High Risk of Graft Failure in Emerging Adult Heart Transplant Recipients

Emerging adulthood (17-24 years) is a period of high risk for graft failure in kidney transplant. Whether a similar association exists in heart transplant recipients is unknown. We sought to estimate the relative hazards of graft failure at different current ages, compared with patients between 20 and 24 years old. We evaluated 11 473 patients recorded in the Scientific Registry of Transplant Recipients who received a first transplant at <40 years old (1988-2013) and had at least 6 months of graft function. Time-dependent Cox models were used to estimate the association between current age (time-dependent) and failure risk, adjusted for time since transplant and other potential confounders. Failure was defined as death following graft failure or retransplant; observation was censored at death with graft function. There were 2567 failures. Crude age-specific graft failure rates were highest in 21-24 year olds (4.2 per 100 person-years). Compared to individuals with the same time since transplant, 21-24 year olds had significantly higher failure rates than all other age periods except 17-20 years (HR 0.92 [95%CI 0.77, 1.09]) and 25-29 years (0.86 [0.73, 1.03]). Among young first heart transplant recipients, graft failure risks are highest in the period from 17 to 29 years of age.

Impact of HLA mismatch at first kidney transplant on lifetime with graft function in young recipients

As HLA matching has been progressively de-emphasized in the American deceased donor (DD) kidney allocation algorithm, concerns have been raised that poor matching at first transplant may lead to greater sensitization and more difficulty finding an acceptable donor for a second transplant should the first transplant fail. We compared proportion of total observed lifetime with graft function after first transplant, and waiting times for a second transplant between individuals with different levels of HLA mismatch (MM) at first transplant. We studied patients recorded in the United States Renal Data System (1988-2009) who received a first DD transplant at age ≤21 years (n = 8433), and the subgroup who were listed for a second DD transplant following first graft failure (n = 2498). Compared with recipients of 2-3 MM first grafts, 4-6 MM graft recipients spent 12% less of their time and 0-1 MM recipients 15% more time with a functioning graft after the first transplant (both p < 0.0001); 4-6 MM recipients were significantly less likely (hazard ratio [HR] 0.87 [95% confidence interval 0.76, 0.98]; p = 0.03), and 0-1 MM recipients more likely (HR 1.26 [0.99, 1.60]; p = 0.06) to receive a second transplant after listing. The benefits of better HLA matching at first transplant on lifetime with graft function are significant, but relatively small.

Change in mortality risk over time in young kidney transplant recipients

Mortality risk for kidney transplant recipients may change with increasing accumulated exposure to the "transplantation milieu." We sought to characterize changes over time in mortality rate and in age-, sex- and race-standardized mortality ratios (SMR) relative to the general population, and to estimate the association between increasing time since first transplant and mortality risk. A total of 18 911 patients who received a first transplant at <21 years old (1983-2006), and whose data were recorded in the USRDS, were studied. There were 2713 deaths over a median follow-up of 8.9 (interquartile range 4.0-14.5; maximum 23) years. Among those with graft function, mortality was highest in the first post transplant year; beyond the first year of the first transplant, age-adjusted mortality rates and SMRs decreased slightly over follow-up. Cause of death was cardiovascular for 34.6%, infection for 19.5%, malignancy for 5.8%, other for 21.4% and unknown for 18.7%. For every 1-year time increment after the end of the first post transplant year, age-adjusted all-cause and cardiovascular mortality rates fell by 1% (p = 0.06) and 16% (p = 0.007), respectively; infection-related mortality rate did not change over time (p = 0.5). These results suggest that exposure to the transplantation milieu has no cumulative negative effects on cardiovascular health over the long term.

Chronic oral administration of CI-994: a phase 1 study

OBJECTIVES

CI-994 (N-acetyl dinaline, PD 123654) is a novel oral agent active in a broad variety of murine and human tumor xenografts. While cytotoxic in the Brown Norway (BN) rat leukemia model, growth inhibition in other murine and human tumor xenografts is predominantly cytostatic. Its specific mechanism of action remains unknown. Following CI-994 administration, inhibition of both histone deacetylation and cellular proliferation at the G1 to S transition phase of the cell cycle are observed. This Phase 1 study in patients with solid tumors was carried out to determine a maximum tolerated daily oral dose (MTD) for CI-994 administered on a chronic basis.

METHODS

Fifty-three patients received CI-994 daily for treatment durations ranging from 2 to 10 weeks. Dosage escalation proceeded in 2 phases; an Acute Dosing Phase (n = 11) to define the MTD for CI-994 administered over 2 weeks and a Chronic Dosing Phase (n = 29) to define the MTD for daily administration for 8 weeks. Upon completion of the Chronic Dosing Phase, a third cohort of patients (n = 13) received CI-994 at the recommended Phase 2 dose and schedule with 2 additional single doses of drug administered separated by a 1-week washout to assess the effect of food on CI-994 pharmacokinetics.

RESULTS

Thrombocytopenia was dose limiting at the MTD of 8 mg/m2/day for 8 weeks. Other toxicities included fatigue and gastrointestinal effects such as nausea, vomiting, diarrhea, constipation and mucositis. Pharmacokinetic studies revealed that peak plasma levels and AUC's generally increased with dose and that food intake did not affect the rate or extent of drug absorption. One patient with heavily pre-treated adenocarcinoma of the lung achieved a Partial Response (PR) lasting over 2 years and 3 additional patients achieved Stable Disease (SD), 1 each with non-small cell lung, colorectal, and renal cancer.

