Acute myeloid leukemia with t(5;18)(q35;q21).

A case of acute myelocytic leukemia with a translocation (5;18)(q35;q21) is reported. Cytogenetic abnormalities of the long arm of chromosome 5 have long been known to affect hematopoiesis. Although translocations between 5q and other chromosomes have been associated with malignancy, this is the first reported case of a t(5;18) resulting in acute myeloid leukemia. Possible molecular mechanisms underlying the pathogenesis of the disease are discussed.

CML vaccines as a paradigm of the specific immunotherapy of cancer.

T cells are implicated in the effective control of chronic myeloid leukemia (CML). Recently, several clinical observations supported by laboratory data, indicate the presence of CML-specific T cells. Many proteins potentially act as leukemia-specific antigens for MHC-restricted cytotoxicity in CML. These include the bcr-abl fusion protein, myeloid-specific differentiation antigens and minor histocompatibility antigens. There is recent evidence to suggest that bcr-abl junctional peptides are capable of eliciting both CD4 and CD8 responses in normal healthy donors and in patients with CML. Moreover, T cell lines can be generated that react with autologous or HLA-matched fresh CML cells, suggesting that the bcr-abl fusion protein can be processed and expressed in the MHC cell surface molecules. Clinical trials exploiting the new understanding of the immunology of CML are underway.

Advances in immunotherapy of hematologic malignancies: cellular and humoral approaches.

Monoclonal antibodies have become an important modality for cancer therapy. Genetically engineered chimeric and humanized antibodies have demonstrated activity against overt lymphoma and leukemia, as well as minimal residual disease. Radioimmunotherapy in both nonmyeloablative and myeloablative regimens has produced significant responses and also minimized radiation exposure to normal tissues. Targeted alpha-particle therapy offers the possibility of selective tumor cell kill. Antibody-drug conjugates have produced remissions in acute leukemia. Many proteins potentially act as leukemia or lymphoma-specific antigens for major histocompatibility complex-restricted T cell cytotoxicity. These include the idiotype proteins, breakpoint cluster region (bcr)-abl and other fusion oncoproteins, myeloid-specific differentiation antigens and minor histocompatibility antigens. Clinical trials exploiting the new understanding of the T cell immunology are underway.

Pharmacokinetics, metabolism, and excretion of irinotecan (CPT-11) following I.V. infusion of [(14)C]CPT-11 in cancer patients.

This study determined the disposition of irinotecan hydrochloride trihydrate (CPT-11) after i.v. infusion of 125 mg/m(2) (100 microCi) [(14)C]CPT-11 in eight patients with solid tumors. Mean +/- S.D. recovery of radioactivity in urine and feces was 95.8 +/- 2.7% (range 92.2-100.3%, n = 7) of dose. Radioactivity in blood, plasma, urine, and feces was determined for at least 168 h after dosing. Fecal excretion accounted for 63.7 +/- 6.8 (range 54.2-74.9%, n = 7) of dose, whereas urinary excretion accounted for 32.1 +/- 6.9% (range 21.7-43.8%; n = 7) of dose. One patient with a biliary T-tube excreted 30.1% of dose in bile, 14.2% in feces, and 48.2% in urine. Quantitative radiometric HPLC revealed that CPT-11 was the major excretion product in urine, bile, and feces. Aminopentane carboxylic acid (APC) and SN-38 glucuronide (SN-38G) were the most significant metabolites in urine and bile, whereas SN-38 and NPC, a primary amine metabolite, were relatively minor excretion products. SN-38 and APC were the most significant metabolites in feces. The relatively higher amount of SN-38 in feces compared with bile is presumably due to hydrolysis of SN-38G to SN-38 by enteric bacterial beta-glucuronidases. There was close correspondence between quantitative fluorescence HPLC and mass balance findings. CPT-11 was the major circulating component in plasma (55% of the mean radiochemical area under the curve), and CPT-11, SN-38, SN-38G, and APC accounted for 93% of the mean radiochemical AUC. These results show that the parent drug and its three major metabolites account for virtually all CPT-11 disposition, with fecal excretion representing the major elimination pathway.

