Clinical Pharmacology for Tibsovo
Mechanism Of Action
Ivosidenib is a small molecule inhibitor that targets the mutant isocitrate dehydrogenase 1 (IDH1) enzyme. In patients with AML, susceptible IDH1 mutations are defined as those leading to increased levels of 2-hydroxyglutarate (2-HG) in the leukemia cells and where efficacy is predicted by 1) clinically meaningful remissions with the recommended dose of ivosidenib and/or 2) inhibition of mutant IDH1 enzymatic activity at concentrations of ivosidenib sustainable at the recommended dosage according to validated methods. The most common of such mutations in patients with AML are R132H and R132C substitutions.
Ivosidenib was shown to inhibit selected IDH1 R132 mutants at much lower concentrations than wild-type IDH1 in vitro. Inhibition of the mutant IDH1 enzyme by ivosidenib led to decreased 2- HG levels and induced myeloid differentiation in vitro and in vivo in mouse xenograft models of IDH1-mutated AML. In blood samples from patients with AML with mutated IDH1, ivosidenib decreased 2-HG levels ex-vivo, reduced blast counts, and increased percentages of mature myeloid cells.
In a patient-derived xenograft intra-hepatic cholangiocarcinoma mouse model with IDH1 R132C, ivosidenib reduced 2-HG levels.
Pharmacodynamics
Multiple doses of ivosidenib 500 mg daily were observed to decrease plasma 2-HG concentrations in patients with hematological malignancies and cholangiocarcinoma to levels similar to those observed at baseline in healthy subjects. In bone marrow of patients with hematological malignancies and in tumor biopsy of patients with cholangiocarcinoma, the mean [% coefficient of variation (%CV)] reduction in 2-HG concentrations were 93.1% (11.1%) and 82.2% (32.4%), respectively.
Cardiac Electrophysiology
The mean increase in QTc was 17 msec (UCI: 20 msec) following administration of TIBSOVO 500 mg in patients with newly diagnosed AML and patients with relapsed or refractory AML. The increase in QTc interval was concentration-dependent [see WARNINGS AND PRECAUTIONS]. A similar mean increase following administration of TIBSOVO 500 mg daily was observed in patients with relapsed or refractory MDS and in patients with solid tumors, including patients with cholangiocarcinoma. Co-administration with moderate or strong CYP3A inhibitors is expected to further increase QTc interval prolongation from baseline.
Pharmacokinetics
The AUC and Cmax of ivosidenib increase in a less than dose-proportional manner from 200 mg to 1,200 mg daily (0.4 to 2.4 times the approved recommended dosage). The following ivosidenib pharmacokinetic parameters (Table 12) were observed following administration of ivosidenib 500 mg as a single dose or daily dose (for steady state), unless otherwise specified. The steady-state pharmacokinetics of ivosidenib 500 mg were comparable between patients with newly diagnosed AML, relapsed or refractory AML, and relapsed or refractory MDS, and were lower in patients with cholangiocarcinoma.
Table 12: Pharmacokinetics of ivosidenib
|
Newly diagnosed AML treated with a combination of TIBSOVO and azacitidine |
Relapsed or refractory AML treated with TIBSOVO |
Relapsed or refractory MDS treated with TIBSOVO |
Cholangio-carcinoma treated with TIBSOVO |
| PK parameters |
|
| Single dose Cmax (ng/mL)a |
4,820 (39%) |
4,503 (38%) |
4,020 (31%) |
4,060 (45%) |
| Steady state Cmax (ng/mL)a |
6,145 (34%) |
6,551 (44%) |
5,820 (37%) |
4,799 (33%) |
| Steady state AUC (nghr/mL)a |
106,326 (41%) |
117,348 (50%) |
103,770 (40%) |
86,382 (34%) |
| Steady state PK |
Within 14 days |
| Accumulation |
| Cmax |
1.2 |
1.5 |
1.4 |
1.2 |
| AUC |
1.6 |
1.9 |
2 |
1.5 |
| Absorption |
|
| Median Tmax (hr) |
2 |
3 |
3 |
2 |
| Effect of Foodb |
| Cmax |
1.98-fold (90% CI: 1.79, 2.19) |
| AUC |
1.24-fold (90% CI: 1.16, 1.33) |
| Distribution |
| In vitro protein binding |
92 to 96% |
| Apparent volume of distribution at steady state (L)a |
504 (22%) |
403 (35%) |
552 (26%) |
706 (45%) |
| Elimination |
|
| Apparent clearance at steady state (L/hr)a |
4.6 (35%) |
5.6 (35%) |
5.1 (35%) |
6.1 (31%) |
| Terminal half-life at steady state (hr)a |
98 (42%) |
58 (42%) |
96 (43%) |
129 (102%) |
| Metabolism |
| Plasmac |
>92% of total radioactivity as ivosidenib |
| Metabolic pathways |
| Major |
CYP3A4 |
| Minor |
N-dealkylation and hydrolytic pathways |
| Excretionc |
| Urine |
17% (10% as unchanged ivosidenib) |
| Feces |
77% (67% as unchanged ivosidenib) |
a PK parameters expressed as mean (%CV).