CONCLUSIONS

The recommended Phase 2 starting dose is 8 mg/m2/day for 8 weeks repeated after a 2-week drug-free interval.

Kawasaki disease complicated by renal artery stenosis

We report the case of a child who developed severe renovascular hypertension six months after acute Kawasaki disease. The hypertension was well controlled with enalapril, but there was a gradual decrease in function of the affected kidney. The lesion, an ostial stenosis of the right main renal artery, was not amenable to percutaneous balloon angioplasty, so was treated with bypass surgery. Vasculitis is an important cause of renovascular hypertension in children. This case highlights the importance of regular blood pressure monitoring in children with a history of systemic vasculitis.

Phase I pharmacokinetic study of the novel antitumor agent SR233377

SR233377 is a novel thioxanthenone analogue that demonstrated solid tumor selectivity in vitro with activity confirmed in vivo against several murine tumors including those of colon, pancreas, and mammary origin. Its primary preclinical dose-limiting toxicities included myelosuppression and neurological toxicity. The neurological toxicity was acute and could be ameliorated in mice when the drug was administered as a 1-h infusion instead of rapid i.v. injection. As a result of its preclinical efficacy profile, SR233377 entered Phase I clinical investigation. The compound was administered i.v. over 2 h on day 1 repeated every 28 days. The starting dose was 33 mg/m2 (one-tenth the mouse LD10). Escalations continued to 445 mg/m2 (six escalations), where dose-limiting toxicity was observed. At this dose, acute ventricular arrhythmias, including one patient with torsades de pointes and transient cardiac arrest, occurred. Because this toxicity might have been related to the plasma peak, the protocol was amended to a 24-h infusion beginning at 225 mg/m2. With this dose, prolongation of the corrected QT interval (QTc) over the pretreatment levels resulted. Because prolonged QTc is a known forerunner to acute ventricular arrhythmias, clinical development of SR233377 was stopped. However, preclinical antitumor and toxicity studies with analogues are underway with hopes of identifying a new clinical candidate with similar antitumor effects that is devoid of cardiac toxic effects.

Effective therapy for severe Henoch-Schonlein purpura nephritis with prednisone and azathioprine: a clinical and histopathologic study

OBJECTIVES

To validate a scoring system to assess the severity of renal lesions and to correlate histology with clinical findings. We also examined the efficacy of treatment with prednisone (1 to 2 mg/kg/d) and azathioprine (1 to 2 mg/kg/d) for severe Henoch-Schonlein purpura (HSP) nephritis.

METHODS

Twenty patients were evaluated retrospectively. All underwent biopsy before treatment, and 13 underwent biopsy after therapy. We developed a scale based on glomerular, tubulointerstitial (TI), and vascular changes and assigned all specimens acuity, chronicity, and TI scores. The outcomes of 17 patients were compared with those of a historical control group.

RESULTS

Chronicity score at initial biopsy increased with increasing delay between onset of renal involvement and first biopsy (rho = 0.55, P =.016) but did not progress after treatment was initiated. Both acuity (rho = 0.57,P =. 016) and TI (rho = 0.69, P =.003) scores correlated with clinical severity at first biopsy. The TI score correlated negatively with serum albumin (rho = -.60, P <.01). Significantly more patients in the study group than in the control group had a favorable outcome (15 [88%] of 17 vs 32 [54%] of 59, P =.011).

CONCLUSIONS

Our scale reflects disease activity and highlights the importance of TI changes in severe HSP nephritis. Outcome comparisons indicate that early treatment with prednisone and azathioprine prevents progression of chronic changes and improves outcome.

Cryptophycin 1 cellular levels and effects in vitro using L1210 cells

Cryptophycin 1 is a natural product that was initially isolated from blue-green algae which has shown potent broad spectrum antitumor activity in preclinical in vitro and in vivo models. The drug strongly binds to tubulin and disrupts microtubule assembly for more than 24 hours after its removal. We evaluated cell survival, intracellular levels and inhibition of macromolecular synthesis in L1210 cells following exposure to cryptophycin 1 in vitro. Cell survival was strongly inhibited following drug exposure for either 1 or 4 hours. Intracellular drug levels were minimally affected by temperature (4 degrees C versus 37 degrees C) or exposure times up to 1 hour. However, extracellular drug concentration in culture media and increasing cell numbers did affect the concentration of intracellular drug levels in a nearly proportional manner. The synthesis of DNA and RNA was inhibited less than 5%, while protein synthesis inhibition was near 30%. Thus, none of the macromolecules were inhibited enough to explain the inhibition of tumor cell growth.

Systemic juvenile rheumatoid arthritis complicated by two different renal lesions

Systemic-onset juvenile rheumatoid arthritis (JRA) is a complex disease which affects many organ systems. Associated renal lesions are unusual, with the possible exception of amyloidosis. We describe a girl with systemic-onset JRA who developed first membranous nephropathy and then, 3.5 years later, a severe crescentic glomerulonephritis. The membranous lesion followed therapy with intravenous immune globulin, and the possibility that this intervention caused the renal disease must be considered. It appears that both of these lesions should be added to the list of possible complications of systemic-onset JRA.

