Quality of T-cell responses versus reduction in viral load: results from an exploratory phase II clinical study of Vacc-4x, a therapeutic HIV vaccine

Background Immunization with Vacc-4x, a peptide-based therapeutic vaccine for HIV-1, has shown a statistically significant reduction in viral load set point compared to placebo during treatment interruption in an exploratory phase II clinical study enrolling 135 subjects (NCT00659789). This vaccine aims to induce sustained cell-mediated immune responses to conserved domains on HIV p24. Methods After 6 immunizations on ART over 28 weeks, treatment was interrupted for up to 24 weeks (Vacc-4x n=88; placebo n=38). Immunological analyses (ELISPOT, proliferation, intracellular cytokine staining (ICS)) to HIV p24 were carried out at central laboratories. The HLA class I profile (Vacc-4x n=73, placebo n=32) was also determined. Results For subjects that remained off ART until week 52 (Vacc-4x n=56, placebo n=25), there was a log 0.44 reduction in viral load set point between the Vacc-4x and placebo groups (p=0.0397). There was a similar distribution of HLA class I alleles in the two treatment arms, with the exception of the B35 allele (27% of Vacc-4x subjects versus 8% placebo subjects). The viral load of ELISPOT positive Vacc-4x subjects was significantly lower than that of placebo subjects (p=0.023). There was no significant difference in T-cell proliferation responses between Vacc-4x and placebo groups, however, the percentage of subjects showing proliferative CD4 and CD8 T-cell responses to Vacc-4x peptides increased over time only for the Vacc-4x group. ICS analysis showed a predominance of CD8-mediated T-cell responses to p24 that were significantly increased from baseline for the Vacc-4x group (p<0.043) but not for the placebo group(p>0.05). There was also a trend towards higher numbers of polyfunctional T-cells in the Vacc-4x group compared to the placebo group (p=0.188). Conclusion These findings suggest Vacc-4x immunization can influence the quality of immune responses to HIV-1 p24 irrespective of HLA status, and contribute to a reduction in viral load

Quantification of the next-generation oral anti-tumor drugs dabrafenib, trametinib, vemurafenib, cobimetinib, pazopanib, regorafenib and two metabolites in human plasma by liquid chromatography-tandem mass spectrometry.

A sensitive and selective method of high performance liquid chromatography (HPLC) coupled to tandem mass spectrometry (MS/MS) has been developed for the simultaneous quantification of six anticancer protein kinase inhibitors (PKIs), dabrafenib, trametinib, vemurafenib, cobimetinib, pazopanib, regorafenib, and two active metabolites (regorafenib-M2 and regorafenib-M5) in human plasma. Plasma protein precipitation with methanol enables the sample extraction of 100 μL aliquot of plasma. Analytes are detected by electrospray triple-stage quadrupole mass spectrometry and quantified using the calibration curves with stable isotope-labeled internal standards. The method was validated based on FDA recommendations, including assessment of extraction yield (74-104%), matrix effects, analytical recovery (94-104%) with low variability (&lt;15%). The method is sensitive (lower limits of quantification within 1 to 200 ng/mL), accurate (intra- and inter-assay bias: -0.3% to +12.7%, and -3.2% to +6.3%, respectively) and precise (intra- and inter-assay CVs within 0.7-7.3% and 2.5-8.0%, respectively) over the clinically relevant concentration range (upper limits of quantification 500 to 100,000 ng/mL). This method is applied in our laboratory for both clinical research programs and routine therapeutic drug monitoring service of PKIs

A Phase IIB, Randomized, Double-Blind, Multicenter, Immunogenicity Study of Vacc-4x Versus Placebo in HIV-1-infected Patients