b Following administration of a single dose in healthy subjects, a high-fat meal (approximately 900 to 1,000 calories, 500 to 600 fat calories, 250 carbohydrate calories and 150 protein calories).
c Data from a single radiolabeled ivosidenib dose in healthy subjects. |
Specific Populations
No clinically significant effects on the pharmacokinetics of ivosidenib were observed based on age (18 years to 89 years), sex, race (White, Asian, Black or African American), body weight (38 to 150 kg), ECOG performance status, mild or moderate hepatic impairment (Child-Pugh A or B) or mild or moderate renal impairment (eGFR ≥ 30 mL/min/1.73m², MDRD). The pharmacokinetics of ivosidenib in patients with severe renal impairment (eGFR < 30 mL/min/1.73m², MDRD) or renal impairment requiring dialysis or severe hepatic impairment (Child-Pugh C) is unknown.
Drug Interaction Studies
Clinical Studies And Model-Based Approaches
Effect Of Strong Or Moderate CYP3A4 Inhibitors On Ivosidenib
Co-administration of 250 mg ivosidenib with a strong CYP3A4 inhibitor (200 mg itraconazole once daily for 18 days) increased ivosidenib single-dose AUC by 269% (90% CI: 245%, 295%) with no change in Cmax in healthy subjects. Co-administration of 500 mg ivosidenib with the moderate CYP3A4 inhibitor fluconazole (dosed to steady-state) increases ivosidenib single-dose AUC by 173% with no change in Cmax. Co-administration of fluconazole following multiple daily ivosidenib doses is predicted to increase ivosidenib steady-state Cmax by 152% and AUC by 190%.
Effect of Strong CYP3A4 Inducers On Ivosidenib
Co-administration of ivosidenib with a strong CYP3A4 inducer (600 mg rifampin once daily for 15 days) is predicted to decrease ivosidenib steady-state AUC by 33%.
Effect Of Ivosidenib On CYP3A4 Substrates
Ivosidenib induces CYP3A4, including its own metabolism. Co-administration of ivosidenib with CYP3A4 substrates, including certain azole anti-fungal agents, is expected to decrease CYP3A4 substrate steady-state AUC.
Effect Of Gastric Acid Reducing Agents On Ivosidenib
No clinically significant ivosidenib pharmacokinetic differences were observed following coadministration with gastric acid reducing agents (e.g., proton pump inhibitors, H2-receptor antagonists, antacids).
In vitro Studies
Metabolic Pathways
Ivosidenib may induce CYP2B6, CYP2C8, and CYP2C9.
Drug Transporter Systems
Ivosidenib is a substrate for P-glycoprotein (P-gp). Ivosidenib is not a substrate for BCRP or hepatic transporters OATP1B1 and OATP1B3.
Ivosidenib is an inhibitor of OAT3 and P-gp. Ivosidenib does not inhibit BCRP, OATP1B1, OATP1B3, OAT1, and OCT2.