Preclinical pharmacokinetic, antitumor and toxicity studies with CI-994 (correction of CL-994) (N-acetyldinaline)

CI-994, a substituted benzamide derivative, is a compound that showed solid tumor selectivity for a variety of solid tumor models compared to L1210 leukemia. Due to its lack of aqueous solubility, it requires oral administration. Female B6D2F1 mice were treated with CI-994 once daily by oral administration of 50 mg/kg for 14 days. Following treatment mice were evaluated for pharmacodynamic effects as well as the pharmacokinetic behavior of CI-994 and the de-acetylated derivative dinaline. Mice samples (plasma, urine, feces) were analyzed using solid phase extraction, reverse phase HPLC and ultraviolet detection. The plasma distribution and elimination half-lives for CI-994 were 51 minutes and 9.4 hours, respectively, on D-1; 31 minutes and 3.4 hours, respectively on D-14. The apparent plasma distribution and elimination half-lives for dinaline were 27 minutes and 2.4 hours, respectively, on D-1; 40 minutes and 7.3 hours, respectively on D-14. The CI-994 AUC on D-1 and D-14 were 2879 and 2407 micrograms/ml x minutes, respectively; while the dinaline AUC on D-1 and D-14 were 87 and 92 micrograms/ml x minutes, respectively. Urinary excretion for CI-994 and dinaline was higher on D-14, while the fecal excretion was the same on both days. The Colon #38 tumor growth in treated mice was reduced to 22% of that observed in the controls by D-19. The levels of all blood cells were reduced in the treated mice when compared to controls and the total WBC was the most affected (median 38%). Recovery to pretreatment levels occurred quickly following treatment cessation. Phase I evaluation of chronic oral administration of CI-994 is currently ongoing.

Pharmacokinetic studies in mice of two new thioxanthenones (183577 and 232759) that showed preferential solid tumor activity

Two new thioxanthenones, 183577 and 232759, have rekindled interest in the development of representatives from this class of structures as useful anticancer agents. Although the mechanism of action is unknown, both compounds demonstrated a similar spectrum of solid tumor selectivity. 232759 was selected for clinical development because it showed no hepatotoxicity in preliminary studies, whereas 183577 showed hepatotoxicity but only at the maximum tolerated dose (MTD). The limiting toxicity for the clinical candidate was myelosuppression in preliminary studies. Plasma and tissue drug levels, as well as protein binding, were studied in mice using optimal administration times at the MTD for each drug (for 183577, this was a 4-h infusion at 1350 mg/m2 and for 232759, it was a 5-min injection at 240 mg/m2), as well as at one-half the MTD for the clinical candidate. The drugs were 96-100% bound by plasma proteins. The peak drug concentrations, half-life, and area under the concentration-time curve in plasma for 183577 were 3483 ng/ml, 465 min, and 2018 microgram/ml. min, respectively. The peak drug concentration, half-life, and area under the concentration-time curve in plasma for 232759 were 5257 ng/ml, 44 min, and 276 microgram/ml. min, respectively, at the MTD and 2810 ng/ml, 40 min, and 110 microgram/ml. min at one-half the MTD. In all instances of simultaneous measurements, drug concentrations were equal or higher in tissues than they were in plasma. Unlike the plasma and kidney concentrations of 183577, the liver concentrations did not show a declining trend over the 8-h observation period. Declines in plasma, liver, kidney, and tumor levels of 232759 were detected over the 8-h observation period. The sustained high 183577 concentration in liver is believed to be responsible for its prolonged half-life and hepatotoxicity. Evidence for metabolism of the parent drugs was based on the finding of additional peaks on the high-pressure liquid chromatography tracings. Future studies will focus on identification and antitumor studies of these presumed metabolites in hopes of a better understanding of the solid tumor activity profiles and toxic effects of these compounds.

HER2-targeted gene transfer

Selective transfer of genes to specific cells remains a barrier to successful utilization of somatic gene therapy. We hypothesized that the human epidermal growth factor receptor-2 (HER2, also called ErbB2), a membrane tyrosine kinase highly expressed in many epithelial tumors, could be an immunological target for gene transfer. To test this hypothesis in vitro, we non-covalently linked a luciferase expression vector (pRSVLuc) to a humanized HER2 antibody (rhuMAbHER2) covalently modified with poly-L-lysine bridges (PL). This complex (PL-rhuMAbHER2) was tested for its ability to direct gene transfer to HER2 expressing cells in vitro using NIH3T3 (HER2 nonexpressing) and NIH3T3.HER2 (HER2 expressing) cell lines as a model system. Twenty-four hours after exposing NIH3T3.HER2 cells to the PL-rhuMAbHER2-pRSVLuc complexes and 100 microM chloroquine, luciferase expression was 180-fold higher than that obtained from a conjugate made with an isotype-matched antibody against an irrelevant target. Exposing the HER2-expressing adenocarcinoma cell lines BT474 and SKBR3 to the HER2-targeted complexes also resulted in successful gene transfer and expression. Gene transfer was specific for the HER2 receptor, because preincubation of HER2-expressing cells with unconjugated rhuMAbHER2 decreased complex-mediated luciferase expression by 95%. These studies suggest that HER2 may be an appropriate target for selective gene transfer and that PL-rhuMAbHER2-DNA complexes may be a useful vehicle for directing gene transfer to cells that express HER2.

