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

Abstract

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.

©2017 American Association for Cancer Research.

Figures

Fig. 1.. Biodistribution of 64Cu-MM-302 in patients.

Maximum-intensity-projection PET images of two patients with HER2-positive breast cancer injected with 30 mg/m2 of MM-302 and a tracer dose of 64Cu-MM-302 (400 MBq). PET/CT Images were acquired at (A) 0.6 and 19 h post-injection in Patient 02, and (B) 0.7, 24, and 47 h post-injection in Patient 06. Immediately post-administration, 64Cu-MM-302 activity was primarily confined in the blood pool because of the extended circulation property of liposomes. On Days 2 and 3, 64Cu-MM-302 uptake was evident in normal spleen and liver, as well as in various tumor lesions.

Fig. 2.. Tissue deposition kinetics of 64Cu-MM-302.

Image-based quantification of 64Cu-MM-302 normal tissue deposition kinetics in HER2-positive breast cancer patients. A spherical ROI was drawn in normal tissues on the PET/CT images to obtain SUVmedian for (A) liver, (B) spleen, (C) muscle (quadriceps), (D) lung, (E) bone marrow, and (F) aorta (blood). Deposition of 64Cu-MM-302 is expressed as percentage of injected dose per kilogram of tissue (%ID/kg) and is decay corrected. (G) Circulation half-life of 64Cu-MM-302 for individual patients was fit with a one-compartment model. The shaded area represents t1/2 (geometric mean, with 95% CI) obtained from Phase 1 MM-302 PK study by measuring doxorubicin content in the patient plasma at 30 mg/m2. Closed and open symbols represent patient data in Arm 3 (no cyclophosphamide) and Arm 4 (with cyclophosphamide) of the Phase 1 study, respectively.

Fig. 3.. Visualization of 64Cu-MM-302 lesion deposition.

Representative PET and fused PET/CT images of 64Cu-MM-302 in lesions at different anatomical locations. Intensity scale bars represent deposition from 0 to 10 %ID/kg (derived from SUVmedian). The regions of interest used to measure tumor deposition of 64Cu-MM-302 are shown in blue or turquoise outlines. 64Cu-MM-302 uptake was detected at above muscle background level in lesions of various anatomical locations that are common for HER2-positive metastatic diseases.

Fig. 4.. Quantification of 64Cu-MM-302 uptake in tumor lesions.

(A) Lesion uptake of 64Cu-MM-302 in patients on Days 2 and 3 in patients treated with (open square) and without (closed circle) cyclophosphamide (cyclo). No significant difference in lesion deposition was observed between the two treatment groups (p ≥ 0.67, Mann-Whitney test). (B)64Cu-MM-302 deposition kinetics in all patient lesions illustrating accumulation of MM-302 in lesions from Day 1 to 3. Statistical difference in lesion uptake was only detectable from Day 1 (p < 0.0001, ANOVA), but not between Days 2 and 3 (p > 0.67). (C) Tumor deposition of 64Cu-MM-302 in individual patients was shown to be highly variable. No correlation of tumor deposition was detected with (D) blood exposure or (E) tumor size. (F)64Cu-MM-302 deposition in lesions of different anatomical locations. Panels (C–F) include data obtained on Day 2, or Day 3 if patient did not undergo PET scan on Day 2.

Fig. 5.. Kinetics of 64Cu-MM-302 deposition in tumor lesions.

Lesion deposition kinetics of 64Cu-MM-302 in a HER2-positive breast cancer patient who received 3 PET/CT scans at 0.7 h, 24 h, and 47 h post-injection (Patient 06). (A) Lesion deposition for each ROI is expressed as %ID/kg derived from SUVmedian (decay-corrected). (B) Sagittal view of PET images illustrating deposition in ROI 3 (chest wall mass) and ROI 4 (left cervical lymph node). (C) Schematic diagram of PK model describing 64Cu-MM-302 transport kinetics post-injection. (D) Blood and lesion deposition data fit to the model described in (C), illustrating 64Cu signal contribution kinetics from tumor vascular vs. tumor tissue compartments at 0 to 168 h post-injection.

Fig. 6.. Patient treatment outcome stratified by deposition of lowest uptake lesion.

(A)64Cu-MM-302 lesion deposition of the lowest uptake lesion within each patient from Days 2 or 3 are shown and aligned in ascending order. A deposition threshold was selected based on the inflection point of the deposition graph and confirmed by ROC analysis, where patients to the left of the inflection point were designated as “low uptake” group. The inset figures illustrate the percentage of patients with >1 lesion that are below or above the cutoff (top inset), and percentage of lesions that are below or above the cutoff (bottom inset). PFS of the imaged patients are shown in (B), where “low uptake” patients are depicted with orange striped bars, and “high uptake” patients are depicted with black solid bars. The best overall response per RECIST v1.1 criteria was captured in (C) stratified into the “low uptake” and “high uptake” groups, where PR, SD, and PD represent partial response, stable disease, and progressive disease, respectively. (D) Patient PFS of the high vs. low uptake patients were shown in a Kaplan-Meier curve.