TY - JOUR

T1 - Therapeutic Cancer Vaccination With a Peptide Derived From the Calreticulin Exon 9 Mutations Induces Strong Cellular Immune Responses in Patients With CALR-Mutant Chronic Myeloproliferative Neoplasms

AU - Handlos Grauslund, Jacob

AU - Holmström, Morten Orebo

AU - Jørgensen, Nicolai Grønne

AU - Klausen, Uffe

AU - Weis-Banke, Stine Emilie

AU - El Fassi, Daniel

AU - Schöllkopf, Claudia

AU - Clausen, Mette Borg

AU - Gjerdrum, Lise Mette Rahbek

AU - Breinholt, Marie Fredslund

AU - Kjeldsen, Julie Westerlin

AU - Hansen, Morten

AU - Koschmieder, Steffen

AU - Chatain, Nicolas

AU - Novotny, Guy Wayne

AU - Petersen, Jesper

AU - Kjær, Lasse

AU - Skov, Vibe

AU - Met, Özcan

AU - Svane, Inge Marie

AU - Hasselbalch, Hans Carl

AU - Andersen, Mads Hald

N1 - Funding Information: This study was supported in part by Kræftens Bekæmpelse grant number R149-A10159-16-S47 and a pre-seed grant from the Novo Nordisk Foundation. Publisher Copyright: © Copyright © 2021 Handlos Grauslund, Holmström, Jørgensen, Klausen, Weis-Banke, El Fassi, Schöllkopf, Clausen, Gjerdrum, Breinholt, Kjeldsen, Hansen, Koschmieder, Chatain, Novotny, Petersen, Kjær, Skov, Met, Svane, Hasselbalch and Andersen.

PY - 2021/2/26

Y1 - 2021/2/26

N2 - Background: The calreticulin (CALR) exon 9 mutations that are identified in 20% of patients with Philadelphia chromosome negative chronic myeloproliferative neoplasms (MPN) generate immunogenic antigens. Thus, therapeutic cancer vaccination against mutant CALR could be a new treatment modality in CALR-mutant MPN. Methods: The safety and efficacy of vaccination with the peptide CALRLong36 derived from the CALR exon 9 mutations was tested in a phase I clinical vaccination trial with montanide as adjuvant. Ten patients with CALRmut MPN were included in the trial and received 15 vaccines over the course of one year. The primary end point was evaluation of safety and toxicity of the vaccine. Secondary endpoint was assessment of the immune response to the vaccination epitope (www.clinicaltrials.gov identifier NCT03566446). Results: Patients had a median age of 59.5 years and a median disease duration of 6.5 years. All patients received the intended 15 vaccines, and the vaccines were deemed safe and tolerable as only two grade three AE were detected, and none of these were considered to be related to the vaccine. A decline in platelet counts relative to the platelets counts at baseline was detected during the first 100 days, however this did not translate into neither a clinical nor a molecular response in any of the patients. Immunomonitoring revealed that four of 10 patients had an in vitro interferon (IFN)-γ ELISPOT response to the CALRLong36 peptide at baseline, and four additional patients displayed a response in ELISPOT upon receiving three or more vaccines. The amplitude of the immune response increased during the entire vaccination schedule for patients with essential thrombocythemia. In contrast, the immune response in patients with primary myelofibrosis did not increase after three vaccines. Conclusion: Therapeutic cancer vaccination with peptide vaccines derived from mutant CALR with montanide as an adjuvant, is safe and tolerable. The vaccines did not induce any clinical responses. However, the majority of patients displayed a marked T-cell response to the vaccine upon completion of the trial. This suggests that vaccines directed against mutant CALR may be used with other cancer therapeutic modalities to enhance the anti-tumor immune response.

AB - Background: The calreticulin (CALR) exon 9 mutations that are identified in 20% of patients with Philadelphia chromosome negative chronic myeloproliferative neoplasms (MPN) generate immunogenic antigens. Thus, therapeutic cancer vaccination against mutant CALR could be a new treatment modality in CALR-mutant MPN. Methods: The safety and efficacy of vaccination with the peptide CALRLong36 derived from the CALR exon 9 mutations was tested in a phase I clinical vaccination trial with montanide as adjuvant. Ten patients with CALRmut MPN were included in the trial and received 15 vaccines over the course of one year. The primary end point was evaluation of safety and toxicity of the vaccine. Secondary endpoint was assessment of the immune response to the vaccination epitope (www.clinicaltrials.gov identifier NCT03566446). Results: Patients had a median age of 59.5 years and a median disease duration of 6.5 years. All patients received the intended 15 vaccines, and the vaccines were deemed safe and tolerable as only two grade three AE were detected, and none of these were considered to be related to the vaccine. A decline in platelet counts relative to the platelets counts at baseline was detected during the first 100 days, however this did not translate into neither a clinical nor a molecular response in any of the patients. Immunomonitoring revealed that four of 10 patients had an in vitro interferon (IFN)-γ ELISPOT response to the CALRLong36 peptide at baseline, and four additional patients displayed a response in ELISPOT upon receiving three or more vaccines. The amplitude of the immune response increased during the entire vaccination schedule for patients with essential thrombocythemia. In contrast, the immune response in patients with primary myelofibrosis did not increase after three vaccines. Conclusion: Therapeutic cancer vaccination with peptide vaccines derived from mutant CALR with montanide as an adjuvant, is safe and tolerable. The vaccines did not induce any clinical responses. However, the majority of patients displayed a marked T-cell response to the vaccine upon completion of the trial. This suggests that vaccines directed against mutant CALR may be used with other cancer therapeutic modalities to enhance the anti-tumor immune response.

KW - calreticulin

KW - cancer immune therapy

KW - cancer vaccines

KW - myeloproliferative neoplasms

KW - neo-antigen

U2 - 10.3389/fonc.2021.637420

DO - 10.3389/fonc.2021.637420

M3 - Journal article

C2 - 33718228

AN - SCOPUS:85102426574

VL - 11

JO - Frontiers in Oncology

JF - Frontiers in Oncology

SN - 2234-943X

M1 - 637420

ER -