CLINICAL PHARMACOLOGY
Mechanism Of Action
CD38 is a transmembrane glycoprotein (48 kDa) expressed on the surface of hematopoietic cells, including multiple myeloma and other cell types and tissues and has multiple functions, such as receptor mediated adhesion, signaling, and modulation of cyclase and hydrolase activity. Daratumumab is an IgG1κ human monoclonal antibody (mAb) that binds to CD38 and inhibits the growth of CD38 expressing tumor cells by inducing apoptosis directly through Fc mediated cross linking as well as by immune-mediated tumor cell lysis through complement dependent cytotoxicity (CDC), antibody dependent cell mediated cytotoxicity (ADCC) and antibody dependent cellular phagocytosis (ADCP). A subset of myeloid derived suppressor cells (CD38+MDSCs), regulatory T cells (CD38+Tregs) and B cells (CD38+Bregs) are decreased by daratumumab.
Pharmacodynamics
NK cells express CD38 and are susceptible to daratumumab mediated cell lysis. Decreases in absolute counts and percentages of total NK cells (CD16+CD56+) and activated (CD16+CD56dim) NK cells in peripheral whole blood and bone marrow were observed with DARZALEX treatment.
Cardiac Electrophysiology
DARZALEX as a large protein has a low likelihood of direct ion channel interactions. There is no evidence from non-clinical or clinical data to suggest that DARZALEX has the potential to delay ventricular repolarization.
Pharmacokinetics
Over the dose range from 1 to 24 mg/kg as monotherapy or 1 to 16 mg/kg of DARZALEX in combination with other treatments, increases in area under the concentration-time curve (AUC) were more than dose-proportional.
Following the recommended dose of 16 mg/kg when DARZALEX was administered as monotherapy or in combination therapy, the mean serum maximal concentration (Cmax) value at the end of weekly dosing, was approximately 2.7 to 3-fold higher compared to the mean serum Cmax following the first dose. The mean ± standard deviation (SD) trough serum concentration (Cmin) at the end of weekly dosing was 573 ± 332 μg/mL when DARZALEX was administered as monotherapy and 502 ± 196 to 607 ± 231 μg/mL when DARZALEX was administered as combination therapy. Split dosing of the first dose resulted in a different PK profile in the first day compared to single dosing; however, similar Cmax and Cmin concentrations were both predicted and observed following the administration of the second split dose on Week 1 Day 2.
When DARZALEX was administered as monotherapy, daratumumab steady state was achieved approximately 5 months into the every 4-week dosing period (by the 21st infusion), and the mean ± SD ratio of Cmax at steady-state to Cmax after the first dose was 1.6 ± 0.5.
Distribution
At the recommended dose of 16 mg/kg, the mean ± SD central volume of distribution was 4.7 ± 1.3 L when DARZALEX was administered as monotherapy and 4.4 ± 1.5 L when DARZALEX was administered as combination therapy.
Elimination
Daratumumab clearance decreased with increasing dose and with multiple dosing. At the recommended dose of 16 mg/kg of DARZALEX as monotherapy, the mean ± SD linear clearance was estimated to be 171.4 ± 95.3 mL/day. The mean ± SD estimated terminal half-life associated with linear clearance was 18 ± 9 days when DARZALEX administered as monotherapy and a mean of 22-23 days when DARZALEX was administered as combination therapy.
Specific Populations
The following population characteristics have no clinically meaningful effect on the pharmacokinetics of daratumumab in patients administered DARZALEX as monotherapy or as combination therapy: sex, age (31 to 93 years), mild [total bilirubin 1 to 1.5 times upper limit of normal (ULN) or aspartate aminotransaminase (AST)>ULN] and moderate (total bilirubin 1.5 to 3 times ULN and any AST) hepatic impairment, or renal impairment [Creatinine clearance (CLcr) 15 -89 mL/min]. The effect of severe (total bilirubin >3 times ULN and any AST) hepatic impairment is unknown. Increasing body weight increased the central volume of distribution and clearance of daratumumab, supporting the body weight-based dosing regimen.
Drug Interactions
Effect Of Other Drugs On Daratumumab
The coadministration of lenalidomide, pomalidomide or bortezomib with DARZALEX did not affect the pharmacokinetics of daratumumab.
