A non-hallucinogenic LSD analog with therapeutic potential for mood disorders.

Hallucinations limit widespread therapeutic use of psychedelics as rapidly acting antidepressants. Here we profiled the non-hallucinogenic lysergic acid diethylamide (LSD) analog 2-bromo-LSD (2-Br-LSD) at more than 33 aminergic G protein-coupled receptors (GPCRs). 2-Br-LSD shows partial agonism at several aminergic GPCRs, including 5-HT2A, and does not induce the head-twitch response (HTR) in mice, supporting its classification as a non-hallucinogenic 5-HT2A partial agonist. Unlike LSD, 2-Br-LSD lacks 5-HT2B agonism, an effect linked to cardiac valvulopathy. Additionally, 2-Br-LSD produces weak 5-HT2A ß-arrestin recruitment and internalization in vitro and does not induce tolerance in vivo after repeated administration. 2-Br-LSD induces dendritogenesis and spinogenesis in cultured rat cortical neurons and increases active coping behavior in mice, an effect blocked by the 5-HT2A-selective antagonist volinanserin (M100907). 2-Br-LSD also reverses the behavioral effects of chronic stress. Overall, 2-Br-LSD has an improved pharmacological profile compared with LSD and may have profound therapeutic value for mood disorders and other indications.

Recognition and Management of Pediatric Sepsis in a Resource-Limited Emergency Department in Mwanza, Tanzania: A Qualitative Study.

OBJECTIVE: The World Health Organization aims to reduce worldwide under-five mortality rates (U5MR), with a focus on resource-limited settings (RLS). Tanzania reports a mean U5MR of 54 per 1000 live births, largely due to treatable infectious diseases that may lead to sepsis, accounting for 40% of the under-five deaths. Bugando Medical Centre in Mwanza, Tanzania represents a resource-limited setting in Sub-Saharan Africa and estimates a 14% pediatric mortality rate. We sought to better understand provider experience in recognizing and managing pediatric sepsis in the emergency department (ED) at Bugando Medical Centre in Mwanza, Tanzania. METHODS: We conducted a qualitative study with a purposive sampling of 14 Bugando Medical Centre ED providers from January to February 2019, via minimally structured interviews, to identify factors influencing the recognition and management of children presenting to the ED with concern for sepsis. Interviews were conducted in English, audio recorded, and transcribed. Data saturation determined the sample size. Three primary coders independently coded all transcripts and developed an initial coding list. Consensus among all authors generated a final coding scheme. A grounded theory approach guided data analysis. RESULTS: We achieved thematic saturation after 13 interviews. Responses identified patient-, provider-, and health care system-related factors influencing sepsis recognition and management in children presenting to the ED. Patient-related factors include the use of traditional healers, limited parent health literacy, and geographic factors impacting access to medical care. Provider-related factors include limited knowledge of pediatric sepsis, lack of a standard communication process among providers, and insufficient experience with procedural skills on children. Health care system-related factors include limited personnel and resources, delayed transfers from referral hospitals, and lack of standard antibiotic-use guidelines. CONCLUSIONS: This qualitative study identified patient, provider, and health care system-related factors that influence the emergency care of children with suspected sepsis in a quaternary hospital in Mwanza, Tanzania. These factors may serve as a framework for educational opportunities to improve the early recognition and management of pediatric sepsis in a resource-limited setting.

Return of the lysergamides. Part VII: Analytical and behavioural characterization of 1-valeroyl-d-lysergic acid diethylamide (1V-LSD).

The psychopharmacological properties of the psychedelic drug lysergic acid diethylamide (LSD) have attracted the interest of several generations of scientists. While further explorations involving novel LSD-type compounds are needed to assess their potential as medicinal drugs, the emergence of novel derivatives as recreational drugs has also been observed. 1-Valeroyl-LSD (also known as 1-valeryl-LSD, 1-pentanoyl-LSD, 1V-LSD, or "Valerie") is a new N1 -acylated LSD derivative that recently appeared on the online market, and it could be viewed as a higher homolog of ALD-52, 1P-LSD, and 1B-LSD. The present study included the analytical characterization and involved various methods of mass spectrometry (MS), gas and liquid chromatography (GC and LC), nuclear magnetic resonance (NMR) spectroscopy, GC-solid-state infrared (GC-sIR) analysis, and Raman spectroscopy. The in vivo activity of 1V-LSD was assessed using the mouse head-twitch response (HTR), a 5-HT2A -mediated head movement that serves as a behavioral proxy in rodents for human hallucinogenic effects. Similar to LSD and other psychedelic drugs, the HTR induced by 1V-LSD was dose dependent, and the median effective dose for 1V-LSD was 373 nmol/kg, which was about a third of the potency of LSD (ED50  = 132.8 nmol/kg). Lysergamides containing the N1 -substituent typically act as weak partial agonists at the 5-HT2A receptor and are believed to serve as prodrugs for LSD. 1V-LSD is also likely to be hydrolyzed to LSD and serve as a prodrug, but studies to assess the biotransformation and receptor pharmacology of 1V-LSD should be performed to fully elucidate its mechanism of action.

