WT1 Analog Peptide Vaccine in Patients With Multiple Myeloma Following Autologous Stem Cell Transplantation

Multiple Myeloma Clinical Trial

Official title: A Pilot Trial of a WT1 Analog Peptide Vaccine in Patients With Multiple Myeloma Following Autologous Stem Cell Transplantation

Status Active, not recruiting

Clinical Trial Summary

The purpose of this study is to see if the investigator can help the immune system to work against myeloma through the use/administration of a peptide vaccine (immunotherapy agent) directed against the Wilms Tumor 1 (WT1) protein called galinpepimut-S (or GPS, for brief). Because cancer is produced by the patient's own body, the immune system does not easily recognize and fight cancer cells. The immune system needs to be "trained" to do this; the latter goal is accomplished by using a vaccine consisting of selected fragments of the target antigen, in this case, WT1.

This disease has been selected for this study because the WT1 protein is often present in myeloma cells. WT1 is a gene that is involved in the normal development of kidneys and other organs. When the WT1 gene becomes abnormal, it can make proteins involved in the development of cancer, i.e., can acquire the properties of a true "oncogene". This study will determine whether the vaccine against the WT1 antigen (present in malignant plasmacytes) can cause an immune response which is safe, but also able to keep the myeloma from either coming back or progressing.

Clinical Trial Description

Key Features:

• This is a Phase 1/2 clinical study conducted in patients with newly diagnosed high-risk multiple myeloma to examine the effects of GPS immunotherapy on clinical and immunobiological indices. The study is titled "A Pilot Trial of a WT1 Analog Peptide Vaccine (Galinpepimut-S) in Patients With Multiple Myeloma Following Autologous Stem Cell Transplantation" and is designed as a single-arm, single-institution, open-label study.

Rationale:

• Overexpression of WT1 in multiple myeloma (MM) cells has been demonstrated by immunocytochemistry (IHC) and in HLA-A*0201 patients by staining with a high-affinity fully human IgG1 mAb (ESK1) specific to the RMFPNAPYL/HLA-A*0201 complex on malignant plasma cells. WT1 also serves as a target for antigen-specific directly immunizing immunotherapeutic approaches, such as peptide vaccines (in this case, galinpepimut-S), in patients with multiple myeloma. Patients with persistent plasma cell leukemia following CD34+-selected allografts treated with adoptive transfer of donor-derived WT1-specific cytotoxic T cells are capable of achieving long-lasting complete remission (CR) status, thus underscoring the therapeutic potential of activated T-cells specifically immunized against WT1 peptides. The above provide the theoretical basis for the possibility of successful immunization after exposure to a WT1-specific vaccine (such as galinpepimut-S), whereby WT1-sensitized T-lymphocytes (both CD8+ and CD4+) from vaccinated MM could be directed to antigen (WT1) expressed on malignant plasma cells.

Galinpepimut-S (GPS) - Key features:

• GPS is a tetravalent peptide vaccine, consisting of an equiweight mixture of 4 WT1-derived peptides which have been chosen to strengthen antigenicity, but also broaden immunogenicity over a wide range of HLA subtypes, being able to stimulate both CD8+ (MHC Class I)- and CD4+ (MHC Class II)-dependent responses. Of note, 2 of the 4 peptides are heteroclitic, i.e., carry by-design introduced missense mutations, in order to decrease tolerogenicity (as these modified peptides are no longer identified as "self" moieties by the vaccinated host's immune system. GPS contains one heteroclitic peptide (WT1-A1) to stimulate CD8+ responses, two longer native peptides (427 long and 331 long) to stimulate CD4+ responses and one longer heteroclitic peptide (122A1 long) that is capable of stimulating both CD8+ and CD4+ cells (with the CD8-activating shorter sequence/locus 'buried' with the lengthier CD4-activating one). Galinpepimut-S is always mixed in emulsion with the immunological adjuvant Montanide™ and is administered after granulocyte-macrophage colony-stimulating factor (GM-CSF; sargramostine; Leukine®) pre-stimulation.

Putative Mechanism of action (MOA) of galinpepimut-S in MM:

• Galinpepimut-S (GPS) is a peptide immunogen of the vaccine type, capable of inducing in the treated host WT1-specific antigenicity and eventual systemic immunogenicity against WT1-expressing deposits of cancerous cells. The above principles are applicable in MM patients treated with this immunotherapeutic. It is very likely that the antigen presenting cell (APC)-CD8-CD4 cross-activating circuits are markedly amplified in subjects receiving galinpepimut-S, leading to specific and direct immunization against WT1 and eventual killing of WT1-expressing malignant plasma cells via activated immunocytes (mainly lymphocytes and natural killer [NK] cells). This MOA represents a plausible model for the immunobiological basis of the observed clinical activity of galinpepimut-S against various tumor types (other than MM) tested to-date, and is poised to be applicable in MM as well. ;

Related Conditions & MeSH terms

• High-Risk Cancer
• Minimal Residual Disease
• Multiple Myeloma
• Neoplasm, Residual
• Neoplasms, Plasma Cell

• NCT number: NCT01827137
• Study type: Interventional
• Source: Sellas Life Sciences Group
• Status: Active, not recruiting
• Phase: N/A
• Start date: April 2013
• Completion date: August 2020