Phase II, two-stage, single-arm trial of the histone deacetylase inhibitor (HDACi) romidepsin in metastatic castration-resistant prostate cancer (CRPC).

BACKGROUND: Histone deacetylase blockade can promote heat shock protein 90 (HSP90) acetylation, abrogating androgen receptor signaling. A phase II trial of the histone deacetylase inhibitor (HDACi) romidepsin was conducted in patients with progressing, metastatic, castration-resistant prostate cancer (CRPC). PATIENTS AND METHODS: A dose of 13 mg/m(2) was administered i.v. over 4 h on days 1, 8 and 15 every 28 days. The primary end point was rate of disease control defined as no evidence of radiological progression at 6 months. A sample size of 16 assessable patients in stage 1 and nine assessable patients in stage 2 was selected; progression to stage 2 required one or more patients with disease control in stage 1 (H(o) = 0.10, H(a) = 0.30; alpha and beta = 0.10). RESULTS: Thirty-five patients were enrolled. Two patients achieved a confirmed radiological partial response (RECIST) lasting > or = 6 months, along with a confirmed prostate-specific antigen decline of > or = 50%. Eleven patients experienced toxicity necessitating early discontinuation. The commonest adverse events were nausea (30 patients; 85.7%), fatigue (28 patients; 80.0%), vomiting (23 patients; 65.7%) and anorexia (20 patients; 57.1%). There was no significant cardiac toxicity. CONCLUSIONS: At the dose and schedule selected, romidepsin demonstrated minimal antitumor activity in chemonaive patients with CRPC. Further studies of improved HDACi, alone and in combination with other therapies, should nevertheless be investigated.

Plasma pharmacokinetics of adriamycin and its metabolites in humans with normal hepatic and renal function.

A new, nondestructive, plasma extraction technique ultilizing chloroform:isopropyl alcohol (1:1) and ammonium sulfate saturation has been devised to isolate adriamycin and its metabolites from human plasma. Adriamycin was the most prominent species in plasma. It disappeared according to a triphasic pattern with a mean half-life of 30 hr. Six metabolites have been clearly separated from adriamycin by thin-layer chromatography. Three were aglycones and three were polar metabolites, one of which has been identified as adriamycinol. All metabolites appeared rapidly in plasma and disappeared according to a biphasic or tri-phasic pattern. The polar metabolites in plasma were found in similar relative concentration to those in urine. In contrast to the small Quantities of aglycones in urine, however, significant concentrations of aglycones were found in plasma. The least prominent metabolite was adriamycin aglycone; the most prominent metabolite was a less polar aglycone, most likely deoxyadriamycin aglycone, and a more polar aglycone, presumably demethyl deoxyadriamycinol aglycone, was the only metabolite to show variable pharmacokinetics in different patients. The nondestructive plasma extraction technique has verified the presence of extensive human metabolism of adriamycin and demonstrated the presence of aglycone and polar metabolites.

Comparative anthracycline metabolism in rats: loss of marcellomycin fluorescence.

The in vitro metabolism of marcellomycin by rat tissue fractions showed conversion of marcellomycin to 7-deoxypyrromycinone, bisanhydropyrromycinone, and an as yet unidentified compound by rat liver homogenate, microsomes, cytosol, and mitochondria, and purified hepatic reduced nicotinamide adenine dinucleotide phosphate-cytochrome P-450 reductase, under anaerobic conditions and in the presence of reduced nicotinamide adenine dinucleotide phosphate. All these fractions except the purified reductase subsequently induced a progressive loss of fluorescence. Mitochondria, however, were much less active than microsomes, cytosol, and homogenate in inducing this latter phenomenon. Marcellomycin was converted to 7-deoxyaglycones only partially by nuclei. No loss of fluorescence was observed with this subcellular fraction. No loss of fluorescence was observed when doxorubicin or daunorubicin were incubated under similar conditions. The appearance of a compound with distinct spectrophotometric properties was demonstrated by absorbance spectrometry. The formation of a compound with different fluorescent characteristics was excluded, as was the binding of the aglycones to subcellular components. The activity inducing the loss of fluorescence was studied in greater detail with cytosol. It predominated in the liver and required both an electron donor and anaerobic conditions. The optimal pH for the reaction was between 7.5 and 8.0. Our results suggest the existence of an enzymatic pathway capable of converting the fluorescent nucleus of marcellomycin to a nonfluorescent metabolite.