Phase I clinical trial of pyrazoloacridine NSC366140 (PD115934)

The pyrazoloacridine (PZA) analogue NSC366140 (PD115934) entered clinical trial based on unique preclinical characteristics including solid tumor selectivity in vitro, marked antitumor activity in vivo against murine solid tumors, selectivity against noncycling cells, and activity against multidrug-resistant tumor cells. After identification of the pre-clinical efficacy and an acceptable toxicity profile, a Phase I study of PZA was carried out. A total of 28 patients was entered and received a total of 67 treatment courses. The drug was administered via a 1-h infusion every 21 days. The starting dose was 30 mg/m2 with 2-fold dose escalations through 480 mg/m2. The next dose escalation was 50%, to 720 mg/m2. Grade I through grade IV toxicities were observed. Since no dose-limiting toxicities were observed at 480 mg/m2, and up to grade IV toxicities were observed at 720 mg/m2, an intermediate dose, 600 mg/m2, was evaluated. Dose-limiting toxicities at 720 mg/m2 were hematological (grade III and IV neutropenia) in four of six patients and neurological (up to grade III cerebral toxicities, including restlessness, dizziness, agitation/anxiety, personality changes, and nightmares, as well as myoclonus) in three of six patients treated. The pharmacokinetic parameters which helped predict these toxicities included area under the curve and peak plasma level. Pharmacokinetic studies showed interpatient variations in all parameters studied. The mean area under the curve levels of PZA at the highest two dose levels in patients were near the level detected in mice at their maximum tolerated total dose. The recommended starting dose for Phase II trials using this schedule is 600 mg/m2.

Pharmacokinetics of 9-methoxy-N,N-dimethyl-5-nitropyrazolo [3,4, 5-kl]acridine-2(6H)-propanamine (PZA, PD 115934, NSC 366140) in mice: guidelines for early clinical trials1

Pharmacokinetic studies that consisted of measuring the plasma drug profile, tissue drug distribution, and elimination in urine and feces were performed in female C57BL/6 x DBA/2 (hereafter called B6D2F1) and male B6D2F1A/2 and C57BL/6 x CH3 (hereafter called B6C3F1) mice following treatment with a 1-h i.v. infusion of the PZA, PD115934 (NSC 366140). This drug is the first of a new class of cytotoxic agents and was selected for clinical trials because of both its broad antitumor activity in vivo against murine solid tumors and human xenografts, and its in vivo toxicity profile that was predictable based on drug dose and schedule of administration. The pharmacokinetic results obtained here in mice have been used to facilitate the dose escalations during the Phase I trial and to determine pharmacokinetic drug exposure targets for its acute and sub-acute toxic effects. Plasma samples from three to four mice per time point were pooled, and then individual tissue samples from the same mice were collected at specified times following treatment. All samples were prepared using solid-phase extraction and assayed using high pressure liquid chromatography. The acute dose-limiting toxicity was neurological and occurred immediately after treatment at 300 mg/m2. The peak plasma level range at the acute maximum tolerated dose was 1040-1283 ng/ml. Thus, peak plasma levels <1000 ng/ml were the acute toxicity target. Variations in the area under the plasma drug concentration x the time curve were observed that did not appear to be related to sex or age. The previously defined subacute dose-limiting toxicity was myelosuppression that occurred at a maximum tolerated dose of 600 mg/m2 (300 mg/m2 x 2) in B6D2F1 females. Thus, the area under the plasma drug concentration x the time curve in B6D2F1 females at this dose (1048 microg/ml x min) was the area under the plasma drug concentration x the time curve target. Drug levels were detected at 60 min following treatment in all tissues examined with a plasma:tissue ratio as high as 1:500. The organs with the highest levels were kidney, pancreas, liver, lung, and brain. Fecal excretion was low (range, 0.04-0.20% of the dose administered) and was not clearly different between males and females. Urinary excretion was higher (range, 5-28% of the dose administered) and did show evidence of sex-related differences, with male urinary drug excretion being higher than female urinary drug excretion. The drug was >/=95% protein bound. Preliminary evidence for drug metabolism was found in urine and feces and will be further explored.

Phase I trial of Adozelesin using the treatment schedule of daily x5 every 3 weeks

CC-1065 is a unique alkylating agent that preferentially binds in the minor groove of double-stranded DNA at adenine-thymine-rich sites. Although it has broad antitumor activity in preclinical models its development was discontinued because of deaths observed during preclinical toxicology studies. Adozelesin is a potent synthetic analog that was chosen for clinical development because it had a similar preclinical antitumor spectrum, but did not produce deaths similar to CC-1065 at therapeutic doses. Phase I evaluations using a variety of Adozelesin treatment schedules have been conducted. This report describes our experience using a multiple dose treatment schedule. Endpoints including antitumor response, maximum tolerated dose, dose limiting toxicity as well as other toxicities and the recommended Phase II starting dose were determined. Adozelesin was given as a 10 minute IV infusion for 5 consecutive days every 21 days or upon recovery from toxicity. The dose range evaluated was 6-30 mcg/m2/day. All patients had refractory solid tumors and had received prior cytotoxic treatment. Thirty-three patients (22 men: 11 women) were entered onto the study and 87 courses were initiated. Dose limiting toxicity was cumulative myelosuppression (leucopenia, thrombocytopenia). The maximum tolerated dose was 30 mcg/m2/day. The only other significant toxicity was an anaphylactoid syndrome that occurred in 2 patients. A partial response was observed in a patient with refractory soft tissue sarcoma. The recommended Phase II starting dose of Adozelesin using a 10 minute IV infusion for 5 consecutive days is 25 mcg/m2/day to be repeated every 4-6 weeks to allow recovery from myelotoxicity, based on our experience. Additional Phase I and II studies with Adozelesin are recommended.

