Belatacept Pharmacokinetic Trial in Renal Transplantation

Pharmacokinetic (PK) sampling started from pre-dose (0 hour) on Day 84 and ended at 672 hour (h) on Day 112 (between Weeks 12 to 16). The samples were analyzed for belatacept by enzyme-linked immunosorbent assay (ELISA) using a validated method and measured as nanograms/milliliter (ng/mL). Less than the lower limit of quantification (LLQ), 3.000 ng/mL concentration value was treated as missing.

Cmax, Cmin are measured in micrograms per milliliter (µg/mL). At Day 84, blood samples obtained from pre-dose (0 hour) and ended at 672 hour (h) on Day 112. Serum samples were analyzed for belatacept by enzyme-linked immunosorbent assay (ELISA) using a validated method. Individual participant PK parameters were derived from serum concentration versus time data using a non-compartmental method, using a validated PK analysis program (KineticaTM 4.4.1 within the eToolbox [version 2.6.1]). Actual sampling times were used for PK calculations. The Cmax, and the Cmin were recorded directly from experimental observations. Using no weighting factor, the terminal log-linear phase of the concentration-time curve was identified by least-square linear regression of at least 3 data points that yielded a maximum G-criteria, which is also referred to as adjusted R-squared. Values below lower limits of quantification (LLQ), 0.003 µg/mL, were set to 0.0015 for computation of summary statistics.

Tmax measured in hours (h). At Day 84, blood samples obtained from pre-dose (0 hour) and ended at 672 (h) on Day 112 . The samples were analyzed for belatacept by enzyme-linked immunosorbent assay (ELISA) using a validated method. Individual participant PK parameters were derived from serum concentration versus time data using a non-compartmental method, using a validated PK analysis program (KineticaTM 4.4.1 within the eToolbox [version 2.6.1]). Actual sampling times were used for PK calculations.

At Day 84, blood samples obtained from pre-dose (0 hour) and ended at 672 hour (h) on Day 112. The samples were analyzed for belatacept by enzyme-linked immunosorbent assay (ELISA) using a validated method. Individual participant PK parameters were derived from serum concentration versus time data using a non-compartmental method, using a validated PK analysis program (KineticaTM 4.4.1 within the eToolbox [version 2.6.1]). The area under the concentration-time curve in one dose interval [AUC(TAU), where TAU = 4 weeks] were calculated using the mixed log-linear trapezoidal algorithm in Kinetica. Actual sampling times were used for PK calculations. AUC (TAU) was measured as micrograms multiplied by time(h) per milliliter (µg*h/mL).

At Day 84, blood samples obtained from pre-dose (0 hour) and ended at 672 hour (h) on Day 112. The samples were analyzed for belatacept by enzyme-linked immunosorbent assay (ELISA) using a validated method. Individual participant PK parameters were derived from serum concentration versus time data using a non-compartmental method, using a validated PK analysis program (KineticaTM 4.4.1 within the eToolbox [version 2.6.1]). Actual sampling times were used for PK calculations. CLT was calculated by dividing the dose by AUC(TAU) and was adjusted to body weight. CLT was measured as milliliter per time per kg body weight (mL/h/kg).

At Day 84, blood samples obtained from pre-dose (0 hour) and ended at 672 hour (h) on Day 112. The samples were analyzed for belatacept by enzyme-linked immunosorbent assay (ELISA) using a validated method. Individual participant PK parameters were derived from serum concentration versus time data using a non-compartmental method, using a validated PK analysis program (KineticaTM 4.4.1 within the eToolbox [version 2.6.1]). Actual sampling times were used for PK calculations. Vss was calculated by dividing the dose by AUC and multiply the mean residence time (MRT). Vss was adjusted to body weight and measured as liter per kilogram body weight (l/kg).

At Day 84, blood samples obtained from pre-dose (0 hour) and ended at 672 hour (h) on Day 112. The samples were analyzed for belatacept by enzyme-linked immunosorbent assay (ELISA) using a validated method. Individual participant PK parameters were derived from serum concentration versus time data using a non-compartmental method, using a validated PK analysis program (KineticaTM 4.4.1 within the eToolbox [version 2.6.1]). Actual sampling times were used for PK calculations. T-HALF was calculated as ln2/Lz, where Lz is the absolute value of the slope of the terminal log-linear phase. T-HALF is measured in hours (h).

Blood samples were obtained pre and post dose at designated time points up to Day 112 and thereafter, pre-dose samples were obtained at Days 168 and 364, and then once yearly up to end of Year 3. The samples were analyzed for belatacept by enzyme-linked immunosorbent assay (ELISA) using a validated method. Individual participant PK parameters were derived from serum concentration versus time data using a non-compartmental method, using a validated PK analysis program (KineticaTM 4.4.1 within the eToolbox [version 2.6.1]). Actual sampling times were used for PK calculations. The trough serum concentration (Cmin), was recorded directly from experimental observations. Using no weighting factor, the terminal log-linear phase of the concentration-time curve was identified by least-square linear regression of at least 3 data points that yielded a maximum G-criteria, which is also referred to as adjusted R-squared. Cmin was measured as micrograms per milliliter (µg/mL).

Acute rejection of transplant defined as a clinicopathological event requiring clinical evidence and biopsy confirmation by central pathologist. Graft loss was defined as either functional loss or physical loss. Day 1 is day of transplantation.

Indoleamine 2,3 dioxygenase (IDO) is a tryptophan catabolizing enzyme that can be induced in antigen-presenting cells by the engagement of B7 by cytotoxic lymphocyte antigen 4 (CTLA-4). Tryptophan depletion in cellular microenvironments has an inhibitory effect on T cells and may be part of a broader immuno-regulatory effect of IDO induction. The IDO activity was determined by measuring the quantity of tryptophan and its metabolite, kynurenine, in serum samples using a validated high performance liquid chromatography (HPLC) method. Baseline is defined as pre-dose. Tryptophan was measured in micromoles (µM)

Indoleamine 2,3 dioxygenase (IDO) is a tryptophan catabolizing enzyme that can be induced in antigen-presenting cells by the engagement of B7 by CTLA-4. Tryptophan depletion in cellular microenvironments has an inhibitory effect on T cells and may be part of a broader immuno-regulatory effect of IDO induction. The IDO activity was determined by measuring the quantity of tryptophan and its metabolite, kynurenine, in serum samples using a validated high performance liquid chromatography (HPLC) method. Baseline is defined as pre-dose. Kynurenine was measured in micromoles (µM).