-human Phase 1 study under protocol AST-008-101 (NCT03086278; https://clinicaltrials.gov/ct2/show/NCT03086278).

Methods

Healthy participants aged 18 to 40 years were enrolled to evaluate four dose levels of cavrotolimod across four cohorts. Each cohort included four participants, and all received a single subcutaneous dose of cavrotolimod. The dose levels were 5, 10, 12.5 and 18.8 µg/kg.

Results and discussion

Cavrotolimod was well tolerated and elicited no serious adverse events or dose limiting toxicities at the doses tested. The results demonstrated that cavrotolimod is a potent innate immune activator, specifically stimulating Th1-type immune responses, and exhibits PD properties that may result in anti-tumor effects in patients with cancer. This study suggests that cavrotolimod is a promising clinical immunotherapy agent.

Abstract OT2-01-01: Phase 1 study of ST101, a first-in-class peptide antagonist of CCAAT/enhancer-binding protein β (C/EBPβ), in patients with advanced solid tumors, with a phase 2 expansion in patients with hormone receptor positive breast cancer (HR+ BC)

Background: CCAAT/Enhancer Binding Protein Beta (C/EBPβ) is a transcription factor that is active during embryofetal development but held in an inactive state in most mature cells. C/EBPβ is upregulated or overactivated in multiple cancers, where it inversely correlates with disease prognosis. In breast cancer, C/EBPβ drives the expression of factors that promote tumor survival, proliferation and inhibit differentiation. ST101 is a cell-penetrating all D amino acid peptide antagonist of C/EBPβ. ST101 exposure inhibits C/EBPβ target gene expression, leading to selective tumor cell death in multiple human cancer cell lines, including hormone receptor positive breast cancer (HR+ BC) and triple negative breast cancer (TNBC), without impacting normal cell viability. In vivo, ST101 displays rapid uptake into multiple organs, the ability to cross the blood-brain barrier, and a long plasma half-life due to its resistance to proteolytic degradation. Potent ST101 anti-tumor activity, demonstrated by dose-dependent inhibition of tumor growth in subcutaneous HR+ and orthotopic TNBC xenograft models in vivo, supported advancing ST101 into clinical development.Trial design: This phase 1-2 study uses a standard 3+3 design with dose doubling for the first 4 dose levels then 50% escalations thereafter. The recommended phase 2 dose will be used in 4 expansion cohorts in specific tumor types, including HR+ BC. Patients receive intravenous ST101 once weekly.Eligibility criteria: The dose-escalation phase is enrolling patients ≥18 years of age with advanced, unresectable metastatic solid tumors refractory to or intolerant of other therapeutic options. In expansion, patients with HR+ BC must have progressed after 1-3 prior hormone-based therapies. Previous treatment with CDK 4/6 inhibitor, mTOR inhibitor, or chemotherapy is allowed as monotherapy or in combination. Specific aims: The primary objective of phase 1 is to evaluate safety and tolerability of ST101. Secondary objectives include the recommendation of a dose and regimen of ST101 for further evaluation, analysis of pharmacokinetics, assessment of several pharmacodynamic measures, and to assess preliminary efficacy. Statistical design: The recommended phase 2 dose will be used in a 15-30 patient HR+ BC expansion cohort, with a Simon 2-stage design, which requires one response to expand the cohort to 30 patients. Up to 120 patients are planned in a total of four expansion cohorts, which should be enrolling by Q3 2021.Accrual: We began recruitment in August 2020. Enrollment is ongoing, and by July 2021, 18 patients were recruited in five dose-escalation cohorts up to 6 mg/kg; a 6th cohort (9 mg/kg) is ongoing. Dose escalation should be complete by Sept 2021, and the phase 2 portion in the HR+ BC cohort will be underway (n=15-30). Please contact rob.michel@bexonclinical.com if you have a specific interest in this trial.

