A B Parameters HV SCD - GBT · PK parameters in whole blood at ... Samples were then incubated in a...
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Table 1: PK parameters in whole blood at steady state (Day 15 or Day 28) for healthy volunteers and SCD patients. A dose dependent increase in C max and AUC is observed. Compared to healthy volunteers , patients have a higher %CV. This high %CV is likely due to differences in RBC turnover and hemolytic rates. a Excluded subjects who discontinued study drug due to an adverse event b Excluded subject due to dose reduction • To determine the Pharmacokinetics of GBT440 in Healthy Volunteers and SCD patients • To evaluate Oxygen Equilibrium Curves as a Pharmacodynamics marker • To determine PK and PD relationship Pharmacokinetics and Pharmacodynamics of GBT440, a Novel Hemoglobin S Polymerization Inhibitor for the Treatment of Sickle Cell Disease, in Healthy Volunteers and SCD Patients ©2016 Global Blood Therapeutics Introduction Results and Discussion Methods Conclusions • GBT440 demonstrates linear, dose-proportional PK in Healthy Volunteers and SCD patients (see poster #P371) • GBT440 has a half-life of 2.8 and 1.6 days in Healthy Volunteers and SCD Patients, respectively, which supports once daily dosing • The relatively high %CV in SCD patients (~40%) compared to Healthy Volunteers is likely due to differences in RBC turnover and hemolytic rates • At the predicted therapeutic range (10-30% Hb modification), p20 is a more sensitive indicator of the GBT440-induced left shift in the Hb OEC than p50 • A dose-dependent decrease in p20 and p50 is observed, indicating that increasing GBT440 blood levels lead to increased oxygen affinities • % Hb modification using GBT440 PK/blood levels is a good predictor of changes in oxygen affinity based on OECs measurements SS blood Source Whole blood (in 3.2 % sodium citrate vacutainers) from sickle cell patients was obtained from the University of North Carolina Comprehensive Sickle Cell Program [Chapel Hill, NC, IRB # 88-0343 (GCRC-101)] or from Sanguine Biosciences, Inc. (Valencia, Ca). The donors were 2-3 months post-transfusion with blood routinely containing 70%-90% HbS and variable amounts of HbA and HbF. Dose and Patients Data reported is a subset of data collected in the GBT440-001 clinical trial. Healthy volunteers were dosed with a single dose of 1000 mg of GBT440 and SCD patients were dosed with either a single dose of 1000 mg and with multiple doses of 500, 700 and 1000 mg of GBT440 for 28 days. Analysis of Blood and Plasma GBT440 Concentrations Concentration of GBT440 in whole blood and plasma were determined using validated LCMS methods. Concentration of GBT440 in RBCs was calculated using the GBT440 concentrations in blood and plasma. In vitro Hemoximetry GBT440 (in 80 mM stocks in 100% DMSO) or DMSO (for controls) was mixed with plasma prior to the addition of autologous RBCs. Samples were then incubated in a 37 °C water bath and gently shaken for one hour. After incubation, the samples were diluted in a 30 mM TES buffer. Diluted samples were loaded into Hemox Analyzer (TCS Scientific, New Hope, PA) cuvettes and oxygenated for 20 minutes using compressed air. After oxygenation, the samples were deoxygenated using nitrogen gas until the pO 2 reached 1.6 millimeters of mercury (mm Hg). During the deoxygenation step, data was collected into Oxygen Equilibrium Curve (OEC) files using the Hemox Analytical Software (HAS). OEC files from the