Pharmacokinetics of carbetocin, a long-acting oxytocin analogue, following intravenous administration in horses.

REASON FOR PERFORMING STUDY: Current therapy protocols to treat persistent post mating endometritis and retained fetal membranes in mares typically include the administration of ecbolic drugs. Evaluation of the pharmacokinetics and tolerability of carbetocin, a long-acting oxytocin analogue, after i.v. administration is required. OBJECTIVES: To determine the pharmacokinetic parameters (principally half-life) of carbetocin in horses. METHODS: Five mature mares and one gelding received 0.175 mg carbetocin i.v. All animals were monitored periodically throughout the study for elevation in rectal temperature, heart rate, respiratory rate and signs of pain or discomfort. Plasma samples were collected for determination of carbetocin concentrations by radioimmunoassay. RESULTS: Administration of carbetocin was well tolerated by all horses and its half-life was 17.2 min. CONCLUSIONS: The half-life of carbetocin is greater than that previously reported for oxytocin (6.8 min). POTENTIAL RELEVANCE: Carbetocin is an attractive alternative to oxytocin therapy in broodmare management.

Phase I clinical and pharmacokinetic study of hexamethylene bisacetamide (NSC 95580) administered as a five-day continuous infusion.

Hexamethylene bisacetamide (HMBA), a potent differentiating agent, was tested in patients with refractory, solid tumors. Twenty patients received 25 evaluable courses. HMBA was given by continuous i.v. infusion for 5 consecutive days with courses repeated every 4 wk, provided there was acceptable, reversible toxicity. The starting dose was 4.8 g/m2/day for 5 days with escalations in subsequent cohorts of patients to 43.2 g/m2/day for 5 days. The patients included 12 females and eight males with median age of 56 yr (range 35 to 75 yr) and a median performance status of 80% (range, 60 to 100%). All except two patients had received prior chemotherapy, radiation therapy, or both. Metabolic acidosis and neurotoxicity, consisting of agitation, hallucinations, confusion, and alteration of consciousness, were dose dependent and dose limiting. The one patient treated with 43.2 m/m2/day became acidotic, agitated, and disoriented but recovered to his previous mental and electrolyte status by 8 days after the end of the HMBA infusion. One patient treated with 33.6 g/m2/day became severely acidotic (pH 7.07) and obtunded and also developed myocardial and cerebral infarctions during the HMBA infusion. The other two patients treated with 33.6 g/m2/day became mildly agitated during drug infusion. Six patients were treated at 24 g/m2/day without neurotoxicity. Transient renal insufficiency was seen in the two patients with severe neurotoxicity and in three other patients. Dose-related, mild to moderate nausea and vomiting were observed in ten patients. Four patients developed cutaneous herpes infections during treatment. White blood cell depression was not dose related, and at 24 g/m2/day, the median white blood cell nadir was 4,500/microliter (range, 2,000 to 7,900/microliter). Thrombocytopenia was dose related. At 24 g/m2/day, the median platelet count nadir was 207,000/microliter (range, 66,000 to 542,000/microliter). No objective tumor regressions were noted. HMBA pharmacokinetics was studied at all dosages. Plasma and urine samples from 20 patients were analyzed by gas-liquid chromatography for parent compound. HMBA plasma steady-state concentrations (Css) were achieved in all patients by 12 to 24 h into infusion. Once Css was achieved, daily variation was generally less than or equal to 10% from the mean Css. HMBA plasma Css increased linearly with dose, but there was variation in the Css achieved in individual patients at each dose. Doses of 24 to 33.6 g/m2/day consistently produced plasma HMBA Css of 1 to 2 mM matching concentrations required for differentiation in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)

Prospective validation of a pharmacologically based dosing scheme for the cis-diamminedichloroplatinum(II) analogue diamminecyclobutanedicarboxylatoplatinum.