Clinical Studies
Newly Diagnosed AML
Newly Diagnosed AML In Combination With Azacitidine
The efficacy of TIBSOVO was evaluated in a randomized (1:1), multicenter, double-blind, placebo-controlled clinical trial (Study AG120-C-009, NCT03173248) of 146 adult patients with newly-diagnosed AML with an IDH1 mutation who were 75 years or older, or had comorbidities that precluded the use of intensive induction chemotherapy based on at least one of the following criteria: baseline Eastern Cooperative Oncology Group (ECOG) performance status of 2, severe cardiac or pulmonary disease, hepatic impairment with bilirubin > 1.5 times the upper limit of normal, creatinine clearance < 45 mL/min, or other comorbidity. IDH1 mutations were confirmed centrally using the Abbott RealTime™ IDH1 Assay. Local diagnostic tests were permitted for screening and randomization provided a bone marrow or peripheral blood sample was sent for central confirmation. Gene mutation analysis to document IDH1 mutated disease from a bone marrow or peripheral blood sample was conducted for all patients. Patients were randomized to receive either TIBSOVO 500 mg or matched placebo orally once daily on Days 1- 28 in combination with azacitidine 75 mg/m²/day either subcutaneously or intravenously on Days 1-7 or Days 1-5 and 8-9 of each 28-day cycle beginning on Cycle 1 Day 1. Patients were treated for a minimum of 6 cycles unless they experienced disease progression, unacceptable toxicity or undergoing hematopoietic stem cell transplantation. Baseline demographic and disease characteristics are shown in Table 13.
Table 13: Baseline Demographic and Disease Characteristics in Patients with Newly Diagnosed AML (Study AG120-C-009)
| Demographic and Disease Characteristics |
TIBSOVO + azacitidine (500 mg daily)
N=72 |
Placebo + azacitidine
N=74 |
| Demographics |
|
| Age (Years) Median (Min, Max) |
76 (58, 84) |
76 (45, 94) |
| Age Categories, n (%) |
| < 65 years |
4 (6) |
4 (5) |
| ≥ 65 years to < 75 years |
29 (40) |
27 (36) |
| ≥ 75 years |
39 (54) |
43 (58) |
| Sex, n (%) |
|
|
| Male |
42 (58) |
38 (51) |
| Female |
30 (42) |
36 (49) |
| Race, n (%) |
| Asian |
15 (21) |
19 (26) |
| White |
12 (17) |
12 (16) |
| Black or African American |
0 |
2 (3) |
| Other |
1 (1) |
1 (1) |
| Not provided |
44 (61) |
40 (54) |
| Disease Characteristics |
|
| ECOG PS, n (%) |
| 0 |
14 (19) |
10 (14) |
| 1 |
32 (44) |
40 (54) |
| 2 |
26 (36) |
24 (32) |
| IDH1 Mutation, n (%)1 |
| R132C |
45 (63) |
51 (69) |
| R132H |
14 (19) |
12 (16) |
| R132G |
6 (8) |
4 (5) |
| R132L |
3 (4) |
0 |
| R132S |
2 (3) |
6 (8) |
| Wild type |
1 (1) |
0 |
| Missing |
1 (1) |
1 (1) |
| Cytogenetic risk status2 n (%) |
| Favorable |
3 (4) |
7 (9) |
| Intermediate |
48 (67) |
44 (59) |
| Poor |
16 (22) |
20 (27) |
| Other |
3 (4) |
1 (1) |
| Missing |
2 (3) |
2 (3) |
| Transfusion Dependent at Baseline3, n (%) |
39 (54) |
40 (54) |
| Type of AML, n (%) |
| De novo AML |
54 (75) |
53 (72) |
| Secondary AML |
18 (25) |
21 (28) |
| Therapy-related AML |
2 (3) |
1 (1) |
| MDS related |
10 (14) |
12 (16) |
| MPN related |
4 (6) |
8 (11) |
ECOG PS: Eastern Cooperative Oncology Group Performance Status; MPN = Myeloproliferative Neoplasm; MDS = Myelodysplastic syndrome
1 Using confirmatory Abbott RealTime IDH1 assay testing results.
2 Cytogenetic risk status: National Comprehensive Cancer Network (NCCN) guidelines.
3 Patients were defined as transfusion dependent at baseline if they received any red blood cell or platelet transfusion within 56 days prior to the first dose of TIBSOVO. |
Efficacy was established on the basis of event-free survival (EFS), overall survival (OS), and rate and duration of complete remission (CR). EFS was defined as the time from randomization until treatment failure, relapse from remission, or death from any cause, whichever occurred first. Treatment failure was defined as failure to achieve CR by 24 weeks. The efficacy results are shown in Table 14 and Figure 1.