various data sets were analyzed to determine the p20, and p50 values. Delta values were obtained by subtracting the control p20 or p50 from the sample p20 or p50 value. Clinical Hemoximetry Blood samples collected in sodium citrate vacutainers were kept at 4°C until analysis. Clinical trial samples were analyzed within 12-43 hours of the draw. Following hematocrit (Hct) determination, the samples were then diluted 50 or 100-fold based upon the Hct into 37°C TES buffer (30 mM TES, 130 mM NaCl, 5 mM KCl, pH 7.4). Samples were subsequently transferred to the Hemox Analyzer sample chamber where they were saturated with compressed air for 20 minutes and then deoxygenated with pure nitrogen. During the deoxygenation step, data was collected into Oxygen Equilibrium Curve (OEC) files using the Hemox Analytical Software (HAS). OEC files from the various data sets were analyzed to determine the p20, and p50 values. Delta values for % Hb modification calculations were obtained by subtracting the Day -1 p20 or p50 from the sample p20 or p50 value . Data Analysis of Clinical Samples OEC files from the clinical samples were analyzed to determine the p20, and p50. [GBT440] RBC was calculated using [GBT440] blood , [GBT440] plasma and Hct. Mira Patel 1 , Athiwat Hutchaleelaha 1 , Vincent Siu 1 , Abel Silva 1 , Donna Oksenberg 1 , Josh Lehrer-Graiwer 1 , Timothy Mant 2 , Eleanor Ramos 1 1 Global Blood Therapeutics, Inc., South San Francisco, CA 94080, 2 Quintiles Drug Research Unit at Guy’s Hospital, London, United Kingdom Pharmacokinetic Model of GBT440 Pharmacodynamics at Steady State in SCD Patients Figure 4: A summary of the p20 and p50 values observed in SCD subjects after 28 days of dosing. A dose-dependent decrease in p20 and p50 is observed, showing that increasing levels of drug leads to increased oxygen affinities. Sidak's multiple comparisons tests were used to measure statistical significance 0.0 0.1 1.0 10.0 100.0 1000.0 0 96 192 288 384 480 576 672 Blood GBT440 Concentration (μM) Time (hr) Healthy Subject SCD Parameters HV SCD C max (μg/mL) 58.2 36 AUC 0-∞ (µg•hr/mL) 6730 2480 T 1/2 (days) 2.8 1.6 1 10 100 1000 10000 0 4 8 12 16 20 24 Concentration (μM) Time (hr) Day 1-RBC Day 1-Blood Day 1-Plasma Day 28-RBC Day 28-Blood Day 28-Plasma Oral Administration 440 Protein | 440 complex 440 Hb l 440 complex 440 Tissue l 440 complex RBC Plasma Tissues/organs Elimination Purpose Sickle cell disease (SCD) is an inherited disorder caused by a point mutation in the β-globin gene leading to the formation of hemoglobin S (HbS). A primary and obligatory event in the molecular pathogenesis of SCD is the polymerization of deoxygenated HbS and the resulting sickling of red blood cells (RBC). Sickle cell disease is characterized by hemolytic anemia and vaso-occlusion leading to progressive end-organ damage with a clinical course of life-long pain, disability, and early death. A drug that inhibits HbS polymerization and has pancellular distribution has the potential to provide efficacy. Because oxyhemoglobin is a potent inhibitor of HbS polymerization, allosteric modification of hemoglobin to increase the proportion of oxyhemoglobin is a promising strategy to achieve inhibition of HbS polymerization in all RBCs. By delaying polymerization, the irreversible damage done to the RBC membrane can be prevented and thereby alter the downstream pathophysiology of the disease. In order to fulfill this unmet need, Global Blood Therapeutics (GBT) is conducting clinical trials