Cyclophosphamide pharmacokinetics: correlation with cardiac toxicity and tumor response

BACKGROUND

Cyclophosphamide, which forms the nucleus for virtually all preparative regimens for autologous bone marrow transplantation (ABMT), is an alkylating agent of which cytotoxicity is not directly caused by the parent compound but by its biologically active metabolites. Its nonmyelosuppressive toxicity in the ABMT setting is cardiomyopathy. We attempted to determine any correlation between plasma levels of total cyclophosphamide and the subsequent development of cardiac dysfunction.

PATIENTS AND METHODS

Analyses of plasma levels and the derivation of plasma concentration-time curves (area under the curve [AUC]) were performed in 19 women with metastatic breast carcinoma, who received a continuous 96-hour infusion of cyclophosphamide, thiotepa, and carboplatin (CTCb) with ABMT. The assay for total cyclophosphamide measures the inactive parent compound; reliable assays of the active metabolites of cyclophosphamide are not yet available.

RESULTS

Six of 19 women developed moderate, but transient, congestive heart failure (CHF) as assessed by clinical and radiologic criteria. These patients had a significantly lower AUC of total cyclophosphamide (median, 2,888 mumol/L/h) than patients who did not develop CHF (median, 6,121 mumol/L/h) (P less than .002). Median duration of tumor response in these patients was also more durable; at least 22 months in patients with lower AUCs versus a median of 5.25 months in those with higher AUCs (P = .008).

CONCLUSION

These pharmacokinetic data support the premise that enhancement of cyclophosphamide activation may lead to both greater tumor cytotoxicity and increased but reversible end-organ toxicity. Early analysis of pharmacokinetic data may allow modulation of cyclophosphamide administration in an attempt to enhance therapeutic efficacy.

Mobilization of peripheral blood progenitor cells by chemotherapy and granulocyte-macrophage colony-stimulating factor for hematologic support after high-dose intensification for breast cancer

High-dose therapy with autologous marrow support results in durable complete remissions in selected patients with relapsed lymphoma and leukemia who cannot be cured with conventional dose therapy. However, substantial morbidity and mortality result from the 3- to 6-week period of marrow aplasia until the reinfused marrow recovers adequate hematopoietic function. Hematopoietic growth factors, particularly used after chemotherapy, can increase the number of peripheral blood progenitor cells (PBPCs) present in systemic circulation. The reinfusion of PBPCs with marrow has recently been reported to reduce the time to recovery of adequate marrow function. This study was designed to determine whether granulocyte-macrophage colony-stimulating factor (GM-CSF)-mobilized PBPCs alone (without marrow) would result in rapid and reliable hematopoietic reconstitution. Sixteen patients with metastatic breast cancer were treated with four cycles of doxorubicin, 5-fluorouracil, and methotrexate (AFM induction). Patients responding after the first two cycles were administered GM-CSF after the third and fourth cycles to recruit PBPCs for collection by two leukapheresis per cycle. These PBPCs were reinfused as the sole source of hematopoietic support after high doses of cyclophosphamide, thiotepa, and carboplatin. No marrow or hematopoietic cytokines were used after progenitor cell reinfusion. Granulocytes greater than or equal to 500/microL was observed on a median of day 14 (range, 8 to 57). Transfusion independence of platelets greater than or equal to 20,000/microL occurred on a median day of 12 (range, 8 to 134). However, three patients required the use of a reserve marrow for slow platelet engraftment. In retrospect, these patients were characterized by poor baseline bone marrow cellularity and poor platelet recovery after AFM induction therapy. When compared with 29 historical control patients who had received the same high-dose intensification chemotherapy using autologous marrow support, time to engraftment, antibiotic days, transfusion requirements, and lengths of hospital stay were all significantly improved for the patients receiving PBPCs. Thus, autologous PBPCs can be efficiently collected during mobilization by chemotherapy and GM-CSF and are an attractive alternative to marrow for hematopoietic support after high-dose therapy. The enhanced speed of recovery may reduce the morbidity, mortality, and cost of high-dose treatment. Furthermore, PBPC support may enhance the effectiveness of high-dose therapy by facilitating multiple courses of therapy.