Table 14: Efficacy Results in Patients with Newly Diagnosed AML (Study AG120-C-009)
| Endpoint |
TIBSOVO (500 mg daily) + azacitidine
N=72 |
Placebo + azacitidine
N=74 |
| EFS, events (%) |
47 (65) |
62 (84) |
| Treatment Failure |
43 (60) |
59 (80) |
| Relapse |
3 (4) |
2 (3) |
| Death |
1 (1) |
1 (1) |
| Hazard ratio1 (95% CI) |
0.35 (0.17, 0.72) |
| p-value2 |
0.0038 |
| OS events (%) |
28 (39) |
46 (62) |
| Median OS (95% CI) months |
24.0 (11.3, 34.1) |
7.9 (4.1, 11.3) |
| Hazard ratio1 (95% CI) |
0.44 (0.27, 0.73) |
| p-value2 |
0.0010 |
| CR, n (%) |
34 (47) |
11(15) |
| 95% CI3 |
(35, 59) |
(8, 25) |
| Risk difference4 (95% CI), (%) |
31 (17, 46) |
| p-value5 |
< 0.0001 |
| Median duration of CR (95% CI), months |
NE (13.0, NE) |
11.2 (3.2, NE) |
| CR +CRh, n (%) |
37 (51) |
13 (18) |
| 95% CI3 |
(39, 63) |
(10, 28) |
| Risk difference4 (95% CI), (%) |
33 (18, 47) |
| p-value5 |
< 0.0001 |
| Median duration of CR + CRh (95% CI), months |
NE (13.0, NE) |
9.2 (5.8, NE) |
Abbreviations: EFS = Event free survival; CI: confidence interval; OS = Overall survival; CR = Complete remission; CRh = Complete remission with partial hematologic recovery; NE = Not estimable.
The 2-sided p-value boundaries for EFS, OS, CR, and CR+CRh are 0.0095, 0.0034, 0.0174, and 0.0174, respectively.
1 Hazard ratio is estimated using a Cox’s proportional hazards model stratified by the randomization stratification factors (AML status and geographic region) with Placebo + azacitidine as the denominator.
2 Two-sided p-value is calculated from the log-rank test stratified by the randomization stratification factors (AML status and geographic region).
3 CI of percentage is calculated with the Clopper and Pearson (exact Binomial) method.
4 Mantel-Haenszel estimate of risk difference in percentage between TIBSOVO + azacitidine and Placebo + azacitidine is calculated.
5 Two-sided p-value is calculated from the Cochran-Mantel-Haenszel test stratified by the randomization stratification factors (AML status and geographic region). |
Figure 1: Kaplan-Meier Curve for Overall Survival in AG120-C-009
The median time to first CR for TIBSOVO with azacitidine was 4 months (range, 1.7 to 11.9 months).
The median time to first CR + CRh for TIBSOVO with azacitidine was 4 months (range, 1.7 to 11.9 months).
Monotherapy In Newly Diagnosed AML
The efficacy of TIBSOVO was evaluated in an open-label, single-arm, multicenter clinical trial (Study AG120-C-001, NCT02074839) that included 28 adult patients with newly diagnosed AML with an IDH1 mutation. IDH1 mutations were identified by a local or central diagnostic test and confirmed retrospectively using the Abbott RealTime™ IDH1 Assay. The cohort included patients who were age 75 years or older or who had comorbidities that precluded the use of intensive induction chemotherapy based on at least one of the following criteria: baseline ECOG performance status of ≥ 2, severe cardiac or pulmonary disease, hepatic impairment with bilirubin > 1.5 times the upper limit of normal, or creatinine clearance < 45 mL/min. TIBSOVO was given orally at a starting dose of 500 mg daily until disease progression, development of unacceptable toxicity, or undergoing hematopoietic stem cell transplantation. Two (7%) of the 28 patients went on to stem cell transplantation following TIBSOVO treatment.
The baseline demographic and disease characteristics are shown in Table 15.
