Exploratory Food Effect Assessment in Patients in Early Clinical Development of Oncology Drugs.

Instructions for administration with regard to food are a key aspect of how patients experience oral drugs. Through potential effects on pharmacokinetics, the food condition can influence safety and efficacy, and thereby is one of many dimensions of dose optimization. Regulatory guidance from major health authorities advocates for the early investigation of food effect (FE) in clinical development. In oncology, exploratory FE (eFE) evaluation is often incorporated into the first-in-human (FIH) studies in patients to inform food condition of later clinical studies. However, the design aspects of such exploratory assessments are generally under-reported and barely described, and yet complex, due to uniqueness of FIH study design and drug development process in oncology. Herein, we review literature of eFE assessment study design in oncology in patients, and present the Novartis experience in the design, execution, and impact of eFE in FIH oncology studies from 2014 to 2021. Based on this, we propose a roadmap for eFE assessment in early clinical drug development for oncology drugs in patients, including a framework for common study design options with a focus on study- and patient-level timing for typical scenarios. We also provide a broad spectrum of decision-making factors which should be evaluated to drive the design and implementation of eFE assessment, spanning from clinical development strategy, FIH study design, to compound-specific features.

Phase 1 study of the ATR inhibitor berzosertib in combination with cisplatin in patients with advanced solid tumours.

BACKGROUND: Berzosertib (formerly M6620, VX-970) is a highly potent and selective, first-in-class ataxia telangiectasia-mutated and Rad3-related protein kinase (ATR) inhibitor. We assessed the safety, tolerability, pharmacokinetics, and preliminary efficacy of berzosertib plus cisplatin. METHODS: Adult patients with advanced solid tumours refractory or resistant to standard of care therapies received ascending doses of cisplatin (day 1) and berzosertib (days 2 and 9) every 3 weeks (Q3W). RESULTS: Thirty-one patients received berzosertib (90-210 mg/m2) and cisplatin (40-75 mg/m2) across seven dose levels. The most common grade ≥3 treatment-emergent adverse events were neutropenia (20.0%) and anaemia (16.7%). There were two dose-limiting toxicities: a grade 3 hypersensitivity reaction and a grade 3 increase in alanine aminotransferase. Berzosertib 140 mg/m2 (days 2 and 9) and cisplatin 75 mg/m2 (day 1) Q3W was determined as the recommended Phase 2 dose. Cisplatin had no apparent effect on berzosertib pharmacokinetics. Of the 31 patients, four achieved a partial response (two confirmed and two unconfirmed) despite having previously experienced disease progression following platinum-based chemotherapy. CONCLUSIONS: Berzosertib plus cisplatin is well tolerated and shows preliminary clinical activity in patients with advanced solid tumours, warranting further evaluation in a Phase 2 setting. CLINICAL TRIALS IDENTIFIER: NCT02157792.

Phase 1 study of the ATR inhibitor berzosertib (formerly M6620, VX-970) combined with gemcitabine ± cisplatin in patients with advanced solid tumours.

BACKGROUND: Berzosertib (formerly M6620, VX-970) is a highly potent and selective, first-in-class inhibitor of ataxia telangiectasia and Rad3-related protein kinase (ATR). We assessed multiple ascending doses of berzosertib + gemcitabine ± cisplatin in patients with resistant/refractory advanced solid tumours. METHODS: We evaluated the safety, tolerability, pharmacokinetics (PK) and preliminary efficacy of intravenous berzosertib + gemcitabine ± cisplatin using a standard 3 + 3 dose-escalation design. The starting doses were berzosertib 18 mg/m2, gemcitabine 875 mg/m2 and cisplatin 60 mg/m2. RESULTS: Fifty-two patients received berzosertib + gemcitabine and eight received berzosertib + gemcitabine + cisplatin. Four patients receiving berzosertib + gemcitabine had a total of seven dose-limiting toxicities (DLTs) and three receiving berzosertib + gemcitabine + cisplatin had a total of three DLTs. Berzosertib 210 mg/m2 (days 2 and 9) + gemcitabine 1000 mg/m2 (days 1 and 8) Q3W was established as the recommended Phase 2 dose (RP2D); no RP2D was determined for berzosertib + gemcitabine + cisplatin. Neither gemcitabine nor cisplatin affected berzosertib PK. Most patients in both arms achieved a best response of either partial response or stable disease. CONCLUSIONS: Berzosertib + gemcitabine was well tolerated in patients with advanced solid tumours and showed preliminary efficacy signs. CLINICAL TRIAL IDENTIFIER: NCT02157792.