Citation Format: Alice S Bexon, Hendrik-Tobias Arkenau, Jeff Evans, Gerald S Falchook, Stefan N Symeonides, Meredith A McKean, Elisa Fontana, Manojkumar Bupath, Alistair McLaren, Sreenivasa Chandana, Tze-en Ding, Emerson A Lim, Jim Rotolo, Gina Capiaux, Rob Michel, Stephen Kaesshaefer, Nehal J Lakhani. Phase 1 study of ST101, a first-in-class peptide antagonist of CCAAT/enhancer-binding protein β (C/EBPβ), in patients with advanced solid tumors, with a phase 2 expansion in patients with hormone receptor positive breast cancer (HR+ BC) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT2-01-01.

Abstract P06-03: ST101, a peptide targeting oncogenic transcription factor C/EBPβ: initial safety, efficacy, pharmacokinetic (PK) and pharmacodynamic (PD) data from an ongoing phase 1 dose escalation study in patients with advanced, metastatic solid tumors

Introduction: The oncogenic transcription factor CCAAT/enhancer-binding protein β (C/EBPβ) is normally active in embryofetal development, but inactive and suppressed in mature cells. Upregulation or activation of C/EBPβ in cancer promotes tumor survival and proliferation while inhibiting its differentiation. ST101 is a peptide antagonist of C/EBPβ, with anti-tumor activity in glioblastoma (GBM), breast cancer (BC), prostate cancer (PC), melanoma, and other models. ST101 penetrates the blood-brain barrier, as demonstrated in a mouse model and biodistribution studies. We have also demonstrated the tumor-specificity of ST101 in numerous in vitro cell lines. Methods: We conducted the phase 1 portion of a phase 1-2 study in patients with refractory solid tumors. The primary objective was to evaluate safety and tolerability of ST101. Secondary and exploratory objectives included PK, preliminary efficacy, and PD from serial biopsies. The study used a 3+3 design, dosing ST101 IV at 0.5, 1, 2, 4, 6, and 8 (now modified to 9) mg/kg weekly (QW). Phase 2 will include four cohorts of patients with specific cancers: HR+ breast cancer, cutaneous melanoma, GBM, and castrate-resistant PC at the recommended phase 2 dose (RP2D). Results: As of July 2021, 18 pts were enrolled, and the last cohort (9 mg/kg) is underway. Patients received a median of 6 weeks’ treatment (range 2 – 45). There were no dose-limiting toxicities, dose modifications, or SAEs related to ST101. The only adverse events (AEs) of note were G1-2 histaminergic infusion-related reactions (IRRs), largely pruritis and urticaria, managed with antihistamines, montelukast, and interruption/slowing of infusion. IRRs affected 100% pts on the 1st dose of ST101 at 4mg/kg. Montelukast was added to the antihistamine premedication regimen in the 6 mg/kg cohort, which attenuated IRRs. 66% of patients in the 6 mg/kg experienced an IRR on the first dose. The intensity and frequency of IRRs decreased with repeat dosing across all cohorts. No other AEs were consistently reported. PK was dose-proportionate, with continued exposure. There was no evidence of accumulation, and no anti-drug antibodies were detected. Tumor immunohistochemistry showed dose-proportionate staining for ST101 and a trend of decreased Ki67 staining (proliferation marker) after ST101 exposure. One confirmed partial response in a patient with metastatic cutaneous melanoma refractory to standard therapy is still on study, and 3 pts with varied histologies have had stable disease lasting 18-45 weeks (1 ongoing). Conclusions: ST101 demonstrated safety at all doses explored and evidence of efficacy across dose levels, particularly higher doses. PK and PD support a dose relationship for efficacy, and we will select a QW RP2D for the phase 2 expansion cohorts by September 2021.

Citation Format: Nehal J. Lakhani, Hendrik-Tobias Arkenau, Stefan N. Symeonides, Jeffry Evans, Meredith A. McKean, Elisa Fontana, Manojkumar Bupath, Alistair McLaren, Sreenivasa Chandana, Tze-en Ding, Emerson A. Lim, Jim Rotolo, Gina Capiaux, Rob Michel, Stephen Kaesshaefer, Alice S. Bexon, Gerald S. Falchook. ST101, a peptide targeting oncogenic transcription factor C/EBPβ: initial safety, efficacy, pharmacokinetic (PK) and pharmacodynamic (PD) data from an ongoing phase 1 dose escalation study in patients with advanced, metastatic solid tumors [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 P06-03.