A phase I-II trial of 4'-deoxydoxorubicin (esorubicin) in refractory or relapsed acute leukemia.

In a phase I-II study, 21 patients with relapsed or refractory acute leukemia were treated with 4'-deoxydoxorubicin (esorubicin), the 4'-deoxy derivative of doxorubicin. Four of 14 evaluable patients with acute nonlymphocytic leukemia (ANLL) in relapse or refractory to other anthracyclines achieved partial response (28.5%). Pharmacokinetics were similar to those of the parent compound, doxorubicin. Esorubicin has activity in ANLL and has pharmacologic properties comparable to those of other anthracyclines. Dose-limiting toxicity occurs in the form of mucositis, which may limit its use in combination with other antileukemic drugs.

Bilary disposition of adriamycin.

A patient with a choledochal T tube and normal liver function received adriamycin as therapy for abdominal histiocytic lymphoma. Plasma, urine, and bile samples were collected after drug administration. Adriamycin and its metabolites were extracted from the samples and separated by thin-layer chromatography. The pharmacokinetics of adriamycin and metabolites in plasma urine resembled those of previous patients, with a plasma elimination half-life for adriamycin of 25.2 hr. Bile contained adriamycin and 11 metabolites, 4 of which were not present in plasma or urine. Forty-one percent of the administered dose of adriamycin appeared in the bile in 7 days; of this amount, 42% was adriamycin, 22% was adriamycinol, the major metabolite, and 36% was other metabolites. Hepatic clearances of adriamycin and adriamycinol showed early, rapid removal of drug by the liver, with subsequent slowing of removal rate as plasma drug concentration declined. Adriamycin was more efficiently cleared than adriamycinol by both liver and kidney. Disease states which impair the capacity of the liver to excrete adriamycin may result in prolonged, high drug levels and increased toxicity.

Combination chemotherapy with adriamycin and streptozotocin. II. Clincopharmacologic correlation of augmented adriamycin toxicity caused by streptozotocin.

Plasma pharmacokinetics were compared in patients with advanced sarcomas receiving adriamycin, 60 mg/m2 intravenously (iv) on day 1 every 3 wk in combination with streptozotocin, 500 mg/m2/day iv on days 1 to 5 every 3 wk, and patients receiving adriamycin alone in the same dose and schedule. The combination-treated group had greater adriamycin drug exposure (concentration X time) when serial plasma levels were analyzed by fluorescence assay and by radioimmunoassay (RIA). The plasma t 1/2 of adriamycin equivalents measured by fluorescence assay was also significantly prolonged in the combination-treated group. These changes correlated well with an increase in adriamycin-related toxicity--mucositis and myelosuppression-seen in the patients who received the combination drug therapy. Plasma streptozotocin kinetics and the incidence of streptozotocin-related side effects--hepatic and renal function abnormalities--were those published for streptozotocin alone. Evidence is presented to support the hypothesis that the increased incidence of adriamycin side effects is due to streptozotocin-related hepatic dysfunction, affecting both the detoxification and excretion of adriamycin. Combination of other drugs with adriamycin should take into account their potential for inducing hepatic dysfunction which may affect the therapeutic index of adriamycin.

Plasma adriamycin and daunorubicin levels by fluorescence and radioimmunoassay.

In 38 adriamycin experiments and 4 daunorubicin experiments, radioimmunoassay readily and reproducibly detects and estimates these drugs and immunologically similar metabolites in patients' plasma and urine to at least 120 hr after dosing without interference by concurrent medication. The plasma drug decay follows first-order kinetics in a triphasic pattern. Radioimmunoassay and fluorescence assay show similar decay up to 4 hr but diverge at that point with the fluorescence assay yielding higher values. Pharmocokinetic differences are amplified in patients with liver dysfunction and may be caused by fluorescent drug metabolites not sensitive to radioimmunoassay or nonspecific fluorescent materials. The radioimmunoassay offers the capability to measure adriamycin and daunorubicin in clinical settings in which fluorescence assay is not available.