A phase II study of high-dose cyclophosphamide, thiotepa, and carboplatin with autologous marrow support in women with measurable advanced breast cancer responding to standard-dose therapy

PURPOSE

The study was designed to determine the duration of complete response (CR) for patients with unresectable or metastatic breast cancer treated with high-dose cyclophosphamide, thiotepa, and carboplatin (CTCb) while responding to conventional-dose therapy.

METHODS

Eligibility criteria included histologically documented metastatic or unresectable breast cancer, at least a partial response (PR) to conventional-dose therapy, no prior pelvic radiotherapy, cumulative doxorubicin of less than 500 mg/m3, and physiologic age between 18 and 55 years. Patients with inadequate renal, hepatic, pulmonary, and/or cardiac function or tumor involvement of marrow or CNS were excluded. Cyclophosphamide 6,000 mg/m2, thiotepa 500 mg/m2, and carboplatin 800 mg/m2 were given by continuous infusion over 4 days. After recovery, sites of prior bulk disease were to be radiated or resected if feasible.

RESULTS

Of 29 registered patients, one died of toxicity (3%; hemorrhage). CRs and PRs continued a median of 16 and 5 months after transplant, respectively (26 and 9 months from initiation of chemotherapy for metastatic disease). Of 10 patients transplanted in CR, four have not progressed at 17 to 31 months after transplantation (25 to 43 months after beginning standard-dose therapy). One of four patients with uptake on bone scan as their only sites of residual disease before transplant and one of three who converted from PR to CR with transplant have not progressed at 27 and 29 months, respectively, after transplant.

CONCLUSIONS

CTCb is an intensification regimen with a low mortality that delivers a significantly increased dose of agents with known activity at conventional doses in breast cancer. Although the duration of PR is short as expected, CRs appear to be durable.

GM-CSF potentiated peripheral blood progenitor cell (PBPC) collection with or without bone marrow as hematologic support of high-dose chemotherapy: two protocols

High-dose chemotherapy with autologous bone marrow support (ABMS) achieves prolonged relapse-free survival in relapsed lymphomas and leukemias and has provided durable complete responses in certain solid tumors. The principal morbidity and mortality result from the infectious and bleeding complications during the 3-4 week aplasia until the bone marrow autograft can recover. Hematopoietic growth factors, alone or used after chemotherapy, increase the number of circulating progenitor cells in the peripheral blood compartment. In one trial, 12 patients with solid tumors were treated with high-dose chemotherapy and supported with both bone marrow and peripheral blood progenitor cells (PBPC) collected after GM-CSF administration. Reconstitution of bone marrow function occurred quickly (ANC greater than 500/microliters by day 17; platelet-transfusion independence by day 16), resulting in short hospital stays (median, 28 days). In a second study, 12 patients with metastatic breast cancer responding to induction chemotherapy (doxorubicin, 5-fluorouracil, and methotrexate) were given GM-CSF during induction to collect PBPCs during leukocyte recovery. These PBPCs were used as the sole hematopoietic support during high-dose chemotherapy with cyclophosphamide, thiotepa, and carboplatin. Granulocyte and platelet reconstitution were extremely rapid (median, 14 and 12 days, respectively). When compared with 29 patients undergoing the same intensification therapy using ABMT as sole support, time to hematopoietic recovery, transfusion requirements, and duration of hospital stay were all significantly improved for the patients receiving PBPC. PBPC with or without marrow may enhance the safety, tolerance, and cost of high-dose therapy. Moreover, PBPC may render multiple course combination, high-dose therapy feasible.

Escalating doses of carboplatin with high-dose ifosfamide using autologous bone marrow as support: a phase I study

