Table 9 provides the results of exploratory analyses of the frequency and severity of NCI CTCAE Grade 3 or 4 adverse reactions reported in more pemetrexed-treated patients who did not receive vitamin supplementation (never supplemented) as compared with those who received vitamin supplementation with daily folic acid and vitamin B
12 from the time of enrollment in Study JMCH (fully-supplemented).
The following adverse reactions occurred more frequently in patients who were fully vitamin supplemented than in patients who were never supplemented:
- hypertension (11% versus 3%),
- chest pain (8% versus 6%),
- thrombosis/embolism (6% versus 3%).
Additional Experience Across Clinical Trials
Sepsis, with or without neutropenia, including fatal cases: 1%
Severe esophagitis, resulting in hospitalization: <1%
Absorption
The pharmacokinetics of pemetrexed when pemetrexed was administered as a single agent in doses ranging from 0.2 to 838 mg/m
2 infused over a 10-minute period have been evaluated in 426 cancer patients with a variety of solid tumors. Pemetrexed total systemic exposure (AUC) and maximum plasma concentration (C
max) increased proportionally with increase of dose. The pharmacokinetics of pemetrexed did not change over multiple treatment cycles.
Distribution
Pemetrexed has a steady-state volume of distribution of 16.1 liters. In vitro studies indicated that pemetrexed is 81% bound to plasma proteins.
Elimination
The total systemic clearance of pemetrexed is 91.8 mL/min and the elimination half-life of pemetrexed is 3.5 hours in patients with normal renal function (creatinine clearance of 90 mL/min). As renal function decreases, the clearance of pemetrexed decreases and exposure (AUC) of pemetrexed increases.
Metabolism
Pemetrexed is not metabolized to an appreciable extent.
Excretion
Pemetrexed is primarily eliminated in the urine, with 70% to 90% of the dose recovered unchanged within the first 24 hours following administration. In vitro studies indicated that pemetrexed is a substrate of OAT3 (organic anion transporter 3), a transporter that is involved in the active secretion of pemetrexed.
Specific Populations
Age (26 to 80 years) and sex had no clinically meaningful effect on the systemic exposure of pemetrexed based on population pharmacokinetic analyses.
Racial Groups
The pharmacokinetics of pemetrexed were similar in Whites and Blacks or African Americans. Insufficient data are available for other ethnic groups.
Patients with Hepatic Impairment
Pemetrexed has not been formally studied in patients with hepatic impairment. No effect of elevated AST, ALT, or total bilirubin on the PK of pemetrexed was observed in clinical studies.
Patients with Renal Impairment
Pharmacokinetic analyses of pemetrexed included 127 patients with impaired renal function. Plasma clearance of pemetrexed decreases as renal function decreases, with a resultant increase in systemic exposure. Patients with creatinine clearances of 45, 50, and 80 mL/min had 65%, 54%, and 13% increases, respectively in systemic exposure (AUC) compared to patients with creatinine clearance of 100 mL/min
[see Dosage and Administration (
2.3) and Warnings and Precautions (
5.2)]
.
Third-Space Fluid
The pemetrexed plasma concentrations in patients with various solid tumors with stable, mild to moderate third-space fluid were comparable to those observed in patients without third space fluid collections. The effect of severe third space fluid on pharmacokinetics is not known.
Drug Interaction Studies
Drugs Inhibiting OAT3 Transporter
Ibuprofen, an OAT3 inhibitor, administered at 400 mg four times a day decreased the clearance of pemetrexed and increased its exposure (AUC) by approximately 20% in patients with normal renal function (creatinine clearance >80 mL/min).
In Vitro Studies
Pemetrexed is a substrate for OAT3. Ibuprofen, an OAT3 inhibitor inhibited the uptake of pemetrexed in OAT3-expressing cell cultures with an average [l
µ]/lC
50 ratio of 0.38. In vitro data predict that at clinically relevant concentrations, other NSAIDs (naproxen, diclofenac, celecoxib) would not inhibit the uptake of pemetrexed by OAT3 and would not increase the AUC of pemetrexed to a clinically significant extent.
[see Drug Interactions (
7)]
.