for the treatment of SCD with GBT440, an oral small molecule designed to increase the oxygen affinity of Hb, delay Hb polymerization and prevent RBC sickling. Oxygen Equilibrium Curves of GBT440 in SS Blood and the Correlation to % Hb modification Figure 2: (A) OECs show the dose-dependent increase in oxygen affinity as evidenced by decreasing p50 and p20 values. Due to the nature of biphasic curves, p20 is a more sensitive parameter than p50 at lower GBT440 concentrations. (B and C) Change in p20 (B) and change in p50 (C) at various % Hb modifications. The different correlations (R 2 of 0.78 for Δp20 and R 2 of 0.55 for Δp50) indicate that in the efficacious range Δp20 will be a better predictor of % Hb modification. The equation, y=0.27x-0.16, was used to calculate % Hb modification in the clinical trial. pO 2 (mm Hg) O 2 Saturation (% ) 0 20 40 60 80 100 120 140 0 20 40 60 80 100 30% Hb modification 15% Hb modification 10% Hb modification 5% Hb modification Control ] [ ] 440 [ * 100 mod % Hb GBT ification Hb spiked 10 20 30 40 50 -5 0 5 10 15 % Hb modification p20 (mm Hg) R 2 =0.78 y=0.27x-0.16 N=132 10 20 30 40 50 -5 0 5 10 15 % Hb modification p50 (mm Hg) R 2 =0.55 y=0.12x-0.05 N=132 A B C IN VITRO PHARMACODYNAMIC MODEL Pharmacokinetics of GBT440 in Healthy Volunteers and SCD Patients after Single and Multiple Doses A B Figure 1: (A) Mean ± SD Blood Concentration-time Profiles of GBT440 in Healthy Volunteers and SCD Patients Following an Oral Administration of 1000 mg. Inset Table shows the PK parameters derived from these profiles. The difference in PK between Healthy Volunteers and SCD Patients is likely due to lower hematocrit and more rapid turnover of RBC in SCD patients. The long half-life in Healthy Volunteers and SCD Patients supports once daily dosing. (B) Mean ± SD GBT440 Concentrations on Day 1 and Day 28 following daily dosing of 700 mg in SCD patient. Exposure of GBT440 was ~3-fold higher at steady-state compared to Day 1. The RBC/Plasma ratio was 75:1 PHARMACOKINETICS STUDIES Healthy Volunteers SCD Patients Dose (N) 300 mg (6) 600 mg (5) a 900 mg (5) a 700 mg (11) b C max μg/mL Mean 97.9 209 294 84.6 %CV 14.4% 13.5% 9.4% 40.4% AUC 0-24 hr*μg/mL Mean 2149 4359 5968 1771 %CV 12.3% 11.1% 7.4% 42.5% Figure 5: OECs were collected at baseline as well as during various time points throughout dosing and wash out periods. Δp20 values were calculated by subtracting the sample from the baseline p20. This Δp20 value was then used to calculate “% Hb modification (derived from OECs)”. Correlation illustrates a linear relationship between the “% Hb modification (derived from OECs)” and the “% Hb modification (derived from [GBT440] RBC )”. Therefore, Hb modification using GBT440 PK/blood levels is a good predictor of changes in oxygen affinity based on OECs measurements. Pharmacokinetics Correlates with Changes in Hb-O 2 Affinity IN VIVO PHARMACOKINETIC/PHARMACODYNAMIC MODEL IN VIVO PHARMACODYNAMIC DATA 10 20 30 40 -20 0 20 40 % Hb modification (derived from [GBT440] RBC ) %Hb modification (derived from OECs) R 2 =0.70 Y = 0.94*X + 0.15 N=172 0.5 1.0 1.5 2.0 [GBT440] RBC (mM) Placebo 500 mg 700 mg 1000 mg 0 5 10 15 20 25 Dose p20 (mm Hg) Day -1 Day 28 ns ns *** **** Placebo 500 mg 700 mg 1000 mg 20 25 30 35 40 45 Dose p50 (mmHg) Day -1 Day 28 ns * ns ns A B To access the poster digitally, please use the following QR code
Transcript of A B Parameters HV SCD - GBT · PK parameters in whole blood at ... Samples were then incubated in a...