We previously correlated both renal function and thrombocytopenia, the dose limiting toxicity of carboplatin, with the plasma pharmacokinetics of carboplatin. From these correlations, we developed equations to calculate carboplatin dosage for any patient based on that patient's creatinine clearance, body surface area, pretreatment platelet count, desired platelet nadir, and status of prior chemotherapy. We prospectively applied these equations in 44 courses of carboplatin given to 24 patients. There were 13 males and 11 females with median age 53 (range, 33-77), median Karnofsky performance status 80 (range, 50-100), and creatinine clearance 32 to 118 ml/min. Ten patients had creatinine clearances less than 60 ml/min. Precision of the equations used for dose calculation was evaluable in 38 courses administered to 23 patients. In 23 courses of carboplatin administered to 12 patients without extensive prior chemotherapy, the observed change in platelets = 1.04 X predicted change -48,000 (r = 0.96). In the 15 courses of carboplatin administered to 11 heavily pretreated patients, the observed change in platelets = 1.13 X predicted change +6,600 (r = 0.97). For the overall combined population, the observed change in platelets = 0.96 X predicted change -7,000 (r = 0.94). These relationships which nearly define the line of identity (observed = expected) validate our initial observations. Only 2 patients developed WBC less than 2,000, but 12 patients developed hematocrit less than or equal to 29% and 8 required RBC transfusions. Fifteen patients had nausea and vomiting greater than or equal to grade 2. There were no other nonhematological toxicities observed. In view of continuing documentation of the antitumor activity of carboplatin, these equations allow safe and rational drug dosing of patients with potentially platinum-responsive tumors but with renal function too poor to receive cisplatin. Among the 9 patients in this study evaluable for response, there was 1 partial response in a patient with malignant melanoma and 1 objective response (less than partial response) in a patient with adenocarcinoma of the cervix.

Pharmacokinetics and dosage reduction of cis-diammine(1,1-cyclobutanedicarboxylato)platinum in patients with impaired renal function.

cis-Diammine(1,1-cyclobutanedicarboxylato)platinum (CBDCA) is a nonnephrotoxic but myelosuppressive analogue of cisplatin (DDP) with greatly reduced protein binding and greatly increased renal excretion. Thus, CBDCA might produce undue toxicity in patients with decreased renal function. Twenty-two patients [14 females and 8 males; median age, 66 (range, 35 to 83); median Karnofsky performance status, 70 (range, 40 to 90)] with refractory tumors and renal dysfunction [creatinine clearance (CCr) 6 to 83 ml/min] were treated with 31 courses of i.v. bolus CBDCA every 4 to 5 weeks. Dosages were determined by pretreatment CCr. Patients with CCr greater than or equal to 40 ml/min received 400 mg/sq m; patients with CCr 20 to 39 ml/min received 250 mg/sq m; and patients with CCr 0 to 19 ml/min received 150 mg/sq m. Toxicities were assessed by weekly clinical and laboratory assessment. Responses were assessed in patients with measurable disease. Plasma pharmacokinetics and urinary excretion of total and ultrafilterable platinum were measured with flameless atomic absorption spectrometry. Observed toxicities were similar to those in patients with normal renal function. Myelosuppression, especially thrombocytopenia, was the major toxicity. Nausea and vomiting were mild to moderate. There was no ototoxicity, neurotoxicity, or nephrotoxicity or reduction in CCr due to CBDCA. Total body clearance of ultrafilterable platinum correlated highly with CCr. The percentage of reduction in platelet count correlated highly and linearly with the area under the curve (AUC) of plasma-ultrafilterable platinum. However, for any AUC, there was 17% greater platelet reduction in patients who had previously received extensive myelosuppressive chemotherapy than in nonpretreated patients. Since total body clearance is proportional to CCr, platelet reduction is proportional to AUC, and total body clearance = dosage/AUC, we have derived an equation to calculate a dosage that will produce a desired reduction in platelet count. Calculations for theoretical patients (both pretreated and nonpretreated) with CCr of 100 ml/min produce dosages very close to maximum tolerated dosages derived in actual Phase I trials. The actual clinical utility of these predictive equations must await validation in prospective studies with larger numbers of patients.

Human pharmacokinetics, excretion, and metabolism of the anthracycline antibiotic menogaril (7-OMEN, NSC 269148) and their correlation with clinical toxicities.