Pemetrexed is a substrate for OAT4. In vitro, ibuprofen and other NSAIDs (naproxen, diclofenac, celecoxib) are not inhibitors of OAT4 at clinically relevant concentrations.
Aspirin
Aspirin, administered in low to moderate doses (325 mg every 6 hours), does not affect the pharmacokinetics of pemetrexed.
Cisplatin
Cisplatin does not affect the pharmacokinetics of pemetrexed and the pharmacokinetics of total platinum are unaltered by pemetrexed.
Vitamins
Neither folic acid nor vitamin B
12 affect the pharmacokinetics of pemetrexed.
Drugs Metabolized by Cytochrome P450 Enzymes
In vitro studies suggest that pemetrexed does not inhibit the clearance of drugs metabolized by CYP3A, CYP2D6, CYP2C9, and CYP1A2.
Maintenance Treatment Following First-line Non-Pemetrexed Containing Platinum-Based Chemotherapy
The efficacy of pemetrexed as maintenance therapy following first-line platinum-based chemotherapy was evaluated in Study JMEN (NCT00102804), a multicenter, randomized (2:1), double-blind, placebo-controlled study conducted in 663 patients with Stage IIIb/IV NSCLC who did not progress after four cycles of platinum-based chemotherapy. Patients were randomized to receive pemetrexed 500 mg/m
2 intravenously every 21 days or placebo until disease progression or intolerable toxicity. Patients in both study arms received folic acid, vitamin B
12, and dexamethasone
[see Dosage and Administration (
2.4)]
. Randomization was carried out using a minimization approach [Pocock and Simon (1975)] using the following factors: gender, ECOG PS (0 versus 1), response to prior chemotherapy (complete or partial response versus stable disease), history of brain metastases (yes versus no), non-platinum component of induction therapy (docetaxel versus gemcitabine versus paclitaxel), and disease stage (IIIb versus IV). The major efficacy outcome measures were progression-free survival based on assessment by independent review and overall survival; both were measured from the date of randomization in Study JMEN.
A total of 663 patients were enrolled with 441 patients randomized to pemetrexed and 222 patients randomized to placebo. The median age was 61 years (range 26-83 years); 73% were male; 65% were White, 32% were Asian, 2.9% were Hispanic or Latino, and <2% were other ethnicities; 60% had an ECOG PS of 1; and 73% were current or former smokers. Median time from initiation of platinum-based chemotherapy to randomization was 3.3 months (range 1.6 to 5.1 months) and 49% of the population achieved a partial or complete response to first-line, platinum-based chemotherapy. With regard to tumor characteristics, 81% had Stage IV disease, 73% had non-squamous NSCLC and 27% had squamous NSCLC. Among the 481 patients with non-squamous NSCLC, 68% had adenocarcinoma, 4% had large cell, and 28% had other histologies.
Efficacy results are presented in Table 13 and Figure 5.
Table 13: Efficacy Results in Study JMENEfficacy Parameter | Pemetrexed
| Placebo |
Overall survival
| N=441 | N=222 |
Median (months)
(95% CI)
| 13.4
(11.9-15.9)
| 10.6
(8.7-12.0)
|
Hazard ratio
a (95% CI)
| 0.79
(0.65-0.95)
|
p-value | p=0.012 |
Progression-free survival per independent review | N=387 | N=194 |
Median (months)
(95% CI)
| 4.0
(3.1-4.4)
| 2.0
(1.5-2.8)
|
Hazard ratio
a (95% CI)
| 0.60
(0.49-0.73)
|
p-value | p<0.00001 |
a Hazard ratios are adjusted for multiplicity but not for stratification variables.
Figure 5: Kaplan-Meier Curves for Overall Survival in Study JMEN
The results of pre-specified subgroup analyses by NSCLC histology are presented in Table 14 and Figures 6 and 7.
