The stability of ifosfamide in aqueous solution and its suitability for continuous 7-day infusion by ambulatory pump

Cost savings realized by use of the PhaSeal® closed-system transfer device for preparation of antineoplastic agents

Purpose

Medication cost is a major factor associated with increasing health care costs in the United States. Expenditures for prescription drugs in 2013 are estimated to be $283.7 billion. Closed system transfer devices are widely used for preparation of hazardous drugs. Reports indicate the Phaseal® closed system transfer device maintains sterility in vials for 7 days, suggesting the unused portion of single-use vials could be salvaged. This study was done to determine whether using a closed system transfer device to extend the beyond-use date of single-use vials of antineoplastic medications would result in a measurable cost saving.

Methods

A list of 25 drugs available in single-use vials, with a chemical stability of at least 48 hours, was compiled. Use of these agents was recorded during a 50-day period in April through June 2012. Use from a total of 296 vials of 21 antineoplastic agents was recorded. After allowing for the initial use of each vial, the mean potential percentage of drug waste was calculated to be 57.03%.

Results

Actual savings during the study period was $96,348.70. The pharmacy avoided nearly half of the potential waste and saved a mean of 29% of each vial. The cost-saving during the study period represents a $703,047.67 annual saving; which more than offsets the $106,556.55 the pharmacy spent for the Phaseal® system in 2012.

Conclusion

In addition to being a protective measure to reduce exposure to hazardous agents, use of the Phaseal® system results in a reduction in drug waste, and a noticeable cost saving for antineoplastic agents.

Prolonged 14-day continuous infusion of high-dose ifosfamide with an external portable pump: feasibility and efficacy in refractory pediatric sarcoma

BACKGROUND

Ifosfamide is currently used to treat pediatric sarcomas and increasing its dosage may be associated with a better response rate. Prolonged continuous infusion seems an attractive administration modality.

METHODS

Ifosfamide 14 g/m(2) (with mesna 14 g/m(2)) was administered through an ambulatory portable pump over 14 days as a continuous infusion, starting every 3 weeks, in 14 patients with relapsing sarcomas. No growth factors were given.

RESULTS

Acute grade 3 hematological toxicity was observed in only 13/66 cycles and red cell transfusions were given in two patients. Hematuria and dysuria occurred in three cases. The response rate was: five partial responses, five stable disease. The median time to progression was 3 months (range: 2-19 months). The best response rate was seen for synovial sarcoma and Ewing sarcoma.

CONCLUSION

Prolonged 14-day continuous infusion of high-dose ifosfamide is well tolerated. Potentially interesting preliminary responses in pediatric patients already treated with ifosfamide are reported.

Chemical stability and fate of the cytostatic drug ifosfamide and its N-dechloroethylated metabolites in acidic aqueous solutions

31P NMR spectroscopy was used to study the products of the decomposition of the antitumor drug ifosfamide (IF, 1d) and its N-dechloroethylated metabolites, namely, 2,3-didechloroethylIF (1a) and 2- (1b) and 3-dechloroethylIF (1c), in buffered solutions at acidic pH. The first stage of acid hydrolysis of these four oxazaphosphorines is a P-N bond cleavage of the six-membered ring leading to the phosphoramidic acid monoesters (2a-d) of type R'HN(CH(2))(3)OP(O)(OH)NHR, with R and/or R' = H or (CH(2))(2)Cl. The electron-withdrawing chloroethyl group at the endocyclic and/or exocyclic nitrogens counteracts the endocyclic P-N bond hydrolysis. This effect is even more marked when the N-chloroethyl group is in the exocyclic position since the order of stability is 1d > 1c > 1b > 1a. In the second stage of hydrolysis, the remaining P-N bond is cleaved together with an intramolecular attack at the phosphorus atom by the non-P-linked nitrogen of the compounds 2a-d. This leads to the formation of a 2-hydroxyoxazaphosphorine ring with R = H (3a coming from compounds 2a,c) or (CH(2))(2)Cl (3b coming from compounds 2b,d) and to the release of ammonia or chloroethylamine. The third step is the P-N ring opening of the oxazaphosphorines 3a,b leading to the phosphoric acid monoesters, H(2)N(CH(2))(3)OP(O)(OH)(2) (4a) and Cl(CH(2))(2)HN(CH(2))(3)OP(O)(OH)(2) (4b-1), respectively. For the latter compound, the chloroethyl group is partially (at pH 5.5) or totally (at pH 7.0) cyclized into aziridine (4b-2), which is then progressively hydrolyzed into an N-hydroxyethyl group (4b-3). Compounds 3a,b are transient intermediates, which in strongly acidic medium are not observed with (31)P NMR. In this case, cleavage of the P-N bond of the type 2 phosphoramidic acid monoesters leads directly to the type 4 phosphoric acid monoesters. The phosphate anion, derived from P-O bond cleavage of these latter compounds, is only observed at low levels after a long period of hydrolysis. Compounds 1a-c and some of their hydrolytic degradation products (4b-1, 4b-2, diphosphoric diester [Cl(CH(2))(2)NH(CH(2))(3)OP(O)(OH)](2)O (5), and chloroethylamine) did not exhibit, as expected, any antitumor efficacy in vivo against P388 leukemia. (31)P NMR determination of the N-dechloroethylated metabolites of IF or its structural isomer, cyclophosphamide (CP), and their degradation compounds could provide an indirect and accurate estimation of chloroacetaldehyde amounts formed from CP or IF.