Routine Computer Tomography Imaging for the Detection of Recurrences in High-Risk Melanoma Patients.

BACKGROUND: The use of routine CT imaging for surveillance in asymptomatic patients with cutaneous melanoma is controversial. We report our experience using a surveillance strategy that included CT imaging for a cohort of patients with high-risk melanoma. METHODS: A total of 466 patients with high-risk cutaneous melanoma enrolled in adjuvant immunotherapy trials were followed for tumor progression by physical examination, labs, and CT imaging as defined by protocol. Evaluations were obtained at least every 6 months for year 1, every 6 months for year 2, and then annually for the remainder of the 5-year study. Time to tumor progression, sites of recurrence, and the method of relapse detection were identified. RESULTS: The patient cohort consisted of 115 stage II patients, 328 stage III patients, and 23 patients with resected stage IV melanoma. The medium time to progression for the 225 patients who developed tumor progression was 7 months. Tumor progression was detected by patients, physician examination or routine labs, or by CT imaging alone in 27, 14, and 59% of cases respectively. Melanoma recurrences were noted to be locoregional in 36% of cases and systemic in 64% of cases. Thirty percent of patients with locoregional relapse and 75% of patients with systemic relapse were detected solely by CT imaging. CONCLUSIONS: CT imaging alone detected the majority of sites of disease progression in our patients with high-risk cutaneous melanoma. This disease was not heralded by symptoms, physical examination, or blood work. Although the benefit of the early detection of advanced melanoma is unknown, this experience is relevant because of the rapid development and availability of potentially curative immunotherapies.

Randomized, Prospective Evaluation Comparing Intensity of Lymphodepletion Before Adoptive Transfer of Tumor-Infiltrating Lymphocytes for Patients With Metastatic Melanoma.

PURPOSE: Adoptive cell transfer, the infusion of large numbers of activated autologous lymphocytes, can mediate objective tumor regression in a majority of patients with metastatic melanoma (52 of 93; 56%). Addition and intensification of total body irradiation (TBI) to the preparative lymphodepleting chemotherapy regimen in sequential trials improved objective partial and complete response (CR) rates. Here, we evaluated the importance of adding TBI to the adoptive transfer of tumor-infiltrating lymphocytes (TIL) in a randomized fashion. PATIENTS AND METHODS: A total of 101 patients with metastatic melanoma, including 76 patients with M1c disease, were randomly assigned to receive nonmyeloablative chemotherapy with or without 1,200 cGy TBI before transfer of tumor-infiltrating lymphcytes. Primary end points were CR rate (as defined by Response Evaluation Criteria in Solid Tumors v1.0) and overall survival (OS). Clinical and laboratory data were analyzed for correlates of response. RESULTS: CR rates were 24% in both groups (12 of 50 v 12 of 51), and OS was also similar (median OS, 38.2 v 36.6 months; hazard ratio, 1.11; 95% CI, 0.65 to 1.91; P = .71). Thrombotic microangiopathy was an adverse event unique to the TBI arm and occurred in 13 of 48 treated patients. With a median potential follow-up of 40.9 months, only one of 24 patients who achieved a CR recurred. CONCLUSION: Adoptive cell transfer can mediate durable complete regressions in 24% of patients with metastatic melanoma, with median survival > 3 years. Results were similar using chemotherapy preparative regimens with or without addition of TBI.

Chemotherapy-refractory diffuse large B-cell lymphoma and indolent B-cell malignancies can be effectively treated with autologous T cells expressing an anti-CD19 chimeric antigen receptor.