In a Phase I study, menogaril (7-OMEN) was administered daily for 5 days/course, every 21-28 days. Dosages of 3.5, 7, 11.5, 17, and 31.5 mg/m2 were infused over 1 h, and dosages of 42, 50, and 56 mg/m2 were infused over 2 h. Pharmacokinetics was studied at all dosages. Plasma and urine samples were collected from 24 patients, and bile samples were also collected from 2 patients. 7-OMEN and metabolites were measured by high performance liquid chromatography. 7-OMEN was the major plasma fluorescent species at all times, with only trace amounts of N-demethyl menogaril observed. 7-OMEN disappeared from plasma biexponentially with t1/2 alpha 0.19 +/- 0.04 (mean +/- SE) h and t1/2 beta 13.22 +/- 1.54 h. Plasma pharmacokinetics of 7-OMEN was linear from 3.5-56 mg/m2; area under the curve increased proportionally with dosage. Total body clearance of 7-OMEN was 28.18 +/- 3.33 liter/m2/h, Vc was 224 +/- 30.8 liter/m2, and Vss was 370 +/- 25.7 liter/m2. Plasma pharmacokinetics of 7-OMEN studied on multiple days of a given course were similar. Urinary excretion of 7-OMEN and fluorescent metabolites accounted for 5.4 +/- 0.4% of the daily dose. Parent compound still represented greater than or equal to 80% of urinary drug fluorescence after 24 h. N-demethyl menogaril was the only other fluorescent drug species detected in urine. In two patients with biliary tract drains, biliary excretion of drug fluorescence accounted for 2.2-4.2% of the daily dose. Only 7-OMEN and N-demethyl menogaril were detected in bile by high performance liquid chromatography and thin layer chromatography. 7-OMEN was the major fluorescent biliary species, but, by 24 h, N-demethyl menogaril accounted for approximately 40% of biliary drug fluorescence. When considered in light of each patient's observed toxicities, excellent relationships were observed between the plasma area under the curve of 7-OMEN and the percentage of decreases in WBC and absolute neutrophil count. These latter findings should be useful in developing more precise and intelligent dosing schemes for 7-OMEN.

Ovarian expression of insulin-like growth factor-I (IGF-I), IGF binding proteins, and growth hormone (GH) receptor in heifers actively immunized against GH-releasing factors.

Active immunization against GRF at 6 months of age delays puberty in beef heifers. The objectives of the present study were to determine whether active immunization against GRF at an earlier age would affect normal onset of puberty and follicular growth and to determine whether these changes were related to alterations in ovarian insulin-like growth factor I (IGF-I) or IGF binding protein (IG-FBP) messenger RNA (mRNA) levels. Heifers were immunized against human serum albumin (HSAi; n = 15) or against GRF conjugated to HSA (GRFi; n = 18) at 3 months of age. A third group of heifers was not immunized (CON; n = 16). Immunization against GRF delayed puberty beyond 13 months of age in 75% of treated heifers. Unilateral ovariectomy at 191 days of age revealed that the delay in puberty was associated with a reduction in the number of large ( > or = 7 mm in diameter) follicles. Large follicles were present in only 22% of GRFi heifers compared to 77% of HSAi heifers. The number of small ( < or = 3 mm in diameter) and medium (4 to 6 mm in diameter) follicles was not affected by GRFi. The percentage of 1- to 3-mm follicles that were atretic was not different between HSAi (65%) and GRFi (62%) heifers. Unilateral ovariectomy had no effect on age at puberty. Immunization against GRF decreased (P < 0.01) concentrations of IGF-I in serum (23 +/- 2 ng/ml) compared to HSAi heifers (109 +/- 11 ng/ml). IGF-I levels in follicular fluid (FFL) of medium and small follicles were also decreased by GRFi from 82 +/- 3 ng/ml in HSAi heifers to 48 +/- 6 ng/ml (P < 0.01). Levels of IGFBP-3 (determined by ligand blot analysis) in serum and FFL of small follicles were decreased by GRFi (P < 0.01). In contrast, IGFBP-2 serum levels were increased from 422 +/- 32 ng/ml in HSAi heifers to 657 +/- 6 ng/ml in GRFi heifers (P < 0.05). Likewise, IGFBP-2 levels in FFL from small and medium follicles were increased from 785 +/- 44 ng/ml to 926 +/- 44 ng/ml (P < 0.05). Ligand blot analysis indicated that IGFBP levels were lower in FFL from large vs. small follicles. The band intensities of IGFBP-4 and -5 were drastically reduced ( > 80%) while the decreases in IGFBP-2 and -3 were less marked ( < 50%). The decreased levels of IGFBP-5 in FFL from large follicles was not associated with an increase in proteolytic fragments detectable by immunoblot analysis. While mRNA transcripts for IGF-I, GH receptor, and IGFBP-2, -3, -4, and -5 were readily detectable in ovarian tissue, GRFi had no effect on ovarian levels of mRNA for each of these proteins. This suggests that the decrease in follicular development associated with GRFi may be related to changes in circulating IGF-I and/or IGFBPs.

