showing multiple myeloma
Bone marrow smear
The US Food and Drug Administration (FDA) has granted fast track designation to the cancer vaccine galinpepimut-S (GPS) for the treatment of multiple myeloma (MM).
GPS consists of 4 modified peptide chains that induce an innate immune response (CD4+/CD8+ T cells) against the Wilms’ tumor 1 (WT1) antigen.
GPS is administered in combination with an adjuvant and an immune modulator to improve the immune response to the target.
GPS has been tested in a phase 2 trial of patients with MM. Results from this trial were presented at the 44th Annual Meeting of the EBMT in March.
Phase 2 trial
The study enrolled 19 MM patients. Fifteen of them had high-risk cytogenetics at diagnosis, and 18 were at least minimal residual disease-positive after autologous stem cell transplant (ASCT).
Patients began receiving GPS within 22 days of ASCT. Initially, they received 6 doses (administered subcutaneously with the oil emulsifier montanide) every 2 weeks. Injection sites were pre-stimulated with granulocyte-macrophage colony-stimulating factor (70 μg) on days -2 (± 1 day) and 0 of each GPS vaccination.
The patients underwent assessment 2 to 4 weeks after the 6th GPS dose. Then, they received 6 additional monthly doses of GPS in conjunction with lenalidomide maintenance (10 mg daily), starting on day 100 post-ASCT. Patients were assessed 2 to 4 weeks after the 12th GPS dose.
The researchers found that GPS stimulated time-dependent CD4+ or CD8+ T-cell immune responses specific for all 4 WT1 peptides within GPS, 2 of which are heteroclitic.
Immune responses were confirmed in up to 91% of patients, with multivalent immune responses in up to 64% of patients. Three-quarters of patients had multifunctional cross-epitope T-cell reactivity to antigenic epitopes against which the hosts were not specifically immunized, in a pattern akin to epitope spreading.
In patients who received all 12 doses of GPS (n=12), there was a “strong” association between clinical benefit—defined as complete response (CR) or very good partial response (VGPR)—and frequency of CD4/CD8 immune responses.
Of those patients who had achieved CR/VGPR upon completion of GPS treatment, 100% (n=11) had CD4 immune responses, and 81.8% (n=9) had CD8 immune responses.
The median progression-free survival was 23.6 months, and the median overall survival was not reached. At 18 months, the rate of progression-free survival was 62%, and the rate of overall survival was 88%.
About fast track designation
The FDA’s fast track development program is designed to expedite clinical development and submission of applications for products with the potential to treat serious or life-threatening conditions and address unmet medical needs.
Fast track designation facilitates frequent interactions with the FDA review team, including meetings to discuss the product’s development plan and written communications about issues such as trial design and use of biomarkers.
Products that receive fast track designation may be eligible for accelerated approval and priority review if relevant criteria are met. Such products may also be eligible for rolling review, which allows a developer to submit individual sections of a product’s application for review as they are ready, rather than waiting until all sections are complete.