Population pharmacokinetics of ATR inhibitor berzosertib in phase I studies for different cancer types.

PURPOSE: Berzosertib (formerly M6620) is the first-in-class inhibitor of ataxia-telangiectasia and Rad3-related protein, a key component of the DNA damage response, and being developed in combination with chemotherapy for the treatment of patients with advanced cancers. The objectives of this analysis were to characterize the pharmacokinetics (PK) of berzosertib across multiple studies and parts, estimate inter-individual variability, and identify covariates that could explain such variability. METHODS: A population PK analysis was performed using the combined dataset from two phase I clinical studies (NCT02157792, EudraCT 2013-005100-34) in patients with advanced cancers receiving an intravenous infusion of berzosertib alone or in combination with chemotherapy. The analysis included data from 240 patients across 11 dose levels (18-480 mg/m2). Plasma concentration data were modeled with a non-linear mixed-effect approach and clinical covariates were evaluated. RESULTS: PK data were best described by a two-compartment linear model. For a typical patient, the estimated clearance (CL) and intercompartmental CL were 65 L/h and 295 L/h, respectively, with central and peripheral volumes estimated to be 118 L and 1030 L, respectively. Several intrinsic factors were found to influence berzosertib PK, but none were considered clinically meaningful due to a very limited effect. Model simulations indicated that concentrations of berzosertib exceeded p-Chk1 (proximal pharmacodynamic biomarker) IC50 at recommended phase II doses in combination with carboplatin, cisplatin, and gemcitabine. CONCLUSIONS: There was no evidence of a clinically significant PK interaction between berzosertib and evaluated chemo-combinations. The covariate analysis did not highlight any need for dosing adjustments in the population studied to date. CLINICAL TRIAL INFORMATION: NCT02157792, EudraCT 2013-005100-34.

Longitudinal PET Imaging to Monitor Treatment Efficacy by Liposomal Irinotecan in Orthotopic Patient-Derived Pancreatic Tumor Models of High and Low Hypoxia.

PURPOSE: Hypoxia is linked to aggressiveness, resistance to therapy, and poor prognosis of pancreatic tumors. Liposomal irinotecan (nal-IRI, ONIVYDE®) has shown potential in reducing hypoxia in the HT29 colorectal cancer model, and here, we investigate its therapeutic activity and ability to modulate hypoxia in patient-derived orthotopic tumor models of pancreatic cancer. PROCEDURES: Mice were randomized into nal-IRI treated and untreated controls. Magnetic resonance imaging was used for monitoring treatment efficacy, positron emission tomography (PET) imaging with F-18-labelled fluoroazomycinarabinoside ([18F]FAZA) for tumor hypoxia quantification, and F-18-labelled fluorothymidine ([18F]FLT) for tumor cell proliferation. RESULTS: The highly hypoxic OCIP51 tumors showed significant response following nal-IRI treatment compared with the less hypoxic OCIP19 tumors. [18F]FAZA-PET detected significant hypoxia reduction in treated OCIP51 tumors, 8 days before significant changes in tumor volume. OCIP19 tumors also responded to therapy, although tumor volume control was not accompanied by any reduction in [18F]FAZA uptake. In both models, no differences were observable in [18F]FLT uptake in treated tumors compared with control mice. CONCLUSIONS: Hypoxia modulation may play a role in nal-IRI's mechanism of action. Nal-IRI demonstrated greater anti-tumor activity in the more aggressive and hypoxic tumor model. Furthermore, hypoxia imaging provided early prediction of treatment response.

Nanoliposome targeting in breast cancer is influenced by the tumor microenvironment.

MM-302 is an anti-HER2 antibody-targeted pegylated liposomal doxorubicin designed to deliver doxorubicin specifically to HER2-expressing solid tumors. The delivery and activity of MM-302 were evaluated in orthotopic, transgenic, and intravenous breast cancer models expressing varying levels of HER2 that metastasize to some of the most common sites of dissemination for breast cancer, namely, lung, liver, and brain. Metastatic burden was quantified by gross evaluation, immunohistochemistry (IHC), and bioluminescent imaging. Liposome delivery was quantified by IHC and ex vivo fluorescent imaging. Unlike its non-targeted counterpart, pegylated liposomal doxorubicin (PLD), MM-302 showed activity at controlling both primary and metastatic tumor burden in all models tested. The effect of HER2-targeting was greatest in the lung where lymphatic vessel density and MM-302 delivery were highest. Our data indicate that the therapeutic advantage of actively targeting a nanoliposome with an antibody is influenced by both target expression and the tumor microenvironment.