Table 14: Efficacy Results in Study JMEN by Histologic SubgroupEfficacy Parameter | Overall Survival
| Progression-Free Survival Per Independent Review
|
Pemetrexed (N=441) | Placebo (N=222) | Pemetrexed (N=387)
| Placebo (N=194)
|
Non-squamous NSCLC (n=481) |
Median (months) | 15.5 | 10.3 | 4.4 | 1.8 |
HR
a
(95% CI)
| 0.70
(0.56-0.88)
| 0.47
(0.37-0.60)
|
Adenocarcinoma (n=328) |
Median (months) | 16.8 | 11.5 | 4.6 | 2.7 |
HR
a
(95% CI)
| 0.73
(0.56-0.96)
| 0.51
(0.38-0.68)
|
Large cell carcinoma (n=20) |
Median (months) | 8.4 | 7.9 | 4.5 | 1.5 |
HR
a
(95% CI)
| 0.98
(0.36-2.65)
| 0.40
(0.12-1.29)
|
Other
b (n=133)
|
Median (months) | 11.3 | 7.7 | 4.1 | 1.6 |
HR
a
(95% CI)
| 0.61 (0.40-0.94) | 0.44
(0.28-0.68)
|
Squamous cell NSCLC (n=182) |
Median (months) | 9.9 | 10.8 | 2.4 | 2.5 |
HR
a
(95% CI)
| 1.07
(0.77-1.50)
| 1.03
(0.71-1.49)
|
a Hazard ratios are not adjusted for multiplicity
b Primary diagnosis of NSCLC not specified as adenocarcinoma, large cell carcinoma, or squamous cell carcinoma.
Figure 6: Kaplan-Meier Curves for Overall Survival in Non-squamous NSCLC in Study JMEN
Figure 7: Kaplan-Meier Curves for Overall Survival in Squamous NSCLC in Study JMEN
Maintenance Treatment Following First-line Pemetrexed Plus Platinum Chemotherapy
The efficacy of pemetrexed as maintenance therapy following first-line platinum-based chemotherapy was also evaluated in PARAMOUNT (NCT00789373), a multi-center, randomized (2:1), double-blind, placebo-controlled study conducted in patients with Stage IIIb/IV non-squamous NSCLC who had completed four cycles of pemetrexed in combination with cisplatin and achieved a complete response (CR) or partial response (PR) or stable disease (SD). Patients were required to have an ECOG PS of 0 or 1. Patients were randomized to receive pemetrexed 500 mg/m
2 intravenously every 21 days or placebo until disease progression. Randomization was stratified by response to pemetrexed in combination with cisplatin induction therapy (CR or PR versus SD), disease stage (IIIb versus IV), and ECOG PS (0 versus 1). Patients in both arms received folic acid, vitamin B
12, and dexamethasone. The main efficacy outcome measure was investigator-assessed progression-free survival (PFS) and an additional efficacy outcome measure was overall survival (OS); PFS and OS were measured from the time of randomization.
A total of 539 patients were enrolled with 359 patients randomized to pemetrexed and 180 patients randomized to placebo. The median age was 61 years (range 32 to 83 years); 58% were male; 95% were White, 4.5% were Asian, and <1% were Black or African American; 67% had an ECOG PS of 1; 78% were current or former smokers; and 43% of the population achieved a partial or complete response to first-line, platinum-based chemotherapy. With regard to tumor characteristics, 91% had Stage IV disease, 87% had adenocarcinoma, 7% had large cell, and 6% had other histologies.
Efficacy results for PARAMOUNT are presented in Table 15 and Figure 8.
Table 15: Efficacy Results in PARAMOUNTEfficacy Parameter | Pemetrexed (N=359)
| Placebo (N=180)
|
Overall survival |
Median (months)
(95% CI)
| 13.9
(12.8-16.0)
| 11.0
(10.0-12.5)
|
Hazard ratio (HR)
a (95% CI)
| 0.78
(0.64-0.96)
|
p-value | p=0.02 |
Progression-free survival
b |
Median (months)
(95% CI)
| 4.1
(3.2-4.6)
| 2.8
(2.6-3.1)
|
Hazard ratio (HR)
a
(95% CI)
| 0.62
(0.49-0.79)
|
p-value | p<0.0001 |
a Hazard ratios are adjusted for multiplicity but not for stratification variables.
b Based on investigator’s assessment.
