Intradermal naked DNA vaccination for mounting tumor-specific immunity in stage IV melanoma patients: a phase I clinical study

Advanced-stage melanoma has a very poor prognosis. With standard chemotherapy
consisting of single agent dacarbazine or DTIC an objective response rate of
10-15% can be achieved, very few of which are durable. Hence, the need for
novel treatment strategies is high, and most strategies being developed aim to
raise melanoma-specific T cell immunity. Naked DNA vaccination appears to be a
powerful and safe strategy to mount antigen-specific cellular immunity.
Recently, we have developed a novel intradermal DNA delivery strategy. We make
use of a permanent make-up or tattoo device to inject a DNA vaccine into the
skin through thousands of skin punctures. This strategy has been developed in a
mouse model and validated in a non-human primate model.
Patients with disease progression upon standard chemotherapy will be asked to
participate in this phase I clinical trial. The DNA vaccine encodes a fusion
protein of the non-toxic domain 1 of tetanus toxin fragment c and the MART-1
epitope (ELAGIGILTV) under the CMV early promoter.

Objective:
Primary objective:
1.) To study the toxicity of naked DNA vaccines encoding CD8+ T cell epitope
from melanosomal antigen MART-1 genetically linked to the gene encoding domain
1 of tetanus toxin subunit C by dose escalation in advanced-stage melanoma
patients with disease progression upon standard chemotherapy.
2.) To study the toxicity of a novel intradermal application strategy
employing a permanent make-up or tattoo device.

Secondary objective:
1.) To study the efficacy of this naked DNA vaccine in inducing tumor-specific
T cell immunity as measured by accumulation of MART-1-specific T cells at the
vaccination site in skin biopsies and MHC tetramer staining of peripheral blood
T cells.
2.) To study objective clinical responses
3.) To measure PFS and OS

Study design: Dose escalating phase I clinical trial
Dose levels: 0.5 mg; 1 mg; 2 mg; 4 mg

Intervention: Intradermal DNA vaccine delivery by permanent make-up device on
days 1, 3, and 6 and boost vaccination 4 weeks later.

Nature and extent of the burden and risks associated with participation,
benefit and group relatedness: Eligible (HLA-A2+) patients will undergo a tumor
biopsy to reveal expression of MART-1 and HLA class I by tumor cells. If
present patients will receive intradermal DNA vaccination on days 0, 3, and 6,
and boost vaccinations after 4 weeks (days 28, 31, and 34). At time points 1,
3, 4, 6, 8, 9, 12, 16 weeks patients will be seen at the outpatient clinic
including physical examination and evaluation of toxicity. Blood and urine
samples will be taken and frozen for analyses. Prior to vaccination, at t=14
days and t=42 days a skin biopsy will be taken from the vaccination site, and
at day 42 also from a non-vaccination site.
For this group of patients no standard treatment exists. Their median life
expectancy is less than 6 months. Vaccination using melanoma antigens is being
studied extensively worldwide and is in general non-toxic. DNA vaccination is
considered a safe mode of vaccination. The vaccine that is being used in this
clinical trial does not contain factors favoring integration, nor does it
contain sequences that can lead to replication, or that can become part of
viruses or bacteria. Preclinical data show that intradermal DNA vaccination
using a permanent make-up device is much more potent than classic intramuscular
DNA vaccination. Tattooing of skin is a commonly used method for treatment of
scars or as part of reconstructive surgery (nipple tattooing after breast
reconstructive surgery for breast cancer patients). It may induce a burning
sensation during tattooing, which will stop the moment the tattooing is ended.
Using this method DNA will be applied intra-epidermally (in the epidermis),
therewith limiting spread to other tissues (in contrast to intramuscular of
intravenous delivery). We therefore consider the physical discomfort associated
with participation in this study as mild. As for participation in any phase I
clinical study the intensity of site visits, physical exams, blood tests and
other tests, is not different in this study.