Table 1:PK parameters in whole blood at steady state (Day 15 or Day 28) forhealthy volunteers and SCD patients. A dose dependent increase in Cmax
and AUC is observed. Compared to healthy volunteers , patients have ahigher %CV. This high %CV is likely due to differences in RBC turnoverand hemolytic rates.
a Excluded subjects who discontinued study drug due to an adverse eventb Excluded subject due to dose reduction
• To determine the Pharmacokinetics of GBT440 in Healthy Volunteers and SCD patients
• To evaluate Oxygen Equilibrium Curves as a Pharmacodynamics marker
• To determine PK and PD relationship
Pharmacokinetics and Pharmacodynamics of GBT440, a Novel Hemoglobin S Polymerization Inhibitor for the Treatment of Sickle Cell Disease, in Healthy Volunteers and SCD Patients
©2016 Global Blood Therapeutics
Introduction Results and Discussion
Methods
Conclusions• GBT440 demonstrates linear, dose-proportional PK in Healthy Volunteers and SCD patients (see poster #P371)• GBT440 has a half-life of 2.8 and 1.6 days in Healthy Volunteers and SCD Patients, respectively, which supports once
daily dosing• The relatively high %CV in SCD patients (~40%) compared to Healthy Volunteers is likely due to differences in RBC
turnover and hemolytic rates• At the predicted therapeutic range (10-30% Hb modification), p20 is a more sensitive indicator of the GBT440-induced
left shift in the Hb OEC than p50• A dose-dependent decrease in p20 and p50 is observed, indicating that increasing GBT440 blood levels lead to
increased oxygen affinities• % Hb modification using GBT440 PK/blood levels is a good predictor of changes in oxygen affinity based on OECs
measurements
SS blood SourceWhole blood (in 3.2 % sodium citrate vacutainers) from sickle cell patients was obtained from the University of North CarolinaComprehensive Sickle Cell Program [Chapel Hill, NC, IRB # 88-0343 (GCRC-101)] or from Sanguine Biosciences, Inc. (Valencia, Ca).The donors were 2-3 months post-transfusion with blood routinely containing 70%-90% HbS and variable amounts of HbA and HbF.
Dose and PatientsData reported is a subset of data collected in the GBT440-001 clinical trial. Healthy volunteers were dosed with a single dose of1000 mg of GBT440 and SCD patients were dosed with either a single dose of 1000 mg and with multiple doses of 500, 700 and1000 mg of GBT440 for 28 days.
Analysis of Blood and Plasma GBT440 ConcentrationsConcentration of GBT440 in whole blood and plasma were determined using validated LCMS methods. Concentration of GBT440in RBCs was calculated using the GBT440 concentrations in blood and plasma.
In vitro HemoximetryGBT440 (in 80 mM stocks in 100% DMSO) or DMSO (for controls) was mixed with plasma prior to the addition of autologousRBCs. Samples were then incubated in a 37 °C water bath and gently shaken for one hour. After incubation, the samples werediluted in a 30 mM TES buffer. Diluted samples were loaded into Hemox Analyzer (TCS Scientific, New Hope, PA) cuvettes andoxygenated for 20 minutes using compressed air. After oxygenation, the samples were deoxygenated using nitrogen gas until thepO2 reached 1.6 millimeters of mercury (mm Hg). During the deoxygenation step, data was collected into Oxygen EquilibriumCurve (OEC) files using the Hemox Analytical Software (HAS). OEC files from the various data sets were analyzed to determine thep20, and p50 values. Delta values were obtained by subtracting the control p20 or p50 from the sample p20 or p50 value.
Clinical HemoximetryBlood samples collected in sodium citrate vacutainers were kept at 4°C until analysis. Clinical trial samples were analyzed within12-43 hours of the draw. Following hematocrit (Hct) determination, the samples were then diluted 50 or 100-fold based uponthe Hct into 37°C TES buffer (30 mM TES, 130 mM NaCl, 5 mM KCl, pH 7.4). Samples were subsequently transferred to the HemoxAnalyzer sample chamber where they were saturated with compressed air for 20 minutes and then deoxygenated with purenitrogen. During the deoxygenation step, data was collected into Oxygen Equilibrium Curve (OEC) files using the HemoxAnalytical Software (HAS). OEC files from the various data sets were analyzed to determine the p20, and p50 values. Delta valuesfor % Hb modification calculations were obtained by subtracting the Day -1 p20 or p50 from the sample p20 or p50 value .