Phase I trial with pharmacokinetics of CB10-277 given by 24 hours continuous infusion

The dose limiting toxicities of the short infusion trial of the dacarbazine analog, CB10-277, were nausea and vomiting which appeared to be related to the peak plasma level of the parent drug. In addition, based on mouse studies, these dose limiting toxicities occurred at a less than optimal level of the monomethyl metabolite, the presumed species required for antitumour activity. An alternative schedule that would avoid the parent drug peak plasma levels of short infusion, while possibly allowing an increase in the amount of monomethyl metabolite produced was considered. Thus, a 24 h continuous infusion schedule, repeated every 21 days was explored. Twenty-two patients received 42 courses with a dose range of 4,700-15,000 mg m-2. The dose limiting toxicity was myelosuppression (leucopenia and thrombocytopenia). Although nausea and vomiting also occurred, it was manageable with routine antiemetic therapy. Other toxicities included diarrhoea, hallucinations, malaise, muscle ache, headache and flushing and all were < or = WHO grade 2. Pharmacokinetic studies were performed with 13 courses which included all dose levels. The mean t1/2 of the parent drug was 178 min. Area under the concentration x time curve (AUC) at the highest dose for the parent drug and the monomethyl metabolite were 2,350 and 9 mM x minutes, respectively. This monomethyl metabolite AUC and the associated myelosuppression showed a more favourable comparison to the preclinical data determined in mice than the results from the short infusion trial of CB10-277. Therefore, the recommended Phase II dose and schedule of this drug was 12,000 mg m-2 given by 24 h continuous infusion.

Preclinical, phase I and pharmacokinetic studies with the dimethyl phenyltriazene CB10-277

Decarbazine is an imidazole dimethyltriazene with reproducible activity in patients with metastatic melanoma. CB10-277 is a phenyl dimethyltriazene which, like dacarbazine, requires metabolic activation to its corresponding monomethyl species for antitumour activity. In preclinical models (human melanoma xenografts and transplantable rodent tumours) CB10-277 showed a similar spectrum and level of activity when compared to dacarbazine. Pharmacokinetic studies were performed with CB10-277 in mice treated i.v. at the LD10 (750 mg m-2) and plasma analysed by HPLC. The parent drug area under the plasma concentration vs time curve (AUC) was 142 mM x minutes. Drug metabolism occurred as evidenced by the HPLC identification of the monomethyl species (AUC = 8 mM x minutes) as well as other metabolites. A Phase I trial using a short infusion with doses repeated every 21 days has been performed. Thirty-six patients received 80 courses over a dose range of 80-6,000 mg m-2. The dose limiting toxicity was nausea and vomiting which occurred in 80% of the evaluable courses > or = 900 mg m-2. The only other common side effect was a flushing or warm sensation, which occurred in over 75% of courses at > or = 1,350 mg m-2. There were no hemodynamic consequences. Responses occurred in patients with melanoma (one complete, two partial, one mixed/11), sarcoma (one mixed/6) and carcinoid (one partial/l). Pharmacokinetics were performed in 46 courses. The CB10-277 AUC increased linearly with dose (r = 0.9203, P < 0.001) up to 700 mM x minutes at 6,000 mg m-2). Evidence of CB10-277 metabolism was observed, as in mice, by detection of the monomethyl species and other metabolites. However, the plasma levels of the monomethyl species in patients (1.8 and 3.7 mM x minutes at 6,000 mg m-2) were less than those predicted from studies in mice. Despite this, antitumour activity in dacarbazine sensitive histologies was observed and additional studies with CB10-277 are recommended.

Phase I trial of the anthrapyrazole CI-941: prospective evaluation of a pharmacokinetically guided dose-escalation

The development of new drugs in early clinical trials is currently based upon the results of preclinical antitumour and toxicity studies in animals. More recently, the use of preclinical pharmacokinetic information in mice has been proposed to also provide information that might expedite early clinical trials and more specifically phase I studies. The anthrapyrazole CI-941 was one of three chosen for phase I anticancer drug development. In addition, because of the predictability of the preclinical dose limiting toxicity and linear CI-941 pharmacokinetics in mice; a pharmacokinetically guided dose escalation scheme was attempted during the phase I trial, but had to be abandoned. 44 patients were entered who received 95 courses of treatment using a bolus injection every 21 days. The dose range was 5-55 mg/m2. The dose limiting toxicity was leucopenia and other toxicities, which included nausea and vomiting, mucositis, diarrhoea, alopecia and skin discolouration were either mild or manageable. Pharmacokinetic studies were performed with 27 courses. There were wide interpatient variations in the dose-AUC relationship (r = 0.7496) that hampered application of the proposed pharmacokinetically guided dose escalation scheme as planned. No complete or partial responses were observed. The recommended phase II dose using this schedule is 50 mg/m2.

Clinical pharmacokinetics of the anthrapyrazole CI-941: factors compromising the implementation of a pharmacokinetically guided dose escalation scheme

The pharmacokinetics of the anthrapyrazole CI-941 has been investigated in conjunction with the Phase I evaluation of the drug with the intent of applying a pharmacokinetically guided dose escalation strategy. A starting dose of 5 mg/m2 was chosen, based on one-tenth the 10% lethal dose in mice. Due to the steep dose lethality relationship and nonlinear pharmacokinetics in mice, a target area under the CI-941 plasma concentration x time curve (AUC) of 110 microM x min (i.e., 40% of the mouse 10% lethal dose AUC) was chosen. This AUC was achieved in mice at 40 mg/m2. A total of 37 patients received 74 courses of CI-941 (5 to 55 mg/m2), with 26 patients consenting to pharmacokinetic monitoring. CI-941 was rapidly cleared from plasma, and a triexponential open model could be fitted to the data (t1/2 alpha = 7.6 +/- 2 min, t1/2 beta = 65 +/- 27 min, t1/2 zeta = 21 +/- 9 h). CI-941 was subjected to only limited urinary elimination, accounting for 5.2 +/- 2.8% of the administered dose. Wide interpatient variability in plasma CI-941 clearance at the starting dose and subsequent doses precluded the implementation of a pharmacokinetically guided dose escalation scheme, and the dose was escalated in 5-mg/m2 increments until the maximally tolerated dose was achieved. A number of investigations were performed to study potential reasons for variability in CI-941 clearance. However, CI-941 plasma protein binding (95 +/- 1%) and measures of pretreatment renal (51Cr-EDTA clearance), hepatic (plasma alanine transaminase and alkaline phosphatase levels), or cardiac function (left ventricular ejection fractions) did not relate strongly to CI-941 clearance. In patients treated at 40 mg/m2, the AUC values (156 to 415 microM x min) approximated or exceeded the target AUC. Fifty mg/m2 was the Phase II recommended dose. Further prospective studies are warranted to assess the utility of pharmacokinetically guided dose escalation strategies and to determine whether or not the variability encountered in clearance is unique to CI-941.

