Forlì, March 1-2, 2007 Anti-cancer vaccines Peptide-based vaccines: The INT experience Giorgio Parmiani, MD Department of Oncology, San Raffaele Scientific Institute
Strategies of anti-cancer therapeutic vaccines 1. I rradiated and genetically modified tumor cells 2. TAAs 3. Antigenic peptides with adjuvants or dendritic cells 4. Tumor-derived h eat shock proteins - as whole proteins plus adjuvants
as genes transduced in normal cells
as plasmid DNA
as DNA contained in viral or non-viral vectors
Known sequence and biochemistry
Easy to synthesize (large availability)
Allow a specific immune-monitoring of the patient response
Allow to assess expression of targeted antigens in patient tumor cells
Peptide-based vaccines ( cont .)
Easy degradable in absence of adjuvants
Require appropriate HLA allele to be recognized (patient selection)
Induce T cells that may not recognize tumor cells
Issues in peptide-based cancer vaccines
Nature of tumor-associated antigens
Quantity and quality of immune response
First generation of vaccines (1994-2004): Immmune and clinical response
Immune suppression/tumor escape
Tumor-associated antigens (TAA): Their nature is crucial for anti-tumor immune response
Antigens recognized by T cells (Novellino et al., Cancer Immunol Immunother 2005): 1)Shared, self differentiation proteins expressed also on normal cells( e.g. MART-1, CEA, PSA ) 2)Shared self Cancer/Testis expressed by different tumors and by normal testis or placenta ( e.g. MAGE, NY-ESO-1 ) 3) Shared but predominantly expressed on tumor cells ( e.g. RAS/m, survivin, hTERT ) 4) Unique , expressed only by a single tumor( e.g.CDK4/m, α -actin-m )
1 and 2. In vitro and ex - vivo T cell natural immune response to shared “self” TAAs
0.0 0.1 0.2 0.3 0.3 0.8 1.3 1.8 2.3 2.8 3.3 n.s. *** 0.0 0.1 0.2 0.3 0.3 0.8 1.3 1.8 2.3 2.8 3.3 n.s. *** ** gp100 209-217 Tyrosinase 368-377 Melan-A/MART-1 26-35 FREQUENCY OF SPONTANEOUS CIRCULATING ANTI-MAA CD8+ T LYMPHOCYTES ( Mortarini et al., Cancer Res 2004 ) 0.0 0.1 0.2 0.3 0.3 0.8 1.3 1.8 2.3 2.8 3.3 *** *** ** *** Patients Donors Stage I-II Stage III-IV Patients Donors Stage I-II Stage III-IV Patients Donors Stage I-II Stage III-IV
A hierarchy exists in the natural recognition of “self” TAAs by T cells.
MelanA/MART-1 e CEA induce the most frequent T cell response in melanoma and CRC.
Recognition of “self” TAAs increases with the increased tumor burden.
Antigens recognized by T cells:
Shared, self differentiation proteins expressed also on normal cells (e.g. MART-1, CEA, PSA)
Shared self Cancer/Testis expressed by different tumors and by normal testis or placenta (e.g. MAGE, NY-ESO-1)
Shared but predominantly expressed on tumor cells (e.g. RAS/m, survivin , hTERT)
Unique, expressed only by a single tumor (e.g. CDK4/m, α -actin-m)
abundant during fetal development
silenced in normal adult tissues
over-expressed in most common human cancers
• Member of AIPs (Apoptosis Inhibitory Proteins ) Survivin is a universal TAA that can elicit both HLA-I and HLA-II-restricted T cells
IN VITRO INDUCTION OF HLA CLASS I-RESTRICTED ANTI-SVV T CELLS IN PBMCs OF RECTAL CANCER PATIENTS Autologous PBMCs SVV-1 Medium IFN γ spots/50,000 cells Patient 1 Patient 2 + anti-HLA-I Ab ( Casati et al., Cancer Research 2003 )
N. IFN gamma spots/2x10 5 PBMCs In vitro recognition of prostate antigens-deriving peptides by T lymphocytes of prostate cancer patients
Antigens recognized by T cells:
Shared but expressed on tumor cells only
Shared Cancer/Testis expressed by different tumors and by normal testis or placenta
Shared, differentiation proteins expressed also on normal cells
Unique , mutation-derived,expressed only by a single tumor ( e.g. CDK4/m, α -actin-m )
Unique human TAAs recognized by HLA-restricted T cells (Parmiani et al., Journal of Immunology 2007 )
Tumor No. Class I No. Class II
Melanoma 11 6
NSCLC 3 1
H/N 2 0
RCC 2 1
Bladder cancer 1
Total 19 8
Most of these unique TAA have a pathogenetic role in neoplastic transformation/ progression.