Vaccination of patients with chronic myelogenous leukemia with bcr-abl oncogene breakpoint fusion peptides generates specific immune responses.

Chronic myelogenous leukemia (CML) presents a unique opportunity to develop therapeutic strategies using vaccination against a truly tumor-specific antigen that is also the oncogenic protein required for neoplasia. CML is characterized by the t(9;22) that results in the bcr-abl fusion oncogene and in the expression of a chimeric protein product p210. Previously we have shown that peptides derived from amino acid sequences crossing the b3a2 fusion breakpoint in p210 elicit class I restricted cytotoxic T lymphocytes and class II responses, respectively, in vitro. Such sequences may thus comprise absolutely tumor-specific antigens in a peptide-based vaccine. We evaluated the safety and immunogenicity of a multidose, bcr-abl breakpoint peptide vaccine in 12 adults with chronic-phase CML. Cohorts of 3 patients each received either 50 microg, 150 microg, 500 microg, or 1500 microg total peptide mixed with 100 microg QS-21 as an immunological adjuvant. Delayed-type hypersensitivity (DTH), humoral responses, and unprimed ex vivo autologous proliferation ((3)H-thymidine incorporation) and cytotoxicity (chromium-51 release) responses were measured. All 68 vaccinations were well tolerated without significant adverse effects. In 3 of the 6 patients treated at the 2 highest dose levels of vaccine, peptide-specific, T-cell proliferative responses (n = 3) and/or DTH responses (n = 2) were generated that lasted up to 5 months after vaccination. Cytotoxic T lymphocytes have not been identified. In conclusion, a tumor-specific, bcr-abl derived peptide vaccine can be safely administered to patients with chronic-phase CML and can elicit a bcr-abl peptide-specific immune response despite the presence of active disease in these patients and approximately 10(12) leukemia cells. (Blood. 2000;95:1781-1787)

Effectiveness of a home program intervention for young children with autism.

This project evaluated the effectiveness of a TEACCH-based home program intervention for young children with autism. Parents were taught how to work with their preschool autistic child in the home setting, focusing on cognitive, academic, and prevocational skills essential to later school success. To evaluate the efficacy of the program, two matched groups of children were compared, a treatment group and a no-treatment control group, each consisting of 11 subjects. The treatment group was provided with approximately 4 months of home programming and was tested before and after the intervention with the Psychoeducational Profile-Revised (PEP-R). The control group did not receive the treatment but was tested at the same 4-month interval. The groups were matched on age, pretest PEP-R scores, severity of autism, and time to follow-up. Results demonstrated that children in the treatment group improved significantly more than those in the control group on the PEP-R subtests of imitation, fine motor, gross motor, and nonverbal conceptual skills, as well as in overall PEP-R scores. Progress in the treatment group was three to four times greater than that in the control group on all outcome tests. This suggests that the home program intervention was effective in enhancing development in young children with autism.

Evaluation of the pharmacokinetics and tolerability of tirilazad mesylate, a 21-aminosteroid free radical scavenger: II. Multiple-dose administration.