Diaziquone, 2,5-diaziridinyl-3,6-biscarboethoxyamino-1,4-benzoquinone, plasma and cerebrospinal fluid kinetics.

Plasma and cerebrospinal fluid (CSF) kinetics of diaziquone, 2,5-diaziridinyl-3,6-biscarboethoxyamino-1,4-benzoquinone (AZQ), were evaluated after intravenous injection in patients with implanted Ommaya reservoirs. After a 30-min infusion plasma disappearance was very rapid, with a disposition half-life of 2 to 6 min and on elimination half-life of 25 to 35 min. Area under the concentration-time curve for CSF was 22% to 42% of the corresponding plasma area. Based upon total plasma AZQ concentration, volume of distribution for AZQ was 2.0 to 10.0 l/m2. Plasma binding of AZQ was 79% in one normal subject. When the effect of plasma binding is considered, distribution volumes are more plausible and it appears that free plasma AZQ is completely available to the CSF.

Carcinomatous leptomeningitis in small cell lung cancer: a clinicopathologic review of the National Cancer Institute experience.

CLM developed in 60 of 526 patients (11%) with SCLC seen at the NCI between August 1969 and June 1980. Life table analysis revealed an overall 25% risk of CLM at 3 years. CLM was diagnosed during all phases of the patients' clinical course, but the majority (83%) were cases diagnosed at the time of progressive systemic disease. Univariate log rank analysis indicated that pretreatment factors associated with the development of CLM included: involvement of the brain, spinal cord, bone marrow, liver or bone; extensive disease; and male sex. Patients who did not obtain a complete response to systemic therapy were at greater risk of developing CLM than complete responders. Multivariate analysis of these factors indicated that liver metastases were most strongly associated with the time to development of CLM, followed in order of importance by bone and CNS metastases. Patients usually presented with signs and symptoms reflecting involvement of multiple areas of the neuraxis including the cerebrum, cranial nerves and spinal cord; 51 of the 60 patients had intracerebral metastases and 27 had spinal cord lesions during their clinical course. Autopsy features including focal or diffuse involvement of the leptomeninges with infiltration of the Virchow-Robin spaces were similar to meningeal lymphoma and leukemia, except that CLM was rarely the sole manifestation of CNS tumor. Median survival following the diagnosis of CLM was 7 weeks. However, most deaths were attributed to systemic disease, and treatment with intrathecal chemotherapy and irradiation often provided palliation. With the increased awareness of this complication, an antemortem diagnosis increased from 39% prior to 1977, to 88% of patients after 1977.

Doxorubicin, cyclophosphamide, etoposide and platinum, doxorubicin, cyclophosphamide and etoposide for small-cell carcinoma of the lung.

Small-cell lung cancer (SCLC) is a disseminated disease regardless of our ability to document all sites. Chemotherapy is thus the cornerstone of treatment. There are multiple active single agents, resulting in many combination chemotherapy regimens. Optimal combinations are probably derived from the use of synergistic drug interactions. A three drug combination of doxorubicin (Adriamycin), cyclophosphamide, and etoposide (ACE) has been used at the University of Maryland Cancer Center (UMCC) for more than a decade in sequential studies. Two hundred four patients, 143 men and 61 women, were treated on these studies. Eighty-five had limited disease (LD) and 119 had extensive disease (ED). The complete response (CR) frequencies were 65% and 43% for LD and ED, respectively, and the median survivals were 15 and 9.5 months, respectively. Twenty-two percent of the LD patients were alive at 2 years. To improve upon response or survival, and because of synergy, cisplatin was added to ACE (PACE). PACE chemotherapy was administered in two studies--study 1 at UMCC for both LD and ED, and study 2 by Cancer and Acute Leukemia Group B (CALGB) for ED only. Preliminary review suggests that CR frequencies for LD (53%, study 1) and ED (44%, study 1; 37%, study 2) were similar to prior studies, but median survivals (LD, 18+ months, study 1; ED, 15 months, study 1, 10.5 months, study 2) appears superior to previous studies. However, PACE is more toxic than ACE. Further studies of PACE are needed to assess if the additional toxicities are warranted.

Comparison of Oculab Tono-Pen readings obtained from various corneal and scleral locations.