PURPOSE: T cells can be genetically modified to express an anti-CD19 chimeric antigen receptor (CAR). We assessed the safety and efficacy of administering autologous anti-CD19 CAR T cells to patients with advanced CD19(+) B-cell malignancies. PATIENTS AND METHODS: We treated 15 patients with advanced B-cell malignancies. Nine patients had diffuse large B-cell lymphoma (DLBCL), two had indolent lymphomas, and four had chronic lymphocytic leukemia. Patients received a conditioning chemotherapy regimen of cyclophosphamide and fludarabine followed by a single infusion of anti-CD19 CAR T cells. RESULTS: Of 15 patients, eight achieved complete remissions (CRs), four achieved partial remissions, one had stable lymphoma, and two were not evaluable for response. CRs were obtained by four of seven evaluable patients with chemotherapy-refractory DLBCL; three of these four CRs are ongoing, with durations ranging from 9 to 22 months. Acute toxicities including fever, hypotension, delirium, and other neurologic toxicities occurred in some patients after infusion of anti-CD19 CAR T cells; these toxicities resolved within 3 weeks after cell infusion. One patient died suddenly as a result of an unknown cause 16 days after cell infusion. CAR T cells were detected in the blood of patients at peak levels, ranging from nine to 777 CAR-positive T cells/µL. CONCLUSION: This is the first report to our knowledge of successful treatment of DLBCL with anti-CD19 CAR T cells. These results demonstrate the feasibility and effectiveness of treating chemotherapy-refractory B-cell malignancies with anti-CD19 CAR T cells. The numerous remissions obtained provide strong support for further development of this approach.

Durable complete responses in heavily pretreated patients with metastatic melanoma using T-cell transfer immunotherapy.

PURPOSE: Most treatments for patients with metastatic melanoma have a low rate of complete regression and thus overall survival in these patients is poor. We investigated the ability of adoptive cell transfer utilizing autologous tumor-infiltrating lymphocytes (TIL) to mediate durable complete regressions in heavily pretreated patients with metastatic melanoma. EXPERIMENTAL DESIGN: Ninety-three patients with measurable metastatic melanoma were treated with the adoptive transfer of autologous TILs administered in conjunction with interleukin-2 following a lymphodepleting preparative regimen on three sequential clinical trials. Ninety-five percent of these patients had progressive disease following a prior systemic treatment. Median potential follow-up was 62 months. RESULTS: Objective response rates by Response Evaluation Criteria in Solid Tumors (RECIST) in the 3 trials using lymphodepleting preparative regimens (chemotherapy alone or with 2 or 12 Gy irradiation) were 49%, 52%, and 72%, respectively. Twenty of the 93 patients (22%) achieved a complete tumor regression, and 19 have ongoing complete regressions beyond 3 years. The actuarial 3- and 5-year survival rates for the entire group were 36% and 29%, respectively, but for the 20 complete responders were 100% and 93%. The likelihood of achieving a complete response was similar regardless of prior therapy. Factors associated with objective response included longer telomeres of the infused cells, the number of CD8(+)CD27(+) cells infused, and the persistence of the infused cells in the circulation at 1 month (all P(2) < 0.001). CONCLUSIONS: Cell transfer therapy with autologous TILs can mediate durable complete responses in patients with metastatic melanoma and has similar efficacy irrespective of prior treatment. Clin Cancer Res; 17(13); 4550-7. ©2011 AACR.

CD8+ enriched "young" tumor infiltrating lymphocytes can mediate regression of metastatic melanoma.

PURPOSE: Tumor-infiltrating lymphocytes (TIL) and interleukin (IL)-2 administered following lymphodepletion can cause the durable complete regression of bulky metastatic melanoma in patients refractory to approved treatments. However, the generation of a unique tumor-reactive TIL culture for each patient may be prohibitively difficult. We therefore investigated the clinical and immunologic impact of unscreened, CD8+ enriched "young" TIL. EXPERIMENTAL DESIGN: Methods were developed for generating TIL that minimized the time in culture and eliminated the individualized tumor-reactivity screening step. Thirty-three patients were treated with these CD8+ enriched young TIL and IL-2 following nonmyeloablative lymphodepletion (NMA). Twenty-three additional patients were treated with CD8+ enriched young TIL and IL-2 after lymphodepletion with NMA and 6 Gy of total body irradiation. RESULTS: Young TIL cultures for therapy were successfully established from 83% of 122 consecutive melanoma patients. Nineteen of 33 patients (58%) treated with CD8+ enriched young TIL and NMA had an objective response (Response Evaluation Criteria in Solid Tumors) including 3 complete responders. Eleven of 23 patients (48%) treated with TIL and 6 Gy total body irradiation had an objective response including 2 complete responders. At 1 month after TIL infusion the absolute CD8+ cell numbers in the periphery were highly correlated with response. CONCLUSIONS: This study shows that a rapid and simplified method can be used to reliably generate CD8+ enriched young TIL for administration as an individualized therapy for advanced melanoma, and may allow this potentially effective treatment to be applied at other institutions and to reach additional patients.

