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We describe the large-scale, GMP-compliant production process of doxorubicin-loaded and anti-EGFR-coated immunoliposomes (anti-EGFR-ILs-dox) used in a first-in-man, dose escalation clinical trial. 10 batches of this nanoparticle have been produced in clean room facilities. Stability data from the pre-GMP and the GMP batch indicate that the anti-EGFR-ILs-dox nanoparticle was stable for at least 18 months after release. Release criteria included visual inspection, sterility testing, as well as measurements of pH (pH 5.0-7.0), doxorubicin HCl concentration (0.45-0.55 mg/ml), endotoxin concentration (<1.21 IU/ml), leakage (<10%), particle size (Z-average of Caelyx ± 20 nm), and particle uptake (uptake absolute: >0.50 ng doxorubicin/μg protein; uptake relatively to PLD: >5 fold). All batches fulfilled the defined release criteria, indicating a high reproducibility as well as batch-to-batch uniformity of the main physico-chemical features of the nanoparticles in the setting of the large-scale GMP process. In the clinical trial, 29 patients were treated with this nanoparticle between 2007 and 2010. Pharmacokinetic data of anti-EGFR-ILs-dox collected during the clinical study revealed stability of the nanocarrier in vivo. Thus, reliable and GMP-compliant production of anti-EGFR-targeted nanoparticles for clinical application is feasible., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: The role of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) in the treatment of patients with advanced non-small cell lung cancer (NSCLC) and unknown EGFR mutation status has recently been questioned., Patients and Methods: We conducted a retrospective study of patients with unknown EGFR mutation status and long-term response (LTR) to gefitinib in the Swiss Iressa expanded access program (EAP). We assessed patient characteristics, and performed Sanger sequencing and next generation sequencing on archived tumor tissue. We hypothesized that EGFR mutations are prevalent in patients with LTR., Results: Of 430 patients in the EAP, 18 (4%) fulfilled our definition of LTR, and 16 of them had archived tumor tissue. Patient characteristics were as expected for age, sex, and smoking history. Median duration of therapy was 38 months (range 24-142 months). Sanger sequencing revealed EGFR exon 18-21 mutations in 6 (38%) of the tumors. Next generation sequencing revealed no further EGFR-mutated cases, but reported in 15 (94%) of the tumors mutations in other genes (ALK, BRAF, DDR2, KEAP1, MET, PTEN, STK11) previously associated with NSCLC., Conclusion: Larger studies are needed to define the prognostic values of different driver mutations in patients with NSCLC., (© 2015 S. Karger GmbH, Freiburg.)