In this phase I study, 16 adult cancer patients were treated with concurrent 4-day continuous infusions of ifosfamide at 12 g/m2 and escalating doses of carboplatin (400-1600 mg/m2) to determine the major non-haematological dose-limiting toxicity of the combination. Mesna was given by continuous infusion over 5 days for uroprotection (total dose per course = 15 g/m2). Autologous bone marrow support, which was mandated for subsequent dose levels once granulocytes remained below 500/microliters for more than 14 days in at least 2 patients entered at a given dose level, was used at dose levels above 400 mg/m2 carboplatin. Renal toxicity became dose-limiting at the maximum tolerated dose level of 1600 mg/m2 carboplatin. Temporary creatinine elevations above 2 mg/dl (median peak 2.6 mg/dl) were observed in 3 and irreversible renal toxicity occurred in 1 (peak creatinine 6.9 mg/dl, chronic creatinine 5-6 mg/dl) of the 5 patients entered at this dose level. Severe confusion and lethargy associated with rising creatinine developed in 2 patients. Two complete and four partial responses were documented in 14 heavily pretreated evaluable patients. The complete responses continue at 14+ and 20+ months in a patient with germ cell carcinoma and Ewing's sarcoma, respectively. Carboplatin appears to contribute to the renal toxicity of ifosfamide. Nevertheless, the combination of carboplatin and ifosfamide at 80% and 75% of the single-agent maximal tolerated doses respectively produced acceptable non-haematological toxicity. Further studies in the treatment of sarcoma, germ cell, ovarian and lung carcinomas with this combination are warranted.

A phase I study of high-dose ifosfamide and escalating doses of carboplatin with autologous bone marrow support

The dose-limiting toxicity in two separate phase I trials of the high-dose single agents ifosfamide and carboplatin was renal insufficiency at 18 g/m2 and hepatic and ototoxicity at 2,400 mg/m2, respectively. In this phase I study, 16 adults were treated with ifosfamide at 75% of the single-agent maximum-tolerated dose (MTD) (12 g/m2) and escalating doses of carboplatin (400 to 1,600 mg/m2) to determine the nonhematologic dose-limiting toxicity and the maximum-tolerated dose of the combination. Both drugs as well as mesna for uroprotection were given by continuous infusion over 4 days with an additional day of mesna (total dose per course, 15 g/m2). Autologous bone marrow support was stipulated for subsequent dose levels once granulocytes remained less than 500/microL for more than 14 days in two of three to five patients entered at a given dose level. Autologous bone marrow support was used at doses above the 400 mg/m2 carboplatin dose level. At the maximum-tolerated dose level of 1,600 mg/m2 of carboplatin, renal toxicity precluded further dose escalation. Of the five patients entered at this dose level, reversible creatinine elevation greater than 2 mg/dL (median peak, 2.6 mg/dL) was observed in three patients, and irreversible renal failure occurred in an additional patient (peak creatinine, 6.9 mg/dL. Transient gross hematuria appeared more common with the combination than with ifosfamide alone. Two patients developed severe somnolence and confusion associated with a rising creatinine. There were two complete (CRs) and four partial responses (PRs) in 14 heavily pretreated assessable patients (including four partial or complete responses in eight assessable patients with advanced refractory sarcoma, and one CR in two patients with germ cell carcinoma). Carboplatin and ifosfamide appear to have overlapping renal toxicity. Nevertheless, carboplatin and ifosfamide can be combined at 80% and 75% of the single-agent maximum-tolerated doses, respectively, with acceptable nonhematologic toxicity. Ifosfamide and carboplatin are an attractive core combination for further studies in the treatment of sarcoma, germ cell, ovarian, and lung carcinomas.

Hepatic venoocclusive disease in autologous bone marrow transplantation of solid tumors and lymphomas

Retrospective review of 291 solid tumor and lymphoma patients undergoing autologous bone marrow transplantation (BMT) was performed to determine the influence of pretransplant characteristics and preparative regimen to the development of hepatic venoocclusive disease (VOD). Twelve patients (4.1%) developed a clinical syndrome of right upper quadrant (RUQ) tenderness or hepatomegaly, jaundice, and ascites, with or without encephalopathy, within 40 days of marrow reinfusion. Evidence of metastatic liver disease was the only pretransplant characteristic predictive for VOD (P = .0002). Sex, age, histology, hepatitis B serology, and elevated liver function tests were not predictive. No individual preparative agent had a significant effect on the development of VOD. However, a single 2-hour infusion of carmustine (BCNU) (greater than or equal to 450 mg/m2) led to an increased incidence of VOD when compared with the same dose administered in a fractionated schedule (P = .0258) when given with two other chemotherapeutic agents. Seven of eight autopsy specimens confirmed the clinical diagnosis of VOD. The four patients in whom clinical VOD resolved had lower median peak bilirubins (7.3 v 15.9 mg/dL), lower median peak creatinines (2.1 v 4.1 mg/dL), and relatively quick engraftment of neutrophils (mean, 18.7 days). One of the four patients in whom VOD resolved had other grade 4 (life-threatening) toxicities in contrast to eight of eight who succumbed. In summary, VOD is an uncommon complication in autotransplantation of solid tumors and lymphomas. Our data suggest caution in selecting patients with known metastatic liver disease and consideration of a fractionated BCNU schedule especially in combination with other alkylating agents.