Initial observations on the effects of delta 9-tetrahydrocannabinol on the plasma pharmacokinetics of cyclophosphamide and doxorubicin.

We studied the effect of THC upon the pharmacokinetics of cyclophosphamide (CTX) and doxorubicin (ADR). Plasma THC was determined by RIA. Plasma concentrations of CTX and ADR were measured by GLC and fluorescence, respectively. RIA confirmed plasma levels of THC greater than 20 ng/ml for patients who received THC. CTX half-life was not significantly changed with use of THC (7.7 +/- 3.6 hours without versus 5.25 +/- 2.6 hours with THC). ADR half-life with THC was greater than without THC (175 +/- 197 hours versus 92 +/- 92 hours, respectively). Total drug exposure as determined by areas under the curves were similar (12.4 +/- 6 microM . hr without versus 13.8 +/- 4 microM . hr with THC). These preliminary data suggest that RIA is reliable for assessing THC plasma concentrations. THC induces no apparent alterations of CTX or ADR pharmacokinetics.

Mathematical model for adriamycin (doxorubicin) pharmacokinetics.

Adriamycin (doxorubicin), an active antineoplastic drug, is rapidly distributed across cell membranes and is concentrated within cells. Binding to protein and to tissue readily occurs. The drug is metabolized to both fluorescent and nonfluorescent compounds, the liver being the main organ of biotransformation and elimination. A multicompartment, open model that accounts for these processes has been derived. The model assumes an initial volume of distribution of 60% of body weight and includes two peripheral adriamycin compartments and a subsystem for adriamycinol, a major metabolite. Plasma and urine concentrations of adriamycin and adriamycinol were determined for four patients treated with adriamycin (60 mg/m2), and these concentrations were used to calculate rate constants for the model. Concentrations were measured by fluorescence assay after thin-layer chromatographic separation of parent compound and metabolites. Differential equations were solved by the SAAM computer program. Evaluation of adriamcinol pharmacokinetics suggests that the previously reported high concentrations of adriamycinol immediately after IV infusion of adriamycin are an artifact of the fluorescence method and that observed plasma concentrations of adriamycinol are the sum of adriamycinol concentrations and approximately 10% of the adriamycin concentrations. Corrected peak plasma concentrations of adriamycinol occur 2--12 h after infusion of adriamycin.

Human pharmacokinetics of marcellomycin.

In conjunction with two phase I clinical trials, we have investigated the pharmacokinetics of marcellomycin (MCM), a new class II anthracycline antibiotic, in nine patients with normal renal and hepatic functions and no third-space fluid accumulation. MCM was infused IV over 15 min at a dosage of 27.5, 40, or 50 mg/m2. Plasma and urine samples were collected up to 72 h. MCM and metabolites were assayed by thin-layer chromatography and quantified by specific fluorescence. The disappearance of total MCM-derived fluorescence from plasma followed first-order kinetics and lacked the rebound in total fluorescence that has been described for the structurally similar agent, aclacinomycin A. After 40-50 mg/m2, the peak MCM concentration in plasma was 1.67 +/- 0.61 microM; MCM disappeared from plasma in a triexponential fashion and was undetectable by 48 h after infusion. The area under the plasma concentration-time plot (AUC), including the infusion time, was 1.11 +/- 0.39 microM X h; plasma clearance of MCM was 1.50 +/- 0.88 l/min/m2. Five other fluorescent compounds were consistently observed in plasma. M2 was a contaminant present in the parent drug. P1 and P2 were conjugates of MCM and M2, respectively. G1 and G2 were aglycones. The peak concentrations of the metabolites were 25% or less or the peak concentration for MCM, but their persistence resulted in higher AUCs than that for MCM. For the dosage of 27.5 mg/m2, fewer data were available; but the pharmacokinetics of MCM and metabolites appeared to be similar to that at higher dosage. Urinary excretion of total fluorescence amounted to 8.0% +/- 1.6% of the total dose at 40-50 mg/m2, and to 7.0% +/- 2.3% at 27.5 mg/m2. No correlation was detected among the various pharmacokinetic parameters and toxicities encountered in these patients.

