Caspofungin Acetate 5 mg/mL Injection, Powder, Lyophilized, For Solution, 1 vial — NDC 72266-106-01 (Billing 72266-0106-01)

12 CLINICAL PHARMACOLOGY

12.1Mechanism of Action Caspofungin is an echinocandin antifungal drug [see Microbiology (12.4)].

12.3Pharmacokinetics Adult and pediatric pharmacokinetic parameters are presented in Table 8. Distribution Plasma concentrations of caspofungin decline in a polyphasic manner following single 1-hour IV infusions. A short α-phase occurs immediately postinfusion, followed by a β-phase (half-life of 9 to 11 hours) that characterizes much of the profile and exhibits clear log-linear behavior from 6 to 48 hours postdose during which the plasma concentration decreases 10-fold.

An additional, longer half-life phase, γ-phase, (half-life of 40-50 hours), also occurs. Distribution, rather than excretion or biotransformation, is the dominant mechanism influencing plasma clearance. Caspofungin is extensively bound to albumin (~97%), and distribution into red blood cells is minimal.

Mass balance results showed that approximately 92% of the administered radioactivity was distributed to tissues by 36 to 48 hours after a single 70 mg dose of [ 3 H] caspofungin acetate. There is little excretion or biotransformation of caspofungin during the first 30 hours after administration. Metabolism Caspofungin is slowly metabolized by hydrolysis and N-acetylation.

Caspofungin also undergoes spontaneous chemical degradation to an open-ring peptide compound, L-747969. At later time points (≥5 days postdose), there is a low level (≤7 picomoles/mg protein, or ≤1.3% of administered dose) of covalent binding of radiolabel in plasma following single-dose administration of [ 3 H] caspofungin acetate, which may be due to two reactive intermediates formed during the chemical degradation of caspofungin to L-747969. Additional metabolism involves hydrolysis into constitutive amino acids and their degradates, including dihydroxyhomotyrosine and N-acetyl-dihydroxyhomotyrosine.

These two tyrosine derivatives are found only in urine, suggesting rapid clearance of these derivatives by the kidneys. Excretion Two single-dose radiolabeled pharmacokinetic studies were conducted. In one study, plasma, urine, and feces were collected over 27 days, and in the second study plasma was collected over 6 months.

Plasma concentrations of radioactivity and of caspofungin were similar during the first 24 to 48 hours postdose; thereafter drug levels fell more rapidly. In plasma, caspofungin concentrations fell below the limit of quantitation after 6 to 8 days postdose, while radiolabel fell below the limit of quantitation at 22.3 weeks postdose. After single intravenous administration of [ 3 H] caspofungin acetate, excretion of caspofungin and its metabolites in humans was 35% of dose in feces and 41% of dose in urine.

A small amount of caspofungin is excreted unchanged in urine (~1.4% of dose). Renal clearance of parent drug is low (~0.15 mL/min) and total clearance of caspofungin is 12 mL/min. Special Populations Renal Impairment In a clinical study of single 70 mg doses, caspofungin pharmacokinetics were similar in healthy adult volunteers with mild renal impairment (creatinine clearance 50 to 80 mL/min) and control subjects.

Moderate (creatinine clearance 31 to 49 mL/min), severe (creatinine clearance 5 to 30 mL/min), and end-stage (creatinine clearance less than 10 mL/min and dialysis dependent) renal impairment moderately increased caspofungin plasma concentrations after single-dose administration (range: 30 to 49% for AUC). However, in adult patients with invasive aspergillosis, candidemia, or other Candida infections (intra-abdominal abscesses, peritonitis, or pleural space infections) who received multiple daily doses of caspofungin 50 mg, there was no significant effect of mild to end-stage renal impairment on caspofungin concentrations.

No dosage adjustment is necessary for patients with renal impairment. Caspofungin is not dialyzable, thus supplementary dosing is not required following hemodialysis. Hepatic Impairment Plasma concentrations of caspofun… [Excerpted — this section continues on DailyMed.]

12.1Mechanism of Action Caspofungin is an echinocandin antifungal drug [see Microbiology (12.4)].

12.3Pharmacokinetics Adult and pediatric pharmacokinetic parameters are presented in Table 8. Distribution Plasma concentrations of caspofungin decline in a polyphasic manner following single 1-hour IV infusions. A short α-phase occurs immediately postinfusion, followed by a β-phase (half-life of 9 to 11 hours) that characterizes much of the profile and exhibits clear log-linear behavior from 6 to 48 hours postdose during which the plasma concentration decreases 10-fold.