The multiple dose tolerability and pharmacokinetics of tirilazad mesylate, a 21-aminosteroid free radical scavenger, were assessed in 50 healthy male volunteers. Volunteers were randomized to receive intravenous normal saline placebo (n = 10), citrate vehicle placebo (n = 10), or 0.5 mg/kg/day (n = 6), 1.0 mg/kg/day (n = 6), 2.0 mg/kg/day (n = 6), 4.0 mg/kg/day (n = 6), or 6.0 mg/kg/day (n = 6) tirilazad mesylate in divided doses every 6 hours for 5 days, for a total of 21 doses. Drug was infused over 10 or 30 minutes. All tirilazad mesylate treatment groups and the citrate vehicle group had significantly more frequent and more intense pain at the injection site than did the saline group, but the pain intensity did not require interruption of dosing. Three episodes of clinical thrombophlebitis were observed. No statistically significant effects of tirilazad mesylate on blood pressure, heart rate, electrocardiograms, or renal function were apparent. Moderate and transient increases in serum alanine transaminase were observed in several subjects. In the 6.0 mg/kg/day group, 50% of the subjects exhibited increased alanine transaminase. Tirilazad mesylate did not significantly affect measures of glucocorticoid activity (blood glucose, adrenocorticotropic hormone, cortisol, eosinophil, or lymphocyte levels). Tirilazad mesylate pharmacokinetics were linear over the dosage range studied. Steady state appeared to be achieved by the fifth day of dosing. After the last dose, a mean terminal half-life of 35 hours was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the pharmacokinetics and tolerability of tirilazad mesylate, a 21-aminosteroid free radical scavenger: I. Single-dose administration.

The single-dose tolerability and pharmacokinetics of tirilazad mesylate, a 21-aminosteroid free radical scavenger, were assessed in 47 healthy male subjects. Subjects were randomized to receive citrate vehicle (n = 12) or 0.25 mg/kg (n = 9), 0.5 mg/kg (n = 9), 1.0 mg/kg (n = 8), or 2.0 mg/kg (n = 9) tirilazad mesylate by 0.5-hour intravenous infusion. Injection site pain was observed with approximately equal frequency in both vehicle and tirilazad mesylate treatment groups. No statistically significant effects of tirilazad mesylate on blood pressure, heart rate, electrocardiograms, liver enzymes, or renal function were apparent. Tirilazad mesylate did not significantly affect measures of glucocorticoid activity (blood glucose, adrenocorticotropic hormone, cortisol, eosinophil, or lymphocyte levels). Maximal plasma concentrations of tirilazad mesylate increased linearly with dose. Limited assay sensitivity at the lower two doses prevented determination of the dose proportionality of tirilazad area under the curve. The apparent elimination half-life at the higher doses was 3.7 hours. Clearance of tirilazad mesylate approached liver blood flow. Results indicate that intravenous infusions at these doses are well tolerated and devoid of glucocorticoid effects. Tirilazad mesylate appears to be efficiently cleared by the liver, and its pharmacokinetics are apparently linear over the dosage range studied.

Pharmacokinetic and tolerance studies of cefpodoxime after single- and multiple-dose oral administration of cefpodoxime proxetil.

Cefpodoxime proxetil, a third generation, broad-spectrum, oral cephalosporin, was administered in single doses of 100, 200, 400, 600, and 800 mg (dose expressed as cefpodoxime equivalents) and multiple doses of 100, 200, and 400 mg twice daily to healthy volunteers. The pharmacokinetics of the active metabolite, cefpodoxime, and tolerance of cefpodoxime proxetil were determined. Results from the single-dose study indicate that cefpodoxime exhibits nonlinear pharmacokinetics over the dose range of 100 to 800 mg. This nonlinearity is primarily due to differences in dose-normalized AUC and Cmax, urinary recovery, and half-life between one or more of the higher-dose treatment groups and the 100-mg dosing group. After multiple-dose (twice daily) administration for 15 days, steady state is achieved on the second day of dosing, and there is no drug accumulation. Cefpodoxime pharmacokinetics are linear with dose over the clinically relevant dosing range of 100 to 400 mg. Microbiologic and HPLC plasma assay results are highly correlated, with close agreement between HPLC- and microbiologic-determined pharmacokinetic parameter estimates. Cefpodoxime proxetil was well tolerated in both studies. The most frequent medical events were related to gastrointestinal problems and consisted of transient loose stools in three subjects in the single-dose study and antibiotic-associated diarrhea in one subject in the multiple-dose study.

