Phase I/II clinical trial of a helper peptide vaccine plus PD-1 blockade in PD-1 antibody-naïve and PD-1 antibody-experienced patients with melanoma (MEL64).

BACKGROUND: A vaccine containing 6 melanoma-associated peptides to stimulate helper T cells (6MHP) is safe, immunogenic, and clinically active. A phase I/II trial was designed to evaluate safety and immunogenicity of 6MHP vaccines plus programmed death 1 (PD-1) blockade. PARTICIPANTS AND METHODS: Participants with advanced melanoma received 6MHP vaccines in an incomplete Freund's adjuvant (6 vaccines over 12 weeks). Pembrolizumab was administered intravenously every 3 weeks. Tumor biopsies at baseline and day 22 were analyzed by multiplex immunohistochemistry. Primary end points were safety (Common Terminology Criteria for Adverse Events V.4.03) and immunogenicity (ex vivo interferon-γ ELISpot assay). Additional end points included changes in the tumor microenvironment (TME) and clinical outcomes. RESULTS: Twenty-two eligible participants were treated: 6 naïve to PD-1 antibody (Ab) and 16 PD-1 Ab-experienced. Median follow-up was 24.4 months. Most common treatment-related adverse events (any grade) included injection site reactions, fatigue, anemia, lymphopenia, fever, elevated aspartate aminotransferase, pruritus, and rash. Treatment-related dose-limiting toxicities were observed in 3 (14%) participants, which did not cross the study safety bound. A high durable T cell response (Rsp) to 6MHP was detected in only one participant, but twofold T cell Rsps to 6MHP were detected in 7/22 (32%; 90% CI (16% to 52%)) by week 13. Objective clinical responses were observed in 23% (1 complete response, 4 partial responses), including 4/6 PD-1 Ab-naïve (67%) and 1/16 PD-1 Ab-experienced (6%). Overall survival (OS) was longer for PD-1 Ab-naïve than Ab-experienced participants (HR 6.3 (90% CI (2.1 to 28.7)). In landmark analyses at 13 weeks, OS was also longer for those with T cell Rsps (HR 6.5 (90% CI (2.1 to 29.2)) and for those with objective clinical responses. TME evaluation revealed increased densities of CD8+ T cells, CD20+ B cells, and Tbet+ cells by day 22. CONCLUSIONS: Treatment with the 6MHP vaccine plus pembrolizumab was safe, increased intratumoral lymphocytes, and induced T cell Rsps associated with prolonged OS. The low T cell Rsp rate in PD-1 Ab-experienced participants corroborates prior murine studies that caution against delaying cancer vaccines until after PD-1 blockade. The promising objective response rate and OS in PD-1 Ab-naïve participants support consideration of a larger study in that setting.

Immunogenicity in humans of a transdermal multipeptide melanoma vaccine administered with or without a TLR7 agonist.

BACKGROUND: Experimental cancer vaccines are traditionally administered by injection in subcutaneous tissue or muscle, commonly with adjuvants that create chronic inflammatory depots. Injection of melanoma-derived peptides induces T cell responses; however, the depots that form following injection may inhibit optimization of the immune response. In skin, epidermal Langerhans cells (LC) are a dominant source of professional antigen presenting cells. We hypothesized that: (1) applying melanoma-derived peptides topically, in proximity to LC, could be immunogenic and safe, with low vaccine-site toxicity and (2) topical toll-like receptor 7 (TLR7) agonist would increase immunogenicity of the peptide vaccine. METHODS: Twelve melanoma peptides plus a tetanus helper peptide were combined with granulocyte macrophage colony stimulating factor (GM-CSF) and were administered topically on days 1, 8, and 15, to 28 patients randomized to one of four adjuvant preparations: (1) incomplete Freund's adjuvant (IFA); (2) IFA plus a TLR7 agonist (imiquimod) administered on days 0, 7, 14; (3) dimethyl sulfoxide (DMSO) or (4) DMSO+ imiquimod administered on day 0, 7, 14. Every 3 weeks thereafter (x 6), the peptides were combined with GM-CSF and were injected into the dermis and subcutis in an emulsion with IFA. Toxicities were recorded and immune responses assayed by ELIspot. RESULTS: CD8+ T cell responses to transdermal vaccination in DMSO occurred in 83% of participants in group 3 and 86% in group 4, and responses to vaccination in IFA were observed in 29% of participants in group 1 and 14% in group 2. Overall, 61% of participants had CD4+ T cell immune responses to the tetanus peptide, with large, durable responses in groups 3 and 4. Five of seven participants in group 4 had a severe rash, one that was dose limiting. Ten-year overall survival was 67% and disease-free survival was 44%. CONCLUSIONS: These data provide proof of principle for immunogenicity in humans of transdermal immunization using peptides in DMSO. Further study is warranted into the pharmacokinetics and immunobiology of TLR agonists as vaccine adjuvants during transcutaneous application. Overall survival is high, supporting further investigation of this immunization approach.

