The observed rational mechanism-based efficacy of Gem+Clo+Ed based on the synergistic convergence of several pro-death and anti-apoptotic signaling pathways in three very different cell backgrounds provides a powerful foundation for undertaking clinical trials of this drug combination for the treatment of lymphomas.AB - Treatments for lymphomas include gemcitabine (Gem) and clofarabine (Clo) which inhibit DNA synthesis.
Severe and fatal hepatotoxicity, including hepatitis and hepatic failure, has occurred with the use of Clofarabine . In clinical studies, Grade 3-4 liver enzyme elevations were observed in pediatric patients during treatment with Clofarabine at the following rates: elevated aspartate aminotransferase (AST) occurred in 36% of patients; elevated alanine aminotransferase (ALT) occurred in 44% of patients. AST and ALT elevations typically occurred within 10 days of Clofarabine administration and returned to Grade 2 or less within 15 days. Grade 3 or 4 elevated bilirubin occurred in 13% of patients, with 2 events reported as Grade 4 hyperbilirubinemia (2%), one of which resulted in treatment discontinuation and one patient had multi-organ failure and died. Eight patients (7%) had Grade 3 or 4 elevations in serum bilirubin at the last time point measured; these patients died due to sepsis and/or multi-organ failure. Monitor hepatic function and for signs and symptoms of hepatitis and hepatic failure. Discontinue Clofarabine immediately for Grade 3 or greater liver enzyme and/or bilirubin elevations .
lists the incidence of treatment-emergent laboratory abnormalities after Clofarabine administration at 52 mg/m among pediatric patients with ALL and AML (N=115).
The data described below reflect exposure to Clofarabine in 115 pediatric patients with relapsed or refractory Acute Lymphoblastic Leukemia (ALL) (70 patients) or Acute Myelogenous Leukemia (AML) (45 patients).
Fatal and serious cases of enterocolitis, including neutropenic colitis, cecitis, and colitis, have occurred during treatment with clofarabine. This has occurred more frequently within 30 days of treatment, and in the setting of combination chemotherapy. Enterocolitis may lead to necrosis, perforation, hemorrhage or sepsis complications. Monitor patients for signs and symptoms of enterocolitis and treat promptly .
Clofarabine may cause acute renal failure. In Clofarabine treated patients in clinical studies, Grade 3 or 4 elevated creatinine occurred in 8% of patients and acute renal failure was reported as Grade 3 in three patients (3%) and Grade 4 in two patients (2%). Patients with infection, sepsis, or tumor lysis syndrome may be at increased risk of renal toxicity when treated with Clofarabine. Hematuria occurred in 13% of Clofarabine treated patients overall. Monitor patients for renal toxicity and interrupt or discontinue Clofarabine as necessary .
Patients who have previously received a hematopoietic stem cell transplant (HSCT) are at higher risk for veno-occlusive disease (VOD) of the liver following treatment with clofarabine (40 mg/m) when used in combination with etoposide (100 mg/m) and cyclophosphamide (440 mg/m). Severe hepatotoxic events have been reported in a combination study of clofarabine in pediatric patients with relapsed or refractory acute leukemia. Two cases (2%) of VOD in the mono-therapy studies were considered related to study drug. Monitor for and discontinue Clofarabine if VOD is suspected.
Clofarabine may cause a cytokine release syndrome (e.g., tachypnea, tachycardia, hypotension, pulmonary edema) that may progress to the systemic inflammatory response syndrome (SIRS) with capillary leak syndrome and organ impairment which may be fatal. Monitor patients frequently for these conditions. In clinical trials, SIRS was reported in two patients (2%); capillary leak syndrome was reported in four patients (4%). Symptoms included rapid onset of respiratory distress, hypotension, pleural and pericardial effusion, and multi-organ failure. Close monitoring for this syndrome and early intervention may reduce the risk. Immediately discontinue Clofarabine and provide appropriate supportive measures. The use of prophylactic steroids (e.g., 100 mg/m hydrocortisone on Days 1 through 3) may be of benefit in preventing signs or symptoms of SIRS or capillary leak. Consider use of diuretics and/or albumin. After the patient is stabilized and organ function has returned to baseline, re-treatment with Clofarabine can be considered with a 25% dose reduction.
Clofarabine is sequentially metabolized intracellularly to the 5'-monophosphate metabolite by deoxycytidine kinase and mono- and di-phospho-kinases to the active 5'-triphosphate metabolite. Clofarabine has affinity for the activating phosphorylating enzyme, deoxycytidine kinase, equal to or greater than that of the natural substrate, deoxycytidine. Clofarabine inhibits DNA synthesis by decreasing cellular deoxynucleotide triphosphate pools through an inhibitory action on ribonucleotide reductase, and by terminating DNA chain elongation and inhibiting repair through incorporation into the DNA chain by competitive inhibition of DNA polymerases. The affinity of clofarabine triphosphate for these enzymes is similar to or greater than that of deoxyadenosine triphosphate. In preclinical models, clofarabine has demonstrated the ability to inhibit DNA repair by incorporation into the DNA chain during the repair process. Clofarabine 5'-triphosphate also disrupts the integrity of mitochondrial membrane, leading to the release of the pro-apoptotic mitochondrial proteins, cytochrome C and apoptosis-inducing factor, leading to programmed cell death.
S.PY - 2014/1/1Y1 - 2014/1/1N2 - Treatments for lymphomas include gemcitabine (Gem) and clofarabine (Clo) which inhibit DNA synthesis.
The population pharmacokinetics of Clofarabine were studied in 40 pediatric patients aged 2 to 19 years (21 males/19 females) with relapsed or refractory acute lymphoblastic leukemia (ALL) or acute myelogenous leukemia (AML). At the given 52 mg/m dose, similar concentrations were obtained over a wide range of body surface areas (BSAs). Clofarabine was 47% bound to plasma proteins, predominantly to albumin. Based on non-compartmental analysis, systemic clearance and volume of distribution at steady-state were 28.8 L/h/m and 172 L/m, respectively. The terminal half-life was 5.2 hours. No apparent difference in pharmacokinetics was observed between patients with ALL and AML or between males and females.