Continuous infusion of vincristine, ifosfamide and epirubicin over 6 weeks in treatment-resistant advanced breast cancer

28 patients with recurrent advanced breast cancer were treated with a salvage regimen consisting of vincristine, epirubicin and ifosfamide/mesna (VIE). All patients had poor prognostic characteristics defined as relapse within 12 months of chemotherapy or as relapse within a radiotherapy field. Chemotherapy was infused continuously through a central venous catheter using a portable pump. Ifosfamide (3 g/m2) mixed with mesna (3 g/m2) was infused for 7 days followed by epirubicin (50 mg/m2) mixed with vincristine (1.5 mg/m2) over a further seven days and alternated for a total of 6 weeks. 9 of the 28 patients (32%) responded to VIE (six partial and three complete responses). This included 6 of the 18 patients (33%) who had previously received doxorubicin or mitoxantrone, 6 of the 17 patients (35%) who had an inoperable in-field relapse after radiotherapy for locally advanced cancer, and 5 of the 21 patients (24%) relapsing within 6 months of previous chemotherapy. Median duration of response and overall survival were 3.7 and 6.9 months, respectively. Myelotoxicity was mild. One patient had neutropenic sepsis, 3 patients ahd grade 3 nausea and vomiting and one patient developed paralytic ileus attributed to vincristine. Central venous catheter complications occurred in 12 of 33 catheters requiring removal in 6. Continuous infusional chemotherapy using vincristine, epirubicin and ifosfamide achieves a 32% overall response rate in treatment-resistant advanced breast cancer, and is associated with minimal toxicity and a short treatment period. VIE may be a suitable alternative to conventional chemotherapy.

A randomised study of bolus vs continuous pump infusion of ifosfamide and doxorubicin with oral etoposide for small cell lung cancer

One hundred and fifty-nine previously untreated patients with small cell lung cancer (SCLC), who were not eligible for intensive chemotherapy, were entered into a randomised study of intravenous (i.v.) doxorubicin and ifosfamide (with mesna) and oral etoposide. The i.v. drugs were given either by bolus therapy or by a continuous infusion (CI) pump over 7 days via a central venous line. Therapy was given for 6 weeks only. On weeks 1, 3 and 5 IV doxorubicin 35 mg m-2 was given with 5 days of oral etoposide 100 mg m-2 daily. On weeks 2, 4 and 6 IV ifosfamide 5 g m-2 was given with equidose mesna. The overall median survival was 25 weeks for patients in the bolus arm and 30 weeks for the CI therapy (P = 0.45). The overall response rate was 64% (18% complete response-CR) and 69% (30% CR) respectively (P = 0.13). The median WHO score for haematological toxicity was 4 for bolus therapy and 3 for CI therapy (P = 0.0007). Despite a trend for less supportive care for patients on CI therapy there were no significant differences in the use of i.v. antibodies and blood or platelet transfusions. There were fewer treatment delays due to myelotoxicity in the CI arm (P = 0.04). The median WHO score for non-haematological toxicity was 2 in both treatment groups. There was significantly less nausea (P = 0.037) but more mucositis (P = 0.01) in the CI arm. Weekly chemotherapy using CI treatment was as effective as bolus therapy. It was well accepted by patients. The assessment of quality of life in a subgroup of patients showed a statistically significant reduction in anxiety and depression for both groups of patients during therapy.