Figure 8: Kaplan-Meier Curves for Overall Survival in PARAMOUNT
Treatment of Recurrent Disease After Prior Chemotherapy
The efficacy of pemetrexed was evaluated in Study JMEI (NCT00004881), a multicenter, randomized (1:1), open-label study conducted in patients with Stage III or IV NSCLC that had recurred or progressed following one prior chemotherapy regimen for advanced disease. Patients were randomized to receive pemetrexed 500 mg/m
2 intravenously or docetaxel 75 mg/m
2 as a 1-hour intravenous infusion once every 21 days. Patients randomized to pemetrexed also received folic acid and vitamin B
12. The study was designed to show that overall survival with pemetrexed was non-inferior to docetaxel, as the major efficacy outcome measure, and that overall survival was superior for patients randomized to pemetrexed compared to docetaxel, as a secondary outcome measure.
A total of 571 patients were enrolled with 283 patients randomized to pemetrexed and 288 patients randomized to docetaxel. The median age was 58 years (range 22 to 87 years); 72% were male; 71% were White, 24% were Asian, 2.8% were Black or African American, 1.8% were Hispanic or Latino, and <2% were other ethnicities; 88% had an ECOG PS of 0 or 1. With regard to tumor characteristics, 75% had Stage IV disease; 53% had adenocarcinoma, 30% had squamous histology; 8% large cell; and 9% had other histologic subtypes of NSCLC.
The efficacy results in the overall population and in subgroup analyses based on histologic subtype are provided in Tables 16 and 17, respectively. Study JMEI did not show an improvement in overall survival in the intent-to-treat population. In subgroup analyses, there was no evidence of a treatment effect on survival in patients with squamous NSCLC; the absence of a treatment effect in patients with NSCLC of squamous histology was also observed Studies JMDB and JMEN
[see Clinical Studies (
14.1)]
.
Table 16: Efficacy Results in Study JMEIEfficacy Parameter | Pemetrexed (N=283)
| Docetaxel (N=288)
|
Overall survival |
Median (months)
(95% CI)
| 8.3
(7.0-9.4)
| 7.9
(6.3-9.2)
|
Hazard ratio
a (95% CI)
| 0.99
(0.82-1.20)
|
Progression-free survival |
Median (months)
(95% CI)
| 2.9
(2.4-3.1)
| 2.9
(2.7-3.4)
|
Hazard ratio
a (95% CI)
| 0.97
(0.82-1.16)
|
Overall response rate (95% CI)
| 8.5%
(5.2-11.7)
| 8.3%
(5.1-11.5)
|
aHazard ratios are not adjusted for multiplicity or for stratification variables.
Table 17: Exploratory Efficacy Analyses by Histologic Subgroup in Study JMEIHistologic Subgroups | Pemetrexed (N=283)
| Docetaxel (N=288)
|
Non-squamous NSCLC (N=399) |
Median (months)
(95% CI)
| 9.3
(7.8-9.7)
| 8.0
(6.3-9.3)
|
HR
a (95% CI)
| 0.89
(0.71-1.13)
|
Adenocarcinoma (N=301) |
Median (months)
(95% CI)
| 9.0
(7.6-9.6)
| 9.2
(7.5-11.3)
|
HR
a (95% CI)
| 1.09
(0.83-1.44)
|
Large Cell (N=47) |
Median (months)
(95% CI)
| 12.8
(5.8-14.0)
| 4.5
(2.3-9.1)
|
HR
a (95% CI)
| 0.38
(0.18-0.78)
|
Other
b (N=51)
|
Median (months)
(95% CI)
| 9.4
(6.0-10.1)
| 7.9
(4.0-8.9)
|
HR
a (95% CI)
| 0.62
(0.32-1.23)
|
Squamous NSCLC (N=172) |
Median (months)
(95% CI)
| 6.2
(4.9-8.0)
| 7.4
(5.6-9.5)
|
HR
a (95% CI)
| 1.32
(0.93-1.86)
|
a Hazard ratio unadjusted for multiple comparisons.
b Primary diagnosis of NSCLC not specified as adenocarcinoma, large cell carcinoma, or squamous cell carcinoma.