Trial to evaluate the immunogenicity and safety of a melanoma helper peptide vaccine plus incomplete Freund's adjuvant, cyclophosphamide, and polyICLC (Mel63).

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.

A multipeptide vaccine plus toll-like receptor agonists LPS or polyICLC in combination with incomplete Freund's adjuvant in melanoma patients.

BACKGROUND: Cancer vaccines require adjuvants to induce effective immune responses; however, there is no consensus on optimal adjuvants. We hypothesized that toll-like receptor (TLR)3 agonist polyICLC or TLR4 agonist lipopolysaccharide (LPS), combined with CD4 T cell activation, would support strong and durable CD8+ T cell responses, whereas addition of an incomplete Freund's adjuvant (IFA) would reduce magnitude and persistence of immune responses. PATIENTS AND METHODS: Participants with resected stage IIB-IV melanoma received a vaccine comprised of 12 melanoma peptides restricted by Class I MHC (12MP), plus a tetanus helper peptide (Tet). Participants were randomly assigned 2:1 to cohort 1 (LPS dose-escalation) or cohort 2 (polyICLC). Each cohort included 3 subgroups (a-c), receiving 12MP + Tet + TLR agonist without IFA (0), or with IFA in vaccine one (V1), or all six vaccines (V6). Toxicities were recorded (CTCAE v4). T cell responses were measured with IFNγ ELIspot assay ex vivo or after one in vitro stimulation (IVS). RESULTS: Fifty-three eligible patients were enrolled, of which fifty-one were treated. Treatment-related dose-limiting toxicities (DLTs) were observed in 0/33 patients in cohort 1 and in 2/18 patients in cohort 2 (11%). CD8 T cell responses to 12MP were detected ex vivo in cohort 1 (42%) and in cohort 2 (56%) and in 18, 50, and 72% for subgroups V0, V1, and V6, respectively. T cell responses to melanoma peptides were more durable and of highest magnitude for IFA V6. CONCLUSIONS: LPS and polyICLC are safe and effective vaccine adjuvants when combined with IFA. Contrary to the central hypothesis, IFA enhanced T cell responses to peptide vaccines when added to TLR agonists. Future studies will aim to understand mechanisms underlying the favorable effects with IFA. TRIAL REGISTRATION: The clinical trial Mel58 was performed with IRB (#15781) and FDA approval and is registered with Clinicaltrials.gov on April 25, 2012 (NCT01585350). Patients provided written informed consent to participate. Enrollment started on June 24, 2012.

A randomized pilot trial testing the safety and immunologic effects of a MAGE-A3 protein plus AS15 immunostimulant administered into muscle or into dermal/subcutaneous sites.