Safety and pharmacokinetics of MM-302, a HER2-targeted antibody-liposomal doxorubicin conjugate, in patients with advanced HER2-positive breast cancer: a phase 1 dose-escalation study.

BACKGROUND: This phase 1 dose-escalation trial studied MM-302, a novel HER2-targeted PEGylated antibody-liposomal doxorubicin conjugate, in HER2-positive locally advanced/metastatic breast cancer. METHODS: Patients were enrolled in four cohorts: MM-302 monotherapy (8, 16, 30, 40, and 50 mg/m2 every 4 weeks [q4w]); MM-302 (30 or 40 mg/m2 q4w) plus trastuzumab (4 mg/kg q2w); MM-302 (30 mg/m2) plus trastuzumab (6 mg/kg) q3w; MM-302 (30 mg/m2) plus trastuzumab (6 mg/kg) and cyclophosphamide (450 mg/m2) q3w. RESULTS: Sixty-nine patients were treated. The most common adverse events (AEs) were fatigue and nausea. Grade 3/4 AEs of special interest included neutropenia, fatigue, mucosal inflammation, anemia, thrombocytopenia, febrile neutropenia, and palmar-plantar erythrodysesthesia. The MTD was not reached. With MM-302 ≥ 30 mg/m2, overall response rate (ORR) was 13% and median progression-free survival (mPFS) 7.4 months (95% CI: 3·5-10·9) in all arms. In 25 anthracycline-naïve patients, ORR was 28·0% and mPFS 10·9 months (95% CI: 1·8-15·3). Imaging with 64Cu-labeled MM-302 visualized tumor-drug penetrance in tumors throughout the body, including the brain. CONCLUSION: MM-302 monotherapy, in combination with trastuzumab, or trastuzumab plus cyclophosphamide, was well tolerated and showed promising efficacy. The selected phase 2 MM-302 dose was 30 mg/m2 plus 6 mg/kg trastuzumab q3w.

Liposomal Irinotecan Achieves Significant Survival and Tumor Burden Control in a Triple Negative Breast Cancer Model of Spontaneous Metastasis.

Triple negative breast cancer (TNBC) represents a significant therapeutic challenge due to its highly aggressive nature and lack of effective treatment options. Liposomal irinotecan (nal-IRI, ONIVYDE) was approved in 2015 (by the Food and Drug Administration, European Medicines Agency, and Therapeutic Goods Administration) and is a topoisomerase inhibitor indicated, in combination with fluorouracil and leucovorin, for the treatment of patients with metastatic adenocarcinoma of the pancreas after disease progression following gemcitabine-based therapy. This study investigates the potential therapeutic benefit of nal-IRI for the treatment of advanced TNBC in a clinically relevant mouse model of spontaneous metastasis (LM2-4). Female SCID mice were orthotopically inoculated with TNBC LM2-4-luc cells in the lower mammary fat pad. Following primary tumor resection, bioluminescence imaging (BLI) was used to monitor both metastasis formation and spread as well as response to treatment with nal-IRI. Weekly treatment with 10 mg/kg of nal-IRI provided a 4.9-times longer median survival compared to both 50 mg/kg irinotecan treated and untreated animals. The survival benefit was supported by a significant delay in the regrowth of the primary tumor, effective control, and eventual regression of metastases assessed using longitudinal BLI, which was confirmed at the study end point with magnetic resonance (MR) imaging and post-mortem observation. This preclinical investigation demonstrates that, at a five-times lower dose compared to the free drug, liposomal irinotecan provides significant survival benefit and effective management of metastatic disease burden in a clinically relevant model of spontaneous TNBC metastases. These findings support the evaluation of nal-IRI in patients with advanced and metastatic TNBC.

Companion Diagnostic 64Cu-Liposome Positron Emission Tomography Enables Characterization of Drug Delivery to Tumors and Predicts Response to Cancer Nanomedicines.