Does melanin affect the low LET radiation response of Cloudman S91 mouse melanoma cell lines?

Melanin contains melanin-free radicals and can both absorb and produce additional free radicals and active oxygen species on exposure to various stimuli. Yet its role in the radiation responses of malignant melanoma has been little studied. In this report, three subclones of Cloudman S91 mouse melanoma clone PC1A varying in constitutive melanin content were compared with respect to killing by gamma irradiation. Radiation responses correlated with melanin content. The least melanotic line, S91/amel, was most sensitive and the most melanotic line, S91/I3, was most resistant. Curve fitting using the linear-quadratic model suggests that S91/amel is killed only by single event inactivations; S91/I3, only by double event inactivations; and S91/M1B, with intermediate melanin and radiation response, by both types of inactivations. Split dose experiments confirmed a lack of immediate split dose recovery in S91/amel and its existence in S91/I3. Potentially lethal damage and its repair could be demonstrated in both S91/amel and S91/I3. Double strand break (DSB) induction was evaluated as a function of gamma ray dose in DNA of S91/I3 and S91/amel, as well as in EMT6, a mouse mammary cancer line that lacks tyrosinase and melanin. The rates of induction were proportional to cellular melanization, i.e., the rate of DSB induction was greatest in S91/I3, least in EMT6. Levels of thioredoxin reductase (TR), glutathione reductase (GR), superoxide dismutase (SOD), and catalase (CAT) were determined in S91/amel and S91/I3. TR was the same in both cell lines, while the other three enzymes were 3- to 4-fold lower in S91/amel.(ABSTRACT TRUNCATED AT 250 WORDS)

Disposition of cefmetazole in healthy volunteers and patients with impaired renal function.

The disposition of cefmetazole was studied in 25 subjects with various degrees of renal function after a 1,000-mg, constant-rate, 30-min intravenous infusion of cefmetazole sodium. In six subjects with creatinine clearance (CLCR) of greater than 90 ml/min per 1.73 m2 (group 1), the terminal elimination half-life (t1/2 beta) was 1.31 +/- 0.54 h (mean +/- standard deviation), cefmetazole total body clearance (CLP) was 132.8 +/- 25.1 ml/min per 1.73 m2, and volume of distribution at steady state was 0.165 +/- 0.025 liter/kg. The fraction of dose excreted unchanged in the urine was 84.0% +/- 26.1%. Subjects with CLCRS of 40 to 69 (group 2, n = 6) and 10 to 39 (group 3, n = 6) ml/min per 1.73 m2 demonstrated prolongation of the t1/2 beta (3.62 +/- 1.06 and 5.93 +/- 1.81 h, respectively) and significant reductions in cefmetazole CLP (52.8 +/- 14.3 and 30.2 +/- 10.2 ml/min per 1.73 m2, respectively), compared with group 1. In seven subjects on chronic hemodialysis (group 4) studied during an interdialytic period, the cefmetazole t1/2 beta was increased to 24.10 +/- 8.12 h and the CLP was reduced to 6.8 +/- 2.1 ml/min per 1.73 m2. Cefmetazole CLP correlated positively with CLCR (r = 0.951, P less than 0.001): CLP = (1.181 . CLCR) -- 0.287. The disposition of cefmetazole was also assessed in six group 4 subjects during an intradialytic period. The t1/2 beta during hemodialysis (2.09 +/- 0.69 h) was significantly shorter than that observed during the interdialytic period. The hemodialysis clearance of cefmetazole was 86.1 +/- 20.1 ml/min, and the fraction of cefmetazole removed during hemodialysis was 59.8% +/- 5.9%. It is recommended that patients with renal insufficiency received standard doses of cefmetazole at extended intervals and patients on maintenance hemodialysis received standard doses after hemodialysis.