INTRODUCTION: Methods to induce T cell responses to protein vaccines have not been optimized. The immunostimulant AS15 has been administered with the recombinant MAGE-A3 protein (recMAGE-A3) i.m. but not i.d. or s.c. This study tests hypotheses that the i.d./s.c. route is safe and will increase CD4(+) and CD8(+) T cell responses to MAGE-A3. PATIENTS AND METHODS: Twenty-five patients with resected stage IIB-IV MAGE-A3(+) melanoma were randomized to immunization with recMAGE-A3 combined with AS15 immunostimulant (MAGE-A3 immunotherapeutic) either i.m. (group A, n = 13) or i.d./s.c. (group B, n = 12). Adverse events were recorded. Ab responses to MAGE-A3 were measured by ELISA. T cell responses to overlapping MAGE-A3 peptides were assessed in PBMC and a sentinel immunized node (SIN) after 1 in vitro stimulation with recMAGE-A3, by IFN-γ ELISPOT assay and by flow cytometry for multifunctional (TNF-α/IFN-γ) responses. RESULTS: Both routes of immunization were well tolerated without treatment-related grade 3 adverse events. All patients had durable Ab responses. For all 25 patients, the T cell response rate by ELISPOT assay was 30 % in SIN (7/23) but only 4 % (1/25) in PBMC. By flow cytometry, multifunctional CD8(+) T cell responses were identified in one patient in each group; multifunctional CD4(+) T cell response rates for groups A and B, respectively, were 31 and 64 % in SIN and 31 and 50 % in PBMC. CONCLUSION: The MAGE-A3 immunotherapeutic was well tolerated after i.d./s.c. administration, with trends to higher CD4(+) T cell response rates than with i.m. administration. This study supports further study of AS15 by i.d./s.c. administration.

A melanoma helper peptide vaccine increases Th1 cytokine production by leukocytes in peripheral blood and immunized lymph nodes.

BACKGROUND: Cancers produce soluble and cell-associated molecules that can suppress or alter antitumor immunity. Preclinical studies suggest the disease burden may alter the cytokine profile of helper T cell responses to cancer antigens. We studied cytokine production by helper T cells responding to vaccination with 6 melanoma helper peptides (6MHP) in blood and lymph nodes. METHODS: Twenty-three patients with stage IIIB-IV melanoma received a 6MHP vaccine. Antigen-reactive T cells from blood and draining lymph nodes were cultured, exposed to antigen, and then supernatants (days 2 and 5) were assayed for Th1 and Th2 cytokines. Results from 4 time points were compared to pre-vaccine levels. RESULTS: Cytokine responses to vaccinating peptides were observed in 83% of patients. Th1 favoring responses were most common (17 of 19 responders). The most abundant cytokines produced were IFN-γ and IL-5 in the PBMC's. IL-2 responses predominated in cells obtained from draining lymph nodes in 2-day culture but not in 5-day cultures. Patients with clinically measurable disease produced similar levels of total cytokine and similar degree of Th1 polarization as patients with no evidence of disease (NED). CONCLUSIONS: The MHC class II-associated peptides used in this study induced helper T cells with a Th1-biased cytokine response in both PBMC and sentinel immunized nodes. Most patients can mount a Th1 dominant response to these peptides. Future studies are needed to test newer vaccine adjuvants in combination with these peptides. TRIAL REGISTRATION: CDR0000378171, Clinicaltrials: NCT00089219.

Immunologic hierarchy, class II MHC promiscuity, and epitope spreading of a melanoma helper peptide vaccine.

Immunization with a combination melanoma helper peptide (6MHP) vaccine has been shown to induce CD4(+) T cell responses, which are associated with patient survival. In the present study, we define the relative immunogenicity and HLA allele promiscuity of individual helper peptides and identify helper peptide-mediated augmentation of specific CD8(+) T cell responses. Thirty-seven participants with stage IIIB-IV melanoma were vaccinated with 6MHP in incomplete Freund's adjuvant. The 6MHP vaccine is comprised of 6 peptides representing melanocytic differentiation proteins gp100, tyrosinase, Melan-A/MART-1, and cancer testis antigens from the MAGE family. CD4(+) and CD8(+) T cell responses were assessed in peripheral blood and in sentinel immunized nodes (SIN) by thymidine uptake after exposure to helper peptides and by direct interferon-γ ELIspot assay against 14 MHC class I-restricted peptides. Vaccine-induced CD4(+) T cell responses to individual epitopes were detected in the SIN of 63 % (22/35) and in the peripheral blood of 38 % (14/37) of participants for an overall response rate of 65 % (24/37). The most frequently immunogenic peptides were MAGE-A3281-295 (49 %) and tyrosinase386-406 (32 %). Responses were not limited to HLA restrictions originally described. Vaccine-associated CD8(+) T cell responses against class I-restricted peptides were observed in 45 % (5/11) of evaluable participants. The 6MHP vaccine induces both CD4(+) and CD8(+) T cell responses against melanoma antigens. CD4(+) T cell responses were detected beyond reported HLA-DR restrictions. Induction of CD8(+) T cell responses suggests epitope spreading and systemic activity mediated at the tumor site.