Background: Results of preclinical studies have shown that EGFR immunoliposomes have substantial antitumour effects. We aimed to assess the tolerability, safety, pharmokinetics, and efficacy of anti-EGFR immunoliposomes loaded with doxorubicin (anti-EGFR ILs-dox) in patients with solid tumours., Methods: In this first-in-man, open-label, phase 1 clinical study, we enrolled patients at University Hospital of Basel, Switzerland, who had EGFR-overexpressing advanced solid tumours no longer amenable to standard treatment. Anti-EGFR ILs-dox nanoparticles were constructed by covalently linking pegylated liposomes containing doxorubicin to antigen-binding fragments (Fab') of cetuximab. We intravenously infused the nanoparticle at escalating doses (doxorubicin 5 mg/m(2), 10 mg/m(2), 20 mg/m(2), 30 mg/m(2), 40 mg/m(2), 50 mg/m(2), and 60 mg/m(2)) once every 4 weeks for a maximum of six cycles. The primary endpoint was to establish the maximum tolerated dose. We analysed patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT01702129., Findings: Between Jan 30, 2007, and March 4, 2010, we gave the drug to 29 patients, three of whom were withdrawn from the study because we could not complete a safety assessment. Of the 26 patients assessed for the primary endpoint, two who received a dose of 60 mg/m(2) had dose-limiting toxicities (one had neutropenia and the other had anaemia); therefore, the maximum tolerated dose was defined as 50 mg/m(2). At all lower doses, anti-EGFR ILs-dox was well tolerated; grade 1 skin toxicity occurred in two patients only. We recorded 22 serious adverse events (SAEs) in 17 patients, mostly due to tumour progression. Three SAEs were fatal. Only three SAEs (febrile neutropenia, septicaemia, and a fatal massive oral bleed) were probably or possibly related to study drug. No patients had palmar-plantar erythrodysaesthesia, alopecia, cardiotoxicity, or cumulative toxicity. Best response to treatment included one complete response, one partial response, and ten stable disease lasting 2-12 months (median 5·75 months)., Interpretation: Because anti-EGFR ILs-dox was well tolerated up to 50 mg doxorubicin per m(2), and we recorded clinical activity, further assessment of this nanoparticle at this dose in phase 2 trials is warranted., Funding: Cancer League Basel, Swiss Cancer League, Schoenmakers-Müller Foundation, and Werner Geissberger Foundation., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Immunoliposomes (ILs) can be constructed to target the epidermal growth factor receptor (EGFR) to provide efficient intracellular drug delivery in tumor cells. We hypothesized that this approach might be able to overcome drug resistance mechanisms, which remain an important obstacle to better outcomes in cancer therapy. ILs were evaluated in vitro and in vivo against EGFR-overexpressing pairs of human cancer cells (HT-29 and MDA-MB-231) that either lack or feature the multidrug resistance (mdr) phenotype. In multidrug-resistant cell lines, ILs loaded with doxorubicin (DOX) produced 19-216-fold greater cytotoxicity than free DOX, whereas in nonresistant cells, immunoliposomal cytotoxicity of DOX was comparable with that of the free drug. In intracellular distribution studies, free DOX was efficiently pumped out of the multidrug-resistant tumor cells, whereas immunoliposomal DOX leads to 3.5-8 times higher accumulation of DOX in the cytoplasm and 3.5-4.9 times in the nuclei compared with the free drug. Finally, in vivo studies in the MDA-MB-231 Vb100 xenograft model confirmed the ability of anti-EGFR ILs-DOX to efficiently target multidrug-resistant cells and showed impressive antitumor effects, clearly superior to all other treatments. In conclusion, ILs provide efficient and targeted drug delivery to EGFR-overexpressing tumor cells and are capable of completely reversing the multidrug-resistant phenotype of human cancer cells.

We hypothesized that immunoliposomes (ILs) constructed using Fab' from the humanized anti-EGFR monoclonal antibody, EMD72000, can provide efficient intracellular drug delivery in EGFR-overexpressing colorectal tumor cells.ILs were constructed modularly with various MAb fragments, including Fab' from EMD72000 (matuzumab) or C225 (cetuximab, Erbitux) covalently linked to stabilized liposomes containing chemotherapeutic drugs or probes. Immunoliposome preparation was optimized, including Fab' reduction and linkage, and evaluated for specific binding and cytotoxicity in epidermal growth factor receptor (EGFR)--overexpressing colorectal cancer cell lines in vitro. Flow cytometry showed that EGFR-targeted ILs, but not non-targeted liposomes or irrelevant ILs, were efficiently bound and internalized by a variety of EGFR-overexpressing colorectal cancer cells. Linkage of the Fab' to a longer PEG chain (Mal-PEG3400-DSPE) resulted in an increased uptake of immunoliposomal constructs when compared to previously used materials (Mal-PEG2000-DSPE). ILs derived from EMD72000-Fab' were used to deliver doxorubicin to EGFR-overexpressing target cells in vitro. Immunoliposomal doxorubicin was significantly more cytotoxic than the corresponding non-targeted liposomal drug in target cells, such as HCT116, while equivalent in cells lacking EGFR-overexpression, such as Colo205. We conclude that EGFR-targeted ILs derived from the humanized MAb EMD72000 provide efficient and targeted delivery of anticancer drugs in colorectal cancer cells overexpressing EGFR.