An additional, longer half-life phase, γ-phase, (half-life of 40-50 hours), also occurs. Distribution, rather than excretion or biotransformation, is the dominant mechanism influencing plasma clearance. Caspofungin is extensively bound to albumin (~97%), and distribution into red blood cells is minimal.

Mass balance results showed that approximately 92% of the administered radioactivity was distributed to tissues by 36 to 48 hours after a single 70 mg dose of [ 3 H] caspofungin acetate. There is little excretion or biotransformation of caspofungin during the first 30 hours after administration. Metabolism Caspofungin is slowly metabolized by hydrolysis and N-acetylation.

Caspofungin also undergoes spontaneous chemical degradation to an open-ring peptide compound, L-747969. At later time points (≥5 days postdose), there is a low level (≤7 picomoles/mg protein, or ≤1.3% of administered dose) of covalent binding of radiolabel in plasma following single-dose administration of [ 3 H] caspofungin acetate, which may be due to two reactive intermediates formed during the chemical degradation of caspofungin to L-747969. Additional metabolism involves hydrolysis into constitutive amino acids and their degradates, including dihydroxyhomotyrosine and N-acetyl-dihydroxyhomotyrosine.

These two tyrosine derivatives are found only in urine, suggesting rapid clearance of these derivatives by the kidneys. Excretion Two single-dose radiolabeled pharmacokinetic studies were conducted. In one study, plasma, urine, and feces were collected over 27 days, and in the second study plasma was collected over 6 months.

Plasma concentrations of radioactivity and of caspofungin were similar during the first 24 to 48 hours postdose; thereafter drug levels fell more rapidly. In plasma, caspofungin concentrations fell below the limit of quantitation after 6 to 8 days postdose, while radiolabel fell below the limit of quantitation at 22.3 weeks postdose. After single intravenous administration of [ 3 H] caspofungin acetate, excretion of caspofungin and its metabolites in humans was 35% of dose in feces and 41% of dose in urine.

A small amount of caspofungin is excreted unchanged in urine (~1.4% of dose). Renal clearance of parent drug is low (~0.15 mL/min) and total clearance of caspofungin is 12 mL/min. Special Populations Renal Impairment In a clinical study of single 70 mg doses, caspofungin pharmacokinetics were similar in healthy adult volunteers with mild renal impairment (creatinine clearance 50 to 80 mL/min) and control subjects.

Moderate (creatinine clearance 31 to 49 mL/min), severe (creatinine clearance 5 to 30 mL/min), and end-stage (creatinine clearance less than 10 mL/min and dialysis dependent) renal impairment moderately increased caspofungin plasma concentrations after single-dose administration (range: 30 to 49% for AUC). However, in adult patients with invasive aspergillosis, candidemia, or other Candida infections (intra-abdominal abscesses, peritonitis, or pleural space infections) who received multiple daily doses of caspofungin 50 mg, there was no significant effect of mild to end-stage renal impairment on caspofungin concentrations.

No dosage adjustment is necessary for patients with renal impairment. Caspofungin is not dialyzable, thus supplementary dosing is not required following hemodialysis. Hepatic Impairment Plasma concentrations of caspofungin after a single 70 mg dose in adult patients with mild hepatic impairment (Child-Pugh score 5 to 6) were increased by app… [Excerpted — this section continues on DailyMed.]

14 CLINICAL STUDIES

14.1Empirical Therapy in Febrile, Neutropenic Patients A double-blind study enrolled 1111 febrile, neutropenic (<500 cells/mm3) patients who were randomized to treatment with daily doses of caspofungin (50 mg/day following a 70-mg loading dose on Day 1) or AmBisome (3 mg/kg/day). Patients were stratified based on risk category (high-risk patients had undergone allogeneic stem cell transplantation or had relapsed acute leukemia) and on receipt of prior antifungal prophylaxis. Twenty-four percent of patients were high risk and 56% had received prior antifungal prophylaxis.

Patients who remained febrile or clinically deteriorated following 5 days of therapy could receive 70 mg/day of caspofungin or 5 mg/kg/day of AmBisome. Treatment was continued to resolution of neutropenia (but not beyond 28 days unless a fungal infection was documented). An overall favorable response required meeting each of the following criteria: no documented breakthrough fungal infections up to 7 days after completion of treatment, survival for 7 days after completion of study therapy, no discontinuation of the study drug because of drug-related toxicity or lack of efficacy, resolution of fever during the period of neutropenia, and successful treatment of any documented baseline fungal infection.