A case of spontaneous systemic immunity to melanoma associated with cure after amputation for extensive regional recurrence.

PURPOSE: Survival after amputation for melanoma is short; however, rare long-term survivors are reported. The mechanism for durable systemic tumor control in patients with regional failure is not known. To explore whether systemic tumor immunity may be implicated, tumor and circulating immune responses were examined in a patient who survived disease-free 14 years after hip disarticulation. METHODS: A 71-year-old female with extensive regional metastases of melanoma in the left lower extremity underwent amputation for palliative reasons. Tumor was collected at surgery, and blood was collected during follow-up. Tumor sections were evaluated for lymphocytic infiltration and NY-ESO-1 expression by immunohistochemistry. Cellular immune responses to defined tumor antigens were evaluated by ELISPOT assay, and antibody responses to a panel of tumor antigens were assayed by ELISA. RESULTS: The patient's tumor had minimal lymphocytic infiltrate (immunotype A). NY-ESO-1 was strongly expressed by the melanoma cells. Circulating T-cell responses to NY-ESO-1 peptides were observed 6 and 12 years postoperatively, and antibodies to NY-ESO-1 were detected 2-6 years after surgery. CONCLUSION: The patient described in this report experienced relentless regional tumor progression, with intravascular metastases, and then 14-year systemic disease-free survival after palliative resection, without evidence of melanoma recurrence before death from other causes. Her immune response to NY-ESO-1 likely failed to control established regional metastases because T cells were unable to infiltrate them. It is possible, however, that among other factors, the host immune response may have contributed to systemic protection.

Clinical activity and safety of combination therapy with temsirolimus and bevacizumab for advanced melanoma: a phase II trial (CTEP 7190/Mel47).

PURPOSE: A CTEP-sponsored phase II trial was conducted to evaluate safety and clinical activity of combination therapy with CCI-779 (temsirolimus) and bevacizumab in patients with advanced melanoma. EXPERIMENTAL DESIGN: Patients with unresectable stage III to IV melanoma were treated intravenously with temsirolimus 25 mg weekly and bevacizumab 10 mg every 2 weeks. Adverse events were recorded using CTCAE v3.0. Tumor response was assessed by Response Evaluation Criteria in Solid Tumors and overall survival was recorded. Correlative studies measured protein kinases and histology of tumor biopsies and immune function in peripheral blood. RESULTS: Seventeen patients were treated. Most patients tolerated treatment well, but 2 had grade 4 lymphopenia and 1 developed reversible grade 2 leukoencephalopathy. Best clinical response was partial response (PR) in 3 patients [17.7%, 90% confidence interval (CI) 5, 0-39.6], stable disease at 8 weeks (SD) in 9 patients, progressive disease (PD) in 4 patients, and not evaluable in 1 patient. Maximal response duration for PR was 35 months. Ten evaluable patients had BRAF(WT) tumors, among whom 3 had PRs, 5 had SD, and 2 had PD. Correlative studies of tumor biopsies revealed decreased phospho-S6K (d2 and d23 vs. d1, P < 0.001), and decreased mitotic rate (Ki67(+)) among melanoma cells by d23 (P = 0.007). Effects on immune functions were mixed, with decreased alloreactive T-cell responses and decreased circulating CD4(+)FoxP3(+) cells. CONCLUSION: These data provide preliminary evidence for clinical activity of combination therapy with temsirolimus and bevacizumab, which may be greater in patients with BRAF(wt) melanoma. Mixed effects on immunologic function also support combination with immune therapies.