When estimating intraocular pressure in patients who are uncooperative or who have central corneal disturbances, the physician may find it either impractical or undesirable to place the small tip of a portable electronic applanation tonometer (Tono-Pen) over the central cornea. To gauge better the usefulness of Tono-Pen readings obtained from various locations, we compared such readings measured through the central cornea, midperipheral cornea, limbal cornea, and sclera of 15 cannulated eye bank eyes. Mean Tono-Pen readings from the midperipheral and clear limbal cornea did not differ significantly from central corneal readings over a 10- to 35-mm Hg range of intraocular pressures and were within +/- 2.4 mm Hg of mean central corneal readings. Mean readings taken from the sclera, however, were 8.8 to 17.0 mm Hg higher than mean central corneal readings over the 10- to 40-mm Hg range. We concluded that multiple noncentral corneal readings with the Tono-Pen provided a useful approximation of intraocular pressure, whereas scleral readings did not.

Sources of error with use of Goldmann-type tonometers.

There are many sources of error in the use of Goldmann-type applanation tonometers. In clinically normal corneas hypofluorescence of the precorneal tear film, accommodation, the Valsalva maneuver and vertical gaze are preventable causes of large tonometric errors. Repeated tonometry may induce a decline in the intraocular pressure (IOP). Variations in the corneal resistance to indentation between eyes cause significant errors. The most significant cause of error in clinically abnormal eyes is corneal epithelial edema, which causes a marked underestimation of IOP. Measurements obtained with Goldmann-type tonometers can be used with confidence to monitor changes in the IOP of an individual, but should not be relied on to determine the absolute manometric pressure within an eye or to compare the IOPs in eyes of different individuals.

Outpatient sedation for ocular examination.

Outpatient sedation of infants, uncooperative children and, rarely, adults provides an opportunity to perform certain ophthalmologic diagnostic procedures such as tonometry, ophthalmoscopy and various electrophysiological studies (e.g., electroretinography and visual evoked response testing) without the expense and usage of an operating room. Many drugs have been recommended and used; all have limitations. The advantages and disadvantages of the more commonly used agents are reviewed. The known effects of these drugs on ocular function are presented.

A phase I trial of continuous infusion VP16-213 (etoposide).

Since there appears to be a schedule dose relationship for VP16-213, the current dose seeking study of 5 day continuous infusion was initiated. Patients not candidates for other treatments were started at 75 mg/m2/day X 5. Eight patients had prior chemotherapy, eight had radiotherapy plus chemotherapy and one patient had prior interferon. The median age was 53 (range 23-65) and the median performance status was 60 (range 50-90). Seventeen patients received 20 courses; two at 75 mg/m2/day, seven at 100 mg/m2/day, ten at 125 mg/m2/day, and six at 150 mg/m2/day. The major toxicity was hematologic and median WBC count nadirs (ranges) were respectively: 3.5 (2.3-4.7) X 10(3)/microliters, 1.6 (0.2-3.4) X 10(3)/microliters, 2.4 (0.1-3.6) X 10(3)/microliters, 0.4 ( less than 0.1-0.7) 10(3)/microliters. Platelet count nadirs were respectively: 150, 78 (20-189), 138 (26-326), 16 (9-88) X 10(3)/microliters. The median days to WBC nadir and recovery and did not vary with dose and were 15 (9-21) and 24 (19-38) respectively. Median days to platelet count nadir were 12 (10-29) the recovery 24 (20-38) and did not vary with dose. Non-hematologic toxicities included mild nausea and vomiting, mild mucositis on six courses, diarrhea with two courses and fever during granulocytopenia during seven courses. Three patients manifested evidence of myocardial diseases two with infarction and one with congestive failure during treatment. Two patients showed objective evidence of tumor regression, one patient with seminoma and one patient with renal cell carcinoma. The latter response was short. The current studies demonstrate that high dose continuous infusion VP16-213 is tolerable with acceptable toxicity using doses up to 125 mg/m2/day (625 mg/m2 over 5 days).

Doxorubicin, Cyclophosphamide and VP16-213 (ACE) in the treatment of small cell lung cancer.