A review of the stability and compatibility of antineoplastic drugs for multiple-drug infusions

It is important that the stability of reconstituted parenteral antineoplastic agents be established, particularly in the context of ambulatory infusion systems for delivery. The stability of selected agents within each of the five classes of compounds (antimetabolites, alkylating agents, antibiotics, alkaloids and glycosides, and metals) is reviewed from the literature together with additional data from studies carried out using high-performance liquid chromatographic (HPLC) technology in clinically applicable volumes and concentrations for ambulatory infusion. The stability of reconstituted drugs varies from a few minutes (mecloethamine) to many months (FU). Compatibility data on two- and three-drug admixtures of cytotoxic agents are reported for a number of common multidrug regimens. Tabular presentation of the drug-drug compatibilities and incompatibilities is included along with a discussion of the mechanisms for drug-drug interaction. The use of a broad spectrum of compatible cytotoxic drugs is possible, including fluoropyrimidine-, anthracycline-, and platinum-based combinations, providing the capability of carrying out multidrug infusions for 4-7 days in an ambulatory delivery system.

Ifosfamide continuous infusion plus etoposide in the treatment of elderly patients with aggressive lymphoma: a phase II study

A prospective phase II study was performed to evaluate efficacy and toxicity of continuous infusion ifosfamide plus etoposide combination in elderly patients (older than 70 years) with intermediate or high grade non Hodgkin's lymphoma. Chemotherapy was administered with mesna in order to avoid hemorrhagic cystitis. The 21 patients included were either unable to receive the usual front-line chemotherapy given in our institution or relapsing after or not responding to conventional chemotherapy. Only one out of 97 courses of chemotherapy was followed by serious complication consisting in non-lethal pneumonitis. Four out of seven previously untreated patients and five patients treated in first relapse achieved complete response (75 per cent). Out of nine refractory or previously multi-treated patients, only one achieved complete response. We conclude that combination of continuous infusion ifosfamide plus etoposide deserves to be evaluated on a larger scale so that the optimum doses and schedule may be defined.

Ifosfamide continuous infusion without mesna. A phase I trial of a 14-day cycle

Twenty patients received 27 courses of ifosfamide administered as a 24-hour continuous infusion for 14 days without Mesna. The goal of the study was to deliver a dose rate and total cumulative dose of ifosfamide that would be comparable to standard bolus or short-term infusions administered with Mesna. Dose escalations proceeded from 200 to 300, 400, 450, 500, and 550 mg/m2/d. Four patients developed transient microscopic hematuria at 400, 450, and 500 mg/m2/d. There were no instances of macroscopic hematuria. At 550 mg/m2/d, three patients experienced nonurologic toxicity; confusion (1), nausea (1), and Grade 2 leukopenia (1). The recommended dose of 500 mg/m2/d delivers a total dose of 7 g/m2 per cycle, which is comparable to that delivered in clinical practice for bolus or short-term infusion. Because few patients received multiple courses over time, the cumulative effects are indeterminate in the present trial. The frequency and predictability of hematuria are not precise, and at least daily monitoring by urine Hematest is essential, adding Mesna to the infusate in patients with persistent hematuria. The protracted infusion schedule for ifosfamide permits convenient outpatient administration without Mesna and reduces the drug cost of clinical usage of this agent by up to $890 per cycle. Clinical activity was demonstrated in a single patient, but a comparative trial of standard bolus schedules with the protracted infusion schedule will be necessary to determine if the clinical effectiveness of the drug is maintained.

A systematic study on the chemical stability of ifosfamide

The degradation kinetics of ifosfamide in aqueous solution have been investigated over the pH region 1-13 at 70 degrees C. A stability indicating high-performance liquid chromatographic assay with UV detection was used to separate degradation products from the parent compound. The degradation kinetics were studied as related to pH, buffer composition, ionic strength, temperature and drug concentration. A pH-rate profile at 70 degrees C, obtained from (pseudo) first-order kinetic plots, was constructed after corrections for buffer effects were made. The degradation reactions of ifosfamide were found to be largely independent of pH, although proton or hydroxyl catalysis occurs at extreme pH values. Ifosfamide shows maximum stability in the pH region 4-9, corresponding to a half-life of 20 h.

The stability of mesna in beverages and syrup for oral administration

We evaluated the stability of the aqueous formulation of mesna during storage in syringes and after dilution in beverages and syrups. Measurements of the concentrations of mesna showed that the undiluted formulation was stable for at least 9 days in standard polypropylene syringes at 5 degrees, 24 degrees, and 35 degrees C. There was no detectable oxidation of mesna to dimesna over the course of at least 1 week when mesna was diluted 1:2 and 1:5 in syrups and incubated at 24 degrees C in capped tubes. Concentration changes were clinically negligible for 1:2, 1:10, and 1:100 dilutions of mesna in six carbonated drinks, two juices, and milk after incubation for 24 h at 5 degrees C. Thus, the aqueous mesna formulation is stable when diluted and stored in a variety of beverages and syrups under conditions suitable for oral administration.