Different adjuvanticity of incomplete freund's adjuvant derived from beef or vegetable components in melanoma patients immunized with a peptide vaccine.

Adjuvants are requisite components of many vaccines designed to elicit T-cell immunity although the exact components of commonly used adjuvants are not always fully defined. In 2006, owing to concerns of prion contamination, the formulation of Montanide ISA 51 Incomplete Freund's Adjuvant (IFA) was changed from using oleic acid isolated from beef tallow to that isolated from olives. In sequential clinical trials in the Surgery Branch, NCI patients at high risk for recurrence of melanoma were immunized with the gp100 melanoma/melanocyte antigenic peptide, gp100: 209-217 (210M), emulsified in the beef-derived IFA or the olive-derived IFA. The in vivo generation of gp100 reactive T cells was significantly less in patients receiving the olive compared with the beef IFA as assessed by both ELISPOT (P2=0.0001) and in vitro sensitization assays (P2=0.0001). Local skin reactions to the peptide emulsion were also far less severe using the olive IFA (P2=0.0003). Thus it seems likely that contaminants in the beef-derived IFA played an important role in the increased adjuvanticity of this preparation compared with the olive-derived IFA. These findings raise serious concerns related to the use of the available olive-derived IFA for immunization in clinical trials. A survey of ongoing clinical trials listed in ClinicalTrials.gov revealed 36 trials currently accruing patients that are using the olive-derived Montanide ISA 51 IFA.

Adoptive cell therapy for patients with metastatic melanoma: evaluation of intensive myeloablative chemoradiation preparative regimens.

PURPOSE: The two approved treatments for patients with metastatic melanoma, interleukin (IL)-2 and dacarbazine, mediate objective response rates of 12% to 15%. We previously reported that adoptive cell therapy (ACT) with autologous antitumor lymphocytes in lymphodepleted hosts mediated objective responses in 51% of 35 patients. Here, we update that study and evaluate the safety and efficacy of two increased-intensity myeloablative lymphodepleting regimens. PATIENTS AND METHODS: We performed two additional sequential trials of ACT with autologous tumor-infiltrating lymphocytes (TIL) in patients with metastatic melanoma. Increasing intensity of host preparative lymphodepletion consisting of cyclophosphamide and fludarabine with either 2 (25 patients) or 12 Gy (25 patients) of total-body irradiation (TBI) was administered before cell transfer. Objective response rates by Response Evaluation Criteria in Solid Tumors (RECIST) and survival were evaluated. Immunologic correlates of effective treatment were studied. RESULTS: Although nonmyeloablative chemotherapy alone showed an objective response rate of 49%, when 2 or 12 Gy of TBI was added, the response rates were 52% and 72% respectively. Responses were seen in all visceral sites including brain. There was one treatment-related death in the 93 patients. Host lymphodepletion was associated with increased serum levels of the lymphocyte homeostatic cytokines IL-7 and IL-15. Objective responses were correlated with the telomere length of the transferred cells. CONCLUSION: Host lymphodepletion followed by autologous TIL transfer and IL-2 results in objective response rates of 50% to 70% in patients with metastatic melanoma refractory to standard therapies.

IL-7 administration to humans leads to expansion of CD8+ and CD4+ cells but a relative decrease of CD4+ T-regulatory cells.

Lymphopenia is a serious consequence of HIV infection and the administration of cancer chemotherapeutic agents. Although growth factors can be administered to patients to increase circulating neutrophils, there is no effective method to stimulate CD8+ lymphocyte production in humans, in vivo. This report is the first to describe the administration of recombinant interleukin-7 to humans and demonstrates the ability of this cytokine to mediate selective increases in CD4+ and CD8+ lymphocytes along with a decrease in the percentage of CD4+ T-regulatory cells. These studies suggest an important role for interleukin-7 in the treatment of patients with lymphopenia.