Cyclophosphamide, carmustine, and etoposide with autologous bone marrow transplantation in refractory Hodgkin's disease and non-Hodgkin's lymphoma: a dose-finding study

Cyclophosphamide, carmustine (BCNU), and etoposide (VP-16) (CBV) is a widely used conditioning regimen in autologous bone marrow transplantation (ABMT) of patients with refractory and relapsed lymphoma. However, the maximum-tolerated dose (MTD) of these agents when used in combination has not been systematically explored. We treated 58 patients (28 with non-Hodgkin's lymphoma [NHL], 30 with Hodgkin's disease [HD]) at seven dose levels of CBV. Doses were cyclophosphamide 4,500 to 7,200 mg/m2, BCNU 450 to 600 g/m2, and VP-16 1,200 to 2,000 mg/m2. The MTD was cyclophosphamide 7,200 mg/m2, BCNU 450 mg/m2, and VP-16 2,000 mg/m2. Six hundred milligrams per square meter of BCNU was associated with five of 18 cases of interstitial pneumonitis versus two of 40 at 450 mg/m2 (P = .02). Treatment-related mortality was 5% at dose levels less than or equal to the MTD and 22% at the highest dose. In this heavily pretreated patient population, most of whom had high volume residual disease, complete responses (CRs) to CBV and ABMT occurred in 25% of assessable patients with NHL and 43% of patients with HD. Thirteen of 28 patients with NHL and 14 of 30 with HD remain free from disease progression with median follow-up of 212 and 215 days, respectively. CBV can be administered with acceptable toxicity over a wide range of doses to patients with refractory and relapsed lymphoma.

Organization and structure of the Qa genes of the major histocompatibility complex of the C3H mouse: implications for Qa function and class I evolution

We have determined the structure and organization of the entire Qa family of class I genes from the major histocompatibility complex of the C3H mouse. Restriction maps of overlapping lambda and cosmid clones reveal that there are only five Qak genes: Q1k, Q2k, Q4k, Q10k and a Q5/9 hybrid, presumably generated by unequal homologous recombination. The resulting deletion of Q6-Q9 is consistent with the Qa-2null phenotype of this mouse strain. We have sequenced the Qak genes, and predict that each may encode a class I molecule with a structure comparable with that proposed for the transplantation antigens. Furthermore, these Qa products should be able to bind peptides and interact with appropriate T-cell receptors. Interestingly, in comparing Qak and H-2k sequences, we find limited evidence of interlocus gene conversion between Qa and H-2 loci, suggesting that the Qa genes are not likely to serve as a reservoir of genetic information for the generation of H-2 diversity within this haplotype.

Repetitive ovarian response to gonadotropin stimulation in an in vitro fertilization program

The temporal changes of estradiol levels in 19 women undergoing ovulation induction for in vitro fertilization (IVF) and embryo replacement were described by a mathematical model. The model was analyzed for differences between treatment cycles of an individual woman and between cycles of different women. This model was also used to evaluate the results of IVF treatment. The variation between cycles within individuals was found to be less than that between different women. The parameters that describe this model were found to correlate with follicular growth but not with number of oocytes retrieved, fertilized or cleaved.