Small cell lung cancer requires aggressive combination chemotherapy. The three active agents, doxorubicin (A) 45 mg/m2 i.v. day 1, cyclophosphamide (C) 1.0 mg/m2 i.v. day 1 and VP16-213 (E) 50 mg/m2/day i.v. days 1-5 were given together. The combination (ACE) was given every 21 days without chest irradiation. One hundred and seventy-four patients have been stratified for extent of disease and randomized on three sequential studies testing ACE vs ACE + MER immunotherapy (38 patients), or ACE vs ACE alternating with CCNU, methotrexate, vincristine and procarbazine (109 patients), or ACE vs ACE II (ACE with continuous VP16-213 - 100 mg/m2/day X 5 days - 27 patients - ongoing). The immunotherapy and the alternating non-cross resistant combination have not proven beneficial with respect to response or survival. The ACE combination, regardless of additional treatments, has produced greater than 90% response overall. In limited disease the complete response (CR) frequency is 65%. The median survival for limited disease overall is 14 months and 18 months for patients achieving CR. In extensive disease the CR frequency is 40% with a median survival of 9 months overall and 13 months for patients achieving CR. Response frequency and survival are identical in the first two studies and 20-30% of patients with limited disease are long-term survivors with one late relapse (greater than 3 years). Patients who achieved CR had a significantly longer survival regardless of other factors such as performance status or extent of disease. Prophylactic cranial irradiation was demonstrated to be useful in prevention or delaying CNS metastases in patients who achieved CR. The third generation study of high-dose VP16-213 infusion seeks to increase the CR frequency. ACE chemotherapy without chest irradiation is a highly effective treatment for all patients with small cell lung cancer and compares favorably with all other studies with or without adjuvant radiotherapy.

Plasma kinetics of aclacinomycin A and its major metabolites in man.

The plasma pharmacokinetics of the antineoplastic anthracycline antibiotic aclacinomycin A (Acm) and its metabolites were studied in 12 patients treated with 60-120 mg/m2 during a phase I clinical trial. Total plasma drug fluorescence initially declined very rapidly, but from 2 to 24 h after injection, fluorescence rose progressively to intensities greater than those measured 1 min after Acm injection. Plasma total drug fluorescence slowly declined from 24 to 72 hours after Acm administration. These events reflected the rapid disappearance of Acm and the subsequent appearance of two highly fluorescent metabolites. One metabolite co-chromatographed with and had a fluorescence spectrum identical to known metabolite F1 (bisanhydroaklavinone). The other metabolite did not co-chromatograph with any previously described Acm metabolite. This metabolite had a fluorescence spectrum unlike any previously described Acm metabolite and was not altered by treatment for 60 min with 0.2 N HCl at 100 degrees C or by treatment for 24 h at 37 degrees C with bacterial beta-glucuronidase or limpet aryl sulfatase.

Renal failure and platinum pharmacokinetics in three patients treated with cis-diamminedichloroplatinum(II) and whole-body hyperthermia.

Three patients with advanced refractory malignancies were treated with whole-body hyperthermia (WBH: 42-42.3 degrees C) for 2 h during which time they also received an infusion of 60 or 80 mg/m2 of cis-diamminedichloroplatinum II (DDP). Each patient developed an elevated serum creatinine (2.7-13.6 mg/dl), with maximum creatinine occurring between days 7 and 12 after treatment. WBH did not alter plasma or urinary pharmacokinetics of total or ultrafilterable platinum compared with pharmacokinetic data of the same or other patients given DDP euthermically. Although the mechanism of the renal damage is unclear, it appears that WBH can potentiate the nephrotoxic actions of DDP and that further study of this combination is not warranted.

Phase I and pharmacokinetic trial of liposome-encapsulated doxorubicin.