Ability of four potential topoisomerase II inhibitors to enhance the cytotoxicity of cis-diamminedichloroplatinum (II) in Chinese hamster ovary cells and in an epipodophyllotoxin-resistant subline.

Four drugs known to interact with topoisomerase II were assessed for their ability to enhance the cytotoxicity of cis-diamminedichloroplatinum(II) (CDDP) in Chinese hamster ovary (CHO) cell lines sensitive and resistant to VM-26. The combination treatments were analyzed by isobologram methodology. On 24 h exposure, there was no significant difference in the cytotoxicity of novobiocin or ciprofloxacin toward either cell line. The resistant cells were approximately 9-fold more resistant to 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA) and approximately 170-fold more resistant to etoposide after a 24-h exposure. The combination of novobiocin and cisplatin produced greater than additive cell kill over the entire dose range of cisplatin tested in both cell lines. m-AMSA and CDDP produced cell kill that fell within the envelope of additivity. Etoposide and CDDP resulted in cytotoxicity that was slightly greater than additive at low CDDP concentrations and additive at the highest concentration of CDDP tested in the parental cell line and was slightly greater than additive in the resistant cell line. Ciprofloxacin and CDDP, like novobiocin, resulted in greater than additive cell kill in both cell lines. The enhancement of CDDP cytotoxicity by novobiocin that was seen in exponentially growing cells was lost in stationary-phase cultures. In these studies, novobiocin and, to a lesser degree, ciprofloxacin produced greater than additive cell kill in combination with CDDP in parental and epipodophyllotoxin-resistant CHO cells.

Pharmacokinetics of intravenously administered cefmetazole and cefoxitin and effects of probenecid on cefmetazole elimination.

Sixteen healthy male volunteers participated in a randomized, balanced, three-way crossover study comparing the pharmacokinetics of cefmetazole, cefoxitin, and cefmetazole with probenecid pretreatment. Single 2-g doses of cefmetazole sodium and cefoxitin sodium were given intravenously as a 5-min infusion. Concentrations of cefmetazole and cefoxitin were determined by using a specific semiautomated high-performance liquid chromatographic method. Concentration-time profiles of cefmetazole and cefoxitin declined in a biexponential manner from peak levels. Compared with cefoxitin, cefmetazole had a significantly (P less than 0.05) higher mean (+/- standard error of the mean) peak concentration in serum (290 +/- 11 versus 244 +/- 10 micrograms/ml), a longer terminal disposition half-life (1.50 +/- 0.14 versus 0.81 +/- 0.04 h), lower systemic clearance (111.7 +/- 4.7 versus 279 +/- 12 ml/min) and renal clearance (78.7 +/- 4.3 versus 221 +/- 14 ml/min) of intact drug, and a slightly smaller steady-state volume of distribution (10.3 +/- 0.21 versus 12.8 +/- 0.48 liters). Mean recoveries of cefmetazole and cefoxitin in urine were approximately 71 and 77%, respectively. Pretreatment of volunteers with probenecid (1 g orally) significantly (P less than 0.05) increased concentrations of cefmetazole in serum 1 h after drug administration without significantly increasing maximum concentrations in serum. Mean areas under the concentration-time curve (466 +/- 27 versus 295 +/- 13 micrograms.h/ml) and terminal disposition half-lives (2.27 +/- 0.13 versus 1.50 +/- 0.14 h) of cefmetazole increased. Systemic clearance (72.1 +/- 4.0 versus 111.7 +/- 4.7 ml/min) and renal clearance (47.4 +/- 4.0 versus 78.7 +/- 4.3 ml/min) of intact antibiotic decreased. Mean recoveries (65.9 +/- 3.7 versus 71.0 +/- 3.2%) of intact cefmetazole in urine were not significantly (P > 0.05) different. Elimination of cefmetazole in urine was also significantly prolonged by probenecid, with substantial concentrations of cefmetazole (>/= 20 micrograms/ml) found in the 12- to 24-h urine collection for 14 to 16 volunteers. The results show that cefmetazole remains at clinically relevant concentrations (1 to 2 micrograms/ml) approximately twice as long as cefoxitin, that serum cefmetazole can be maintained longer at clinically significant concentrations with preadministration of probenecid, and that cefmetazole is partially eliminated by renal tubule secretion.