Patient treatment on a compassionate basis: documentation of high adverse drug reaction rate

The special exception mechanism was established by the Division of Cancer Treatment (DCT), National Cancer Institute (NCI), for the provision of anticancer drugs not yet approved by the Food and Drug Administration (FDA) to patients on a compassionate basis. Strict guidelines have been established for the distribution of drugs through this mechanism and for the reporting of adverse drug reactions (ADRs) with investigational drugs. These guidelines have been used to format the data base which is maintained on all ADRs submitted by investigators. In this paper, the incidence of ADRs with the eleven investigational drugs most frequently administered on special exception protocols was determined for a twelve month time period, January 1, 1985 through December 31, 1985. On special exception protocols, the overall incidence rate of ADRs was significantly greater than that seen on research protocols for the time period. For three drugs, Methyl-G, DBD, and AMSA, the ADR incidence rate was seven to fifteen-fold greater on special exception protocols than on research protocols. In an analysis of all ADRs submitted to the FDA for the twelve months time period, no difference was found in the frequency of distribution of either types of adverse effects or the causal assessments of ADRs on special exception and research protocols.

A strategy for the development of two clinically active cisplatin analogs: CBDCA and CHIP

The antitumor agent cisplatin has a broad antitumor spectrum and has been incorporated into regimens that are curative for some malignant diseases. However, one of the major limitations to its clinical usefulness is the incidence of severe toxicities involving several major organ systems. Therefore, much enthusiasm has been generated for the development of cisplatin analogs that demonstrate an improved therapeutic index in some preclinical models. The two most promising analogs are CBDCA (carboplatin) and CHIP (iproplatin). The preclinical and early clinical trial results have demonstrated that these two compounds show activity in cisplatin-responsive tumors. The preclinical background providing the rationale for the clinical development of these two analogs is described. We suggest a means of screening for each analog's clinical antitumor activity and determining the analogs' utility against specific malignant diseases compared with that of the parent compound or standard treatment.

The pharmacokinetics and toxicity of the anthrapyrazole anti-cancer drug CI-941 in the mouse: a guide for rational dose escalation in patients

CI-941 is a new synthetic DNA-binding agent selected for phase I clinical evaluation. The drug has broad-spectrum antitumour activity against a number of murine tumours and, in contrast to doxorubicin, is unlikely to induce cardiotoxicity by a free-radical-mediated mechanism. In this study the toxicity and pharmacokinetics of CI-941 were studied in the mouse to enable the implementation of a pharmacokinetically guided dose-escalation strategy in patients. Following a single i.v. bolus injection in mice, CI-941 induced dose-dependent leukopenia. The white blood cell counts were suppressed on day 3 by 18%, 50% and 65% of control, at doses of 10, 15 and 20 mg/kg CI-941, respectively. Other toxicities such as weight loss, alopecia, diarrhoea and convulsions were observed at doses greater than 20 mg/kg. Lethality studies in female Balb-c mice resulted in an LD10 value of 20 mg/kg (95% confidence limits; range, 19-21 mg/kg) and an LD50 value of 22 mg/kg (95% confidence limits; range, 21-23 mg/kg). The pharmacokinetics of CI-941 were studied at four dose levels from 1/10 of the LD10 to the LD10 (20 mg/kg). The drug was rapidly cleared from the plasma (250-400 ml/min per kg) at a rate approaching the cardiac output of mice, displaying triphasic plasma pharmacokinetics. The area under the plasma CI-941 concentration vs time curve (AUC) was linear with respect to the dose, up to and including 15 mg/kg (AUC = 110 microM x min at 15 mg/kg), but became non-linear at 20 mg/kg (AUC = 277 microM x min). Despite 80%-84% plasma protein binding, CI-941 was rapidly and extensively distributed into tissues, especially the kidney. Following i.v. bolus injections at doses of 1.5 and 15 mg/kg, elimination of the parent compound by urinary excretion accounted for 12%-18% of the delivered dose. A phase-I starting dose (based on that equivalent to 1/10 of the LD10 in the mouse) of 5 mg/m2 CI-941 is recommended for single administration schedules. In addition, a pharmacokinetically guided dose-escalation strategy, based on achieving a target AUC of 110 microM x min, is proposed.