Table 15: Baseline Demographic and Disease Characteristics in Patients with Newly Diagnosed AML (Study AG120-C-001)
| Demographic and Disease Characteristics |
TIBSOVO (500 mg daily)
N=28 |
| Demographics |
| Age (Years) Median (Min, Max) |
77 (64, 87) |
| Age Categories, n (%) |
| < 65 years |
1 (4) |
| ≥ 65 years to < 75 years |
8 (29) |
| ≥ 75 years |
19 (68) |
| Sex, n (%) |
| Male |
15(54) |
| Female |
13 (46) |
| Race, n (%) |
| White |
24 (86) |
| Black or African American |
2 (7) |
| Asian |
0 |
| Native Hawaiian/Other Pacific Islander |
0 |
| Other/Not provided |
2 (7) |
| Disease Characteristics |
| ECOG PS, n (%) |
| 0 |
6 (21) |
| 1 |
16 (57) |
| 2 |
5 (18) |
| 3 |
1 (4) |
| IDH1 Mutation, n (%)1 |
| R132C |
24 (86) |
| R132H |
2 (7) |
| R132G |
1 (4) |
| R132L |
1 (4) |
| R132S |
0 |
| ELN Risk Category, n (%) |
| Favorable |
0 |
| Intermediate |
9 (32) |
| Adverse |
19 (68) |
| Transfusion Dependent at Baseline2, n (%) |
17 (61) |
| Type of AML, n (%) |
| De novo AML |
6 (21) |
| AML-MRC3 |
19 (68) |
| Therapy-related AML |
3 (11) |
| Prior Hypomethylating Agent for Antecedent |
| Hematologic Disorder |
13 (46) |
ECOG PS: Eastern Cooperative Oncology Group Performance Status. ELN: European Leukemia Net
1 Using confirmatory Abbott RealTime IDH1 assay testing results.
2 Patients were defined as transfusion dependent at baseline if they received any transfusion occurring within 56 days prior to the first dose of TIBSOVO.
3 AML with myelodysplasia-related changes. |
Efficacy was established on the basis of the rate of complete remission (CR) or complete remission with partial hematologic recovery (CRh), the duration of CR+CRh, and the rate of conversion from transfusion dependence to transfusion independence. The efficacy results are shown in Table 16. The median follow-up was 8.1 months (range, 0.6 to 40.9 months) and median treatment duration was 4.3 months (range, 0.3 to 40.9 months).
Table 16: Efficacy Results in Patients with Newly Diagnosed AML (Study AG120-C-001)
| Endpoint |
TIBSOVO (500 mg daily)
N=28 |
| CR1 n (%) |
8 (28.6) |
| 95% CI |
(13.2, 48.7) |
| Median DOCR2 (months) |
NE3 |
| 95% CI |
(4.2, NE) |
| CRh4 n (%) |
4 (14.3) |
| 95% CI |
(4.0, 32.7) |
| Observed DOCRh2 (months) |
2.8, 4.6, 8.3, 15.7+ |
| CR+CRh n (%) |
12 (42.9) |
| 95% CI |
(24.5, 62.8) |
| Median DOCR+CRh2 (months) |
NE3 |
| 95% CI |
(4.2, NE) |
CI: confidence interval, NE: not estimable
1 CR (complete remission) was defined as < 5% blasts in the bone marrow, no evidence of disease, and full recovery of peripheral blood counts (platelets >100,000/microliter and absolute neutrophil counts [ANC] >1,000/microliter).
2 DOCR (duration of CR), DOCRh (duration of CRh), and DOCR+CRh (duration of CR+CRh) was defined as time since first response of CR, CRh or CR/CRh, respectively, to relapse or death, whichever is earlier. + indicates censored observation.
3 The median durations of CR and CR+CRh were not estimable, with 5 patients (41.7%) who achieved CR or CRh remaining on TIBSOVO treatment (treatment duration range: 20.3 to 40.9 months).
4 CRh (complete remission with partial hematological recovery) was defined as < 5% blasts in the bone marrow, no evidence of disease, and partial recovery of peripheral blood counts (platelets >50,000/microliter and ANC >500/microliter). |
For patients who achieved a CR or CRh, the median time to CR or CRh was 2.8 months (range, 1.9 to 12.9 months). Of the 12 patients who achieved a best response of CR or CRh, 11 (92%) achieved a first response of CR or CRh within 6 months of initiating TIBSOVO.
Among the 17 patients who were dependent on red blood cell (RBC) and/or platelet transfusions at baseline, 7 (41.2%) became independent of RBC and platelet transfusions during any 56-day post-baseline period. Of the 11 patients who were independent of both RBC and platelet transfusions at baseline, 6 (54.5%) remained transfusion independent during any 56-day postbaseline period.
Relapsed Or Refractory AML
The efficacy of TIBSOVO was evaluated in an open-label, single-arm, multicenter clinical trial (Study AG120-C-001, NCT02074839) of 174 adult patients with relapsed or refractory AML with an IDH1 mutation. IDH1 mutations were identified by a local or central diagnostic test and confirmed retrospectively using the Abbott RealTime™ IDH1 Assay. TIBSOVO was given orally at a starting dose of 500 mg daily until disease progression, development of unacceptable toxicity, or undergoing hematopoietic stem cell transplantation. Twenty-one (12%) of the 174 patients went on to stem cell transplantation following TIBSOVO treatment.