Effect Of Daratumumab On Other Drugs
The coadministration of DARZALEX with bortezomib or pomalidomide did not affect the pharmacokinetics of bortezomib or pomalidomide.
Clinical Studies
Newly Diagnosed Multiple Myeloma
Combination Treatment With Bortezomib, Melphalan And Prednisone (VMP) In Patients Ineligible For Autologous Stem Cell Transplant
ALCYONE (NCT02195479), an open-label, randomized, active-controlled Phase 3 study, compared treatment with DARZALEX 16 mg/kg in combination with bortezomib, melphalan and prednisone (D-VMP), to treatment with VMP in patients with newly diagnosed multiple myeloma. Bortezomib was administered by subcutaneous (SC) injection at a dose of 1.3 mg/m2 body surface area twice weekly at Weeks 1, 2, 4 and 5 for the first 6-week cycle (Cycle 1; 8 doses), followed by once weekly administrations at Weeks 1, 2, 4 and 5 for eight more 6-week cycles (Cycles 2-9; 4 doses per cycle). Melphalan at 9 mg/m2, and prednisone at 60 mg/m2 were orally administered on Days 1 to 4 of the nine 6-week cycles (Cycles 1-9). DARZALEX treatment was continued until disease progression or unacceptable toxicity.
A total of 706 patients were randomized: 350 to the D-VMP arm and 356 to the VMP arm. The baseline demographic and disease characteristics were similar between the two treatment groups. The median age was 71 (range: 40-93) years, with 30% of the patients ≥75 years of age. The majority were white (85%), female (54%), 25% had an Eastern Cooperative Oncology Group (ECOG) performance score of 0, 50% had an ECOG performance score of 1 and 25% had an ECOG performance score of 2. Nineteen percent of patients had ISS Stage I, 42% had ISS Stage II and 38% had ISS Stage III disease. Efficacy was evaluated by progression free survival (PFS) based on International Myeloma Working Group (IMWG) criteria.
ALCYONE demonstrated an improvement in PFS in the D-VMP arm as compared to the VMP arm; the median PFS had not been reached in the D-VMP arm and was 18.1 months (95% CI:16.53, 19.91) in the VMP arm (hazard ratio [HR]=0.5; 95% CI: 0.38, 0.65; p<0.0001), representing 50% reduction in the risk of disease progression or death in patients treated with DVMP.
Figure 1: Kaplan-Meier Curve of PFS in ALCYONE
Additional efficacy results from ALCYONE are presented in Table 15 below.
Table 15: Additional efficacy results from ALCYONE
|
D-VMP (n=350) |
VMP (n=356) |
Overall response (sCR+CR+VGPR+PR) n(%)a |
318 (90.9%) |
263 (73.9%) |
p-valueb |
<0.0001 |
|
Stringent complete response (sCR) |
63 (18.0%) |
25 (7.0%) |
Complete response (CR) |
86 (24.6%) |
62 (17.4%) |
Very good partial response (VGPR) |
100 (28.6%) |
90 (25.3%) |
Partial response (PR) |
69 (19.7%) |
86 (24.2%) |
MRD negativity ratea, c n(%) |
78 (22.3%) |
22 (6.2%) |
95% CI (%) |
(18.0, 27.0) |
(3.9, 9.2) |
p-valued |
<0.0001 |
|
MRD negativity rate in patients with CR or betterc n(%) |
74 (49.7%) |
22 (25.3%) |
95% CI (%) |
(41.4, 58.0) |
(16.6, 35.7) |
D-VMP = daratumumab-bortezomib-melphalan-prednisone; VMP = bortezomib-melphalan-prednisone; MRD = minimal residual disease; CI = confidence interval
a Based on intent-to-treat population
b p-value from Cochran Mantel-Haenszel Chi-Squared test.
c Based on threshold of 10-5
d p-value from Fisher’s exact test. |
In responders, the median time to response was 0.79 months (range: 0.4 to 15.5 months) in the D-VMP group and 0.82 months (range: 0.7 to 12.6 months) in the VMP group. The median duration of response had not been reached in the D-VMP group and was 21.3 months (range: 0.5+, 23.7+) in the VMP group.