Based on the composite response rates, caspofungin was as effective as AmBisome in empirical therapy of persistent febrile neutropenia (see Table 9). Table 9: Favorable Response of Patients with Persistent Fever and Neutropenia Caspofungin* Ambisome* % Difference (Confidence Interval) † Number of Patients ‡ 556 539 Overall Favorable Response 190 (33.9%) 181 (33.7%) 0.2 (-5.6,6.0) No document breakthrough fungal infection 527 (94.8%) 515 (95.5%) -0.8 Survival 7 days after end of treatment 515 (92.6%) 481 (89.2%)

3.4No discontinuation due to toxicity or lack of efficacy 499 (89.7%) 461 (85.5 %)

4.2Resolution of fever during neutropenia 229 (41.2 %) 223 (41.4%) -0.2 * Caspofungin: 70 mg on Day 1, then 50 mg once daily for the remainder of treatment (daily dose increased to 70 mg for 73 patients); AmBisome: 3 mg/kg/day (daily dose increased to 5 mg/kg for 74 patients). † Overall Response: estimated % difference adjusted for strata and expressed as caspofungin –AmBisome (95.2% CI); Individual criteria presented above are not mutually exclusive. The percent difference calculated as caspofungin–AmBisome. ‡ Analysis population excluded subjects who did not have fever or neutropenia at study entry.

The rate of successful treatment of documented baseline infections, a component of the primary endpoint, was not statistically different between treatment groups. The response rates did not differ between treatment groups based on either of the stratification variables: risk category or prior antifungal prophylaxis.

14.2Candidemia and the Following other Candida Infections: Intra-Abdominal Abscesses, Peritonitis and Pleural Space Infections In a randomized, double-blind study, patients with a proven diagnosis of invasive candidiasis received daily doses of caspofungin (50 mg/day following a 70-mg loading dose on Day 1) or amphotericin B deoxycholate (0.6 to 0.7 mg/kg/day for non-neutropenic patients and 0.7 to 1 mg/kg/day for neutropenic patients). Patients were stratified by both neutropenic status and APACHE II score. Patients with Candida endocarditis, meningitis, or osteomyelitis were excluded from this study.

Patients who met the entry criteria and received one or more doses of IV study therapy were included in the modified intention-to treat [MITT] analysis of response at the end of IV study therapy. A favorable response at this time point required both symptom/sign resolution/improvement and microbiological clearance of the Candida infection. Two hundred thirty-nine patients were enrolled.

Patient disposition is shown in Table 10. Table 10: Disposition in Candidemia and Other Candida Infections (Intra-abdominal abscesses, peritonitis, and pleural s… [Excerpted — this section continues on DailyMed.]

13 NONCLINICAL TOXICOLOGY

13.1Carcinogenesis & Mutagenesis & Impairment Of Fertility No long-term studies in animals have been performed to evaluate the carcinogenic potential of caspofungin. Caspofungin did not show evidence of mutagenic or genotoxic potential when evaluated in the following in vitro assays: bacterial (Ames) and mammalian cell (V79 Chinese hamster lung fibroblasts) mutagenesis assays, the alkaline elution/rat hepatocyte DNA strand break test, and the chromosome aberration assay in Chinese hamster ovary cells. Caspofungin was not genotoxic when assessed in the mouse bone marrow chromosomal test at doses up to 12.5 mg/kg (equivalent to a human dose of 1 mg/kg based on body surface area comparisons), administered intravenously.

Fertility and reproductive performance were not affected by the intravenous administration of caspofungin to rats at doses up to 5 mg/kg. At 5 mg/kg exposures were similar to those seen in patients treated with the 70-mg dose.

13.2Animal Toxicology and/or Pharmacology In one 5-week study in monkeys at doses which produced exposures approximately 4 to 6 times those seen in adult patients treated with a 70-mg dose, scattered small foci of subcapsular necrosis were observed microscopically in the livers of some animals (2/8 monkeys at 5 mg/kg and 4/8 monkeys at 8 mg/kg); however, this histopathological finding was not seen in another study of 27 weeks duration at similar doses. No treatment-related findings were seen in a 5-week study in infant monkeys at doses which produced exposures approximately 3 times those achieved in pediatric patients receiving a maintenance dose of 50 mg/m 2 daily.