Comparative murine metabolism and disposition of class II anthracycline antibiotics.

The metabolism and tissue distribution of aclacinomycin A (ACL), marcellomycin (MCM), and musettamycin (MST), three new anthracycline antibiotics, were compared after IV administration to mice. In plasma, total MCM- and ACL-derived fluorescence declined according to first-order kinetics, whereas an initial decline followed by a rebound was observed for MST. In plasma, MCM remained the predominant compound. ACL was eliminated more quickly, and was replaced by two metabolites, the reduced glycoside M1, and an aglycone. In the case of MST, two unidentified metabolites were observed in concentrations equivalent to that of the parent drug. The three drugs were distributed widely to organs, but only ACL achieved measurable concentrations in the brain. Initially, high concentrations of all three drugs were present in the lungs, but these decreased quickly to values similar to those present in the liver and kidneys. Intermediate concentrations of the three drugs were measured in heart and skeletal muscle. Splenic concentrations of all three drugs rose progressively, reaching a maximum at 8 h after injection in the case of ACL and MST, and at 24 h after injection in the case of MCM. Concentrations of the metabolites of MCM and MST were low in all organs except liver and kidney, where the aglycones 7-deoxypyrromycinone and bisanhydropyrromycinone were seen. The metabolism of ACL was extensive. Aglycones were dominant in the liver and kidneys, whereas reduced glycosides predominated in the spleen. These observations indicate that the murine pharmacology of these three structurally similar drugs differs markedly.

The plasma pharmacokinetics and tissue distribution of dimethyl sulfoxide in mice.

We defined the plasma and tissue concentrations and pharmacokinetics of dimethyl sulfoxide (DMSO) in 22-34 g male Swiss Webster mice injected i.v. with 15% DMSO at a dosage of 1.5 mg per g. Concentrations of DMSO in alkalinized, perchloric acid extracts of tissue and plasma were determined by gas-liquid chromatography. Plasma concentrations of DMSO declined in a biexponential fashion that was well described by the equation Ct = 2.36 exp(-0.449 t) + 1.28 exp(-0.00768 t), indicating a t 1/2 (alpha) of 1.5 min and t 1/2 (beta) of 90 min. DMSO was rapidly and extensively distributed through tissues and was not concentrated in any particular tissue, although at 1 min after injection, the brain contained the lowest concentration of DMSO of any tissue studied. By 8 hr after injection, there was little DMSO in plasma or any tissue. Intravenous injection of DMSO produced neuro-muscular disturbances, hemolysis, and hemoglobinuria in all animals. Intravenous injection of DMSO produced little increase in plasma osmolality and did not produce any histological evidence of central nervous system or renal tubular damage.

Effect of aspirin and sulindac on methotrexate clearance.

The pharmacokinetics of low dose methotrexate (MTX) were evaluated in 12 rheumatoid arthritis patients in the presence and absence of steady-state levels of salicylic acid (ASA) and sulindac (SU). Using a Latin square design, patients were given MTX plus ASA (mean 3.4 g/day), MTX plus SU (mean 400 mg/day), or MTX alone. On a background of at least one year of regular MTX therapy, patients received 10 mg/m2 MTX iv (mean 17.8 mg) given after at least 2 weeks of treatment with each of the above regimens. Plasma concentrations of MTX and 7-hydroxymethotrexate (7-OH-MTX) were measured using HPLC. No differences in MTX clearance (Cl) were found comparing MTX alone, MTX + ASA, and MTX + SU. However, if one particular subject that had a very low clearance when receiving MTX alone was excluded, there was a statistically significant decrease in MTX clearance when either ASA or SUL were present. It is also noteworthy that ASA significantly increased the exposure of the subject to 7-OH-MTX and, to a lesser extent, so did sulindac. Since 7-OH-MTX has been shown to be an active metabolite when given for cytotoxic effects at higher doses and because it has been show to be nephrotoxic at doses a thousand-fold greater than used in rheumatoid arthritis, nonsteroidal anti-inflammatory drugs should be used cautiously with MTX until further large scale safety studies are conducted. The data indicate that if a clinically significant interaction were to occur, ASA is more likely than SU to interact with MTX.