Relapsed/Refractory Multiple Myeloma
Combination Treatment With Lenalidomide And Dexamethasone
POLLUX (NCT02076009), an open-label, randomized, active-controlled Phase 3 trial, compared treatment with DARZALEX 16 mg/kg in combination with lenalidomide and low-dose dexamethasone (DRd) to treatment with lenalidomide and low-dose dexamethasone (Rd) in patients with multiple myeloma who had received at least one prior therapy. Lenalidomide (25 mg once daily orally on Days 1-21 of repeated 28-day [4-week] cycles) was given with low dose oral or intravenous dexamethasone 40 mg/week (or a reduced dose of 20 mg/week for patients >75 years or body mass index [BMI] <18.5). On DARZALEX infusion days, 20 mg of the dexamethasone dose was given as a pre-infusion medication and the remainder given the day after the infusion. For patients on a reduced dexamethasone dose, the entire 20 mg dose was given as a DARZALEX pre-infusion medication. Dose adjustments for lenalidomide and dexamethasone were applied according to manufacturer’s prescribing information. Treatment was continued in both arms until disease progression or unacceptable toxicity.
A total of 569 patients were randomized; 286 to the DRd arm and 283 to the Rd arm. The baseline demographic and disease characteristics were similar between the DARZALEX and the control arm. The median patient age was 65 years (range 34 to 89 years), 11% were ≥75 years, 59% were male; 69% Caucasian, 18% Asian, and 3% African American. Patients had received a median of 1 prior line of therapy. Sixty-three percent (63%) of patients had received prior autologous stem cell transplantation (ASCT). The majority of patients (86%) received a prior PI, 55% of patients had received a prior immunomodulatory agent, including 18% of patients who had received prior lenalidomide; and 44% of patients had received both a prior PI and immunomodulatory agent. At baseline, 27% of patients were refractory to the last line of treatment. Eighteen percent (18%) of patients were refractory to a PI only, and 21% were refractory to bortezomib. Efficacy was evaluated by progression free survival (PFS) based on International Myeloma Working Group (IMWG) criteria.
POLLUX demonstrated an improvement in PFS in the DRd arm as compared to the Rd arm; the median PFS had not been reached in the DRd arm and was 18.4 months in the Rd arm (hazard ratio [HR]=0.37; 95% CI: 0.27, 0.52; p<0.0001), representing 63% reduction in the risk of disease progression or death in patients treated with DRd.
Figure 2: Kaplan-Meier Curve of PFS in POLLUX
Additional efficacy results from POLLUX are presented in Table 16 below.
Table 16: Additional efficacy results from POLLUXa
|
DRd (n=286) |
Rd (n=283) |
Overall response (sCR+CR+VGPR+PR) |
261 (91.3%) |
211 (74.6%) |
p-valueb |
<0.0001 |
|
Stringent complete response (sCR) |
51 (17.8%) |
20 (7.1%) |
Complete response (CR) |
70 (24.5%) |
33 (11.7%) |
Very good partial response (VGPR) |
92 (32.2%) |
69 (24.4%) |
Partial response (PR) |
48 (16.8%) |
89 (31.4%) |
DRd = daratumumab- lenalidomide-dexamethasone; Rd = lenalidomide-dexamethasone
a Based on Intent-to-treat population
b p-value from Cochran Mantel-Haenszel Chi-Squared test. |
In responders, the median time to response was 1 month (range: 0.9 to 13 months) in the DRd group and 1.1 months (range: 0.9 to 10 months) in the Rd group. The median duration of response had not been reached in the DRd group (range: 1+ to 19.8+ months) and was 17.4 months (range: 1.4 to 18.5+ months) in the Rd group.
With a median follow-up of 13.5 months, 75 deaths were observed; 30 in the DRd group and 45 in the Rd group.