Onapristone Extended Release: Safety Evaluation from Phase I-II Studies with an Emphasis on Hepatotoxicity

Introduction

Antiprogestins have demonstrated promising activity against breast and gynecological cancers, but liver-related safety concerns limited the advancement of this therapeutic class. Onapristone is a full progesterone receptor antagonist originally developed as an oral contraceptive and later evaluated in phase II studies for metastatic breast cancer. Because of liver enzyme elevations identified during clinical studies, further development was halted. Evaluation of antiprogestin pharmacology and pharmacokinetic data suggested that liver enzyme elevations might be related to off-target or metabolic effects associated with clinical drug exposure.

Objective

We explored whether the use of a pharmaceutic strategy targeting efficacious systemic dose concentrations, but with diminished peak serum concentrations and/or total drug exposure would mitigate hepatotoxicity. Twice-daily dosing of an extended-release formulation of onapristone was developed and clinically evaluated in light of renewed interest in antiprogestin therapy for treating progesterone receptor-positive breast and gynecologic cancers. The hepatotoxic potential of extended-release onapristone was assessed from two phase I–II studies involving patients with breast, ovarian, endometrial, and prostate cancer.

Results

Among the 88 patients in two phase I–II studies in progesterone receptor-positive malignancies treated with extended-release onapristone, elevated alanine aminotransferase/aspartate aminotransferase levels were found in 20% of patients with liver metastases compared with 6.3% without metastases. Of five patients with grade 3 or higher alanine aminotransferase elevations with or without bilirubin elevations (four with breast cancer and one with endometrial cancer), four were assessed as unrelated to extended-release onapristone by the safety data review committee. Furthermore, while the fifth patient’s liver enzyme elevations were considered possibly drug related by the study investigator, they were adjudicated as unlikely to be related (< 25% likelihood) by a subsequent independent hepatologist.

Conclusions

These results suggest that the extended-release formulation by reducing drug exposure may be associated with a reduced risk of hepatotoxicity, and supports the continued clinical evaluation of extended-release onapristone for treating progesterone receptor-positive cancers.

Abstract LB-140: Phase 1b/2 study of an intratumoral TLR9 agonist spherical nucleic acid (AST-008) and pembrolizumab: Evidence of immune activation

Background: AST-008 is a novel spherical nucleic acid configuration of a toll-like receptor 9 (TLR9) agonist oligonucleotide, designed to trigger anti-tumor immune responses. Here we focus on immune activation upon AST-008 injection in the phase 1b/2 study in patients with advanced solid tumors (NCT03684785). Materials and Methods: AST-008 was injected intratumorally (IT) into one or more tumors QW for 8 doses, then Q3W thereafter, at doses from 2 to 32 mg. Starting at week 3, pembrolizumab was administered per label until toxicity or progression. Peripheral blood immune cell profiling and cytokine/chemokine analyses were performed before and 24 hours after both the first AST-008 dose (week 1) and the first combination dose (week 3). Serial tumor biopsies of lesions were collected from both AST-008-injected lesions and non-injected (“witness”) lesions at baseline, after IT AST-008 monotherapy, and after combination therapy. Results: Seventeen patients have been enrolled in the dose escalation cohort: median age 66 [range: 30-86], 82% male, median ECOG 1 [0-1]. Dose dependent lymphocyte activation was observed after IT AST-008. AST-008 dosing alone (16 mg cohort, n = 3) increased activated fractions of CD4+ (33%) and CD8+ T cells (64%), monocytes (97%) and NK cells (94%), compared to baseline (15%, 22%, 4%, and 37%, respectively). At AST-008 doses of 8 and 16 mg, the cell activation response within a dose level was generally similar in the presence or absence of pembrolizumab. In addition, the cytokines/chemokines IL-12p40, IL-1RA, IP-10, and MCP-1 were induced in a dose-proportional manner after IT AST-008 mono- or combination therapy. IT AST-008 resulted in average fold increase of 5, 12, and 16 for doses of 2, 4, and 8 mg dose cohorts, respectively, in IP-10 concentration from baseline (n = 11). Generally, combination therapy with pembrolizumab and AST-008 at doses of 2 and 4 mg produced a cytokine/chemokine response that was smaller than AST-008 alone (n = 5), but 8 mg dose responses were similar after monotherapy or combination therapy (n = 3). Preliminary analysis of serial biopsies by Nanostring revealed increased T cells and cytotoxic cells in the injected lesion after AST-008 dosing (n = 4) and in the non-injected witness lesion after combination therapy (n = 6). Combination therapy produced increases in B cells, T cells, cytotoxic cells and macrophages the AST-008 injected lesions (n = 6). Further PD data are being collected. The emerging safety profile consists mostly of grade (G) 1 and 2 injection site reactions and flu-like symptoms, reflecting local and systemic immune activation. One G3 lymphocytopenia has been observed, with no clinical consequences. No AST-008-related serious AEs or DLTs have been reported. Conclusions: IT AST-008 is well tolerated at the doses administered and is associated with dose-proportional systemic immune activation. Gene expression analysis suggests increased lymphocytes in the injected tumor after IT AST-008 and in both injected and witness tumors after combination therapy.