Altered CD8(+) T-cell responses when immunizing with multiepitope peptide vaccines.

Efforts to develop effective cancer vaccines often use combinations of immunogenic peptides to increase the applicability and effectiveness of the immunizations. The immunologic consequences of combining more than 1 self/tumor antigen in a single vaccine emulsion remain unclear, however. We performed 2 sequential clinical trials in patients at high risk for melanoma recurrence. Patients were given the highly immunogenic gp100:209-217(210M) peptide and the less immunogenic tyrosinase:368-376(370D) peptide once every 3 weeks for 4 weeks. This vaccination course was 12 weeks long, and patients were vaccinated for up to 4 courses (16 total vaccinations). In the first trial in 31 patients, the peptides were emulsified separately in incomplete Freund adjuvant and injected at 2 different sites. In the second trial in 33 patients, the peptides were emulsified together and injected at the same site. Cryopreserved lymphocytes were obtained by apheresis after each course and were evaluated for antipeptide activity using tetramer, enzyme-linked immunospot, and in vitro sensitization boost assays. When the peptides were injected at separate sites, robust specific reactivity to the native gp100:209-217 peptide was measured by each of the assays, whereas immunization with the tyrosinase:368-376(370D) peptide was far less effective. When the peptides were emulsified and injected together at the same site, immunization to the gp100:209-217(210M) epitope dropped precipitously, whereas reactivity to the tyrosinase:368-376(370D) peptide was enhanced. These cautionary data indicate that mixing peptides in the same emulsion can alter reactivity compared with peptides injected separately by mechanisms that may include the induction of localized nonspecific inflammation or competitive binding of peptides to major histocompatibility complex molecules.

Tumor progression can occur despite the induction of very high levels of self/tumor antigen-specific CD8+ T cells in patients with melanoma.

The identification of many tumor-associated epitopes as nonmutated "self" Ags led to the hypothesis that the induction of large numbers of self/tumor Ag-specific T cells would be prevented because of central and peripheral tolerance. We report in this study on vaccination efforts in 95 HLA-A*0201 patients at high risk for recurrence of malignant melanoma who received prolonged immunization with the "anchor-modified" synthetic peptide, gp100209-217(210M). Vaccination using this altered peptide immunogen was highly effective at inducing large numbers of self/tumor-Ag reactive T cells in virtually every patient tested, with levels as high as 42% of all CD8+ T cells assessed by tetramer analysis. From 1 to 10% of all CD8+ cells were tumor-Ag reactive in 44% of patients and levels >10% were generated in 17% of patients. These studies were substantiated using the ELISPOT assay and a bulk cytokine release assay. Although our data regarding "tumor escape" were inconclusive, some patients had growing tumors that expressed Ag and HLA-A*0201 in the presence of high levels of antitumor T cells. There was no difference in the levels of antitumor Ag-specific T cells in patients who recurred compared with those that remained disease-free. Thus, the mere presence of profoundly expanded numbers of vaccine-induced, self/tumor Ag-specific T cells cannot by themselves be used as a "surrogate marker" for vaccine efficacy. Further, the induction of even high levels of antitumor T cells may be insufficient to alter tumor progression.

Randomized study of high-dose and low-dose interleukin-2 in patients with metastatic renal cancer.

PURPOSE: This three-arm randomized study compares response rates and overall survival of patients with metastatic renal cell cancer (RCC) receiving high-dose or one of two low-dose interleukin-2 (IL-2) regimens. PATIENTS AND METHODS: Patients with measurable metastatic RCC and a good performance status were randomized to receive either 720,000 U/kg (high-dose [HD]) or 72,000 U/kg (low-dose [LD]), both given by intravenous (IV) bolus every 8 hours. After randomly assigning 117 patients, a third arm of low-dose daily subcutaneous IL-2 was added, and an additional 283 patients were randomly assigned. RESULTS: A total of 156 patients were randomly assigned to HD IV IL-2, and 150 patients to LD IV IL-2. Toxicities were less frequent with LD IV IL-2 (especially hypotension), but there were no IL-2-related deaths in any arm. There was a higher response proportion with HD IV IL-2 (21%) versus LD IV IL-2 (13%; P =.048) but no overall survival difference. The response rate of subcutaneous IL-2 (10%, partial response and complete response) was similar to that of LD IV IL-2, differing from HD IV (P =.033). Response durability and survival in completely responding patients was superior with HD IV compared with LD IV therapy (P =.04). CONCLUSION: Major tumor regressions, as well as complete responses, were seen with all regimens tested. IL-2 was more clinically active at maximal doses, although this did not produce an overall survival benefit. The immunological factors which constrain the curative potential of IL-2 to only a small percentage of patients need to be further elucidated.