The baseline demographic and disease characteristics are shown in Table 17.
Table 17: Baseline Demographic and Disease Characteristics in Patients with Relapsed or Refractory AML (Study AG120-C-001)
| Demographic and Disease Characteristics |
TIBSOVO (500 mg daily)
N=174 |
| Demographics |
| Age (Years) Median (Min, Max) |
67 (18, 87) |
| Age Categories, n (%) |
| < 65 years |
63 (36) |
| ≥ 65 years to < 75 years |
71 (41) |
| ≥ 75 years |
40 (23) |
| Sex, n (%) |
| Male |
88 (51) |
| Female |
86 (49) |
| Race, n (%) |
| White |
108(62) |
| Black or African American |
10 (6) |
| Asian |
6 (3) |
| Native Hawaiian/Other Pacific Islander |
1 (1) |
| Other/Not provided |
49 (28) |
| Disease Characteristics |
| ECOG PS, n (%) |
| 0 |
36 (21) |
| 1 |
97 (56) |
| 2 |
39 (22) |
| 3 |
2 (1) |
| IDH1 Mutation, n (%)1 |
| R132C |
102 (59) |
| R132H |
43 (25) |
| R132G |
12 (7) |
| R132S |
10 (6) |
| R132L |
7 (4) |
| Cytogenetic Risk Status, n (%) |
| Intermediate |
104 (60) |
| Poor |
47 (27) |
| Missing/Unknown |
23 (13) |
| Relapse Type |
| Primary refractory |
64 (37) |
| Refractory relapse |
45 (26) |
| Untreated relapse |
65 (37) |
| Relapse Number |
| 0 |
64 (37) |
| 1 |
83 (48) |
| 2 |
21 (12) |
| ≥ 3 |
6 (3) |
| Prior Stem Cell Transplantation for AML, n (%) |
40(23) |
| Transfusion Dependent at Baseline2, n (%) |
110 (63) |
| Median Number of Prior Therapies (Min, Max) |
2 (1, 6) |
| Type of AML, n (%) |
| De novo AML |
116 (67) |
| Secondary AML |
58(33) |
ECOG PS: Eastern Cooperative Oncology Group Performance Status.
1 Using confirmatory Abbott RealTime IDH1 assay testing results.
2 Patients were defined as transfusion dependent at baseline if they received any transfusion occurring within 56 days prior to the first dose of TIBSOVO. |
Efficacy was established on the basis of the rate of complete remission (CR) plus complete remission with partial hematologic recovery (CRh), the duration of CR+CRh, and the rate of conversion from transfusion dependence to transfusion independence. The efficacy results are shown in Table 18. The median follow-up was 8.3 months (range, 0.2 to 39.5 months) and median treatment duration was 4.1 months (range, 0.1 to 39.5 months).
Table 18: Efficacy Results in Patients with Relapsed or Refractory AML (Study AG120-C-001)
| Endpoint |
TIBSOVO (500 mg daily)
N=174 |
| CR1 n (%) |
43 (24.7) |
| 95% CI |
(18.5, 31.8) |
| Median DOCR2 (months) |
10.1 |
| 95% CI |
(6.5, 22.2) |
| CRh3 n (%) |
14 (8.0) |
| 95% CI |
(4.5, 13.1) |
| Median DOCRh2 (months) |
3.6 |
| 95% CI |
(1, 5.5) |
| CR+CRh4 n (%) |
57 (32.8) |
| 95% CI |
(25.8, 40.3) |
| Median DOCR+CRh2 (months) |
8.2 |
| 95% CI |
(5.6, 12) |
CI: confidence interval
1 CR (complete remission) was defined as < 5% blasts in the bone marrow, no evidence of disease, and full recovery of peripheral blood counts (platelets >100,000/microliter and absolute neutrophil counts [ANC] >1,000/microliter).
2 DOCR (duration of CR), DOCRh (duration of CRh), and DOCR+CRh (duration of CR+CRh) was defined as time since first response of CR, CRh or CR/CRh, respectively, to relapse or death, whichever is earlier.