Citation Format: Mohammed M. Milhem, Cesar A. Perez, Glenn J. Hanna, Trisha M. Wise-Draper, Shailender Bhatia, Alice S. Bexon, Weston L. Daniel, Steven J. O'Day. Phase 1b/2 study of an intratumoral TLR9 agonist spherical nucleic acid (AST-008) and pembrolizumab: Evidence of immune activation [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 LB-140.

Abstract CT044: AST-008, a TLR9 agonist spherical nucleic acid, activated NK cells, T cells, and cytokines in healthy subjects in a Phase I clinical trial

Background

Exicure develops spherical nucleic acid (SNA) constructs, which are 3-dimensional arrangements of oligonucleotides where the nucleic acids are densely packed and radially oriented around a nanoparticle. SNAs have properties that are distinct from the “linear” nucleic acids (i.e., nucleic acids not arranged in the SNA format), which include, most importantly, increased cellular uptake compared to linear nucleic acids.

AST-008 is an SNA configuration of a toll-like receptor 9 (TLR9) agonist oligonucleotide, designed to trigger anti-tumor immune responses in patients with cancer. AST-008 is intended to be administered intratumorally in combination with checkpoint inhibitors for the treatment of solid tumors.

AST-008 has potent antitumor activity as a monotherapy and synergizes with anti-PD-1 antibody therapy in several preclinical tumor models.

Materials and Methods

AST-008 has been evaluated in a Phase 1 study (Protocol number: AST-008-101). The safety, tolerability, pharmacokinetics and pharmacodynamics of single ascending doses of AST-008 were studied in healthy volunteers. Four dose levels of AST-008 were evaluated in four cohorts.

Results

The results indicated that AST-008 was safe and well tolerated after single subcutaneous injections. No serious adverse events or dose limiting toxicity were reported. The most common adverse events observed were flu-like symptoms, injection site reactions, and reversible, short-lived leukopenia and neutropenia.

AST-008 induced an innate immune response after administration to healthy volunteers. Cytokine and chemokine analysis indicated that a Th1-type immune response was elicited. IL-12 (p40), IL-1RA, IL-6, IP-10, and MCP-1 were consistently induced across all doses. AST-008 elicited 9.5 fold and 3.5 fold increases in the fraction of activated T cells and natural killer cells, respectively, compared to baseline at the highest dose tested. These results suggest that the cytokines and immune cell activation elicited by AST-008 will initiate and propagate the cancer immunity cycle in the presence or absence of checkpoint inhibitors. Pharmacokinetic analysis revealed that the concentration of AST-008 in plasma peaked 2 hours after dosing and was dose proportional.

Conclusions

AST-008 elicited no serious adverse events or dose limiting toxicity at the doses tested. AST-008 is a potent innate immune activator and exhibits pharmacodynamic properties that are expected to result in anti-tumor effects in patients with cancer. A Phase 1b/2 study of AST-008 in combination with pembrolizumab in cancer patients is ongoing.

Citation Format: Weston L. Daniel, Ulrike Lorch, Simon Coates, Alice S. Bexon, Scott Mix. AST-008, a TLR9 agonist spherical nucleic acid, activated NK cells, T cells, and cytokines in healthy subjects in a Phase I clinical trial [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 CT044.