Combination Treatment With Bortezomib And Dexamethasone
CASTOR (NCT02136134), an open-label, randomized, active-controlled Phase 3 trial, compared treatment with DARZALEX 16 mg/kg in combination with bortezomib and dexamethasone (DVd), to treatment with bortezomib and dexamethasone (Vd) in patients with multiple myeloma who had received at least one prior therapy. Bortezomib was administered by SC injection or IV infusion at a dose of 1.3 mg/m2 body surface area twice weekly for two weeks (Days 1, 4, 8, and 11) of repeated 21 day (3-week) treatment cycles, for a total of 8 cycles. Dexamethasone was administered orally at a dose of 20 mg on Days 1, 2, 4, 5, 8, 9, 11, and 12 of each of the 8 bortezomib cycles (80 mg/week for two out of three weeks of the bortezomib cycle) or a reduced dose of 20 mg/week for patients >75 years, BMI <18.5, poorly controlled diabetes mellitus or prior intolerance to steroid therapy. On the days of DARZALEX infusion, 20 mg of the dexamethasone dose was administered as a pre-infusion medication. For patients on a reduced dexamethasone dose, the entire 20 mg dose was given as a DARZALEX pre-infusion medication. Bortezomib and dexamethasone were given for 8 three-week cycles in both treatment arms; whereas DARZALEX was given until disease progression. However, dexamethasone 20 mg was continued as a DARZALEX pre-infusion medication in the DVd arm. Dose adjustments for bortezomib and dexamethasone were applied according to manufacturer’s prescribing information.
A total of 498 patients were randomized; 251 to the DVd arm and 247 to the Vd arm. The baseline demographic and disease characteristics were similar between the DARZALEX and the control arm. The median patient age was 64 years (range 30 to 88 years); 12% were ≥75 years, 57% were male; 87% Caucasian, 5% Asian and 4% African American. Patients had received a median of 2 prior lines of therapy and 61% of patients had received prior autologous stem cell transplantation (ASCT). Sixty-nine percent (69%) of patients had received a prior PI (66% received bortezomib) and 76% of patients received an immunomodulatory agent (42% received lenalidomide). At baseline, 32% of patients were refractory to the last line of treatment and the proportions of patients refractory to any specific prior therapy were in general well balanced between the treatment groups. Thirty-three percent (33%) of patients were refractory to an immunomodulatory agent only, with 24% patients in the DVd arm and 33% of patients in the Vd arm respectively refractory to lenalidomide. Efficacy was evaluated by progression free survival (PFS) based on International Myeloma Working Group (IMWG) criteria.
CASTOR demonstrated an improvement in PFS in the DVd arm as compared to the Vd arm; the median PFS had not been reached in the DVd arm and was 7.2 months in the Vd arm (HR [95% CI]: 0.39 [0.28, 0.53]; p-value < 0.0001), representing a 61% reduction in the risk of disease progression or death for patients treated with DVd versus Vd.
Figure 3: Kaplan-Meier Curve of PFS in CASTOR
Additional efficacy results from CASTOR are presented in Table 17 below.
Table 17: Additional efficacy results from CASTORa
|
DVd (n=251) |
Vd (n=247) |
Overall response (sCR+CR+VGPR+PR) |
199 (79.3%) |
148 (59.9%) |
P-valueb |
<0.0001 |
|
Stringent complete response (sCR) |
11 (4.4%) |
5 (2.0%) |
Complete response (CR) |
35 (13.9%) |
16 (6.5%) |
Very good partial response (VGPR) |
96 (38.2%) |
47 (19.0%) |
Partial response (PR) |
57 (22.7%) |
80 (32.4%) |
DVd = daratumumab- bortezomib-dexamethasone; Vd = bortezomib-dexamethasone
a Based on Intent-to-treat population
b p-value from Cochran Mantel-Haenszel Chi-Squared test. |
In responders, the median time to response was 0.8 months (range: 0.7 to 4 months) in the DVd group and 1.5 months (range: 0.7 to 5 months) in the Vd group. The median duration of response had not been reached in the DVd group (range: 1.4+ to 14.1+ months) and was 7.9 months (1.4+ to 12+ months) in the Vd group.
With a median follow-up of 7.4 months, 65 deaths were observed; 29 in the DVd group and 36 in the Vd group were observed.
Combination Treatment With Pomalidomide And Dexamethasone
EQUULEUS (NCT01998971) was an open-label trial in which 103 patients with multiple myeloma who had received a prior PI and an immunomodulatory agent, received 16 mg/kg DARZALEX in combination with pomalidomide and low-dose dexamethasone until disease progression. Pomalidomide (4 mg once daily orally on Days 1-21 of repeated 28-day [4-week] cycles) was given with low dose oral or intravenous dexamethasone 40 mg/ week (reduced dose of 20 mg/week for patients >75 years or body mass index [BMI] <18.5). On DARZALEX infusion days, 20 mg of the dexamethasone dose was given as a pre-infusion medication and the remainder given the day after the infusion. For patients on a reduced dexamethasone dose, the entire 20 mg dose was given as a DARZALEX pre-infusion medication.
