Gut Microbiota and Response to Immunotherapeutic Drugs in Oncology: More Questions Than Answers.

Immuno-oncology drugs (IODs) have revolutionized the treatment of some cancers. Although IODs are enabling some patients with cancer to become long-time survivors, only 30% to 40% respond to these drugs. There is experimental and clinical evidence that the gut microbiome may play a role in IOD response, leading to speculation that manipulation of the gut microenvironment might improve the response rate to IODs. We review the evidence relating to how gut microorganisms may affect response to IODs and discuss the implications of targeting the microbiome to improve IOD response, including the challenges to refine and translate the findings to practical clinical use.

Bioequivalence Study of Rivastigmine 6 mg Capsules (Single Dose) in Healthy Volunteers.

OBJECTIVE: To assess the bioequivalence of generic formulation of rivastigmine (test) and Exelon (reference). METHODS: This randomized, open-label, 2-period, single-dose, 2-treatment, 2-sequence, crossover study was conducted in 40 healthy men under fed condition. Participants were randomized to receive a single dose of Exelon or rivastigmine capsule. RESULTS: A total of 31 participants completed the study. Area under the concentration-time curve from time zero to time t (AUC0- t) and area under the concentration-time curve from time zero to infinity (AUC0-∞) for Exelon (mean [standard deviation], h·ng/mL) were 126.40 (56.95) and 129.46 (59.94), respectively, while they were 122.73 (43.46) and 125.08 (45.39) for rivastigmine. Geometric mean ratios of rivastigmine/Exelon were 99.17% for AUC0- t, 98.81% for AUC0-∞, and 105% for maximum observed plasma concentration ( Cmax). The 90% confidence intervals (CIs) were 94.14% to 104.46%, 93.77% to 104.12%, and 93.08% to 118.44%, respectively. Both formulations were well tolerated. CONCLUSION: The generic and reference formulations were bioequivalent, as the 90% CIs for Cmax, AUC0- t, and AUC0-∞ were within the range of 80% to 125%.

Pharmacokinetics of fixed-dose combination of tenofovir disoproxil fumarate, lamivudine, and efavirenz: results of a randomized, crossover, bioequivalence study.

The objective of this study was to assess the bioequivalence between a fixed-dose combination of tenofovir disoproxil fumarate/lamivudine/efavirenz 300/300/600 mg and the individual innovator products. A randomized, balanced, open-label, two-sequence, two-treatment, two-period, single dose, crossover study in 48 healthy adults was conducted. Dosing was separated by a washout period of 32 days. Twenty-seven blood samples were collected in each period from pre-dose to 72 h post-dose. The data of 45 subjects were analyzed for pharmacokinetics and safety. Ninety percent CIs of geometric mean ratio on Cmax, AUC0-t, and AUC0-inf for tenofovir and lamivudine and on Cmax and AUC0-72 for efavirenz were within the acceptance criteria (80-125%). For tenofovir disoproxil fumarate, the Tmax, Kel, and t1/2 values for the test and reference products were 1.02 versus 0.91 h, 0.04 versus 0.04/h, 18.67 versus 18.46 h, respectively. For lamivudine, the Tmax, Kel, and t1/2 values were: 1.38 versus 1.30 h, 0.21 versus 0.19/h, 3.44 versus 3.91 h, respectively. For efavirenz, the Tmax values for the test and reference products were 3.71 and 3.65 h, respectively. Both the treatments were well tolerated. Our findings suggest that the tested formulation is bioequivalent to the innovators' formulations, and both treatments were well tolerated.

Bioequivalence study of cyclizine hydrochloride 50 mg tablets in healthy volunteers: a randomized, open-label, single-dose study.

BACKGROUND: Cyclizine is used in the treatment and prevention of nausea and vomiting. We aimed to demonstrate bioequivalence between two formulations of cyclizine 50 mg tablets. METHODS/RESULTS: This single-dose, two-treatment, two-period, two-sequence, open-label, randomized crossover study was conducted on 32 healthy male volunteers. The average values for Cmax, Tmax, AUC0-t and AUC0-inf were 21.50 ng/ml, 3.85 h, 423.71 ng.h/ml and 489.26 ng.h/ml, for cyclizine 50 mg (test) versus 20.39 ng/ml, 4.34 h, 410.56 ng.h/ml and 473.86 ng.h/ml for Valoid 50 mg (reference). The 90% CI of the mean ratios of Cmax (geometric mean ratio: 101.81 ng/ml), and AUC0-t (101.81 ng.h/ml) were within the bioequivalence range of 80 to 125%. Both drugs were well tolerated. CONCLUSION: Cyclizine 50 mg is bioequivalent to the reference.

The study of c-Src kinase and pStat3 protein expression in retinoblastoma.