Background: Vacc-4x is a peptide-based HIV therapeutic vaccine to conserved domains on p24Gag. Recently conserved 'sectors' on HIV p24, critical for virus viability and thereby immunologically vulnerable have been identified. Elite controllers target immune responses to such regions. The Vacc-4x peptides lie within a number of these conserved sectors of HIV p24. The co-primary endpoints of this study were to compare changes in CD4 counts and return to ART between treatmentand placebo groups during a 24 week treatment interruption. Secondary endpoints included safety, viral load and immunogenicity.Methods: This prospective, randomized, double blind phase IIB clinical study (NCT00659789) was carried out in 13 European and 5 US centers recruiting 135 patients on ART. After 6 immunizations on ART over 28 weeks, treatment was interrupted for up to 24 weeks (to week 52) (Vacc-4x n = 88; placebo n = 38). Immunological analyses (ELISPOT, proliferation, intracellular cytokine staining) were carried out at central laboratories.Results: There were no Vacc-4x-related serious adverse events. Of the 135 patients recruited (male n = 92; female n = 43), 126 patients completed the study. Median prestudy CD4 count was 712 (Vacc-4x) and 619 cells/mm3 (placebo), and median CD4 nadir 300 (Vacc-4x) and 285 cells/mm3 (placebo). There was no statistically significant difference between the two groups regarding change in CD4 counts (p = 0.12) or ART resumption (p = 0.89) during treatment interruption. A statistically significant treatment difference between Vacc-4x and placebo groupsfor viral load (VL) was found for patients who achieved a 6 month ART-free period (p = 0.0022). There was a positive correlation between ELISPOT responses and lower viral load in the Vacc-4x group compared to placebo (p = 0.02). Long-term follow-up of patients up t o week 104 was completed in June 2011.Conclusion: Vacc-4x was found to be safe and well tolerated. TheVacc-4x group experienced a significant reduction in viral load compared to placebo

Quality of T-cell responses versus reduction in viral load: results from an exploratory phase II clinical study of Vacc-4x, a therapeutic HIV vaccine

Background Immunization with Vacc-4x, a peptide-based therapeutic vaccine for HIV-1, has shown a statistically significant reduction in viral load set point compared to placebo during treatment interruption in an exploratory phase II clinical study enrolling 135 subjects (NCT00659789). This vaccine aims to induce sustained cell-mediated immune responses to conserved domains on HIV p24. Methods After 6 immunizations on ART over 28 weeks, treatment was interrupted for up to 24 weeks (Vacc-4x n=88; placebo n=38). Immunological analyses (ELISPOT, proliferation, intracellular cytokine staining (ICS)) to HIV p24 were carried out at central laboratories. The HLA class I profile (Vacc-4x n=73, placebo n=32) was also determined. Results For subjects that remained off ART until week 52 (Vacc-4x n=56, placebo n=25), there was a log 0.44 reduction in viral load set point between the Vacc-4x and placebo groups (p=0.0397). There was a similar distribution of HLA class I alleles in the two treatment arms, with the exception of the B35 allele (27% of Vacc-4x subjects versus 8% placebo subjects). The viral load of ELISPOT positive Vacc-4x subjects was significantly lower than that of placebo subjects (p=0.023). There was no significant difference in T-cell proliferation responses between Vacc-4x and placebo groups, however, the percentage of subjects showing proliferative CD4 and CD8 T-cell responses to Vacc-4x peptides increased over time only for the Vacc-4x group. ICS analysis showed a predominance of CD8-mediated T-cell responses to p24 that were significantly increased from baseline for the Vacc-4x group (p<0.043) but not for the placebo group(p>0.05). There was also a trend towards higher numbers of polyfunctional T-cells in the Vacc-4x group compared to the placebo group (p=0.188). Conclusion These findings suggest Vacc-4x immunization can influence the quality of immune responses to HIV-1 p24 irrespective of HLA status, and contribute to a reduction in viral load

Development of an optimized closed and semi-automatic protocol for Good Manufacturing Practice manufacturing of tumor-infiltrating lymphocytes in a hospital environment.

Several studies report on Good Manufacturing Process (GMP)-compliant manufacturing protocols for the ex vivo expansion of tumor-infiltrating lymphocytes (TILs) for the treatment of patients with refractory melanoma and other solid malignancies. Further opportunities for improvements in terms of ergonomy and operating time have been identified. To enable GMP-compliant TILs production for adoptive cell therapy needs, a simple automated and reproducible protocol for TILs manufacturing with the use of a closed system was developed and implemented at the authors' institution. This protocol enabled significant operating time reduction during TILs expansion while allowing the generation of high-quality TILs products. A simplified and efficient method of TILs expansion will enable the broadening of individualized tumor therapy and will increase patients' access to state-of-the-art TILs adoptive cell therapy treatment