Deposition of liposomal drugs into solid tumors is a potentially rate-limiting step for drug delivery and has substantial variability that may influence probability of response. Tumor deposition is a shared mechanism for liposomal therapeutics such that a single companion diagnostic agent may have utility in predicting response to multiple nanomedicines. Methods: We describe the development, characterization and preclinical proof-of-concept of the positron emission tomography (PET) agent, MM-DX-929, a drug-free untargeted 100 nm PEGylated liposome stably entrapping a chelated complex of 4-DEAP-ATSC and 64Cu (copper-64). MM-DX-929 is designed to mimic the biodistribution of similarly sized therapeutic agents and enable quantification of deposition in solid tumors. Results: MM-DX-929 demonstrated sufficient in vitro and in vivo stability with PET images accurately reflecting the disposition of liposome nanoparticles over the time scale of imaging. MM-DX-929 is also representative of the tumor deposition and intratumoral distribution of three different liposomal drugs, including targeted liposomes and those with different degrees of PEGylation. Furthermore, stratification using a single pre-treatment MM-DX-929 PET assessment of tumor deposition demonstrated that tumors with high MM-DX-929 deposition predicted significantly greater anti-tumor activity after multi-cycle treatments with different liposomal drugs. In contrast, MM-DX-929 tumor deposition was not prognostic in untreated tumor-bearing xenografts, nor predictive in animals treated with small molecule chemotherapeutics. Conclusions: These data illustrate the potential of MM-DX-929 PET as a companion diagnostic strategy to prospectively select patients likely to respond to liposomal drugs or nanomedicines of similar molecular size.

Liposomal Irinotecan Accumulates in Metastatic Lesions, Crosses the Blood-Tumor Barrier (BTB), and Prolongs Survival in an Experimental Model of Brain Metastases of Triple Negative Breast Cancer.

PURPOSE: The blood-tumor barrier (BTB) limits irinotecan distribution in tumors of the central nervous system. However, given that the BTB has increased passive permeability we hypothesize that liposomal irinotecan would improve local exposure of irinotecan and its active metabolite SN-38 in brain metastases relative to conventional irinotecan due to enhanced-permeation and retention (EPR) effect. METHODS: Female nude mice were intracardially or intracranially implanted with human brain seeking breast cancer cells (brain metastases of breast cancer model). Mice were administered vehicle, non-liposomal irinotecan (50 mg/kg), liposomal irinotecan (10 mg/kg and 50 mg/kg) intravenously starting on day 21. Drug accumulation, tumor burden, and survival were evaluated. RESULTS: Liposomal irinotecan showed prolonged plasma drug exposure with mean residence time (MRT) of 17.7 ± 3.8 h for SN-38, whereas MRT was 3.67 ± 1.2 for non-liposomal irinotecan. Further, liposomal irinotecan accumulated in metastatic lesions and demonstrated prolonged exposure of SN-38 compared to non-liposomal irinotecan. Liposomal irinotecan achieved AUC values of 6883 ± 4149 ng-h/g for SN-38, whereas non-liposomal irinotecan showed significantly lower AUC values of 982 ± 256 ng-h/g for SN-38. Median survival for liposomal irinotecan was 50 days, increased from 37 days (p<0.05) for vehicle. CONCLUSIONS: Liposomal irinotecan accumulates in brain metastases, acts as depot for sustained release of irinotecan and SN-38, which results in prolonged survival in preclinical model of breast cancer brain metastasis.

Liposomal 64Cu-PET Imaging of Anti-VEGF Drug Effects on Liposomal Delivery to Colon Cancer Xenografts.

Liposomes (LP) deliver drug to tumors due to enhanced permeability and retention (EPR). LP were labeled with 64Cu for positron emission tomography (PET) to image tumor localization. Bevacizumab (bev), a VEGF targeted antibody, may modify LP delivery by altering tumor EPR and this change can also be imaged. Objective: Assess the utility of 64Cu-labeled LP for PET in measuring altered LP delivery early after treatment with bev. Methods: HT-29 human colorectal adenocarcinoma tumors were grown subcutaneously in SCID mice. Empty LP MM-DX-929 (Merrimack Pharmaceuticals, Inc. Cambridge, MA) were labeled with 64CuCl2 chelated with 4-DEAP-ATSC. Tumor-bearing mice received ~200-300 µCi of 64Cu-MM-DX-929 and imaged with microPET. All mice were scanned before and after the treatment period, in which half of the mice received bev for one week. Scans were compared for changes in LP accumulation during this time. Initially, tissues were collected after the second PET for biodistribution measurements and histological analysis. Subsequent groups were divided for further treatment. Tumor growth following bev treatment, with or without LP-I, was assessed compared to untreated controls. Results: PET scans of untreated mice showed increased uptake of 64Cu-MM-DX-929, with a mean change in tumor SUVmax of 43.9%±6.6% (n=10) after 7 days. Conversely, images of treated mice showed that liposome delivery did not increase, with changes in SUVmax of 7.6%±4.8% (n=12). Changes in tumor SUVmax were significantly different between both groups (p=0.0003). Histology of tumor tissues indicated that short-term bev was able to alter vessel size. Therapeutically, while bev monotherapy, LP-I monotherapy, and treatment with bev followed by LP-I all slowed HT-29 tumor growth compared to controls, combination provided no therapeutic benefit. Conclusions: PET with tracer LP 64Cu-MM-DX-929 can detect significant differences in LP delivery to colon tumors treated with bev when compared to untreated controls. Imaging with 64Cu-MM-DX-929 is sensitive enough to measure drug-induced changes in LP localization which can have an effect on outcomes of treatment with LP.