Molecular insights on the peripheral and intratumoral effects of systemic high-dose rIL-2 (aldesleukin) administration for the treatment of metastatic melanoma.

PURPOSE: We have previously shown that within tumors, recombinant interleukin-2 (rIL-2, aldesleukin) consistently activates tumor-associated macrophages and upregulates IFN-stimulated genes while inducing minimal migration, activation, or proliferation of T cells. These effects are independent of tumor response to treatment. Here, we prospectively evaluated transcriptional alterations induced by rIL-2 in peripheral blood mononuclear cells (PBMC) and within melanoma metastases. EXPERIMENTAL DESIGN: We evaluated gene expression changes by serially comparing pre- to posttreatment samples in 13 patients and also compared transcriptional differences among lesions displaying different responsiveness to therapy, focusing on 2 lesions decreasing in size and 2 remaining stable (responding lesions) compared with nonresponding ones. RESULTS: As previously described, the effects of rIL-2 were dramatic within PBMCs, whereas effects within the tumor microenvironment were lesion specific and limited. However, distinct signatures specific to response could be observed in responding lesions pretreatment that were amplified following rIL-2 administration. These signatures match the functional profile observed in other human or experimental models in which immune-mediated tissue-specific destruction (TSD) occurs, underscoring common pathways leading to rejection. Moreover, the signatures observed in pretreatment lesions were qualitatively similar to those associated with TSD, underlining a determinism to immune responsiveness that depends upon the genetic background of the host or the intrinsic genetic makeup of individual tumors. CONCLUSIONS: This is the first prospectively collected insight on global transcriptional events occurring during high-dose rIL-2 therapy in melanoma metastases responding to treatment.

Randomized multicenter trial of the effects of melanoma-associated helper peptides and cyclophosphamide on the immunogenicity of a multipeptide melanoma vaccine.

PURPOSE: This multicenter randomized trial was designed to test whether melanoma-associated helper peptides augment CD8(+) T-cell responses to a melanoma vaccine and whether cyclophosphamide (CY) pretreatment augments CD4(+) or CD8(+) T-cell responses to that vaccine. PATIENTS AND METHODS: In all, 167 eligible patients with resected stage IIB to IV melanoma were randomly assigned to four vaccination study arms. Patients were vaccinated with 12 class I major histocompatibility complex-restricted melanoma peptides (12MP) to stimulate CD8(+) T cells and were randomly assigned to receive a tetanus helper peptide or a mixture of six melanoma-associated helper peptides (6MHP) to stimulate CD4(+) T cells. Before vaccination, patients were also randomly assigned to receive CY pretreatment or not. T-cell responses were assessed by an ex vivo interferon gamma ELISpot assay. Clinical outcomes and toxicities were recorded. RESULTS: Vaccination with 12MP plus tetanus induced CD8(+) T-cell responses in 78% of patients and CD4(+) T-cell responses to tetanus peptide in 93% of patients. Vaccination with 12MP plus 6MHP induced CD8(+) responses in 19% of patients and CD4(+) responses to 6MHP in 48% of patients. CY had no significant effect on T-cell responses. Overall 3-year survival was 79% (95% CI, 71% to 86%), with no significant differences (at this point) by study arm. CONCLUSION: Melanoma-associated helper peptides paradoxically decreased CD8(+) T-cell responses to a melanoma vaccine (P < .001), and CY pretreatment had no immunologic or clinical effect. Prior work showed immunologic and clinical activity of 6MHP alone. Possible explanations for negative effects on CD8 responses include modulation of homing receptor expression or induction of antigen-specific regulatory T cells.

Primary pericardial malignant mesothelioma and response to radiation therapy.

We report a case of a primary pericardial malignant mesothelioma. A 59-year-old male presented with episodic chest pain and dyspnea on exertion. Cardiac magnetic resonance imaging revealed a large mass in the pericardium attached to the right ventricle. Partial resection of the mass was undertaken revealing malignant mesothelioma, byphasic type. The patient was treated with chemotherapy intermittently over a period of 3 years, but his disease continued to progress. The patient was then treated with definitive radiation therapy to 64 Gy to the primary tumor using a six field 3D conformal technique. The patient remains free of progressive disease 86 months from the time of diagnosis and 50 months from the completion of his radiotherapy.