The epidermal growth factor receptor (EGFR) is commonly overexpressed in a variety of solid tumours, and clinical trials indicate that this antigen has important roles in cancer aetiology and progression. EGFR thus provides a rational target for cancer therapies and a number of strategies influencing this receptor, and its downstream signal cascades, including monoclonal antibodies, tyrosine-kinase inhibitors, antisense oligonucleotides inhibiting EGFR synthesis and antibody-based immunoconjugates, have been evaluated. In particular, monoclonal antibodies targeting the receptor's extracellular domain and small molecules blocking tyrosine-kinase activation intracellularly have already shown some activity in clinical phase I-III trials. These two major classes of anti-EGFR therapeutics will be the main topic of this review. In the case of tyrosine-kinase inhibitors, amplification, high polysomy of the EGFR gene, high protein expression and mutations of the receptor were found to be significantly associated with better response to such treatment. However, many questions remain unanswered and future issues in the development of EGFR inhibitors will include the identification of biological predictors of response, combination with other therapies and also their use in earlier stages of cancer.

We previously reported the development of epidermal growth factor receptor (EGFR)-targeted immunoliposomes that bind and internalize in tumor cells which overexpress EGFR and/or mutant EGFR variant III (EGFRvIII), enabling intracellular delivery of potent anticancer agents in vitro. We now describe in vivo proof-of-concept for this approach for the delivery of multiple anticancer drugs in EGFR-overexpressing tumor models. Anti-EGFR immunoliposomes were constructed modularly with Fab' fragments of cetuximab (IMC-C225), covalently linked to liposomes containing probes and/or anticancer drugs. Pharmacokinetic and biodistribution studies confirmed long circulation times (t(1/2) = 21 hours) and efficient accumulation in tumors (up to 15% ID/g) irrespective of the presence of the targeting ligand. Although total accumulations of anti-EGFR immunoliposomes and nontargeted liposomes in EGFR-overexpressing tumors were comparable, only immunoliposomes internalized extensively within tumor cells (92% of analyzed cells versus <5% for nontargeted liposomes), indicating different mechanisms of delivery at the cellular level. In vivo therapy studies in a series of xenograft models featuring overexpression of EGFR and/or EGFRvIII showed the superiority of immunoliposomal delivery of encapsulated drugs, which included doxorubicin, epirubicin, and vinorelbine. For each of these drugs, anti-EGFR immunoliposome delivery showed significant antitumor effects and was significantly superior to all other treatments, including the corresponding free or liposomal drug (P < 0.001-0.003). We conclude that anti-EGFR immunoliposomes provide efficient and targeted drug delivery of anticancer compounds and may represent a useful new treatment approach for tumors that overexpress the EGFR.

We hypothesized that immunoliposomes (ILs) that target epidermal growth factor receptor (EGFR) and/or its truncated variant EGFRvIII can be constructed to provide efficient intracellular drug delivery in tumor cells overexpressing these receptors. Monoclonal antibody fragments included Fab' fragments derived from C225, which binds both EGFR and EGFRvIII, or novel anti-EGFR scFv C10, which binds EGFR only. Monoclonal antibody fragments were covalently linked to liposomes containing various reporters or drugs. ILs were evaluated for specific binding, internalization, and cytotoxicity in EGFR/EGFRvIII-overexpressing cell lines in vitro. Flow cytometry and fluorescence microscopy showed that EGFR-targeted ILs, but not nontargeted liposomes or irrelevant ILs, were efficiently bound and internalized by EGFR-overexpressing cells, including glioma cells (U-87), carcinoma cells (A-431 and MDA-MB-468), and EGFRvIII stable transfectants (NR-6M). Furthermore, EGFR-targeted ILs did not bind to non-EGFR-overexpressing cells (MCF-7 and parental NR-6). ILs showed 3 orders of magnitude greater accumulation in NR-6-EGFRvIII stable transfectants versus parental NR-6 cells. Quantitative internalization studies indicated binding of EGFR-targeted ILs to target cells within 5 min, followed by intracellular accumulation beginning at 15 min; total uptake reached approximately 13,000 ILs/cell. ILs were used to deliver cytotoxic drugs doxorubicin, vinorelbine, or methotrexate to EGFR/EGFRvIII-overexpressing target cells in vitro. In each case, the IL agent was significantly more cytotoxic than the corresponding nontargeted liposomal drug in target cells, whereas it was equivalent in cells lacking EGFR/EGFRvIII overexpression. We conclude that EGFR-targeted ILs provide efficient and targeted delivery of anticancer drugs in cells overexpressing EGFR or EGFRvIII.