Extended topoisomerase 1 inhibition through liposomal irinotecan results in improved efficacy over topotecan and irinotecan in models of small-cell lung cancer.

Liposomal irinotecan (irinotecan liposome injection, nal-IRI), a liposomal formulation of irinotecan, is designed for extended circulation relative to irinotecan and for exploiting discontinuous tumor vasculature for enhanced drug delivery to tumors. Following tumor deposition, nal-IRI is taken up by phagocytic cells followed by irinotecan release and conversion to its active metabolite, SN-38. Sustained inhibition of topoisomerase 1 by extended SN-38 exposure as a result of delivery by nal-IRI is hypothesized to enable superior antitumor activity compared with traditional topoisomerase 1 inhibitors such as conventional irinotecan and topotecan. We evaluated the antitumor activity of nal-IRI compared with irinotecan and topotecan in preclinical models of small-cell lung cancer (SCLC) including in a model pretreated with carboplatin and etoposide, a first-line regimen used in SCLC. Nal-IRI demonstrated antitumor activity in xenograft models of SCLC at clinically relevant dose levels, and resulted in complete or partial responses in DMS-53, DMS-114, and NCI-H1048 cell line-derived models as well as in three patient-derived xenograft models. The antitumor activity of nal-IRI was superior to that of topotecan in all models tested, which generally exhibited limited control of tumor growth and was superior to irinotecan in four out of five models. Further, nal-IRI demonstrated antitumor activity in tumors that progressed following treatment with topotecan or irinotecan, and demonstrated significantly greater antitumor activity than both topotecan and irinotecan in NCI-H1048 tumors that had progressed on previous carboplatin plus etoposide treatment. These results support the clinical development of nal-IRI in patients with SCLC.

64Cu-MM-302 Positron Emission Tomography Quantifies Variability of Enhanced Permeability and Retention of Nanoparticles in Relation to Treatment Response in Patients with Metastatic Breast Cancer.

Purpose: Therapeutic nanoparticles are designed to deliver their drug payloads through enhanced permeability and retention (EPR) in solid tumors. The extent of EPR and its variability in human tumors is highly debated and has been proposed as an explanation for variable responses to therapeutic nanoparticles in clinical studies.Experimental Design: We assessed the EPR effect in patients using a 64Cu-labeled nanoparticle, 64Cu-MM-302 (64Cu-labeled HER2-targeted PEGylated liposomal doxorubicin), and imaging by PET/CT. Nineteen patients with HER2-positive metastatic breast cancer underwent 2 to 3 PET/CT scans postadministration of 64Cu-MM-302 as part of a clinical trial of MM-302 plus trastuzumab with and without cyclophosphamide (NCT01304797).Results: Significant background uptake of 64Cu-MM-302 was observed in liver and spleen. Tumor accumulation of 64Cu-MM-302 at 24 to 48 hours varied 35-fold (0.52-18.5 %ID/kg), including deposition in bone and brain lesions, and was independent of systemic plasma exposure. Computational analysis quantified rates of deposition and washout, indicating peak liposome deposition at 24 to 48 hours. Patients were classified on the basis of 64Cu-MM-302 lesion deposition using a cut-off point that is comparable with a response threshold in preclinical studies. In a retrospective exploratory analysis of patient outcomes relating to drug levels in tumor lesions, high 64Cu-MM-302 deposition was associated with more favorable treatment outcomes (HR = 0.42).Conclusions: These findings provide important evidence and quantification of the EPR effect in human metastatic tumors and support imaging nanoparticle deposition in tumors as a potential means to identify patients well suited for treatment with therapeutic nanoparticles. Clin Cancer Res; 23(15); 4190-202. ©2017 AACR.