Tumor necrosis factor and cytotoxic agents. Effect on squamous carcinoma lines.

The cytotoxicity of dactinomycin (actinomycin D), doxorubicin hydrochloride (Adriamycin), cisplatin, fluorouracil, and methotrexate alone and in combination with recombinant human tumor necrosis factor (rHuTNF) on human squamous cell carcinoma lines was studied by an MTT proliferation assay. The rHuTNF alone caused no inhibition after 24 to 72 hours. All lines investigated showed a dose-dependent response to dactinomycin and doxorubicin. Potentiation of dactinomycin and doxorubicin cytotoxicity occurred with four of six cell lines following incubation of rHuTNF and the drug. No synergistic effect on cytotoxicity was seen with rHuTNF and any chemotherapeutic agent on two cell lines. The addition of rHuTNF did not augment the cytotoxic effect seen with cisplatin, methotrexate, or fluorouracil on any cell line. These results show that rHuTNF can enhance the cytotoxic effect of certain chemotherapeutic agents on squamous cell lines in vitro.

Cardiac glycogenolysis in trained and untrained ischemic rat hearts.

The effect of induced myocardial ischemia on cardiac glycogen utilization was investigated in trained and untrained male Sprague-Dawley rats. Following a 12 to 15 week endurance training program, myocardial ischemia was induced by ligation of the left coronary artery. Prior to and at 5 min intervals following ligation, affected tissues of five trained and untrained animals were removed, frozen in liquid nitrogen, and analyzed for glycogen and lactic acid. The glycogen content for both groups declined significantly (p less than 0.05) during the first 5 min, 38% and 15% for the trained and untrained, respectively, with a concomitant rise in the lactic acid of 150% and 40%. Overall, the cardiac lactate in the trained hearts was lower (p less than 0.05) than in untrained hearts but the pattern of response was the same. During the final 5 min of ischemia, cardiac glycogen rose in the trained hearts and declined in the sedentary hearts. The difference between the two groups at 30 min was significant (p less than 0.05). The results show that trained and untrained rat hearts utilize glycogen differently but produce similar quantities of lactic acid during brief periods of myocardial ischemia. Similar lactate despite greater glycogen utilization may indicate reduced anaerobic stress in the trained rat heart.

Metabolic effects of facial cooling in exercise.

Metabolic responses to facial cooling during prolonged exercise was investigated in five male subjects. Exercise on a bicycle ergometer at 50 rpm for 1 h at 60% maximal heart rate was performed twice, once with cold wind (10 degrees C, 6.5 m . s-1) and once without. Resting experiments were conducted under identical conditions. Facial cooling apparently had no effect on plasma FFA or glucose concentration during exercise but did, however, result in significantly (p less than 0.05) greater fat utilization, as indicated by lower respiratory exchange ratios at 60 min of exercise. The respiratory exchange ratio, blood lactate concentration, oxygen consumption, and estimated myocardial oxygen consumption at 5 min of exercise were higher with facial cooling. The results suggest that metabolic changes occur with facial cooling that are related to a general thermoregulatory response and that the stress of exercise is greater with facial cooling.

Cardiovascular and sympathetic reactions to in-flight emergency responses among base fire fighters.

The responses of 12 healthy male fire fighters to simulated and actual in-flight emergencies were investigated. Subjects were aroused from sleep during all emergency responses. The ECG, blood pressure, heart rate (HR), rate-pressure product (RPP), and plasma norepinephrine (NE) responses were determined. Despite a mean HR increase of 112% (75 beats/min) and a 145% rise in RPP, there was no significant elevation in plasma NE concentration during the emergency response. Legible ECG tracings showed no abnormal ST segment deviations or arrhythmias. The HR, BP, and RPP results indicated a greater cardiovascular response to emergencies among inactive fire fighters than among those who were physically active. Based on the observed differences between emergency and simulated emergency responses, we concluded that the physiological reactions during emergency responses were due primarily to the arousal response. When suddenly aroused from sleep, the fire fighter's response to in-flight emergencies produces significant elevations in HR and myocardial oxygen consumption which were unrelated to increases in sympathetic activity.