Recombinant fowlpox viruses encoding the anchor-modified gp100 melanoma antigen can generate antitumor immune responses in patients with metastatic melanoma.

PURPOSE: The purpose of this study was to evaluate the immunological responses and therapeutic effectiveness of immunization with fowlpox vaccines encoding the gp100 melanoma antigen in patients with metastatic melanoma. EXPERIMENTAL DESIGN: In three consecutive clinical trials, patients were immunized with recombinant fowlpox viruses encoding three different forms of the melanoma/melanocyte-associated antigen gp100: (a) the native, full-length gp100 molecule; (b) the gp100 molecule with two amino acids modified to increase binding to HLA-A*0201 molecules; and (c) a "minigene" construct encoding a single, modified epitope gp100:209-217(210M) targeted to the endoplasmic reticulum. The immunogenicity of these constructs was studied using peripheral blood mononuclear cells to measure epitope-specific release of IFN-gamma. RESULTS: Reactivity against gp100 was not seen in any patient before receiving fowlpox immunization. Whereas just one of seven patients developed reactivity after receiving fowlpox encoding native gp100, 10 of 14 patients who received fowlpox encoding the anchor modified full-length gp100 exhibited reactivity against the native gp100 molecule, and 12 of 16 patients were successfully immunized after inoculation with the modified minigene construct (p2 = 0.02). There was no difference in the latter group between those randomized to vaccination by i.v. or i.m. routes. There was one partial cancer regression in the group of 46 patients receiving virus in the absence of interleukin (IL)-2. Once patients showed evidence of progressive disease, they were eligible for "cross-over" treatment to IL-2 alone or with the fowlpox virus. None of the 13 patients receiving the full-length or modified full-length forms of gp100 responded when receiving IL-2, whereas 6 of 12 patients who received the fowlpox containing the minigene construct and then received IL-2 showed objective cancer regressions, including three patients with complete regression. CONCLUSIONS: These data underscore the importance of modifying anchor residues of nonmutated self-antigen peptides to generate cellular immune responses after immunization and support the further investigation of recombinant fowlpox viruses encoding modified epitopes administered in combination with IL-2.

Immunization of patients with metastatic melanoma using both class I- and class II-restricted peptides from melanoma-associated antigens.

Cancer vaccines targeting CD8+ T cells have been successful in eliciting immunologic responses but disappointing in inducing clinical responses. Strong evidence supports the importance of CD4+ T cells in "helping" cytotoxic CD8+ cells in antitumor immunity. We report here on two consecutive clinical trials evaluating the impact of immunization with both human leukocyte antigen class I- and class II-restricted peptides from the gp100 melanoma antigen. In Protocol 1, 22 patients with metastatic melanoma were immunized with two modified class I A*0201-restricted peptides, gp100:209-217(210M) and MART-1:26-35(27L). In Protocol 2, 19 patients received the same class I-restricted peptides in combination with a class II DRB1*0401-restricted peptide, gp100:44-59. As assessed by in vitro sensitization assays using peripheral blood mononuclear cells (PBMC) against the native gp100:209-217 peptide, 95% of patients in Protocol 1 were successfully immunized after two vaccinations in contrast to 50% of patients in Protocol 2 (P(2) < 0.005). Furthermore, the degree of sensitization was significantly lower in patients in Protocol 2 (P = 0.01). Clinically, one patient in Protocol 2 had an objective response, and none did in Protocol 1. Thus, the addition of the class II-restricted peptide gp100:44-59 did not improve clinical response but might have diminished the immunologic response of circulating PBMC to the class I-restricted peptide gp100:209-217. The reasons for this decreased immune reactivity are unclear but may involve increased CD4+CD25+ regulatory T-cell activity, increased apoptosis of activated CD8+ T cells, or the trafficking of sensitized CD8+ reactive cells out of the peripheral blood. Moreover, the sequential, nonrandomized nature of patient enrollment for the two trials may account for the differences in immunologic response.