Correlation between Ferumoxytol Uptake in Tumor Lesions by MRI and Response to Nanoliposomal Irinotecan in Patients with Advanced Solid Tumors: A Pilot Study.

Purpose: To determine whether deposition characteristics of ferumoxytol (FMX) iron nanoparticles in tumors, identified by quantitative MRI, may predict tumor lesion response to nanoliposomal irinotecan (nal-IRI).Experimental Design: Eligible patients with previously treated solid tumors had FMX-MRI scans before and following (1, 24, and 72 hours) FMX injection. After MRI acquisition, R2* signal was used to calculate FMX levels in plasma, reference tissue, and tumor lesions by comparison with a phantom-based standard curve. Patients then received nal-IRI (70 mg/m2 free base strength) biweekly until progression. Two percutaneous core biopsies were collected from selected tumor lesions 72 hours after FMX or nal-IRI.Results: Iron particle levels were quantified by FMX-MRI in plasma, reference tissues, and tumor lesions in 13 of 15 eligible patients. On the basis of a mechanistic pharmacokinetic model, tissue permeability to FMX correlated with early FMX-MRI signals at 1 and 24 hours, while FMX tissue binding contributed at 72 hours. Higher FMX levels (ranked relative to median value of multiple evaluable lesions from 9 patients) were significantly associated with reduction in lesion size by RECIST v1.1 at early time points (P < 0.001 at 1 hour and P < 0.003 at 24 hours FMX-MRI, one-way ANOVA). No association was observed with post-FMX levels at 72 hours. Irinotecan drug levels in lesions correlated with patient's time on treatment (Spearman ρ = 0.7824; P = 0.0016).Conclusions: Correlation between FMX levels in tumor lesions and nal-IRI activity suggests that lesion permeability to FMX and subsequent tumor uptake may be a useful noninvasive and predictive biomarker for nal-IRI response in patients with solid tumors. Clin Cancer Res; 23(14); 3638-48. ©2017 AACR.

Dual HER2 Targeting with Trastuzumab and Liposomal-Encapsulated Doxorubicin (MM-302) Demonstrates Synergistic Antitumor Activity in Breast and Gastric Cancer.

Trastuzumab is the standard of care for HER2-positive breast cancer patients, markedly improving disease-free and overall survival. Combined with chemotherapy, it enhances patient outcomes, but cardiotoxicity due to the trastuzumab treatment poses a serious adverse effect. MM-302 is a HER2-targeted PEGylated liposome that encapsulates doxorubicin to facilitate its delivery to HER2-overexpressing tumor cells while limiting exposure to nontarget tissues, including the heart. In this study, we evaluated the feasibility and preclinical activity of combining MM-302 with trastuzumab. MM-302 and trastuzumab target different domains of the HER2 receptor and thus could simultaneously bind HER2-overexpressing tumor cells in vitro and in vivo. Furthermore, trastuzumab did not disrupt the mechanism of action of MM-302 in delivering doxorubicin to the n0ucleus and inducing DNA damage. Reciprocally, MM-302 did not interfere with the ability of trastuzumab to block prosurvival p-Akt signaling. Interestingly, coadministration of the two agents acutely increased the deposition of MM-302 in human xenograft tumors and subsequently increased the expression of the DNA damage marker p-p53. Finally, the combination of MM-302 and trastuzumab induced synergistic antitumor activity in HER2-overexpressing xenograft models of breast and gastric cancer. Collectively, our findings highlight a novel combination therapy that efficiently targets HER2-overexpressing cells through multiple mechanisms and support the ongoing investigation of combined MM-302/trastuzumab therapy for HER2-positive metastatic breast cancer in a randomized phase II clinical trial.

Cyclophosphamide-Mediated Tumor Priming for Enhanced Delivery and Antitumor Activity of HER2-Targeted Liposomal Doxorubicin (MM-302).