We examine the immunoreactivity of the non-receptor tyrosine kinase, c-Src kinase and its downstream molecule, signal transducer and activator of transcription 3 (pStat3) in retinoblastoma (RB), and correlation with invasiveness and differentiation. Tumor samples from 40 patients with RB were available for the study. There were 18 tumors in group 1 (non-invasive) and 22 tumors in group 2 (invasive). The immunoreactivity of c-Src kinase and pStat3 was compared in the two groups of tumors. Group 1 (non-invasive) RB showed intermediate c-Src kinase immunoreactivity (Allred score 4-5) in 14/18 tumors and low immunoreactivity (Allred score 2-3) in 4/18 tumors. pStat3 was intermediate (Allred score 4-5) in 6/18 tumors and negative (Allred score 0) in 12/18 tumors. Group 2 (invasive) RB showed high c-Src kinase immunoreactivity (Allred score 6-8) in 22/22 tumors and high pStat3 (Allred score 6-8) in 19/22 tumors. The expression of c-Src kinase (P<0.001) and pStat3 (P<0.001) was significantly higher in group 2 RB. Src kinase expression (P<0.05) and pStat3 expression (P<0.05) was higher in the poorly differentiated tumors compared to moderately- and well-differentiated tumors. The increased expression of c-Src kinase and pStat3 expression could play a role in the invasiveness of group 2 tumors. Further characterization of the pathways involved in the pathogenesis of RB will shed light on fundamental mechanisms of tumorigenesis.

Human leukocyte class I antigen and beta2-microglobulin expression in conjunctival dysplasia, carcinoma in situ, and squamous cell carcinoma.

PURPOSE: Malignant transformation of cells is frequently associated with abnormalities in HLA expression. These abnormalities may play a significant role in the clinical course of the disease because the cellular immune response to tumors relies on concomitant recognition of tumor antigens with self-HLA molecules. Since HLA molecules mediate interactions of tumor cells with specific receptors on T and natural killer (NK) cells, tight control of expression of HLA molecules is critical for initiation and implementation of an effective cellular immune response. There is not much information on HLA class I antigens in conjunctival carcinomas. We studied the immunoexpression of HLA class I antigen and beta2-microglobulin (beta2-m) in conjunctival dysplasias and conjunctival squamous cell carcinomas. METHODS: HLA class I antigen and beta2-m expression were analyzed in 10 conjunctival dysplasias, 6 carcinomas in situ, and in 11 conjunctival carcinomas by immunoperoxidase staining with monoclonal antibodies to HLA class I antigen and beta2-m on the archival clinical samples. Immunoanalysis was done according to the International Histocompatibility Working Group Project Description. RESULTS: HLA class I antigen and beta2-m were heterogeneous in 10 conjunctival dysplasias, negative in 6 carcinomas in situ, and 11 conjunctival squamous cell carcinomas. The difference of immunoexpression for HLA class I and beta2-m among the 3 groups was statistically significant (P <0.001). CONCLUSIONS: HLA class I antigens and beta2-m are decreased in conjunctival dysplasias and negative in carcinomas in situ, and carcinomas. The findings support the role of cytotoxic T lymphocyte-mediated control of tumor growth in the clinical course of conjunctival squamous cell carcinomas.

HLA expression in choroidal melanomas: correlation with clinicopathological features.

PURPOSE: In this retrospective study, we analyzed the relevance of human leukocyte antigen (HLA) expression to clinical behavior of uveal melanoma and correlated it with conventional light microscopic parameters. METHODS: HLA class I antigen and Beta 2 microglobulin expression were analyzed in 45 primary choroidal melanoma lesions by immunoperoxidase staining with monoclonal antibodies to HLA class I antigen and beta 2 microglobulin and correlated with the known clinicopathological parameters. Immunoanalysis was done by a semi quantitative method. The tumors were divided into 3 groups. Group A: Tumors with no extrascleral extension/no liver metastases, group B: tumors with only extrascleral extension and group C: tumors with liver metastases. For statistical analysis we analyzed the negative, weak (heterogeneous) and the positive expression of HLA and beta 2 microglobulin with known clinicopathological parameters. RESULTS: In-group A (n = 35) tumors with no extrascleral extension and no liver metastases HLA class I antigen and beta 2 microglobulin are negative (absent staining) in 30 choroidal melanomas. In-group B (n = 4) they are weak (heterogeneous) in 3 tumors. In-group C (n = 6) all the 6 tumors have a positive (bright staining) immunoexpression. No statistical significance was obtained when HLA and beta 2 microglobulin immunoreactivity was compared against largest tumor diameter (LTD), tumor infiltrating lymphocytes (TIL), mitosis and nuclear grade. The difference of HLA class I and beta 2-microglobulin imunoreactivity among the various cell types spindle, mixed and epithelioid was statistically significant (p = 0.003), (p = 0.004). The difference in immunoreactivity between tumors with no liver metastases and tumors with liver metastases was statistically significant (p < 0.001). CONCLUSIONS: HLA class I antigen and beta 2 microglobulin are negative in melanomas with no extrascleral extension and liver metastases and weak in melanomas with extrascleral extension and are positive in melanomas with liver metastases. HLA expression is independent of the conventional markers in uveal melanoma.