Strategies of anti-cancer therapeutic vaccines 1. I rradiated and genetically modified tumor cells 2. TAAs 3. Antigenic peptides with adjuvants or dendritic cells 4. Tumor-derived h eat shock proteins - As whole proteins plus adjuvants
As genes transduced in normal cells
As plasmid DNA
As DNA contained in viral or non-viral vectors
Use of shared “self” or “cancer/testis” TAA peptides as vaccines in patients with metastatic melanoma (1995-2004). Clinical RR 18%. CD8+T cell response in 20-50% of patients but limited expansion of T cells (<1%).
Rationale for a new generation of peptide-based vaccines at INT of Milan
Multiple peptide including universal TAAs
New TLR targeting adjuvants (CpG, HSP)
Down-regulation of Tregs and/or Myeloid Suppressor Cells ( see Licia Rivoltini)
Immune-monitoring in blood and LNs
Assessment of patient polymorphisms
On the basis of pre-clinical results, the SVV-1.HLA-A2 peptide is being used , along with other peptides, in clinical studies of vaccination of patients with prostate and rectal carcinoma and melanoma .
Vaccination HLA-A2-restricted peptides from PMSA1, PSMA2, survivin + Montanide. CPA before vaccination Vaccination with peptides deriving from prostate TAAs in association with Montanide and cyclophosphamide (CPA) Peptides Activation of specific T cells Unit of Immunotherapy of Human Tumors CPA (300 mg/m 2 ) Blocking of suppressive effect of CD4+ CD25+T reg on lymphocyte proliferation Montanide Recruitment of pro-infliammatory cells (APC)
Vaccination with peptide deriving from prostate TAAs in association with Montanide and CPA Group 1 – Adjuvant Vaccination
Malattia localizzata a livello prostatico, resecabile
Vaccinazione in regime neoadiuvante ed adiuvante dopo chirurgia
1° cycle vaccine 2° cycle vaccine C C -3 1 w C C -3 1 month C C Diagnostic biopsy Prostatectomy Unita’ di Immunoterapia dei Tumori Umani Analysis of induction of T lymphocytes recognizing vaccine peptides in PBLs Analysis of tumor infiltrate
Results: Immunologic and clinical responses
Vaccination of prostate cancer patients: Clinical response After the first cycle of vaccination (PSA 1.04 ng/ml -> 0.27 ng/ml) 009 Aftrer the first cycle of vaccination (PSA 0.51 ng/ml -> 0.44 ng/ml) 008 After the first cycle of vaccination (PSA 1.33 ng/ml -> 1.01 ng/ml) 007 PD 006 PD 005 Biochemical SD at 6 months and CR of a prostatic lesion 004 Biochemical SD at 6 months from interruption of hormone therapy 003 Biochemical SD at 8 months from interruption of hormone therapy 002 Biochemical SD at 10 months from interruption of hormone therapy 001 Clinical outcome Patients
Vaccination of high risk stage IIB/IIIC melanoma patients with multipeptides emulsified in Montanide , and given cyclophosphamide and IL-2 vs. observation only. A randomized phase II study
G. Parmiani, M. Santinami, L. Pilla, G. Cutolo, A. Maurichi, R. Patuzzo, A. Carbone, G. Tragni, C. Castelli, L. Rivoltini (INT);
M. Maio (Siena),V. Chiarion (Padua)
Ethics Committee approval: May 2004.
Delayed due to the long term negotiation with Coley to obtain CpG-ODN (not provided).
First patient enrolled in July 2005
Primary end points: Immune response (frequency and intensity)
ELISPOT : Frequency of anti-tumor specific T lymphocytes
Flow-cytometry: Phenotype of anti-tumor T cells
- HLA tetramers
Cytokine intracellular staining
Immunohistochemistry : characterization of tumor cells and of TILs
Clinical objectives Primary: Local and systemic toxicity Secondary: Disease-free survival after 2/3 years Overall survival at 5 years
MECHANISMS OF IMMUNE EVASION Why a more strong immune response and/or a more frequent clinical response was not observed in vaccination trials ?