Inability to immunize patients with metastatic melanoma using plasmid DNA encoding the gp100 melanoma-melanocyte antigen.

Immunization with plasmid DNA represents a theoretically attractive method for increasing T cell responses against cancer antigens. We administered plasmid DNA encoding the gp100 melanoma-melanocyte differentiation antigen to 22 patients with metastatic melanoma and evaluated immunologic and clinical responses. Patients were randomized to receive plasmid DNA either intradermally (n = 10) or intramuscularly (n = 12). One patient (4.5%) exhibited a partial response of several subcentimeter cutaneous nodules. All other patients had progressive disease. Of 13 patients with cells available before and after immunization, no patient exhibited evidence of the development of anti-gp100 cell responses using in vitro boost assays. The same assays were capable of demonstrating immunologic precursors after immunization with fowl poxvirus encoding gp100 or with gp100 peptides. We were thus unable to demonstrate significant clinical or immunologic responses to plasmid DNA encoding the "self" nonmutated gp100 tumor antigen.

Cancer regression and autoimmunity induced by cytotoxic T lymphocyte-associated antigen 4 blockade in patients with metastatic melanoma.

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a critical immunoregulatory molecule (expressed on activated T cells and a subset of regulatory T cells) capable of down-regulating T cell activation. Blockade of CTLA-4 has been shown in animal models to improve the effectiveness of cancer immunotherapy. We thus treated 14 patients with metastatic melanoma by using serial i.v. administration of a fully human anti-CTLA-4 antibody (MDX-010) in conjunction with s.c. vaccination with two modified HLA-A*0201-restricted peptides from the gp100 melanoma-associated antigen, gp100:209-217(210M) and gp100:280-288(288V). This blockade of CTLA-4 induced grade III/IV autoimmune manifestations in six patients (43%), including dermatitis, enterocolitis, hepatitis, and hypophysitis, and mediated objective cancer regression in three patients (21%; two complete and one partial responses). This study establishes CTLA-4 as an important molecule regulating tolerance to "self" antigens in humans and suggests a role for CTLA-4 blockade in breaking tolerance to human cancer antigens for cancer immunotherapy.

Cancer regression and autoimmunity in patients after clonal repopulation with antitumor lymphocytes.

We report here the adoptive transfer, to patients with metastatic melanoma, of highly selected tumor-reactive T cells directed against overexpressed self-derived differentiation antigens after a nonmyeloablative conditioning regimen. This approach resulted in the persistent clonal repopulation of T cells in those cancer patients, with the transferred cells proliferating in vivo, displaying functional activity, and trafficking to tumor sites. This led to regression of the patients' metastatic melanoma as well as to the onset of autoimmune melanocyte destruction. This approach presents new possibilities for the treatment of patients with cancer as well as patients with human immunodeficiency virus-related acquired immunodeficiency syndrome and other infectious diseases.

A phase I study of nonmyeloablative chemotherapy and adoptive transfer of autologous tumor antigen-specific T lymphocytes in patients with metastatic melanoma.

This report describes a phase I clinical trial using nonmyeloablative, lympho-depleting chemotherapy in combination with adoptive immunotherapy in patients with metastatic melanoma. The chemotherapy-conditioning schedule that induced transient lymphopenia consisted of cyclophosphamide (30 or 60 mg/kg per day for 2 days) followed by fludarabine (25 mg/m(2) per day for 5 days). Immunotherapy for all patients consisted of in vitro expanded, tumor-reactive, autologous T-cell clones selected for high avidity recognition of melanoma antigens. Cohorts of three to six patients each received either no interleukin (IL)-2, low-dose IL-2 (72,000 IU/kg intravenously three times a day to a maximum of 15 doses), or high-dose IL-2 (720,000 IU/kg intravenously three times a day for a maximum of 12 doses). The toxicities associated with this treatment were transient and included neutropenia and thrombocytopenia that resolved in all patients. High dose intravenous IL-2 was better tolerated by patients after chemotherapy than during previous immunotherapy cycles without chemotherapy. No patient exhibited an objective clinical response to treatment, although five patients demonstrated mixed responses or transient shrinkage of metastatic deposits. This study established a nonmyeloablative-conditioning regimen that could be safely administered in conjunction with adoptive T-cell transfer and IL-2 in patients with metastatic melanoma.