Targeting immunoliposomes to EGFR-positive glioblastoma

Abstract

Background: We assessed the capacity of epidermal growth factor receptor (EGFR)-targeted immunoliposomes to deliver cargo to brain tumor tissue in patients with relapsed glioblastoma harboring an EGFR amplification. We aimed to assess the tolerability and effectiveness of anti-EGFR immunoliposomes loaded with doxorubicin (anti-EGFR ILs-dox) in glioblastoma multiforme patients.

Patients and methods: Patients with EGFR-amplified, relapsed glioblastoma were included in this phase I pharmacokinetic trial. Patients received up to four cycles of anti-EGFR ILs-dox. Twenty-four hours later, plasma and cerebrospinal fluid (CSF) samples were obtained. In addition, we also treated three patients with anti-EGFR ILs-dox before resection of their relapsed glioblastoma. Doxorubicin concentrations were measured in plasma, CSF, and tumor tissue. Safety and efficacy parameters were also obtained.

Results: There were no or negligible levels of doxorubicin found in the CSF demonstrating that anti-EGFR ILs-dox are not able to cross the blood-brain barrier (BBB). However, significant levels were detected in glioblastoma tissue 24 h after the application, indicating that the disruption of BBB integrity present in high-grade gliomas might enable liposome delivery into tumor tissue. No new safety issues were observed. The median progression-free survival was 1.5 months and the median overall survival was 8 months. One patient undergoing surgery had a very long remission suggesting that neoadjuvant administration may have a positive effect on outcome.

Conclusions: We clearly demonstrate that anti-EGFR-immunoliposomes can be targeted to EGFR-amplified glioblastoma and cargo-in this case doxorubicin-can be delivered, although these immunoliposomes do not cross the intact BBB. (The GBM-LIPO trial was registered as NCT03603379).

Keywords: blood–brain barrier; cerebrospinal fluid; nanomedicine; pharmacokinetic; targeted therapy.

Figure 1

Recurrent tumor biopsies. Top row: Hematoxylin–eosin (H&E)-stained formalin-fixed tissue; note that B1811381 has cryoartifacts. B1726325 has low levels of residual tumor cells in this biopsy. Bottom row: Anti-epidermal growth factor receptor (EGFR) staining. Black bars represent 20 μm.

Figure 2

Visualization of immune cell types in glioblastoma tissue sections of patients after treatment with anti-epidermal growth factor receptor immunoliposomes loaded with doxorubicin (anti-EGFR ILs-dox). (A) Representative mass cytometric images for patient 2 (left), patient 3 (center), and patient 5 (right) are shown. (B) Quantification of different cell populations including macrophages (CD68 cells), cytotoxic lymphocytes (GranzB), and proliferating cells (Ki67). Frequencies were determined as percentage of total cells. Differences were statistically analyzed by one-way analysis of variance testing. ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001. ns, not significant.