FACTORS THAT CAN INTERFERE WITH THE RECOGNITION AND LYSIS OF TUMOR CELLS BY T LYMPHOCYTES
Lack of antigenic peptide or down-regulation of HLA
Dysfunction of antigen presentation
Release of immune-suppressive factors (IL-10, TGF , VEGF)
Tumor counterattack (Fas/FasL)
Cannibalization of T lymphocytes
Immune anergy or ignorance
Lack of tissue homing molecules; defective adhesion
Inactivation of T cells within the tumor (granzyme B)
Induction of anti-peptide but not anti-tumor T cells
T regulatory cells
Myeloid suppressive cells
Acknowledgments Chiara Castelli Licia Rivoltini Chiara Camisaschi Gianluca Cutolo Veronica Huber Manuela Iero Andrea Marrari Luisa Novellino Lorenzo Pilla Roberta Valenti Agata Cova Francesca Rini Gloria Sovena Paola Squarcina Istituto Nazionale Tumori Milan - Italy Vincenzo Mazzaferro Jorgelina Coppa Mario Santinami Roberto Patuzzo Ermanno Leo Filiberto Belli Flavio Arienti Alfonso Marchianò Grazia Barp Annabella Di Florio Pramod K. Srivastava Antigenics, New York Michele Maio Siena
Take home message. Perspectives 1
Antigens : use both cross-reacting self and unique TAA; use both classes I and II HLA-restricted peptides.
Adjuvants : CpG-ODN plus IFA are likely to be the most potent; cytokines: how to use them ? ( IFN- , GM-CSF?, IL-12, IL-15, IL-21, IL-23 ).
Tumor burden : avoid excess tumor burden to prevent release of suppressive factors.
Escape mechanisms : use compounds which may help in restoring normal immune functions (e.g. retinoic acid, cytokines, anti-Treg Ab ).
Combination therapy : vaccination may be combined with anti-angiogenic drugs, radiotherapy and immune-modulating chemotherapy ( non-myeloablative lymphodepletion? )
Modulation of the immune response by anti-Treg and/or anti-CTLA4 antibodies.
REGULATORY T LYMPHOCYTES
Treg assessment during peptide-based vaccination and modulation by Cyclophosphamide
Recurrent rectal carcinoma patients receiving a peptide-based vaccine ( no IL-2)
Stage III melanoma patients receiving a multipeptide-based vaccine ( with IL-2 )
% of CD25+ Foxp3+ (in CD4) Pt#4 Pt#3 Pt#2 Pt#1 Treg (CD4+CD25+Foxp3+) in PBMC of rectal carcinoma patients and their modulation by CTX treatment
CD4+CD25 high CD4+CD25 high CD4+CD25 high % of positive cells CD4+CD25+ CD25+Foxp3+(in CD4) CD4+CD25 brigh Pt#1 Pt#2 Treg in PBMC of Melanoma patients: modulation by CTX and IL-2 treatment
Studi clinici di vaccinoterapia in assenza di cellule dendritiche in pazienti con carcinoma prostatico Vaccino N. HLA Risposta R i s p o s t a Ref. pazienti immune clinica SART, p56LCK , 10 A2402 4/10 1 PR* Naguchi, ’03 ART, CyB 5 SD SART, p56LCK, 16 A2402 10/14 13/13 ** Naguchi, ’05 ART, CyB, PSA, PAP, (71%) (6/13 PR) PSMA estramustine Allo-prostata + BCG 26 A*0201 11/26 11/26§ Pandha, ’05 pVAX/PSA + GM-CSF 9 A*0201 2/9 Non Pisa, ‘04 + IL-2 valutabile Auto-Prostate/GM-CSF 8 NV 7/8 Non Simons, ’99 DTH valutabile FowlPox+VacPSA 64 NA 46% 18 PFS Kaufman ‘04 (78%) * 89% PSA - ** Tutti PSA, con 6/13 > 50%. § Riduzione prolungata e statisticamente significativa di PSA.
Features of peptide vaccines
Peptide length :
8-10 aa for HLA class I-restricted peptides
12-23 aa for HLA class II-restricted peptides
Modified peptides (heteroclitic and/or long peptides)
Highly and rapidly degradable in vivo (adjuvants are required)
1, 2: Shared “self” TAAs
Normal subjects and cancer patients show some forme of tolerance to “self” TAAs ( immune ignorance, peripheral tolerance, central tolerance, low frequency of T cells , etc .).