Modulation of induced resistance to adriamycin in two human breast cancer cell lines with tamoxifen or perhexiline maleate

The clinical utility of adriamycin in the treatment of patients with metastatic breast cancer is often-limited by the development of drug resistance. It has been recognized that in addition to the development of primary resistance against adriamycin, malignant cells can simultaneously develop cross-resistance to other agents. An adriamycin-resistant human breast cancer cell line (MCF 7Ad) was developed by exposing the parent line (MCF 7) to gradually increasing concentrations of adriamycin while the cells were being grown in monolayer. Using these lines in a clonogenic assay, the relative drug sensitivities to adriamycin, vinblastine, melphalan, 5-fluorouracil and methotrexate were studied. MCF 7Ad was 12.5-fold more resistant to adriamycin than MCF 7 and 500-fold cross-resistant to vinblastine. There was no cross-resistance to melphalan, 5-fluorouracil or methotrexate. The resistance of MCF 7Ad was decreased by simultaneous exposure to tamoxifen (by a factor of 3.33) or perhexiline maleate (by a factor of 7.50). This decreased resistance was evidenced by a shift to the left of the sensitivity curves. However, there was no consistent change in the sensitivity curves of MCF 7. At the selected concentration of tamoxifen and perhexiline maleate, the cloning efficiency of MCF 7 and MCF 7Ad was 80%-90% of control values in medium without tamoxifen, perhexiline maleate or cytotoxic drugs. The resistance of MCF 7Ad to adriamycin was associated with a lower accumulation of [14C]adriamycin than exhibited by the sensitive MCF 7 line. There was no consistent change in [14C]adriamycin accumulation in MCF 7 or MCF 7Ad when tamoxifen was added, but when perhexiline maleate was added the [14C] accumulation increased. These results suggest that the tamoxifen-induced change in MCF 7Ad adriamycin resistance was not due to an increase in the amount of cell-associated adriamycin, but rather to some other mechanism that increased the cytotoxicity of the adriamycin.

Hexamethylmelamine: a critical review of an active drug

Hexamethylmelamine is an s-triazine that began clinical trials during the 1960s based on its level of antitumor activity in murine tumor models. Phase I studies were performed using an oral formulation given in divided doses for varying numbers of days. The most frequently reported toxicities included nausea, vomiting, abdominal cramps, anorexia, weight loss and malaise. Less frequently reported toxicities were anemia, thrombocytopenia, leucopenia and peripheral neuropathy. Clinical antitumor activity was noted in the phase I studies in a variety of tumor types. Since then a large number of studies have been performed using hexamethylmelamine as a single agent and in a variety of combinations. Unfortunately, almost none of these studies sought to define the utility of this drug relative to other treatments for the diseases in which it showed activity, or to define the contribution of this drug to the activity of any given combination. Thus its role in the treatment of patients with malignancies remains undefined.

Gallium nitrate: the second metal with clinical activity

Gallium nitrate is the anhydrate salt of the naturally occurring heavy metal. It has demonstrated antitumor activity in a variety of murine tumor models, including Walker carcinosarcoma 256, fibrosarcoma M-89, leukemia K-1964, adenocarcinoma 755, mammary carcinoma YMC, reticulum cell sarcoma A-RCS, lymphoma P1798, and osteosarcoma 124F. Preclinical studies performed in rats, rabbits, dogs, and monkeys showed the dose-limiting toxicity to be renal. The hepatic, pulmonary, gastrointestinal, hematologic, and integumentary systems were also involved. The major route of elimination is the kidneys, with 35%-71% of the infused dose excreted within 24 hours. Three phase I studies suggested the following phase II doses: 700-750 mg/m2 by short infusion, once every 2-3 weeks; 300 mg/m2/day by short infusion for 3 consecutive days, to be repeated every 2 weeks; and 300 mg/m2/day by continuous infusion for 7 consecutive days, to be repeated every 3-5 weeks. The major organ toxicity reported was renal; however, this can be adequately controlled either by hydration and osmotic diuresis or by use of continuous schedule. (Either maneuver appears to allow delivery of the recommended phase II dose with a less than 30% risk of change in serum creatinine.) In limited phase II evaluation, the drug has shown antitumor activity in patients with either refractory lymphomas or small cell lung carcinoma, with total objective response rates of 28% and 11%, respectively. In addition, it has been effective in the treatment of patients with cancer-related hypercalcemia by having an inhibitory effect on calcium reabsorption from bone. Single-agent phase II studies are planned in all major tumor types. Some are already ongoing in patients with genitourinary malignancies (renal, bladder, prostate, testicular), small cell lung carcinoma, and multiple myeloma. Metabolic studies are in progress at Memorial Sloan-Kettering Cancer Center to further elucidate the mechanism or mechanisms of the hypocalcemic effects.

Pentamethylmelamine: review of an aqueous analog of hexamethylmelamine

The s-triazine derivatives have shown preclinical antitumor activity against several histologic types. The most widely used compound of this class in the clinic, hexamethylmelamine, has been largely restricted to oral use because of its low solubility and lack of stability in solutions suitable for parenteral administration. New analogs were sought which were soluble and stable and retained antitumor activity. Pentamethylmelamine (PMM), the monodemethylated derivative, showed these promising characteristics. Preclinical toxicology studies of PMM in mice, dogs, and monkeys showed toxic manifestations that involved the hematopoietic, lymphatic, renal, male reproductive, gastrointestinal, and nervous systems; these changes were both infusion-rate- and dose-dependent. Clinical phase I trials of PMM were performed using a variety of infusion durations and frequency schedules. The dose-limiting toxic effect common to all of these trials was protracted nausea and vomiting. In addition, some studies reported dose-limiting central nervous system manifestations in the form of agitation, drowsiness, somnolence, and even coma. Mild to moderate hematologic changes were noted. Because of the severity and frequency of the gastrointestinal and central nervous system toxic effects observed in the completed trials, no new clinical trials of PMM sponsored by the National Cancer Institute are planned. However, the interest in finding a clinically useful parenteral triazine continues.