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.

Abstract CT051: Preliminary correlative and clinical data from a first-in-human (FIH) study of the intratumoral (IT) oncolytic virotherapy, Voyager-V1, in patients with solid tumors

Introduction Voyager-V1TM is derived from VSV, a bullet-shaped negative sense RNA virus with very low human seroprevalence; it is engineered to selectively replicate in and kill human cancer cells. Voyager-V1 encodes the human IFNβ gene to boost antitumoral immune responses and the thyroidal sodium iodide symporter NIS gene to permit noninvasive imaging of virus spread. FIH studies are underway via both IV and IT routes. Here we report safety and preliminary correlative data from the FIH IT study.

Methods and objectives This is a classical 3+3 phase 1 design, using escalating single IT viral doses from 3 x 106 to 3 x 109 TCID50 into one target lesion. The primary objective is safety and tolerability, monitored by committee. Other objectives include PK by RT-PCR for viral genomes, serum IFNβ levels, Tc-99m SPECT/CT imaging to monitor virus infection in injected lesions, peripheral blood immunophenotyping with 11-color flow cytometry for activation markers on T cells, T-regs, NK cells, and MDSCs, and serial biopsies to assess the tumor microenvironment (TME). IHC was performed on tumor biopsies for CD3, CD8, CD4, FoxP3, CD68, PD-1 and PDL-1 pre and post treatment in non-injected and injected lesions. CD45 staining is ongoing.

Results Dose level 3 is ongoing (n=8+). No DLTs have been observed to date. Most patients were male (75%), white (100%), with ECOG PS1 (75%) and a median of &gt;6 lines of prior systemic therapy. AEs (in 63% patients) reported as related to study drug were mild-moderate, short-lived, and consisted of G1 fever, chills, hot flashes, nausea, vomiting, hyperhidrosis and G2 fatigue. Most patients had some mild AEs (pain, bruising, subclinical pneumothorax) related to biopsy and IT injection procedures and one had an SAE related to biopsy (G2 pneumothorax). There was no difference in incidence, intensity or duration of related AEs between dose levels so far. In patients analyzed to date, at the first three dose levels of 3 x 106, 1 x 107 and 3 x 107 TCID50 (n=7), viremia and serum IFNβ were below levels of detection after IT injection. There is evidence in all patients of an increase in PD-1 expression on CD4 and CD8 T cells, suggesting T cell activation post- single virus injection. One patient at dose level 2 had increased CD4 and CD8 T cells in the peripheral blood. TME analysis revealed increased infiltration of CD3 and CD8 cells in tumors of some patients. In addition, there are changes in numbers of FoxP3 and CD68 positive cells in the injected lesions compared to the pre-treatment and non-injected lesion. Two patients at dose level 3, one with an injected adrenal metastasis of colorectal cancer and another with a chest wall lesion from a head of pancreas primary, have positive SPECT/CTs on days 3-15 showing viral replication in tumor plus concomitant lymphocyte/neutrophil trafficking in the periphery.

Conclusions IT injection of a single dose of the novel oncolytic virotherapy Voyager-V1 has proven safe at doses up to 3 x 107 TCID50. There was evidence of T cell activation with increased PD-1 expression in peripheral blood lymphocytes after a single IT injection. Tumor biopsies indicate increased lymphocyte infiltration. Two patients at the highest dose tested show signs of viral replication in the injected lesion plus evidence of systemic impact on leukocyte populations.

Citation Format: Steven Powell, Manish R. Patel, Jaime R. Merchan, Timothy P. Cripe, James Strauss, Rosa M. Diaz, Nandakumar Packiriswamy, Bethany A. Brunton, Deepak Upreti, Rehan Khan, Lukkana Suksanpaisan, Rianna Vandergaast, Stephen J. Russell, Alice S. Bexon, Kah Whye Peng. Preliminary correlative and clinical data from a first-in-human (FIH) study of the intratumoral (IT) oncolytic virotherapy, Voyager-V1, in patients with solid tumors [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 CT051.