Tolerance needs to be broken in order to induce a T cell immune response against “self” TAAs.
Thus, these TAAs are considered to be “ weak antigens ”
Natural CD8+T cell response of HLA-A2 colorectal cancer (CRC) patients to differentiation antigens (Nagorsen et al., Cancer Res 2000) * ELISPOT assay. Antigen Clinical N. of responding stage N. of tested* Ep-CAM Donors 0/8 A-B 0/9 C-D 4/13 Her2/neu Donors 0/8 A-B 0/9 C-D 5/13 CEA Donors 0/8 A-B 0/9 C-D 6/13
N. IFN γ spots/3x10 4 cells med T2+PSMA T2+PSMA + anti-HLA-I CaP + anti-HLA-I CaP Anti-PSMA T cells CaP Anti-svv T cells med T2+svv T2+svv + anti-HLA-I CaP + anti-HLA-I N. IFN γ spots/3x10 4 cells Fresh PBMC med PSMA svv Flu N. IFN γ spots/10 6 cells A B A . Analisi della frequenza di precursori linfocitari T anti-tumore specifici nel sangue periferico in pazienti con carcinoma della prostata. I PBMC isolati attraverso centrifugazione in gradiente di densità dal sangue periferico di pazienti affetti da carcinoma della prostata HLA-A*0201 sono stati incubati con peptidi di PSMA, survivina e dalla proteina del virus influenzale (M1), come controllo positivo. Il riconoscimento dei vari antigeni da parte dei linfociti e’ stato valutato come rilascio di IFN γ , mediante Elispot. I dati rappresentano 1 dei 2 casi di pazienti con carcinoma prostatico che hanno mostrato un’elevata immunogenicita’ per gli antigeni analizzati. B. Analisi quantitativa dell’attivazione di linfociti T anti-PSMA-specifici derivati da pazienti affetti da carcinoma prostatico. I PBMC di pazienti HLA-A*0201 sono stati stimolati per due settimane con i peptidi tumorali derivanti da PSMA e survivina per due settimane. Al termine di tale periodo la specificità dei linfociti T nei confronti di cellule T2 e di cellule di carcinoma prostatico LNCaP (?), è stata valutata quantificando il rilascio di IFN attraverso analisi immunoenzimatica Elispot.
1 2 3 5 4 6 1 2 3 5 4 6 7 8 9 10 7 8 9 10 T2 + Survivin T2 + Survivin + anti-HLA-I T2 + PSMA P1 T2 + PSMA P1 + anti-HLA-I N. of spots per 30 4 cells N. of spots per 30 4 cells Frequency of TAA-specific T cells precursors after in vitro stimulation with prostatic peptides No. of microcultures tested/patient
Ex-vivo recognition of prostate antigens by patient T cells
No. of patients tested: 112
No. of patients whose peripheral blood T lymphocytes recognized prostate antigens: 65 (58%)
Studio di fase III di vaccinazione con DC di pazienti con carcinoma della prostata ND: non disponibile *Provenge= Proteina di fusione PAP+GM-CSF su cellule dendritiche N. Pazienti Antigene Risposta Risposta P.I. immune clinica 110 vs 108 Provenge* ND Mediana E.Small, Metastatici, vs placebo sopravvivenza 2005 ormone 25.9 vs 21.9 resistenti OS 34% vs 11%
Patient 8- 3R MHC-CLASS II RESTRICTED RESPONSE OF COLORECTAL CANCER PATIENTS TO rSVV PROTEIN OR CANCER LYSATE IFN- ELISA IFN- pg/ml Patient 1- 3R IFN- pg/ml (Casati C et al., Cancer Research, 2003) 0 500 1000 1500 2000 2500 = medium = auto LCL = HCT 116 lysate = melanoma lysate = LCL + rSVV = LCL + rSVV + L243 = LCL + HCT 116 lysate = LCL + HCT 116 lysate + L243 = LCL + C1R/SVV lysate = LCL + C1R/SVV lysate + L243 0 500 1000 1500 2000 2500
The response of autologous T cells to a human melanoma is dominated by mutated neoantigens ( Lennerz V et al., PNAS , 2005 )
Five neoantigens deriving from somatic mutations were found at different time points in different metastases of a melanoma patient.
