Anti-EGFR Immunoliposomes in Solid Tumors

C225-ILS-DOX

This is a phase 1 trial of anti-EGFR-immunoliposomes, an investigative nanoparticle targeted against EGFR-overexpressing tumor cells. The investigators have constructed anti-EGFR immunoliposomes by using Fab' fragments of the chimeric MAb cetuximab (C225, cetuximab, erbitux™, ImClone Systems Corp., NY, USA; Merck KGaA, Darmstadt, Germany), which were covalently conjugated to the liposome membrane. This approach was designed to provide maximal drug delivery to cancer cells via a receptor-targeted and internalizing drug carrier that is stable, non-immunogenic, long-lived with extended blood and tissue residence times and capable of delivering large payloads of diverse types of drugs.

Based on extensive preclinical studies, the investigators decided to perform a first-in-human clinical trial in patients with EGFR-overexpressing solid tumors who have already received all available standard treatments. The therapeutic compound tested in the trial is C225-ILs-dox, a doxorubicin-loaded anti-EGFR-immunoliposome. Doxorubicin is one of the most active agents in many human tumors, and a high percentage of these malignancies do express EGFR. Therefore, the targeting of doxorubicin to EGFR-expressing tumors via the EGFR-specific antibody C225 should enhance the specificity and efficacy of chemotherapy, while the encapsulation of the cytotoxic drug within pegylated liposomes should at the same time decrease its toxicity.

This is a single center, open study. The aim of the trial is the definition of the maximum tolerated dose (MTD) for future phase 2 studies. Secondary endpoints include the overall response rate, the time-to-progression and the assessment of the pharmakokinetic of the compound. The trials follows a canonical 3+3 design and allows an additional recruitment of up to 6 patients on the dose level defined as the MTD. Planned dose levels are as follows:

Level 1 = 5 mg/m2 Level 2 = 10 mg/m2 Level 3 = 20 mg/m2 Level 4 = 30 mg/m2 Level 5 = 40 mg/m2 Level 6 = 50 mg/m2 Level 7 = 60 mg/m2 Level 8 = 70 mg/m2 Level 9 = 80 mg/m2

At each dose level, 3 patients may be enrolled simultaneously. Escalation to the next higher dose will be allowed after patient 3 of a given dose level has received at least one full cycle of therapy if no dose limiting toxicity (DLT) occured at a given dose level. The decision to enter a next dose level will be made by the study team after reviewing all available toxicity data of the previous groups. A DLT is defined as any grade 4 toxicity, any grade 3 toxicity lasting more than one week or/and febrile neutropenia grade 3 (defined as neutrophils < 1.0 x 10e9/l and fever > 38.5 °C). Nausea, vomiting, anorexia, and alopecia (grade 2) will be excluded as dose limiting toxicities. Similarly, adverse events that are clearly related to the primary tumor, such as progression of disease will not be considered as DLTs. In addition, preexisting toxicities must be taken into account when defining and analyzing DLTs.

Patients will be treated until disease progression but for a maximum of 6 cycles. Patients having completed the treatment phase (24 weeks) and showing complete or partial response as well as stable disease will enter the observation phase of the study. This phase will end 12 months after the last patient has been included. At any time during treatment phase or observation phase, patients with signs of disease progression according to RECIST criteria for reporting results of cancer treatment or having discontinued treatment due to unacceptable toxicity will go off study and be treated at the investigator's discretion.