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

Abstract 1646: Synthesis of [11C]onapristone for clinical investigation

Background: Onapristone is a type I anti-progestin, which prevents the progesterone receptor (PR) monomers from dimerizing, inhibits ligand-induced phosphorylation and prevents association of the PR with its co-activators, thus preventing PR-induced transcription. Onapristone has the potential to treat patients with endometrial cancer, breast cancer, uterine sarcomas, a potential subset of ovarian cancer, prostate cancer and other tumors in which the progesterone receptor plays a role in growth, proliferation and metastasis. [11C]-radiolabeled onapristone and its visualization via PET-scan, coupled with pharmacokinetic (PK) studies, has the potential to determine tissue-specific and blood PK parameters including tumor/tissue and plasma concentrations, whole body distribution and half-life of onapristone. The aim of this study is the development of a rapid Good Manufacturing Product (GMP) synthesis of parentally administered [11C]onapristone.

Methods: The production of [11C]-labeled radiopharmaceuticals used a Tracerlab® FX c-Pro (GEMS) synthesis module. Carbon-11 was produced at Institut Curie-Hôpital René Huguenin via the 14N(p,α)11C nuclear reaction using a PETTrace cyclotron (GEMS) equipped with a carbon-11 target. Carbon-11 is delivered from the cyclotron as [11C]CO2 in the synthesis module, and reduced to [11C]CH4. Methane is halogenated to [11C]CH3I and converted to [11C]methyl triflate (CH3OTf). To prepare [11C]onapristone, the module was loaded with 1mg of N-desmethyl-onapristone (Arno Therapeutics) and 500µL of DMSO in the reaction vessel (Sigma®). [11C]CH3OTf was bubbled into the reaction vessel and heated at +50°C for 10 minutes. The reaction mixture was then diluted with 1 ml of mobile phase and purified using a semi-preparative HPLC column: Sunfire C18 5µm 250X10mm (Waters®), mobile phase: acetonitrile (Sigma®)/water (Waters®) 50/50 v/v; flow rate 4 mL/min. The product fraction was collected in 40mL of sterile water and was passed through a C18 SEP PAK (Waters®). This fraction was eluted with isotonic saline (Braun®) and ethanol (Sigma®). The resulting formulation was passed through a 0.22µm sterilizing filter into a sterile dose vial.

Results: 10 tests were performed. Time of synthesis was 50 minutes. The amount of carbon-11 delivered was 12-14GBq for the irradiation parameters as follows: 10 min; 10µA. The decay-corrected yield of reducing [11C]CO2 to [11C]CH4 was &gt;99%. The yields of preparing [11C]CH3I were 27-29%. Time retention of [11C]onapristone was 8.5-9.5 minutes and the non-decay-corrected radiolabelling yields were 1-2%.

Conclusions: We have successfully developed a fully-automated production of [11C]onapristone ready for use in clinical trials.

Citation Format: Olivier Madar, Julien Fouque, Stefan Proniuk, Keyvan Rezai, Samuel Huguet, Alexander Zukiwski, Erard M. Gilles, Alice S. Bexon, François Lokiec. Synthesis of [11C]onapristone for clinical investigation. [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 1646. doi:10.1158/1538-7445.AM2014-1646

Antitumor activity and safety of combination therapy with the Toll-like receptor 9 agonist IMO-2055, erlotinib, and bevacizumab in advanced or metastatic non-small cell lung cancer patients who have progressed following chemotherapy

BACKGROUND

IMO-2055 is a Toll-like receptor 9 (TLR9) agonist that potentially enhances the efficacy of antitumor agents through immune stimulation. The objective of this phase Ib dose-escalation trial (3 + 3 design) was to determine the recommended phase II dose (RP2D) of IMO-2055 when combined with erlotinib and bevacizumab in patients with advanced non-small cell lung cancer (NSCLC).

METHODS

Patients with stage 3/4 NSCLC and progressive disease (PD) following chemotherapy received IMO-2055 0.08, 0.16, 0.32, or 0.48 mg/kg once weekly plus erlotinib 150 mg daily and bevacizumab 15 mg/kg every 3 weeks. Patients could receive treatment until PD or unacceptable toxicity.