CD8+ cytotoxic T cells against mutated TAA were predominant over shared differentiation self TAA over 4-5 years of testing.
Dendritic cells (DC)- based peptide vaccines Characteristics : * Direct stimulation of T cells in lymph nodes. * Ex-vivo preparation of high numbers of DCs and their phenotipic and functional characterization . * High cost and time consuming.
Are unique TAAs spontaneously recognized in v ivo ? T lymphocytes recognizing unique TAAs have been described in long-term surviving patients previously affected by melanoma; NSCLC; head/neck, bladder and renal carcinoma (T. Wolfel, P. Coulie, G. Parmiani, F. Triebel)
Phase I-II studies of DC based therapeutic vaccines in prostate cancer DC loaded with No. % Immune Clinical % Reference pts response response PAP/GM-CSF 31 38 3 ( ↓PSA) 10 Small ’00 PSMA/A2 37 NE 1 CR, 10 PR 31 Murphy ’99 PSA/mRNA 13 100 3 CR 23 Vieweg ’02 Mouse PAP 21 49 6 SD 0 Fong ’01 PSA 24 45 11 ( ↓PSA) 46 Barrou ’04 hTERT/mRNA 20 95 9 ( ↓PSA) 45 Vieweg ‘05 T O T A L 142 46 23
Autologous monocytes pulsed with melanoma-derived HSP70 are recognized by specific T cell clones (from Castelli et al., Cancer Res. 2001) IFN- (pg/ml) Anti-gp100 APC Medium HSP70 HSP70 + W6.32 Auto-Me Anti-MART-1 APC Medium HSP70 Auto-Me Statistically significant inhibition. HSP70 + W6.32 W6.32 = anti-HLA-I mAb Auto-Me = autologous melanoma
Some recent good news in anti-cancer vaccination
Recombinant NY-ESO-1 protein with ISCOMATRIX adjuvant induces broad integrated antibody and CD4+ and CD8+ T cell responses in melanoma Davis et al., (Old LJ, Cebon JS), PNAS 101: 10697-10702, 2004 Treatment Disease-free survival at median follow-up of 2 years* Placebo 2/7(28%) NY-ESO-1 protein only 7/16 (48%) NY-ESO-1 + IMX 17/19 (89%) - Clinical results - * Well balanced for pathological state, primary lesion thickness, etc.
Phase II study of vaccination of hormone-refractory metastatic prostate cancer patients with GVAX ® Cell Genesys , ASCO 2005
No. of patients 22
Median survival time of vaccinated patients was over 29 months.
Median survival time of Taxotere-treated patients is 19 months.
Phase III trials ongoing .
A phase IIb randomized study of vaccination with L-BLP25 in stage IIIb and IV NSCLC after first line chemo
Vaccine : Liposome-MUC1
Overall median survival : 17.4 vs . 13 months in 88 vs . 83 patients
Overall 2 years survival : 43.2 vs . 28.9 %; subset stage IIIb : 60 vs .37 %
Biomira/Merck KGaA, ESMO 2004
Phase II randomized trial of autologous formalin-fixed tumor vaccine for postsurgical recurrence of hepatocellular carcinoma Kuang et al. Clin Cancer Res 2004
No. of patients 41 , after curative resection
Vaccine treatment N= 19 ; no treatment N= 22
Median follow-up of 15 months
Recurrence: Vaccinated 3/18 vs. Control 13/21
Recurrence-free survival P=0.003; OS P= 0.01
Istituto Nazionale Tumori Milano Vaccinazione con 4 Peptidi emulsionati in Montanide (MART-1, gp100, NY-ESO, survivin) allo scopo di diminuire l’emergere di varianti antigene negative Razionale
Cancer Vaccine Pipeline (www.bioseeker.com)
There are more than 260 non-antibody based vaccine drugs, therapeutic and preventive vaccines included. 87 are cancer vaccines.
Vaccines are being developed for over 30 different cancers; 38 companies are involved.