3 CRh (complete remission with partial hematological recovery) was defined as < 5% blasts in the bone marrow, no evidence of disease, and partial recovery of peripheral blood counts (platelets > 50,000/ microliter and ANC > 500/microliter).
4 CR+CRh rate appeared to be consistent across all baseline demographic and baseline disease characteristics with the exception of number of prior regimens. |
For patients who achieved a CR or CRh, the median time to CR or CRh was 2 months (range, 0.9 to 5.6 months). Of the 57 patients who achieved a best response of CR or CRh, all achieved a first response of CR or CRh within 6 months of initiating TIBSOVO.
Among the 110 patients who were dependent on red blood cell (RBC) and/or platelet transfusions at baseline, 41 (37.3%) became independent of RBC and platelet transfusions during any 56-day post-baseline period. Of the 64 patients who were independent of both RBC and platelet transfusions at baseline, 38 (59.4%) remained transfusion independent during any 56-day post-baseline period.
Relapsed Or Refractory MDS
The efficacy of TIBSOVO was evaluated in an open-label, single-arm, multicenter study (study AG120-C-001, NCT02074839) of 18 adult patients with relapsed or refractory MDS with an IDH1 mutation. IDH1 mutations were detected in peripheral blood or bone marrow by a local or central diagnostic test and confirmed retrospectively using the Abbott RealTime™ IDH1 Assay. TIBSOVO was given orally at a starting dose of 500 mg daily continuous for 28-day cycles until disease progression, development of unacceptable toxicity, or undergoing hematopoietic stem cell transplantation. One (6%) of the 18 patients went on to stem cell transplantation following TIBSOVO treatment.
The baseline demographic and disease characteristics are shown in Table 19.
Table 19: Baseline Demographic and Disease Characteristics in Patients with Relapsed or Refractory MDS (Study AG120-C-001)
| Demographic and Disease Characteristics |
TIBSOVO (500 mg daily)
N=18 |
| Demographics |
| Age (Years) Median (Min, Max) |
74 (61, 82) |
| Age Categories, n (%) |
| < 65 years |
3 (17) |
| ≥ 65 years to < 75 years |
7 (39) |
| ≥ 75 years |
8 (44) |
| Sex, n (%) |
| Male |
14 (78) |
| Female |
4 (22) |
| Race, n (%) |
| White |
14 (78) |
| Black or African American |
1 (6) |
| Not Reported |
3 (17) |
| Disease Characteristics |
| ECOG PS, n (%) |
| 0 |
5 (28) |
| 1 |
10 (56) |
| 2 |
3 (17) |
| IDH1 Mutation, n (%)1 |
| R132C |
9 (50) |
| R132H |
5 (28) |
| R132G |
2 (11) |
| R132L |
1 (6) |
| R132S |
1 (6) |
| Cytogenetic Risk Status, n (%) |
| Good |
4 (22) |
| Intermediate |
8 (44) |
| Poor |
5 (28) |
| Missing |
1 (6) |
| Baseline Bone Marrow Blasts, n (%) |
| < 5% |
7 (39) |
| ≥ 5% |
11 (61) |
| Prior Therapies |
| Intensive chemotherapy |
3 (17) |
| Non-intensive chemotherapy |
15 (83) |
| 1 line of HMA-based therapy |
14 (78) |
| 2 lines of HMA-based therapy |
1 (6) |
ECOG PS: Eastern Cooperative Oncology Group Performance Status.
1 Using confirmatory Abbott RealTime IDH1 assay testing results. |
Efficacy was established on the basis of the rate of complete remission (CR) or partial remission (PR) as per the 2006 International Working Group response criteria for MDS, the duration of CR+PR, and the rate of conversion from transfusion dependence to transfusion independence. All observed responses were CRs. The efficacy results are shown in Table 20. The median follow-up was 27.1 months (range 3.7 to 88.7 months) and median duration of exposure to TIBSOVO was 8.3 months (range 3.3 to 78.8 months).
Table 20: Efficacy Results in Patients with Relapsed or Refractory MDS (Study AG120-C-001)
| Endpoint |
TIBSOVO (500 mg daily)
N=18 |
| CR1 n (%) |
7 (38.9) |
| 95% CI |
(17.3, 64.3) |
| DOCR2 (months) median (range) |
NE (1.9, 80.8+3) |
CI: confidence interval, CR: complete remission, NE: not estimable, derived based on Kaplan-Meier method.