RESULTS

Thirty-six patients were enrolled; 35 received at least one treatment dose. Two dose-limiting toxicities were observed across the dose range (Grade 3 dehydration and fatigue) with neither suggestive of a consistent toxicity pattern. IMO-2055 0.32 mg/kg was adopted as RP2D based on clinical and pharmacodynamic data. The most common treatment-emergent adverse events (TEAEs) were diarrhea (74 %), nausea (51 %), fatigue (51 %), rash (51 %), and injection-site reactions (49 %). Four patients experienced serious TEAEs considered to be study drug related. Five patients died, all due to PD. High-grade neutropenia and electrolyte disturbances previously reported with TLR9 agonists combined with platinum-based therapy were not observed in this study. Five of 33 patients evaluable for response (15 %) achieved partial response; another 20 (61 %) had stable disease, including 13 with stable disease ≥4 months.

CONCLUSIONS

IMO-2055 demonstrated good tolerability and possible antitumor activity in combination with erlotinib and bevacizumab in heavily pretreated patients with advanced NSCLC.

Impact of liver transplantation on the survival of patients treated for hepatorenal syndrome type 1

The development of hepatorenal syndrome type 1 (HRS1) is associated with a poor prognosis. Liver transplantation improves this prognosis, but the degree of the improvement is unclear. Most patients receive vasoconstrictors such as terlipressin before transplantation, and this may affect the posttransplant outcomes. We examined a cohort of patients with access to liver transplantation from our previously published study of terlipressin plus albumin versus albumin alone in the treatment of HRS1. The purpose of this analysis was the quantification of the survival benefits of liver transplantation for patients with HRS1. Ninety-nine patients were randomized to terlipressin or placebo. Thirty-five patients (35%) received a liver transplant. Among those receiving terlipressin plus albumin, the 180-day survival rates were 100% for transplant patients and 34% for nontransplant patients; among those receiving only albumin, the rates were 94% for transplant patients and 17% for nontransplant patients. The survival rate was significantly better for those achieving a reversal of hepatorenal syndrome (HRS) versus those not achieving a reversal (47% versus 4%, P < 0.001), but it was significantly lower for the responders versus those undergoing liver transplantation (97%). We conclude that the use of terlipressin plus albumin has no significant impact on posttransplant survival. Liver transplantation offers a clear survival benefit to HRS1 patients regardless of the therapy that they receive or the success or failure of HRS reversal. The most likely benefit of terlipressin in patients undergoing liver transplantation for HRS1 is improved pretransplant renal function, and this should make the posttransplant management of this difficult group of patients easier. For patients not undergoing transplantation, HRS reversal with terlipressin and/or albumin improves survival.

Detailed analysis of a randomized phase III trial: can the tolerability of capecitabine plus docetaxel be improved without compromising its survival advantage?

BACKGROUND

In a phase III trial, 3-weekly capecitabine (1250 mg/m(2) twice daily days 1-14) plus docetaxel (75 mg/m(2) day 1) demonstrated significantly superior overall survival to 3-weekly docetaxel (100 mg/m(2) day 1). We report a retrospective analysis of the impact of capecitabine/docetaxel dose reduction on safety and efficacy.

PATIENTS AND METHODS

Safety and efficacy data were analyzed retrospectively according to the actual doses of capecitabine and docetaxel administered.

RESULTS

More patients receiving capecitabine/docetaxel (65%) had dose reductions for adverse events than docetaxel alone (35%). In most patients requiring dose reduction with the combination (80%), capecitabine and docetaxel were simultaneously reduced to 950 mg/m(2) and 55 mg/m(2), respectively. Subsequently, there were fewer cycles (17%) with grade 3/4 adverse events than with the full doses (34%). Time to progression and overall survival appeared to be similar in patients starting the second cycle with reduced doses of capecitabine/docetaxel and those who continued to receive full doses of capecitabine/docetaxel for at least the first four cycles.

CONCLUSIONS

Capecitabine/docetaxel dosing flexibility allows management of side-effects without compromising efficacy. This retrospective analysis, as well as multiple phase II studies of taxanes with reduced-dose capecitabine, shows that reducing the starting dose of capecitabine with docetaxel is a reasonable strategy for the treatment of patients with metastatic breast cancer. In addition, reducing the dose of both agents may be appropriate.