Effect of novobiocin on the antitumor activity and tumor cell and bone marrow survivals of three alkylating agents.

Our previous in vitro studies demonstrated marked synergy with alkylating agents when novobiocin was present during and after alkylating agent exposure. To determine whether this effect is observed in vivo, novobiocin was administered daily for 3 days prior to alkylating agent treatment, during alkylating agent treatment, and for 2 days after completion of alkylating agent treatment. When combined with cis-diamminedichloroplatinum(II), 1,3-bis(2-chloroethyl)-1-nitrosourea, or cyclophosphamide, there was significant enhancement of the growth delay of the FSaIIC fibrosarcoma implanted s.c. in C3H mice when compared with alkylating agents alone. In a second assay using ex vivo studies of tumor cells exposed in vivo, single doses of 100 mg/kg of novobiocin followed by cis-diamminedichloroplatinum(II) resulted in a 3- to 4-fold increase in tumor cell killing by cis-diamminedichloroplatinum(II). At a dose of 100 mg/kg of 1,3-bis(2-chloroethyl)-1-nitrosourea there was about a 7-fold increase in tumor cell kill upon addition of novobiocin. Cyclophosphamide showed a dose response effect with novobiocin, reaching 13-fold at a dose of 300 mg/kg of cyclophosphamide. In all cases bone marrow elements were affected less than were neoplastic cells, suggesting that the combination of novobiocin and alkylating agents may be a clinically useful strategy.

Preclinical studies and clinical correlation of the effect of alkylating dose.

Dose-response studies were performed with the alkylating agents [nitrogen mustard, N,N'-bis(2-chloroethyl)-N-nitrosourea, melphalan, cisplatin (CDDP), 4-hydroperoxycyclophosphamide (4-HC), and trimethyleneiminethiophosphoramide] in both the MCF-7 human breast carcinoma cell line and the EMT6 and FSaIIC murine tumor lines. Increasing selection pressure with the alkylating agents CDDP, melphalan, and 4-HC in vitro produced low levels (6.5- to 9-fold) of drug resistance, despite an intensive and prolonged treatment program. The MCF-7 sublines made resistant to CDDP and 4-HC did not exhibit cross-resistance to other alkylating agents; however, the MCF-7 subline resistant to melphalan was partially cross-resistant to nitrogen mustard, 4-HC, and CDDP. A log-linear relationship was maintained between surviving fraction of MCF-7 cells in culture and drug concentration with alkylating agents, whereas for nonalkylating agents the survival curves tended to plateau at high drug concentrations. Log-linear tumor cell kill was also obtained over a wide dosage range with several alkylating agents in murine tumors treated in vivo. Tumor cell survival assay by colony formation indicated the continuing importance of dose in the action of the drugs even at high levels of tumor cell kill. With some agents, there was a difference between the slopes of the tumor cell killing curves in vivo as compared to in vitro. Cyclophosphamide was far more potent in vitro (4-HC) than in vivo (cyclophosphamide). Trimethyleneiminethiophosphoramide and N,N'-bis(2-chloroethyl)-N-nitrosourea were both more potent in vivo than in vitro. These differences may be explained by the various metabolic patterns of these drugs. Dose of alkylating agents is clearly a crucial variable particularly where multilog tumor cell kill is the goal, and in this regard, the effect of drug dose on the tumoricidal action of the alkylating agents is substantially greater than for nonalkylating agents.

Glutathione monoethyl ester can selectively protect liver from high dose BCNU or cyclophosphamide.