Results of NCI-sponsored phase I trials with carboplatin

Carboplatin has been developed for clinical trials as a less nephrotoxic, less emetogenic analog of cisplatin. In preclinical tumor models it was less potent than the parent compound on a molar basis, but reduced toxicity allowed comparable antitumor doses to be given. In phase I studies its dose-limiting toxicities were reversible myelosuppression, especially thrombocytopenia. Leucopenia and anemia occurred to a lesser degree. Other reported toxicities included nausea, vomiting, malaise, myalgia, arthralgia, ototoxicity, hypomagnesemia, and proteinuria. Nausea and vomiting occurred frequently, but was much less severe than that observed with cisplatin. The incidence of serum creatinine elevations was low. The increase was usually reversible and occurred only in association with administration of aminoglycosides, or abnormal pretreatment renal function. Recommended phase II doses by schedule are: bolus every 4 weeks, 400-500 mg/m2 (560 mg/m2 in children); 24 hour continuous infusion every 4 weeks, 320-400 mg/m2; weekly bolus for 4 consecutive weeks with 2 weeks rest, 100-125 mg/m2 (175 mg/m2 in children); bolus for 5 consecutive days every 4 weeks, 77-95 mg/m2. Objective responses were observed during these phase I studies in adult patients (head and neck, breast, renal carcinomas) and children (osteosarcoma, brain stem lesions). In addition to phase II evaluations in all major tumor types, plans for phase III studies in selected tumors are underway.

Echinomycin: the first bifunctional intercalating agent in clinical trials

Echinomycin is a quinoxaline antibiotic that was originally isolated from Streptomyces echinatus. Based on its antitumor activity against two i.p. implanted murine tumors, the B16 melanoma, and the P388 leukemia, it was brought into clinical trials by the National Cancer Institute. Recent studies on its cytotoxic action have related its antitumor activity with its ability to bifunctionally intercalate with double stranded DNA. Toxicologic studies were carried out in CDF1 mice and beagle dogs using intravenous injections. For the mice studies the dose ranges were 288-692 mcg/kg (864-2076 mcg/m2) by single bolus, and 112-254 mcg/kg/day (336-762 mcg/m2/day) for five consecutive days. In the dog, dose ranges studied were 8.9-89.4 mcg/kg (178-1788 mcg/m2) by single bolus, and 3.4-33.5 mcg/kg/day (68-670 mcg/m2/day) for five consecutive days. The major toxic effects were found in the gastrointestinal, hepatic, and lymphoreticular systems. These were reversible at all but the highest dose, in dogs that had been treated for five consecutive days. Phase I clinical trials using various intravenous schedules were sponsored by the National Cancer Institute. Nausea, vomiting, reversible liver enzyme abnormalities, and allergic reactions were the most common toxicities encountered. Based on results from these studies, the National Cancer Institute has recently begun phase II trials in a broad range of diseases. These trials will further characterize echinomycin's toxic effects and its antitumor activity.

Potential therapeutic and diagnostic applications of the growth of testicular cancer in soft agar

Sixteen histologically documented testicular cancer specimens obtained at diagnostic procedures following induction chemotherapy with cis-platinum containing regimens were cloned in soft agar. Seven (44%) of the specimens cultured formed colonies with a mean cloning efficiency of .021%. Colony formation was observed with all the common histologic subtypes of testicular cancer (seminoma, embryonal carcinoma, choriocarcinoma and mixed tumors). In vitro drug sensitivity tests were performed using cis-platinum, vinblastine and VP-16. Three of four specimens demonstrated a decrease in colony formation to less than 50% of controls after a 1 h exposure to VP-16 at 300 micrograms/ml. Two of these patients had a response to treatment with a VP-16 based salvage regimen. Immunoperoxidase staining of the colonies for alpha feto protein and human chorionic gonadotropin were correlated with the serum levels of these tumor markers determined at the time the specimen was obtained. In three instances the same markers were elevated in the serum as detected within cells which formed the colonies; however, in two other cases the marker(s) that was elevated in the serum was not expressed in the colonies. In one case a biopsy of a residual retroperitoneal mass following chemotherapy histologically was a teratoma, but it formed colonies in the assay which stained positive for alpha feto protein. This patient subsequently developed an elevated serum alpha feto protein. These studies have demonstrated that (a) testicular cancer can be cloned directly in soft agar; (b) a heterogeneous tumor cell population exists in metastatic testicular cancer specimens; and (c) a dose response exists for VP-16 in relapsed testicular cancer which suggests that increasing the dose of VP-16 may be clinically beneficial.

Review of gentamicin therapy based on pharmacokinetics

The feasibility of using pharmacokinetic estimations of drug serum levels to evaluate gentamicin use was explored. A consecutive series of 40 adult patients who received nonprophylactic "piggyback" gentamicin therapy was retrospectively evaluated. Traditional factors in the evaluation of antibiotic use, such as identity of microbe and sensitivity to antibiotic, were monitored. Additionally, peak and trough drug serum levels were computed for each patient. These were compared with toxic serum levels and minimum inhibitory concentrations as reported in the literature. Certain factors, such as duration of therapy and existence of alternate antibiotic therapy, suggested less than optimal therapy in the study patients. However, computed serum levels revealed that the patients experienced both safe and effective peak and trough gentamicin levels. Only with the use of pharmacokinetic estimations of drug serum levels could a comprehensive conclusion be reached regarding the appropriateness of therapy. Gentamicin therapy was generally rational in the study group. The use of pharmacokinetic principles in the calculation of serum levels may be a useful tool in drug use studies.