The median patient age was 64 years (range: 35 to 86 years) with 8% of patients ≥75 years of age. Patients in the study had received a median of 4 prior lines of therapy. Seventy-four percent (74%) of patients had received prior ASCT. Ninety-eight percent (98%) of patients received prior bortezomib treatment, and 33% of patients received prior carfilzomib. All patients received prior lenalidomide treatment, with 98% of patients previously treated with the combination of bortezomib and lenalidomide. Eighty nine percent (89%) of patients were refractory to lenalidomide and 71% refractory to bortezomib; 64% of patients were refractory to bortezomib and lenalidomide.
Efficacy results were based on overall response rate as determined by Independent Review Committee using IMWG criteria (see Table 18).
Table 18: Efficacy results for EQUULEUS
|
N=103 |
Overall response rate (ORR) 95% CI (%) |
61 (59.2%) (49.1, 68.8) |
Stringent complete response (sCR) |
8 (7.8%) |
Complete response (CR) |
6 (5.8%) |
Very good partial response (VGPR) |
29 (28.2%) |
Partial response (PR) |
18 (17.5%) |
ORR = sCR+CR+VGPR+PR
CI = Confidence Interval |
The median time to response was 1 month (range: 0.9 to 2.8 months). The median duration of response was 13.6 months (range: 0.9+ to 14.6+ months).
Monotherapy
SIRIUS (NCT01985126), was an open-label trial evaluating DARZALEX monotherapy in patients with relapsed or refractory multiple myeloma who had received at least 3 prior lines of therapy including a proteasome inhibitor and an immunomodulatory agent or who were double- refractory to a proteasome inhibitor and an immunomodulatory agent. In 106 patients, DARZALEX 16 mg/kg was administered with pre- and post-infusion medication. Treatment continued until unacceptable toxicity or disease progression.
The median patient age was 63.5 years (range: 31 to 84 years), 49% were male and 79% were Caucasian. Patients had received a median of 5 prior lines of therapy. Eighty percent of patients had received prior autologous stem cell transplantation (ASCT). Prior therapies included bortezomib (99%), lenalidomide (99%), pomalidomide (63%) and carfilzomib (50%). At baseline, 97% of patients were refractory to the last line of treatment, 95% were refractory to both, a proteasome inhibitor (PI) and immunomodulatory agent, and 77% were refractory to alkylating agents.
Efficacy results were based on overall response rate as determined by the Independent Review Committee assessment using IMWG criteria (see Table 19).
Table 19: Efficacy results for SIRIUS
|
N=106 |
Overall response rate (ORR) 95% CI (%) |
31 (29.2%) (20.8, 38.9) |
Stringent complete response (sCR) |
3 (2.8%) |
Complete response (CR) |
0 |
Very good partial response (VGPR) |
10 (9.4%) |
Partial response (PR) |
18 (17.0%) |
ORR = sCR+CR+VGPR+PR
CI = confidence interval |
The median time to response was 1 month (range: 0.9 to 5.6 months). The median duration of response was 7.4 months (range: 1.2 to 13.1+ months).
Study GEN501 (NCT00574288) was an open-label dose escalation trial evaluating DARZALEX monotherapy in patients with relapsed or refractory multiple myeloma who had received at least 2 different cytoreductive therapies. In 42 patients, DARZALEX 16 mg/kg was administered with pre- and post-infusion medication. Treatment continued until unacceptable toxicity or disease progression.
The median patient age was 64 years (range: 44 to 76 years), 64% were male and 76% were Caucasian. Patients in the study had received a median of 4 prior lines of therapy. Seventy-four percent of patients had received prior ASCT. Prior therapies included bortezomib (100%), lenalidomide (95%), pomalidomide (36%) and carfilzomib (19%). At baseline, 76% of patients were refractory to the last line of treatment, 64% of patients were refractory to both, a PI and an immunomodulatory agent, and 60% of patients were refractory to alkylating agents.
Overall response rate was 36% (95% CI: 21.6, 52.0%) with 1 CR and 3 VGPR. The median time to response was 1 month (range: 0.5 to 3.2 months). The median duration of response was not estimable (range: 2.2 to 13.1+ months).