Immunogenicity for CD8+ and CD4+ T cells of 2 formulations of an incomplete freund's adjuvant for multipeptide melanoma vaccines.

An incomplete Freund's adjuvant (IFA) commonly used in experimental cancer vaccines has recently been reformulated. Oleic acid used in the surfactant was purified from a vegetable source (olives, IFA-VG) rather than an animal source (beef tallow, IFA-AN). To provide an insight into the adjuvant properties of the new formulation, we reviewed T-cell responses, by enzyme-linked immunospot assay, to multipeptide vaccines in 2 sequential clinical trials that spanned this transition of adjuvants. Analyses included 194 patients who received either IFA-AN or IFA-VG for all vaccines, and a subset of 93 patients best matched by study arm for vaccine antigens (12 melanoma peptides restricted by major histocompatibility complex class I, 12MP; plus a tetanus helper peptide, tet) administered with IFA but without granulocyte macrophage-colony stimulating factor. Inflammation was observed at vaccine sites clinically for almost all patients, even including ulceration in a subset with each IFA formulation. CD8 T-cell response rates to the 12 melanoma peptides were 53% [95% confidence interval (CI), 44%, 61%)] for IFA-AN and 46% [95% CI, 32%, 59%)] for IFA-VG. In the 93 patient subset, these rates were 73% [95% CI, 61%, 83%)] and 70% [95% CI, 47%, 87%)], respectively. CD4 T-cell responses to tetanus helper peptide were identified in 94% [95% CI, 86%, 98%)] and 96% [95% CI, 78%, 100%)], respectively. Responses to individual human leukocyte antigen (HLA)-A1, A2, and DR associated peptides were largely preserved, but reactivity trended lower for some HLA-A3 associated peptides. Despite the necessarily retrospective nature of the analysis and limitations of multiple comparisons, our summary data support the use of IFA-VG as an adjuvant with multipeptide vaccines in melanoma patients.

Effectiveness of imiquimod limited to dermal melanoma metastases, with simultaneous resistance of subcutaneous metastasis.

Successful management of epithelial skin cancers with imiquimod 5% cream (Aldara), an immunomodulatory agent, led to speculation that it may promote an immune response against melanoma. Studies, mostly case reports, have assessed the value of imiquimod as a topical treatment for dermal melanoma metastases that prove difficult to manage surgically. The precise value of imiquimod, however, in treatment of dermal and subcutaneous metastases remains unclear. A case at our institution elucidates histopathologically that subcutaneous metastases may progress despite excellent treatment of superficial dermis in the same location. In preparation for a clinical trial using imiquimod to treat patients with dermal melanoma metastases, we have treated several patients off protocol. We present a case report in which the observed changes are documented photographically and histologically. The patient experienced dramatic improvement in the locally treated dermis with concurrent regional treatment failure in the subcutaneous space. Our experience supports growing evidence that imiquimod for some provides an effective option for dermal disease. The unique histological documentation we provide regarding the differential effectiveness of imiquimod in treating various tissue components may help guide future investigations regarding optimal clinical application of imiquimod therapy for melanoma metastases.

Effect of granulocyte/macrophage colony-stimulating factor on circulating CD8+ and CD4+ T-cell responses to a multipeptide melanoma vaccine: outcome of a multicenter randomized trial.