Major histocompatibility antigens and antigen-processing molecules in retinoblastoma.

BACKGROUND: Malignant transformation of cells is frequently associated with abnormalities in human leukocyte antigen (HLA) expression. These abnormalities may play a role in the clinical course of the disease, because HLAs mediate interactions of tumor cells with cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. Retinoblastoma is the most common intraocular malignant tumor in childhood and is characterized by direct spread to the optic nerve and orbit as well as hematogeneous and lymphatic spread. Little is known about the role of HLA expression in the progression of this malignant disease. METHODS: HLA Class I antigen, beta2-microglobulin (beta2-m), HLA Class II antigens, and the antigen-processing molecules (APMs) of the HLA Class I pathway, including proteasomal subunits (low-molecular mass polypeptide 2 [LMP-2] and LMP-10), the transporter-associated protein (TAP-1) subunit, the binding protein tapasin, and the chaperone molecule calnexin, were studied in 30 archival retinoblastoma specimens by immunohistochemistry. Immunoanalysis was performed based on the International Histocompatibility Working Group Project Description. RESULTS: HLA Class I antigen, beta2-m, HLA Class II antigen, and APMs were positive in 12 tumors with no invasion and were decreased in 13 tumors with choroidal and optic nerve invasion. The difference in HLA and APM expression between the 2 groups was statistically significant (P < 0.001). CONCLUSIONS: Decreased expression of HLA was observed in aggressive tumors and in poorly differentiated tumors. The current findings support a role for both CTLs and NK cell-mediated control of tumor growth in the clinical course of retinoblastoma.

Expression of HLA class I, beta(2)-microglobulin and HLA class II antigens in primary orbital melanoma.

Major histocompatibility antigens (MHC) play a crucial role in the recognition of tumor cells by the immune system. There is not much information on the role of MHC molecule expression in primary orbital melanomas. In the present study, the authors examined the expression of human leukocyte antigen (HLA) class I, beta(2)-microglobulin (beta(2)-m) and HLA class II antigens in primary orbital melanoma and correlated this with the clinical and pathological findings. HLA class I antigen, beta(2)-m and HLA class II antigen expression were evaluated immunohistochemically in three primary orbital melanomas and correlated with cell type and metastasis. Immunohistochemistry showed heterogeneous expression of HLA class I, beta(2)-m and HLA class II antigen in two cases with no liver metastasis and negative expression in one case with liver metastasis. This preliminary observation deserves further investigation, which may shed more light on the immune escape mechanisms of this tumor and thus make possible novel therapeutic strategies.

Loss of antigen-processing molecules in primary orbital melanoma.

OBJECTIVE: To study the antigen-processing molecules in primary orbital melanomas and correlate them with the clinicopathological features. METHODS AND MATERIALS: Antigen-processing molecules comprising the low molecular weight proteins LMP2 and LMP10, transporter associated with antigen-processing TAP1, the binding protein tapasin and the chaperone protein calnexin were analyzed by immunoperoxidase staining with monoclonal antibodies in three primary orbital melanomas. The results were correlated clinicopathologically. RESULTS: The three primary orbital melanomas were composed of spindle cells. LMP2, LMP10, TAP1, tapasin and calnexin were heterogeneous in the two cases with no hepatic metastasis and negative in one case with hepatic metastasis. CONCLUSIONS: Antigen-processing molecules are decreased in orbital melanomas with increasing aggressiveness. This could have important implications for immunotherapy. This preliminary observation deserves further investigation, which may shed more light on the immune escape mechanisms of this tumor and thus make possible novel therapeutic strategies.

Chromosomal rearrangement in Down syndrome with acute myeloid leukemia.

The incidence of acute leukemia in children with Down syndrome (DS) is high as compared to general population. Recent findings have demonstrated that DS children with acute myeloid leukemia (AML) have the highest event free survival rates with high dose cytosine arabinoside (Ara-C). We present 3 year-old DS female child with AML-M5, whose chromosomal analysis revealed constitutional t(21;21) alongwith del(5)(q31q33) and a unique translocation t(16;20)(q13;q12). After chemotherapy, child achieved complete clinical remission. Karyotype analysis of remission marrow showed disappearance of abnormal clone of der(20) t(16;20)(q13;q12), del(5q) indicating cytogenetic remission too. This case alongwith supportive literature indicate that pediatric DS-AML is a distinct biologic sub-group differs from that of non-DS-AML with respect to chemosensitivity.