Normal Swiss Webster mice were treated with monocrotaline or high doses of three antitumor alkylating agents (BCNU, cyclophosphamide, or mitomycin C), all of which have been connected with hepatic veno-occlusive disease at our clinic. Prior administration of WR-2721 did not improve the survival of monocrotaline-treated animals. Glutathione (GSH) improved the survival of these animals to a small degree. Glutathione monoethyl ester (GSHet) almost completely protected animals from the toxicity of monocrotaline. Pretreatment with WR-2721 produced moderate increases in survival at the highest doses of BCNU, and at the lower BCNU doses none of the animals pretreated with WR-2721 died before they were killed on day 150. Pretreatment with GSHet gave good protection from BCNU toxicity at the highest dose of the drug, and there were no deaths in the groups of animals treated with GSHet 1 hour before BCNU. On a multiple dose schedule, GSH provided some protection from cyclophosphamide toxicity; GSHet gave a very good level of protection from cyclophosphamide. In none of these treatment groups were lesions suggestive of hepatic or pulmonary venoocclusive disease identified. In all three experimental protocols (monocrotaline, BCNU, and cyclophosphamide), there was a consistent decrease in hepatic toxicity after GSHet pretreatment; this was not observed in GSH- or WR-2721-pretreated animals. There was no evidence of protection of the FSaIIC fibrosarcoma growing in C3H mice as assayed by tumor growth delay or tumor cell survival in groups treated with two different doses of GSHet 1 hour before each drug injection compared to those treated with the BCNU or cyclophosphamide alone, or BCNU with cyclophosphamide. Pretreatment with GSHet did not alter the toxicity of these drugs to bone marrow. GSHet appears to be an effective protector of critical normal tissue and does not appear to protect tumor.

Effect of hyperthermia on cis-diamminedichloroplatinum(II) (rhodamine 123)2[tetrachloroplatinum(II)] in a human squamous cell carcinoma line and a cis-diamminedichloroplatinum(II)-resistant subline.

The effect of concomitant hyperthermia on the cytotoxicities of cis-diamminedichloroplatinum(II) (CDDP), a newly synthesized drug, Pt(Rh-123)2, and its chemical components, K2PtCl4 and rhodamine 123, was examined in vitro in a squamous cell tumor line of human origin (SCC-25) and in a CDDP-resistant subline (SCC-25/CP). No difference in the cytotoxicity of hyperthermia alone was observed between these cell lines. The dose-dependent cytotoxicities of 1-h exposures to CDDP and Pt(Rh-123)2 were markedly increased at 42 degrees C and 43 degrees C in comparison to 37 degrees C, and this effect was of the same magnitude in both cell lines (enhancements of approximately 1.5 logs at 42 degrees C and 2.5 logs at 43 degrees C for CDDP and 1.5 logs at 42 degrees C and greater than 3 logs at 43 degrees C for Pt(Rh-123)2). The use of hyperthermia with CDDP, however, did not lower survivals in the SCC-25/CP cells even to the levels seen in the parent line at 37 degrees C. The cytotoxicities of K2PtCl4 and rhodamine 123 were essentially the same in the CDDP-sensitive and -resistant cells at all temperatures tested. The magnitude of the temperature effect was significantly greater for Pt(Rh-123)2 than for its chemical components. No significant effect on CDDP or Pt(Rh-123)2 accumulation was observed at 42, 43, 44 or 45 degrees C in either cell line. DNA lesions, measured by alkaline elution, were significantly enhanced for CDDP in the SCC-25 cells at 42 degrees C. These results suggest that treatment with hyperthermia and either CDDP or Pt(Rh-123)2 should result in supraadditive anti-tumor effects, although the efficacy of CDDP plus hyperthermia will be significantly less once resistance to CDDP has developed. Since resistance to CDDP does not imply cross-resistance to Pt(Rh-123)2, and since the effect of hyperthermia is somewhat greater for Pt(Rh-123)2 than for CDDP at 43 degrees C, Pt(Rh-123)2 may be more selectively toxic to tumor cells when used with local hyperthermia versus normal cells outside the treated area, especially if resistance to CDDP has already developed.