Cervical mucus changes in relationship to urinary luteinizing hormone

In order to evaluate the relationship between the urinary luteinizing hormone (LH) surge as detected by the OvuSTICK (Monoclonal Antibodies, Inc., Mountain View, CA) method and daily cervical mucus parameters, ten spontaneously ovulating women undergoing infertility evaluation were followed during their cycles with twice daily urinary LH testing as well as daily ultrasound, mucus evaluation, and hormonal assays of serum LH, progesterone (P), and estradiol (E2). Maximal cervical mucus scores, as determined using a modified Insler score, were noted to coincide consistently with the urinary LH surge as detected by twice daily testing and to precede ultrasound evidence of ovulation by 0 to 24 hours. Mucus scores rapidly declined in the 24-hour period following the urinary LH surge. Detection of the urinary LH surge may therefore help identify that period of time during which cervical mucus parameters are optimal and therefore facilitate the timing of artificial insemination, intercourse, or postcoital testing.

Estrogen regulation of protein synthesis in the immature rat uterus: the effects of progesterone on proteins released into the medium during in vitro incubations

We have previously identified two major medium proteins secreted from the rat uterus during in vitro incubations that appear to be estrogen regulated. In this study, immature rats were treated with estradiol (E2) progestins, and actinomycin D. Medium proteins were analyzed after incubation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. E2 (1 microgram) increased the synthesis of proteins with mol wt of 115,000 and 65,000. Progesterone inhibited this increase when given in doses of 500 and 250 micrograms and when given within 8 h of estradiol. Lower doses of progesterone were not completely inhibitory. When actinomycin D was given within 6 h of E2, it also inhibited the E2 stimulated increase. This system may provide a useful marker for monitoring hormonal action in the luminal epithelium and may help in understanding hormonal regulation of gene expression.

Endometrial cytosolic and nuclear progesterone receptors in the luteal phase defect

Basal body temperature profiles, serial serum progesterone levels, and serial endometrial biopsies were studied in 15 infertile women during 21 ovulatory cycles. Ten cycles (in 9 women) demonstrated luteal phase defects (LPD), diagnosed by a histological lag in endometrial maturation, normal luteal phase length, and normal luteal phase serum progesterone levels. Both normal and LPD cycles had a maximum amount of endometrial cytosolic progesterone receptor (PgR) on days 13-15, with a significant decline thereafter. LPD cycles had significantly lower endometrial nuclear PgR concentrations than did normal cycles during the proliferative phase, but luteal phase endometrial nuclear PgR levels were similar in both groups. In 2 LPD women treated with dydrogesterone, normal endometrial maturation and a decline in endometrial cytosolic PgR concentrations in the late luteal phase were found. Therefore, with the exception of endometrial nuclear PgR concentrations during the proliferative phase, we found no evidence for a major abnormality in endometrial PgR levels in LPD cycles with a lag in endometrial histology.

Hormonal regulation of rat uterine secretory protein synthesis

Treatment of the rat uterus with estradiol results in many morphological and biochemical changes. In order to examine the biochemical mechanisms of these changes, we are interested in finding a protein which can be used as an end-point indicator or marker. Estradiol administration results in the increased synthesis and release of a 115,000 and 65,000 dalton protein into the incubation media. In this paper, we demonstrate that these proteins are actually subunits of a larger protein having a molecular weight of 180,000 daltons. This protein appears to be specific to the uterus and may be produced mainly or solely by the epithelial cells. In the normal estrous cycle, maximal production is seen at estrus with essentially no production at diestrus. In the immature rat, synthesis of the 180K dalton protein is blocked by the interaction of progesterone and estradiol. However, unlike some uterine responses, the 180K protein is increased by treatment with several antiestrogens. This protein is also present in sufficient quantities to allow for the production of monoclonal antibodies. Thus this protein has many attributes of an excellent "marker protein" and will be of value in future studies aimed at elucidating the molecular mechanism(s) of steroid hormone action in the uterus.

Multiple oncotic intracranial aneurysms and cardiac metastasis from choriocarcinoma: case report and review of the literature

Ten cases of oncotic intracranial aneurysms from choriocarcinoma have been reported previously. We report an eleventh case with four aneurysms secondary to metastatic choriocarcinoma. These aneurysms seemed to arise from cephalic embolization of neoplastic tissue from an implant of choriocarcinoma in the left ventricle of the heart.