PURPOSE: Granulocyte/macrophage colony-stimulating factor (GM-CSF) administered locally together with vaccines can augment T-cell responses in animal models. Human experience has been limited to small and uncontrolled trials. Thus, a multicenter randomized phase II trial was done to determine whether local administration of GM-CSF augments immunogenicity of a multipeptide vaccine. It also assessed immunogenicity of administration in one versus two vaccine sites. EXPERIMENTAL DESIGN: One hundred twenty-one eligible patients with resected stage IIB to IV melanoma were vaccinated with 12 MHC class I-restricted melanoma peptides to stimulate CD8+ T cells plus a HLA-DR-restricted tetanus helper peptide to stimulate CD4+ T cells, emulsified in incomplete Freund's adjuvant, with or without 110 microg GM-CSF. Among 119 evaluable patients, T-cell responses were assessed by IFN-gamma ELIspot assay and tetramer analysis. Clinical outcomes were recorded. RESULTS: CD8+ T-cell response rates to the 12 MHC class I-restricted melanoma peptides (by day 50) with or without GM-CSF were 34% and 73%, respectively (P < 0.001), by direct ELIspot assay. Tetramer analyses corroborated the functional data. CD4+ T-cell responses to tetanus helper peptide were higher without GM-CSF (95% versus 77%; P = 0.005). There was no significant difference by number of vaccine sites. Three-year overall and disease-free survival estimates (95% confidence interval) were 76% (67-83%) and 52% (43-61%), respectively, with too few events to assess differences by study group. CONCLUSIONS: High immune response rates for this multipeptide vaccine were achieved, but CD8+ and CD4+ T-cell responses were lower when administered with GM-CSF. These data challenge the value of local GM-CSF as a vaccine adjuvant in humans.

Evaluation of the sentinel immunized node for immune monitoring of cancer vaccines.

BACKGROUND: We hypothesized that lymph nodes draining sites of cutaneous vaccination could be identified by sentinel node biopsy techniques, and that measuring T-cell response with lymphocytes obtained from these lymph nodes would provide a more sensitive measure of immunogenicity than would the same measurement made with peripheral blood lymphocytes (PBL). METHODS: ELISpot analysis was used to determine the magnitude of vaccine-specific T-cell response in the sentinel immunized nodes (SIN), random lymph nodes, and peripheral blood lymphocytes (PBL) obtained from patients enrolled in clinical trials of experimental melanoma vaccines. RESULTS: The SIN biopsy was successful in 97% of cases and morbidity was very low. The T-cell response to vaccination was detected with greater sensitivity in the SIN (57%) than in PBL (39%), and evaluation of T-cell responses in the SIN and the PBL together yielded T-cell responses in 63% of patients. When the T-cell responses from a SIN and a random lymph node were compared in four patients, immune responses were detected to one of the vaccine peptides in three of these four patients. In all of those cases, responses were present in the SIN but absent from the random lymph node. CONCLUSION: Measurements of T-cell responsiveness to cutaneous immunization are more frequently positive in the SIN than they are in the PBL, however evaluation of both the SIN and PBL permit a more sensitive measure of T-cell immunogenicity than use of either single source.

Helper T-cell responses and clinical activity of a melanoma vaccine with multiple peptides from MAGE and melanocytic differentiation antigens.

PURPOSE: A phase I/II trial was performed to evaluate the safety and immunogenicity of a novel melanoma vaccine comprising six melanoma-associated peptides defined as antigenic targets for melanoma-reactive helper T cells. Source proteins for these peptides include MAGE proteins, MART-1/MelanA, gp100, and tyrosinase. PATIENTS AND METHODS: Thirty-nine patients with stage IIIB to IV melanoma were vaccinated with this six-peptide mixture weekly at three dose levels, with a preceding phase I dose escalation and subsequent random assignment among the dose levels. Helper T-lymphocyte responses were assessed by in vitro proliferation assay and delayed-type hypersensitivity skin testing. Patients with measurable disease were evaluated for objective clinical response by Response Evaluation Criteria in Solid Tumors. RESULTS: Vaccination with the helper peptide vaccine was well tolerated. Proliferation assays revealed induction of T-cell responses to the melanoma helper peptides in 81% of patients. Among 17 patients with measurable disease, objective clinical responses were observed in two patients (12%), with response durations of 1 and 3.9+ years. Durable stable disease was observed in two additional patients for periods of 1.8 and 4.6+ years. CONCLUSION: Results of this study support the safety and immunogenicity of a vaccine comprised of six melanoma helper peptides. There is also early evidence of clinical activity.