Effect of various oxygenation conditions and fluosol-DA on cytotoxicity and antitumor activity of bleomycin in mice.

In an attempt to improve the antitumor efficacy of bleomycin, the effects of the oxygen-carrying emulsion Fluosol-DA and increased levels of inspired oxygen were tested in the mouse FSaIIC fibrosarcoma system. The dose-dependent cytotoxicity of bleomycin toward the FSaIIC cells in vitro was significantly decreased under hypoxic conditions, but it increased in a 95% O2-5% CO2 (carbogen) atmosphere as compared with the cytotoxicity of bleomycin in normally oxygenated cells. Investigations on the FSaIIC tumor in vivo also demonstrated that growth delays induced by bleomycin (10 mg/kg ip given on days 6, 10, 13, and 16) were significantly increased when one of the following treatments was given with each bleomycin injection: carbogen breathing for 2 hours (4.7 days), carbogen breathing for 6 hours (5.7 days), and breathing 3 atm of hyperbaric oxygen (6.3 days) versus normal air (3.3 days). When Fluosol-DA (12 mL/kg iv) was administered just before each bleomycin injection, the following growth delays were produced: 4.8 days with air breathing, 14.6 days with carbogen breathing for 2 hours, 14.9 days with carbogen breathing for 6 hours, and 19.7 days with breathing 100% O2 at 3 atm for 1 hour. Excision studies on the FSaIIC tumor also demonstrated that the cytotoxicity increased approximately fivefold when Fluosol-DA and carbogen breathing for 2 hours were combined with a single treatment with 10 mg of bleomycin/kg. In contrast, no measurable bone marrow toxicity was evident with this combined regimen. These results suggest that the use of Fluosol-DA plus carbogen breathing could add substantially to the clinical antitumor effects of bleomycin.

Effect of fluosol-DA/carbogen on etoposide/alkylating agent antitumor activity.

The tumor growth delay produced by the combination of etoposide with the alkylating agent CDDP or BCNU and Fluosol-DA with carbogen breathing in three model tumor systems was examined. The addition of Fluosol-DA to etoposide treatment increased tumor growth delay 2.8-fold, 3.3-fold and 2.2-fold in the FSaIIC fibrosarcoma, the Lewis lung carcinoma and the SW2 small-cell xenograft, respectively. In both the FSaIIC fibrosarcoma and the Lewis lung carcinoma the combination of etoposide treatment with CDDP produced an additive effect. When Fluosol-DA was added to this combination the tumor growth delay increased 1.9-fold and 1.4-fold in the FSaIIC fibrosarcoma and the Lewis lung carcinoma, respectively. Adding Fluosol-DA to a treatment regimen with etoposide and BCNU produced a 2.2-fold, 2.0-fold and 1.6-fold increase in the tumor growth delay of the FSaIIC fibrosarcoma, the Lewis lung carcinoma and the SW2 small-cell xenograft, respectively. The effect of these various treatment combinations on tumor cell survival was assessed in the FSaIIC fibrosarcoma. When the alkylating agents CDDP or BCNU were prepared in Fluosol-DA, there was an additional increase in tumor cell kill, so that with CDDP there was 2.1-fold and 4.7-fold increase in tumor cell kill and with BCNU there was 1.5-fold and 1.2-fold increase in tumor cell kill compared to the drug plus Fluosol-DA and the drug plus Fluosol-DA/carbogen breathing, respectively. The combination of etoposide and CDDP led to less than additive cell killing, and the combination of etoposide and BCNU appeared to be additive, as predicted by simple product summation, in all of the treatment conditions examined. Both etoposide + CDDP and etoposide + BCNU produced additive or less than additive toxicity to bone marrow as measured by CFU-GM.