Data Analysis of Clinical SamplesOEC files from the clinical samples were analyzed to determine the p20, and p50. [GBT440]RBC was calculated using[GBT440]blood, [GBT440]plasma and Hct.
Mira Patel1, Athiwat Hutchaleelaha1, Vincent Siu1, Abel Silva1, Donna Oksenberg1, Josh Lehrer-Graiwer1, Timothy Mant2, Eleanor Ramos1
1Global Blood Therapeutics, Inc., South San Francisco, CA 94080, 2Quintiles Drug Research Unit at Guy’s Hospital, London, United Kingdom
Pharmacokinetic Model of GBT440
Pharmacodynamics at Steady State in SCD Patients
Figure 4:
A summary of the p20 and p50 values observed in SCD subjects after 28 days of dosing. A dose-dependent decrease in p20 and p50 is observed, showing thatincreasing levels of drug leads to increased oxygen affinities. Sidak's multiple comparisons tests were used to measure statistical significance
0.0
0.1
1.0
10.0
100.0
1000.0
0 96 192 288 384 480 576 672
Blo
od
GB
T44
0 C
on
cen
trat
ion
(µ
M)
Time (hr)
Healthy Subject SCD
Parameters HV SCD
Cmax
(µg/mL)58.2 36
AUC0-∞
(µg•hr/mL)6730 2480
T1/2
(days)2.8 1.6
1
10
100
1000
10000
0 4 8 12 16 20 24
Co
nce
ntr
atio
n (
µM
)
Time (hr)
Day 1-RBC
Day 1-Blood
Day 1-Plasma
Day 28-RBC
Day 28-Blood
Day 28-Plasma
OralAdministration
440Protein
|440
complex
440
Hbl
440 complex
440Tissue
l440 complex
RBC
Plasma Tissues/organs
Elimination
Purpose
Sickle cell disease (SCD) is an inherited disorder caused by a point mutation in the β-globin gene leading to the formation ofhemoglobin S (HbS). A primary and obligatory event in the molecular pathogenesis of SCD is the polymerization of deoxygenatedHbS and the resulting sickling of red blood cells (RBC). Sickle cell disease is characterized by hemolytic anemia and vaso-occlusionleading to progressive end-organ damage with a clinical course of life-long pain, disability, and early death.
A drug that inhibits HbS polymerization and has pancellular distribution has the potential to provide efficacy. Becauseoxyhemoglobin is a potent inhibitor of HbS polymerization, allosteric modification of hemoglobin to increase the proportion ofoxyhemoglobin is a promising strategy to achieve inhibition of HbS polymerization in all RBCs. By delaying polymerization, theirreversible damage done to the RBC membrane can be prevented and thereby alter the downstream pathophysiology of thedisease.
In order to fulfill this unmet need, Global Blood Therapeutics (GBT) is conducting clinical trials for the treatment of SCD withGBT440, an oral small molecule designed to increase the oxygen affinity of Hb, delay Hb polymerization and prevent RBC sickling.
Oxygen Equilibrium Curves of GBT440 in SS Blood and the Correlation to % Hb modification
Figure 2:
(A) OECs show the dose-dependent increase in oxygen affinity as evidenced by decreasing p50 and p20 values. Due to the nature of biphasic curves, p20 is amore sensitive parameter than p50 at lower GBT440 concentrations. (B and C) Change in p20 (B) and change in p50 (C) at various % Hb modifications. Thedifferent correlations (R2 of 0.78 for Δp20 and R2 of 0.55 for Δp50) indicate that in the efficacious range Δp20 will be a better predictor of % Hb modification.The equation, y=0.27x-0.16, was used to calculate % Hb modification in the clinical trial.