Prevention of anthracycline-induced cytotoxicity in hemopoietic cells by hemin

Anthracyclines such as Adriamycin (ADR) and daunomycin markedly inhibit cell growth in vivo and in vitro. These studies demonstrate that 30 microM hemin, which induces hemoglobin synthesis in human and murine erythroleukemia cells in culture, markedly decreases the cytotoxicity of ADR in a variety of hemopoietic cell lines (K562, HEL-1, MEL-745, HL-60, and U937) and in erythroid burst-forming cells from normal human marrow. Hemin failed to protect four of the five nonhemopoietic cell lines tested, including MCF-, breast adenocarcinoma cells, C-205 colon carcinoma cells, mouse 3T3 fibroblasts, and mouse kidney VERO cells. Hemin did protect human neuroblastoma IMP-32 cells from ADR cytotoxicity; however, this nonhemopoietic cell line undergoes dendrite formation in response to hemin induction. Cytofluorographic analysis of cellular ADR content and labeling studies with [3H]daunomycin demonstrated that hemin decreases the intracellular accumulation of these anthracyclines by more than 50% in K562 erythroleukemia cells. These studies indicate that small doses of hemin prevent intracellular accumulation of anthracyclines and thereby markedly reduce anthracycline toxicity to cells. Since this protective effect is observed preferentially with hemopoietic cells, it is possible that this finding could be exploited to protect the bone marrow from the cytotoxic action of anthracyclines during therapy for nonhemopoietic tumors.

BCG treatment of periocular sarcoid

Twenty-six horses and five mules with periocular sarcoids were treated with intralesional injections of a purified bacillus of Calmette and Guerin (BCG) cell walls in oil suspension. All sarcoids were cured and the horses and mules remained free from recurrence of sarcoid during the two-year follow-up period.

Fatty acid composition of the testes of zinc-deficient rats: the effect of docosapentaenoic acid supplementation

To determine if low levels of docosapentaenoic acid (22:5 omega 6), observed in the testis lipids of zinc-deficient rats, are related to some of the symptoms of zinc deficiency in rat testes, four groups of rats were fed egg white- and corn oil (CO)-based semipurified diets. One group was fed a zinc-deficient diet (ZDCO) and a control group was pair-fed a zinc-supplemented diet (PFCO). Two additional groups were treated in an identical fashion, but their diets were supplemented with 1% testis lipid (TL) containing 10-12% 22:5 omega 6 (ZDTL and PFTL). Testes weights and sperm counts were slightly higher in ZDTL compared to ZDCO, but these trends were not statistically significant. Testis zinc concentrations were significantly higher in both TL groups compared to the corresponding CO group. Dietary 22:5 omega 6 appeared to be accumulated in liver lipids; however, there was no difference between TL and CO groups in 22:5 omega 6 level in testes phospholipids or testes total lipids. These results indicate that 22:5 omega 6 concentration and spermatogenesis in the testes of zinc-deficient rats do not appear to be affected by the dietary supplementation of 22:5 omega 6 at the level used in this study.

The effect of zinc deficiency on prostaglandin synthesis in rat testes

The effect of zinc deficiency on prostaglandin synthesis in rat testes was determined by feeding three groups of rats egg white-based semipurified diets. One group (ZD) was fed a zinc-deficient diet and two control groups were pair-fed (PF) or fed ad libitum (AL) a zinc-sufficient diet. The concentration (nanograms/gram) of the prostacyclin metabolite, 6-keto-prostaglandin-F1 alpha (6-keto-PGF1 alpha), in the tunica homogenate was significantly lower in ZD than in PF and AL groups. However, there was no difference when 6-keto-PGF1 alpha concentration was expressed as nanograms/milligrams of tunica protein. Tunica PGE2 concentrations (nanograms/gram) were not significantly altered by zinc deficiency. Concentrations of prostaglandins (PGs) in testis parenchyma were slightly higher in ZD probably as a result of increased levels of the precursor, arachidonic acid (AA). There was a highly significant correlation between PGE2 and AA in parenchyma phospholipids. PG synthesis was much greater in the tunica than in the parenchyma and prostacyclin appeared to be the major PG synthesized in both the tunica and parenchyma. It was concluded that PG synthesis is altered in the testes of zinc-deficient rats probably due to changes in concentrations of protein in the tunica and AA levels in parenchyma lipids.