Major histocompatibility antigens and antigen-processing molecules in uveal melanoma.

PURPOSE: Malignant transformation of cells is frequently associated with abnormalities in the human leukocyte antigen (HLA) expression. These abnormalities may play a role in the clinical course of the disease, because HLA antigens mediate interactions of tumor cells with T cells and natural killer cells. Uveal melanoma is a highly malignant tumor of the eye and is characterized by hematogenic spread to liver. Antigen-processing molecules (APMs) are necessary for efficient expression of HLA class I antigens. We studied the expression of HLA antigens and the APM in uveal melanomas by immunohistochemistry and correlated clinicopathologically. EXPERIMENTAL DESIGN: HLA class I antigen, beta(2)-microglobulin (beta(2)-m), HLA class II antigens, and the APM comprising proteasomal subunits low molecular mass polypeptide (LMP) 2, beta-subunit of LMP2-Delta, LMP 10, transporter associated protein 1 subunit, and chaperone molecules tapasin and calnexin were studied in 41 primary uveal melanoma archival specimens by immunohistochemistry. Immunoanalysis was done by a semiquantitative method and correlated with extrascleral extension, cell types, and the largest tumor diameter. RESULTS: HLA class I antigen, beta(2)-m, HLA class II antigen, and the APM were decreased (negative staining in 29 tumors and dull staining in 3 tumors) in 100% (32 of 32) uveal melanomas with no extrascleral extension. (P = 0.01) and positive (bright staining) in 67% (4 of 9) tumors with liver metastasis. Decreased immunoexpression of HLA antigens and the APM was seen in nonepithelioid cell melanomas. There was no correlation with largest tumor diameter. CONCLUSIONS: Our data suggest decreased expression of HLA, and APM are seen in uveal melanomas with no extrascleral extension and in nonepithelioid cell melanomas. Decreased expression of APM may contribute to decreased HLA class I antigen expression.

HLA class II antigen expression in conjunctival precancerous lesions and squamous cell carcinomas.

PURPOSE: The expression of human leukocyte antigen (HLA) class II molecules on the cell surface is necessary for the presentation of peptide antigens to helper CD4 T lymphocytes of the immune system. We studied the immunoexpression of HLA class II antigen in conjunctival precursor lesions and conjunctival squamous cell carcinomas. METHODS: HLA class II antigen expression was analyzed in 8 conjunctival dysplasias, 6 carcinomas in situ and in 7 conjunctival squamous cell carcinomas, by immunoperoxidase staining with monoclonal antibody to HLA class II antigen on the archival clinical samples. Immunoanalysis was done by a semi quantitative method based on the intensity of staining and the percentage of stained cells. RESULTS: HLA class II antigen immunoexpression was heterogeneous in 8 conjunctival dysplasias and in 6 carcinoma in situ and negative in 7 conjunctival squamous cell carcinomas. CONCLUSIONS: Human leukocyte class II antigen immunoexpression is decreased in conjunctival precancerous and squamous cell carcinomas.

HLA class II antigen expression in uveal melanoma: correlation with clinicopathological features.

The authors examined the immunoexpression of human leukocyte (HLA) class II antigen in uveal melanomas and correlated with the cell types, largest tumour dimension and extrascleral invasion. HLA class II antigen expression was analysed in 45 primary uveal melanoma lesions by immunoperoxidase staining with monoclonal antibody. Immunoanalysis was done by a semi-quantitative method according to the International Histocompatibility Working Group, Project description. The results were correlated clinicopathologically. Among the 45-uveal melanomas, 17 were spindle cell types, 16 were mixed cell types and 12 were epithelioid cell types. Among the 35 tumours with no extrascleral extension, HLA class II antigen was decreased in (100%) 35/35 tumours. Among the 10 tumours with extrascleral extension, HLA class II antigen was positive in the 60% (6/10) tumours with liver metastasis and decreased in 40% (4/10) tumours with no liver metastasis. HLA class II antigen was negative in 94% (16/17) spindle cell melanomas. Decreased HLA class II immunoreactivity in tumours with no extrascleral extension was significant (P<0.001). Negative HLA class II immunoreactivity in the spindle cell melanoma was significant (P<0.001). There was no correlation with largest tumour diameter and immunoreactivity. HLA class II antigen is an independent prognostic marker in uveal melanoma. Thus, HLA class II antigen expression in uveal melanoma in relation to prognosis and cell types are similar to HLA class I antigen expression, where downregulation and presence of spindle cell melanoma correlates with favourable outcome. This may have important implications with respect to proposed T cell based immunotherapy.