The number of vaccine targets has increased to over 50 different molecular targets
Vaccine market is predicted to be of 6 billions USD by 2010
Clinical studies of vaccination with HSPPC-96 1. Liver metastases of colon cancer 2. Metastatic melanoma (HSPPC-96 only) 3. Metastatic melanoma (HSPPC-96 + GM-CSF + IFN)
Vaccination of patients with liver metastases of CRC with autologous HSPPC-96 - TREATMENT SCHEME -
In vivo expansion of anti-CEA T cells in HLA-A2 CRC patients vaccinated with HSPPC-96 CD8 2.14 HLA/ CEA tetramers 0.22 CD8 HLA/ CEA tetramers Day 1------7-------14------21 V1 V5 Patient 045 N. spots/10 4 T cells V1 V5 * 0 100 200 T2 alone T2+CEA T2+CEA+W6.32 Colo206 N. spots/5x10 4 T cells CD8 CD8 Day 1---7—-14—21-------51 V1 V6 HLA/ CEA tetramers 0.11 2.31 V1 V6 * HLA/ CEA tetramers Patient 038
Resection Purification of HSP-GP96 Vaccination Vaccination of metastatic patients with HSPPC-96 derived from the autologous tumor Tumor sample Tumor cell suspension Immunologic monitoring in vivo : DTH in vitro : ELISPOT, tetramers staining
VACCINATION WITH HSPPC-96 IN METASTATIC COLORECTAL CARCINOMA (CRC) Clinical and immunologic responses (Mazzaferro et al., Clin Cancer Res 2003)
DISEASE-FREE SURVIVAL ACCORDING TO T CELL IMMUNE RESPONSE IN PATIENTS WITH LIVER METASTASES FROM CRC 17 14 11 7 6 16 12 9 7 12 1 1 9 1 1 p < 0.0001 Immune responders Immune non-responders Patients at risk Immune responders Immune non-responders September 2004
OVERALL SURVIVAL ACCORDING TO T CELL IMMUNE RESPONSE IN PATIENTS WITH LIVER METASTASES FROM CRC 17 17 17 14 11 Patients at risk 17 17 17 14 Immune responders 12 9 6 3 11 6 5 2 p < 0.0001 2 Immune responders Immune non-responders Immune non-responders September 2004
HSPPC-96 vaccination increases CD8+T cell response to class I HLA-matched CRC lines in 16 out of 29 patients 501 537 698 449 N. spots/1.67 x 10 5 PBMC Patient number
CONCLUSIONS Vaccination of patients with liver metastases of CRC with autologous HSPPC-96 is feasible and safe. Approximately 60% of patients developed a T cell response to CRC antigens and CRC cells. Both OS and DFS were longer in T cell responding than in non-responding subjects,independently from other prognostic factors.
TUMORS FOUND TO BE INFILTRATED BY T REGULATORY LYMPHOCYTES
NSCLC Woo/June, 2001
Pancreatic/breast cancer Liyanage, 2002
Colorectal cancer D. Herlyn, 2002
Gastric/esophageal cancer Ichihara, 2003
Melanoma Javia/Rosenberg, 2003
Ovarian Cancer Curiel, 2004
HCC Ormandy, 2005
Breast cancer Bates, 2006
Giorgio Parmiani Istituto Nazionale Tumori, Milan - Italy Mario Santinami Lorenzo Pilla Roberto Patuzzo Elisabetta Pennacchioli Alfonso Marchianò Licia Rivoltini Chiara Castelli
Phase III studies of DC-based vaccines in patients with melanoma or prostate carcinoma **Provenge (Dendreon) = Fusion protein of PAP+GM-CSF loaded on autologous DCs. * But in the vaccinated arm, a significant benefit in OS was found in the subset of HLA-A2+/B44 patients vs.non-HLA-A2/B44 ones. No. Patients Antigen Immune Clinical P.I. response response 55 vs 53 MAGE1,3; Not available No advantage Schadendorf, 2006* Stage IV MART1, gp100, tyrosine+DTIC vs DTIC 110 vs 108 Provenge** Not done Median Small, 2005 Metastatic, vs placebo survival hormone 25.9 vs 21.9 resistant OS 34% vs 11%
DC-BASED VACCINATION IN PATIENTS WITH METASTASES - C O N C L U S I O N S -
DC-peptide based vaccines induced a frequency of CD8+T cells response higher (up to 100%) than that obtained by peptide only-based vaccines but without a parallele increase in the clinical outcome (tumor response).
Istituto Nazionale Tumori Milano Vaccination with 4 peptides emulsified in Montanide (MART-1, gp100, NY-ESO, survivin) with the aim of reducing the emergence of antigenic negative variants. Rationale Cyclophosfamide : 300 mg/m2: with the aim of down-regulating T regs IL-2 : 3x10 6 IU (s.c.): to expand T cells activated by the vaccine