p O 2 (m m H g )
O2 S
atu
rati
on
(%)
0 2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 00
2 0
4 0
6 0
8 0
1 0 0
3 0 % H b m o d if ic a tio n
1 5 % H b m o d if ic a tio n
1 0 % H b m o d if ic a tio n
5 % H b m o d if ic a tio n
C o n tro l
][]440[*100mod %
HbGBTificationHb spiked
1 0 2 0 3 0 4 0 5 0
-5
0
5
1 0
1 5
% H b m o d if ic a t io n
p
20
(mm
Hg
)
R2
= 0 .7 8
y = 0 .2 7 x -0 .1 6
N = 1 3 2
1 0 2 0 3 0 4 0 5 0
-5
0
5
1 0
1 5
% H b m o d if ic a t io n
p
50
(mm
Hg
)
R2
= 0 .5 5
y = 0 .1 2 x -0 .0 5
N = 1 3 2
A B
C
IN VITRO PHARMACODYNAMIC MODEL
Pharmacokinetics of GBT440 in Healthy Volunteers and SCD Patients after Single and Multiple Doses
A B
Figure 1:
(A) Mean ± SD Blood Concentration-time Profiles of GBT440 in Healthy Volunteers and SCD Patients Following an Oral Administration of 1000 mg. Inset Tableshows the PK parameters derived from these profiles. The difference in PK between Healthy Volunteers and SCD Patients is likely due to lower hematocrit andmore rapid turnover of RBC in SCD patients. The long half-life in Healthy Volunteers and SCD Patients supports once daily dosing. (B) Mean ± SD GBT440Concentrations on Day 1 and Day 28 following daily dosing of 700 mg in SCD patient. Exposure of GBT440 was ~3-fold higher at steady-state compared to Day 1.The RBC/Plasma ratio was 75:1
PHARMACOKINETICS STUDIES
Healthy Volunteers
SCD Patients
Dose(N)
300 mg(6)
600 mg(5)a
900 mg(5)a
700 mg(11)b
Cmax
µg/mL
Mean 97.9 209 294 84.6
%CV 14.4% 13.5% 9.4% 40.4%
AUC0-24
hr*µg/mL
Mean 2149 4359 5968 1771
%CV 12.3% 11.1% 7.4% 42.5%
Figure 5:
OECs were collected at baseline as well as during various timepoints throughout dosing and wash out periods. Δp20 values werecalculated by subtracting the sample from the baseline p20. ThisΔp20 value was then used to calculate “% Hb modification (derivedfrom OECs)”. Correlation illustrates a linear relationship betweenthe “% Hb modification (derived from OECs)” and the “% Hbmodification (derived from [GBT440]RBC)”. Therefore, Hbmodification using GBT440 PK/blood levels is a good predictor ofchanges in oxygen affinity based on OECs measurements.
Pharmacokinetics Correlates with Changes in Hb-O2 Affinity
IN VIVO PHARMACOKINETIC/PHARMACODYNAMIC MODEL
IN VIVO PHARMACODYNAMIC DATA
1 0 2 0 3 0 4 0
-2 0
0
2 0
4 0
% H b m o d if ic a t io n
(d e r iv e d fro m [G B T 4 4 0 ]R B C )
%H
b m
od
ific
ati
on
(de
riv
ed
fro
m O
EC
s)
R2
= 0 .7 0
Y = 0.94*X + 0.15
N = 1 7 2
0 .5 1 .0 1 .5 2 .0
[G B T 4 4 0 ]R B C
(m M )
Pla
cebo
500 m
g
700 m
g
1000 m
g
0
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1 0
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2 0
2 5
D o s e
p2
0
(mm
Hg
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D a y -1
D a y 2 8
n s
n s* * *
* * * *
Pla
cebo
500 m
g
700 m
g
1000 m
g
2 0
2 5
3 0
3 5
4 0
4 5
D o s e
p5
0
(mm
Hg
)
D a y -1
D a y 2 8
n s
*
n s
n s
A B
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