1. Trial to evaluate the immunogenicity and safety of a melanoma helper peptide vaccine plus incomplete Freund's adjuvant, cyclophosphamide, and polyICLC (Mel63).
- Author
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Slingluff CL Jr, Petroni GR, Chianese-Bullock KA, Wages NA, Olson WC, Smith KT, Haden K, Dengel LT, Dickinson A, Reed C, Gaughan EM, Grosh WW, Kaur V, Varhegyi N, Smolkin M, Galeassi NV, Deacon D, and Hall EH
- Subjects
- Administration, Metronomic, Administration, Oral, Antibodies blood, CD4-Positive T-Lymphocytes metabolism, Cancer Vaccines administration & dosage, Cancer Vaccines adverse effects, Cancer Vaccines immunology, Carboxymethylcellulose Sodium administration & dosage, Carboxymethylcellulose Sodium adverse effects, Combined Modality Therapy, Cyclophosphamide adverse effects, Female, Freund's Adjuvant adverse effects, Humans, Lipids adverse effects, Male, Melanoma immunology, Melanoma pathology, Neoplasm Staging, Poly I-C adverse effects, Polylysine administration & dosage, Polylysine adverse effects, T-Lymphocytes, Regulatory metabolism, Treatment Outcome, Vaccines, Subunit adverse effects, Vaccines, Subunit immunology, Carboxymethylcellulose Sodium analogs & derivatives, Cyclophosphamide administration & dosage, Freund's Adjuvant administration & dosage, Lipids administration & dosage, Melanoma drug therapy, Poly I-C administration & dosage, Polylysine analogs & derivatives, Vaccines, Subunit administration & dosage
- Abstract
Background: Peptide vaccines designed to stimulate melanoma-reactive CD4
+ T cells can induce T cell and antibody (Ab) responses, associated with enhanced overall survival. We hypothesized that adding toll-like receptor 3 agonist polyICLC to an incomplete Freund's adjuvant (IFA) would be safe and would support strong, durable CD4+ T cell and Ab responses. We also hypothesized that oral low-dose metronomic cyclophosphamide (mCy) would be safe, would reduce circulating regulatory T cells (T-regs) and would further enhance immunogenicity., Participants and Methods: An adaptive design based on toxicity and durable CD4+ T cell immune response (dRsp) was used to assign participants with resected stage IIA-IV melanoma to one of four study regimens. The regimens included a vaccine comprising six melanoma peptides restricted by Class II MHC (6MHP) in an emulsion with IFA alone (Arm A), with IFA plus systemic mCy (Arm B), with IFA+ local polyICLC (Arm C), or with IFA+ polyICLC+ mCy (Arm D). Toxicities were recorded (CTCAE V.4.03). T cell responses were measured by interferon γ ELIspot assay ex vivo. Serum Ab responses to 6MHP were measured by ELISA. Circulating T-regs were assessed by flow cytometry., Results: Forty-eight eligible participants were enrolled and treated. Early data on safety and dRsp favored enrollment on arm D. Total enrollment on Arms A-D were 3, 7, 6, and 32, respectively. Treatment-related dose-limiting toxicities (DLTs) were observed in 1/7 (14%) participants on arm B and 2/32 (6%) on arm D. None exceeded the 25% DLT threshold for early closure to enrollment for any arm. Strong durable T cell responses to 6MHP were detected ex vivo in 0%, 29%, 67%, and 47% of participants on arms A-D, respectively. IgG Ab responses were greatest for arms C and D. Circulating T-regs frequencies were not altered by mCy., Conclusions: 6MHP vaccines administered with IFA, polyICLC, and mCy were well tolerated. The dRsp rate for arm D of 47% (90% CI 32 to 63) exceeded the 18% (90% CI 11 to 26) rate previously observed with 6MHP in IFA alone. Vaccination with IFA+ polyICLC (arm C) also showed promise for enhancing T cell and Ab responses., Competing Interests: Competing interests: CLS has the following disclosures: Research support to the University of Virginia from Celldex (funding, drug), Glaxo-Smith Kline (funding), Merck (funding, drug), 3M (drug), Theraclion (device staff support); Funding to the University of Virginia from Polynoma for PI role on the MAVIS Clinical Trial; funding to the University of Virginia for roles on Scientific Advisory Boards for Immatics and CureVac. Also CLS receives licensing fee payments through the UVA Licensing and Ventures Group for patents for peptides used in cancer vaccines., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.)- Published
- 2021
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