A total of 21 patients with advanced cancer were entered into a phase I study to determine the maximum tolerable dose (MTD) of liposome-encapsulated doxorubicin (LED) given weekly for 3 consecutive weeks at doses of 20, 30, or 37.5 mg/m2 per week. For a comparison of the pharmacokinetic behavior of LED with that of standard-formulation doxorubicin, 13 patients received a dose of standard-formulation doxorubicin 2 weeks prior to the first dose of LED. All doses were given by 1-h infusion through a central vein. Toxicity was evaluated in 22 courses delivered to 17 patients. The MTD with this schedule was 30 mg/m2 per week x 3. The single patient treated at 37.5 mg/m2 weekly could not complete the entire course due to myelosuppression. At the dose of 30 mg/m2 per week, three of eight patients had grade > or = 3 leukopenia. Other toxicities included mild to moderate thrombocytopenia, nausea, vomiting, fever, alopecia, diarrhea, fatigue, stomatitis, and infection. At the dose of 30 mg/m2 per week, the total doxorubicin AUC and peak total doxorubicin concentrations in plasma were 8.75 +/- 8.80 microM h (mean +/- SD) and 3.07 +/- 1.45 microM, respectively, after LED administration. The total doxorubicin AUC and peak total doxorubicin concentrations in plasma were 3.92 +/- 2.47 microM h and 2.75 +/- 2.70 microM, respectively, after the infusion of standard-formulation doxorubicin. The total body clearance of doxorubicin was 18.42 +/- 11.23 l/h after the infusion of LED and 31.21 +/- 15.48 l/h after the infusion of standard-formulation doxorubicin. The mean elimination half-lives of doxorubicin were similar: 8.65 +/- 5.16 h for LED and 7.46 +/- 5.16 h for standard-formulation doxorubicin. Interpatient variability in pharmacokinetic parameters as demonstrated by the percentage of coefficients of variation was 33%-105%. There was no relationship between the percentage of WBC decrease or the duration of WBC suppression and the total doxorubicin or doxorubicinol AUC. There was no correlation between the duration of leukopenia and drug exposure as reflected by the AUC of liposome-associated doxorubicin. LED can be given in doses similar to those of standard-formulation doxorubicin and produces acute toxicities similar to those caused by standard doxorubicin.

Cisplatin, doxorubicin, cyclophosphamide, and etoposide combination chemotherapy for small-cell lung cancer.

Because of potential synergistic interactions, we added 25 mg/m2 i.v. cisplatin (P) 25 given on days 1-5 to the combination of 45 mg/m2 i.v. doxorubicin (A) given on day 1, 800 mg/m2 i.v. cyclophosphamide (C) given on day 1, and 50 mg/m2 i.v. etoposide (E) given on days 1-5. The resulting PACE regimen was given every 21 days for the first three courses and then every 28 days for the next five courses. PACE was used in two trials: the first, for both limited and extensive disease, was conducted at the University of Maryland Cancer Center and North Shore University Hospital; and the second, for extensive disease, was carried out as a Cancer and Leukemia Group B pilot study. Chest irradiation was not used. Prophylactic cranial irradiation at a dose of 3,000 cGy was given to all patients achieving a complete response (CR). A total of 33 subjects were entered in the first study; 8 of the 15 (53%) presenting with limited disease and 7 of the 18 (39%) exhibiting extensive disease achieved a CR. A partial response (PR) was obtained in 27% and 33% of cases, respectively. Of the 34 patients entered in the second study, 25 were eligible; 8 (32%) achieved a CR and 6 (24%) showed a PR. Toxicity was severe in both studies, including greater than 90% severe or life-threatening leukopenia and thrombocytopenia. Serial creatinine-clearance evaluations in the first study indicated progressive deterioration, which required discontinuation of the cisplatin before the planned completion of treatment in most cases. Since the response rate was no higher than the historic data reported for the three-drug ACE combination and because the toxicity was severe, the studies were stopped and patients were followed for survival. After a follow-up period of greater than 6 years, the median survival was 24 months for limited disease, with 33% and 27% of the patients being alive at 3 and 6.5 years, respectively. The median survival for extensive disease was 15 and 11 months in the first and second studies, respectively. These pilot studies suggest that the addition of cisplatin may augment the activity of the ACE regimen, but at the cost of severe toxicity. Further studies seem warranted if the myelotoxicity can be better controlled.

Clinical applications of auto indirect ophthalmoscopy.

A phakic eye that has undergone vitrectomy and gas-fluid exchange produces a real, inverted aerial image anterior to the cornea similar to that produced by a lens for indirect ophthalmoscopy. This image can be used during surgery to perform a variety of maneuvers that would otherwise require a contact prism, high-minus contact lens, or handheld indirect ophthalmoscope lens. Applications of auto indirect ophthalmoscopy include visualization of the retina and vitreous during endophotocoagulation and while using a vitreous cutter.

Noncontact retinal photocoagulation at the slit-lamp biomicroscope.

Four patients had either ocular conditions that made the use of a contact lens for retinal photocoagulation undesirable, or optical aberrations of the ocular media that made photocoagulation with a conventional contact lens difficult. A hand-held 90-diopter lens permitted retinal photocoagulation to be performed at a conventional slit-lamp biomicroscope laser without corneal contact and assisted in delivering laser burns under physical or optical circumstances that would be difficult or impossible with conventional contact lenses. Four patients without ocular surface or media abnormalities were also treated by this method.