1 CR responders with baseline bone marrow blast < 5% was 43% (3/7).
2 Duration of CR (DOCR) = date of first documented CR (lasted at least 4 weeks) to date of first documented confirmed relapse or death, whichever is earlier.
3 + indicates censored observation. |
For patients who achieved a CR, the median time to CR was 1.9 months (range, 1.0 to 5.6 months).
Among the 9 patients who were dependent on red blood cell (RBC) and/or platelet transfusions at baseline, 6 (67%) became independent of RBC and platelet transfusions during any 56-day post-baseline period. Of the 9 patients who were independent of both RBC and platelet transfusions at baseline, 7 (78%) remained transfusion independent during any 56-day postbaseline period.
Locally Advanced Or Metastatic Cholangiocarcinoma
The efficacy of TIBSOVO was evaluated in a randomized (2:1), multicenter, double-blind, placebo-controlled clinical trial (Study AG120-C-005, NCT02989857) of 185 adult patients with locally advanced or metastatic cholangiocarcinoma with an IDH1 mutation whose disease had progressed following at least 1 but not more than 2 prior regimens, including at least one gemcitabine- or 5-FU-containing regimen. Patients were randomized to receive either TIBSOVO 500 mg orally once daily or matched placebo until disease progression or unacceptable toxicity. Randomization was stratified by number of prior therapies (1 or 2). Eligible patients who were randomized to placebo were allowed to cross over to receive TIBSOVO after documented radiographic disease progression. Patients with IDH1 mutations were selected using a central diagnostic next generation sequencing assay. Tumor imaging assessments were performed every 6 weeks for the first 8 assessments and every 8 weeks thereafter.
The major efficacy outcome measure was Progression Free Survival (PFS) as determined by independent review committee (IRC) according to Response Evaluation Criteria in Solid Tumors (RECIST) v1.1.
The median age was 62 years (range: 33 to 83); 63% were female; 57% were White, 12% Asian, 1.1% Black, 0.5% Native Hawaiian/Other Pacific Islander, 0.5% American Indian or Alaska Native, 28% race missing/not reported; and 37% had an ECOG performance status of 0 (37%) or 1 (62%). All patients received at least 1 prior line of systemic therapy and 47% received two prior lines. Most patients had intrahepatic cholangiocarcinoma (91%) at diagnosis and 92% had metastatic disease. Across both arms, 70% patients had an R132C mutation, 15% had an R132L mutation, 12% had an R132G mutation, 1.1% had an R132H mutation, and 1.6% had an R132S mutation.
The efficacy results are shown in Table 21 and Figure 2. The study demonstrated a statistically significant improvement in PFS.
Table 21: Efficacy Results in Patients with Locally Advanced or Metastatic Cholangiocarcinoma in AG120-C-005
| Endpoint |
TIBSOVO (500 mg daily) |
Placebo |
| Progression-Free Survival by IRC Assessment |
N=124 |
N=61 |
| Events, n (%) |
76 (61) |
50 (82) |
| Progressive Disease |
64 (52) |
44 (72) |
| Death |
12 (10) |
6 (10) |
| Hazard ratio (95% CI)1 |
0.37 (0.25, 0.54) |
| p-value2 |
< 0.0001 |
| Objective Response Rate, n (%) |
3 (2.4) |
0 |
| Overall Survival3 |
N=126 |
N=61 |
| Deaths, n (%) |
100 (79) |
50 (82) |
| Hazard ratio (95% CI)1 |
0.79 (0.56, 1.12) |
| p-value2 |
0.093 |
IRC: Independent Review Committee; CI: Confidence Interval
1 Hazard ratio is calculated from stratified Cox regression model. Stratified by number of prior lines of therapy.
2 P-value is calculated from the one-sided stratified log-rank test. Stratified by number of prior lines of therapy.
3 OS results are based on the final analysis of OS (based on 150 deaths) which occurred 16 months after the final analysis of PFS. The median OS (95% CI) for TIBSOVO was 10.3 (7.8, 12.4) months; and placebo was 7.5 (4.8, 11.1) months without adjusting for crossover. In the analysis of OS, 70% of the patients randomized to placebo had crossed over to receive TIBSOVO after radiographic disease progression. |
Figure 2: Kaplan-Meier Plot of Progression-Free Survival per Independent Review Committee - Before Crossover (ITT)