Given the bulky nature of nanotherapeutics relative to small molecules, it is hypothesized that effective tumor delivery and penetration are critical barriers to their clinical activity. HER2-targeted PEGylated liposomal doxorubicin (MM-302, HER2-tPLD) is an antibody-liposomal drug conjugate designed to deliver doxorubicin to HER2-overexpressing cancer cells while limiting uptake into nontarget cells. In this work, we demonstrate that the administration and appropriate dose sequencing of cyclophosphamide can improve subsequent MM-302 delivery and enhance antitumor activity in preclinical models without negatively affecting nontarget tissues, such as the heart and skin. We demonstrate that this effect is critically dependent on the timing of cyclophosphamide administration. Furthermore, the effect was found to be unique to cyclophosphamide and related analogues, and not shared by other agents, such as taxanes or eribulin, under the conditions examined. Analysis of the cyclophosphamide-treated tumors suggests that the mechanism for improved MM-302 delivery involves the induction of tumor cell apoptosis, reduction of overall tumor cell density, substantial lowering of interstitial fluid pressure, and increasing vascular perfusion. The novel dosing strategy for cyclophosphamide described herein is readily translatable to standard clinical regimens, represents a potentially significant advance in addressing the drug delivery challenge, and may have broad applicability for nanomedicines. This work formed the basis for clinical evaluation of cyclophosphamide for improving liposome deposition as part of an ongoing phase I clinical trial of MM-302 in HER2-positive metastatic breast cancer.

Whole-body organ-level and kidney micro-dosimetric evaluations of (64)Cu-loaded HER2/ErbB2-targeted liposomal doxorubicin ((64)Cu-MM-302) in rodents and primates.

BACKGROUND: Features of the tumor microenvironment influence the efficacy of cancer nanotherapeutics. The ability to directly radiolabel nanotherapeutics offers a valuable translational tool to obtain biodistribution and tumor deposition data, testing the hypothesis that the extent of delivery predicts therapeutic outcome. In support of a first in-human clinical trial with (64)Cu-labeled HER2-targeted liposomal doxorubicin ((64)Cu-MM-302), a preclinical dosimetric analysis was performed. METHODS: Whole-body biodistribution and pharmacokinetic data were obtained in mice that received (64)Cu-MM-302 and used to estimate absorbed radiation doses in normal human organs. PET/CT imaging revealed non-uniform distribution of (64)Cu signal in mouse kidneys. Kidney micro-dosimetry analysis was performed in mice and squirrel monkeys, using a physiologically based pharmacokinetic model to estimate the full dynamics of the (64)Cu signal in monkeys. RESULTS: Organ-level dosimetric analysis of mice receiving (64)Cu-MM-302 indicated that the heart was the organ receiving the highest radiation absorbed dose, due to extended liposomal circulation. However, PET/CT imaging indicated that (64)Cu-MM-302 administration resulted in heterogeneous exposure in the kidney, with a focus of (64)Cu activity in the renal pelvis. This result was reproduced in primates. Kidney micro-dosimetry analysis illustrated that the renal pelvis was the maximum exposed tissue in mice and squirrel monkeys, due to the highly concentrated signal within the small renal pelvis surface area. CONCLUSIONS: This study was used to select a starting clinical radiation dose of (64)Cu-MM-302 for PET/CT in patients with advanced HER2-positive breast cancer. Organ-level dosimetry and kidney micro-dosimetry results predicted that a radiation dose of 400 MBq of (64)Cu-MM-302 should be acceptable in patients.

A gradient-loadable (64)Cu-chelator for quantifying tumor deposition kinetics of nanoliposomal therapeutics by positron emission tomography.

Effective drug delivery to tumors is a barrier to treatment with nanomedicines. Non-invasively tracking liposome biodistribution and tumor deposition in patients may provide insight into identifying patients that are well-suited for liposomal therapies. We describe a novel gradient-loadable chelator, 4-DEAP-ATSC, for incorporating (64)Cu into liposomal therapeutics for positron emission tomographic (PET). (64)Cu chelated to 4-DEAP-ATSC (>94%) was loaded into PEGylated liposomal doxorubicin (PLD) and HER2-targeted PLD (MM-302) with efficiencies >90%. (64)Cu-MM-302 was stable in human plasma for at least 48h. PET/CT imaging of xenografts injected with (64)Cu-MM-302 revealed biodistribution profiles that were quantitatively consistent with tissue-based analysis, and tumor (64)Cu positively correlated with liposomal drug deposition. This loading technique transforms liposomal therapeutics into theranostics and is currently being applied in a clinical trial (NCT01304797) to non-invasively quantify MM-302 tumor deposition, and evaluate its potential as a prognostic tool for predicting treatment outcome of nanomedicines.