Phase 1 Trial of Intranodal Injection of a Melan-A/MART-1 DNA Plasmid Vaccine in Patients With Stage IV Melanoma

Abstract

Nineteen patients with stage IV melanoma were treated in an escalating dose, phase 1 trial of a DNA plasmid vaccine pSEM. The plasmid encoded T-cell epitopes from differentiation antigens Melan-A/melanoma antigen recognized by T cells (MART)-1 and tyrosinase, encompassing amino acids 26-35 and 31-70 from Melan-A/MART-1, and 1-9 as well as 369-377 from tyrosinase. End points of the trial were safety, tolerability, and melanoma antigen-specific immunity by tetramer assay. Intralymph nodal infusions of the vaccine were given 4 times, every 2 weeks over 96 hours each to groin lymph nodes. Vaccine doses were 500, 1000, and 1500 microg of DNA per infusion. Disease evaluation was performed 8 weeks after treatment initiation. The vaccine was well tolerated, with only grade I/II toxicity observed and no dose limiting toxicity at the highest dose of 1500 microg per infusion. Immune response defined prospectively was seen in 4/19 patients, and 5/19 had evidence of preexisting immunity to Melan-A/MART-1. No immune responses to tyrosinase was seen. There was a correlation between time to progression (TTP) and Melan-A/MART-1 immunity (preexisting or induced) for all patients. There was no association between TTP and immune competence assayed by ex vivo polyclonal stimulation of peripheral blood mononuclear cells. No clinical responses were seen. DNA plasmid pSEM vaccine was well tolerated when administered intranodally by 96-hour infusion to patients with stage IV melanoma, and was immunogenic, but did not induce regression of established disease. The association of TTP with preexisting or induced Melan-A immunity supports future attempts to induce potent immunity to this antigen.

Multivalent immunity targeting tumor-associated antigens by intra-lymph node DNA-prime, peptide-boost vaccination

“…Although the preclinical immunogenicity of this approach was superior to immunization using conventional means, 22 the immunological and clinical effects in humans were quite limited. 20,21 More recently, we showed in a preclinical model that an epitope-specific peptide boost after DNA vaccination achieved a significant amplification of the immune response elicited by plasmid. 27 In addition, substantial immune responses achieved through intra-lymph node immunization with peptide and a TLR agonist were a prerequisite for effective control of tumor progression in immune-competent mice.…”

“…18,19 Previously, in an attempt to improve on the in vivo generation and amplification of TAA-specific T cells, we clinically evaluated the intra-lymph node administration of two individual plasmids encompassing either MART-1/Melan-A or tyrosinase antigen fragments in stage-III and IV melanoma patients with measurable disease. [20][21][22] Nevertheless, despite an apparent correlation between immunity and clinical outcome (as measured by time to progression), 20 there were no objective clinical responses (defined by RECIST criteria) in any of these phase-I trials. Evidence from preclinical 23 and clinical studies, especially those involving adoptive T-cell therapy, 9,10 suggested that a robust, continuous presence of TAAspecific T cells with minimal interference by immune inhibitory mechanisms was a prerequisite for an objective tumor response.…”

“…The plasmid was originally referred to as pSEM and described previously. 20 The pNYE-SSX plasmid (Figure 1a) contains cDNA encoding multiple copies of NY-ESO-1 157-165 (SLLMWITQV) and SSX2 (KASEKIFYV) epitopes along with other antigen fragments from NY-ESO-1. The peptides used in this study were E-MEL (MART-1/ Melan-A 26-35 A27Nva, ENvaAGIGILTV); 28 E-TYR (tyrosinase 369-377 V377Nva, YMDGTMSQNva); E-NYE (NY-ESO-1 157-165 L158Nva C165V, SNvaLM-WITQV) and E-SSX (SSX2 41-49 A42 V, KVSEKIFYV) (Figure 1b), designed to bind with higher affinity or more stably to MHC class-I, as compared with the native epitopes (Supplementary Table 1).…”

In situ engineering of the lymph node microenvironment via intranodal injection of adjuvant-releasing polymer particles

“…We note that the clinical feasibility of LN injections in humans is well established from a number of clinical trials (2,8,9), and safe, injectable biomaterials are available that can encapsulate both small molecule and macromolecular cargos. These factors make the approach described here attractive as a general strategy for engineering the LN microenvironment not only for vaccination but also for therapeutic contexts, such as cancer immunotherapy or immunomodulation for allergy or autoimmune disorders.…”

“…Studies have demonstrated as much as 10 6 -fold reductions in antigen dose (5,6), 100-fold reductions in adjuvant dose (7), and enhanced protection with reduced side effects relative to traditional parenteral immunizations (2). Lymph node injection in humans is readily performed using ultrasound guidance, and the promise of i.LN vaccination has been demonstrated in recent clinical trials (2,8,9).…”