Craig L Slingluff, University of Virginia School of Medicine
Karl D Lewis, University of Colorado
Robert Andtbacka, Huntsman Cancer Institute Cancer Hospital
John Hyngstrom
Mohammed Milhem, The University of Iowa Hospitals and Clinics
Svetomir N Markovic, Mayo Clinic Rochester
Tawnya Bowles, Intermountain Medical Center
Omid Hamid, Cedars-Sinai Medical Center Angeles Clinic and Research Institute
Leonel Hernandez-Aya, Washington University School of Medicine in Saint Louis
Joel Claveau, CHU de Quebec-Universite Laval
Sekwon Jang, Inova Health System
Prejesh Philips, University of Louisville
Shernan G Holtan, University of Minnesota Academic Health Center
Montaser F Shaheen, University of Arizona Medical Center
Brendan Curti, Providence Portland Medical Center
William Schmidt, Bend Memorial Clinic
Marcus O Butler, Princess Margaret Hospital Cancer Centre
Juan Paramo, Mount Sinai Medical Center
Jose Lutzky, Sylvester Comprehensive Cancer Center
Arvinda Padmanabhan, Baptist Health Lexington
Sajeve Thomas, MD Anderson Cancer Center Orlando
Daniel Milton, Investigative Clinical Research of Indiana
Andrew Pecora, John Theurer Cancer Center
Takami Sato, Thomas Jefferson UniversityFollow
Eddy Hsueh, St. Louis University Hospital
Suprith Badarinath, Cancer Specialists of North Florida
John Keech, Multicare Institute for Research and Innovation
Sujith Kalmadi, Ironwood Cancer and Research Centers
Pallavi Kumar, Harry and Jeanette Weinberg Cancer Institute at Franklin Square
Robert Weber, St. Mary's Hospital and Medical Center
Edward Levine, Wake Forest School of Medicine
Adam Berger, Rutgers Cancer Institute of New Jersey
Anna Bar, Oregon Health & Science University
J Thaddeus Beck, Highlands Oncology Group
Jeffrey B Travers, Premier Health Partners Inc
Catalin Mihalcioiu, Royal Victoria Hospital
Brian Gastman, Cleveland Clinic
Peter Beitsch, Cancer Solutions
Suthee Rapisuwon, MedStar Washington Hospital Center
John Glaspy, University of California Los Angeles
Edward C McCarron, MedStar Franklin Square Medical Center
Vinay Gupta, MedStar Franklin Square Medical Center
Deepti Behl, Sutter Institute for Medical Research
Brent Blumenstein, Trial Architecture Consulting
Joanna J Peterkin, Polynoma

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This article is the author’s final published version in Journal for ImmunoTherapy of Cancer, Volume 9, Issue 10, October 2021, Article number e003272.

The published version is available at Copyright © Slingluff et al.


Background: Most patients with advanced melanomas relapse after checkpoint blockade therapy. Thus, immunotherapies are needed that can be applied safely early, in the adjuvant setting. Seviprotimut-L is a vaccine containing human melanoma antigens, plus alum. To assess the efficacy of seviprotimut-L, the Melanoma Antigen Vaccine Immunotherapy Study (MAVIS) was initiated as a three-part multicenter, double-blind, placebo-controlled phase III trial. Results from part B1 are reported here.

Methods: Patients with AJCC V.7 stage IIB-III cutaneous melanoma after resection were randomized 2:1, with stage stratification (IIB/C, IIIA, IIIB/C), to seviprotimut-L 40 mcg or placebo. Recurrence-free survival (RFS) was the primary endpoint. For an hypothesized HR of 0.625, one-sided alpha of 0.10, and power 80%, target enrollment was 325 patients.

Results: For randomized patients (n=347), arms were well-balanced, and treatment-emergent adverse events were similar for seviprotimut-L and placebo. For the primary intent-to-treat endpoint of RFS, the estimated HR was 0.881 (95% CI: 0.629 to 1.233), with stratified logrank p=0.46. However, estimated HRs were not uniform over the stage randomized strata, with HRs (95% CIs) for stages IIB/IIC, IIIA, IIIB/IIIC of 0.67 (95% CI: 0.37 to 1.19), 0.72 (95% CI: 0.35 to 1.50), and 1.19 (95% CI: 0.72 to 1.97), respectively. In the stage IIB/IIC stratum, the effect on RFS was greatest for patients <60 years old (HR=0.324 (95% CI: 0.121 to 0.864)) and those with ulcerated primary melanomas (HR=0.493 (95% CI: 0.255 to 0.952)).

Conclusions: Seviprotimut-L is very well tolerated. Exploratory efficacy model estimation supports further study in stage IIB/IIC patients, especially younger patients and those with ulcerated melanomas.

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This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License

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