Paul A. J. Speth

Cellular and plasma adriamycin concentrations in long-term infusion therapy of leukemia patients

SummaryTo determine whether long-term adriamycin (ADM) infusions resulted in cellular ADM concentrations at least comparable to those observed after bolus injections, ADM cellular and plasma concentrations were measured in 18 patients with leukemia. ADM was administered at 30 mg/m2 per day for 3 days, either as bolus injections or as 4-, 8-, or 72-h infusions. Negligible accumulation of plasma ADM was observed. Peak plasma ADM concentrations after bolus injections were 1640±470 ng/ml (n=7). Maximum levels were 176±34 ng/ml during 4-h infusion (n=5); 85±50 ng/ml during 8-h infusion (n=4); and 47±5 ng/ml (n=2) after 72-h infusion. ADM concentrations in nucleated blood and bone marrow cells correlated well (r=0.82, n=47). ADM accumulated in leukemic cells up to 30–100 times the plasma concentrations. The shorter the administration time-span, the higher the peak leukemic cell concentration and the greater the loss of drug immediately after the end of the administration. The final cellular ADM half-life was approximately 85–110 h. After long-term infusion and bolus injection of the same dose, similar areas under the curve for plasma or leukemic blast cell ADM concentrations were attained. Since comparable therapeutic efficacy was observed in all regimens, the antileukemic effect appeared not to be related to the peak plasma concentrations, while acute toxicity phenomena decreased with increasing duration of the infusion. Long-term ADM infusion deserves more attention in the treatment of patients with anthracyclines.

Propylene glycol pharmacokinetics and effects after intravenous infusion in humans.

Knowledge of the pharmacokinetics of propylene glycol (PG) is scarce, though it is used in a number of preparations for intravenous use. Although systemic toxicity appears to be uncommon, PG has been reported to cause lactic acidosis and other adverse effects. We describe a rapid gas chromatographic assay method for PG and the plasma pharmacokinetics after intravenous administration to six patients on nine occasions. The pharmacokinetics were nonlinear, based on a saturable clearance. The apparent first-order half-life was 2.3 ± 0.7 h. There was no evidence of lactic acidosis, hemolysis, or increase in osmolality at 3–15 g/m2 PG infused over periods of 4 h.

Plasma and cellular adriamycin concentrations in patients with myeloma treated with ninety-six-hour continuous infusion.

Adriamycin (ADM) concentrations in neoplastic plasma cells, nucleated blood cells, bone marrow cells, and plasma were measured in seven patients with advanced multiple myeloma. ADM was administered as a 96‐hour infusion of 9 mg/m2/24 hr. Maximum plasma ADM concentrations were 15.8 ± 4.4 ng/ml. ADM concentrations in nucleated blood cells, bone marrow cells, and plasma cells increased continuously throughout the 96‐hour infusion. Maximum cellular levels were up to 200‐fold higher than the maximum plasma concentration and were similar to levels observed shortly after administration of the total dose in one rapid injection. The cellular AUC for 96‐hour infusion and bolus injection were comparable. Thus continuous infusion is the equivalent of bolus injection in delivering ADM to the target cells in bone marrow, although plasma ADM concentrations remained very low. These results provide support for administering ADM as a continuous infusion with less toxicity and better patient tolerance.

Selective incorporation of iododeoxyuridine into DNA of hepatic metastases versus normal human liver

Fourteen patients received 5‐iodo‐21‐deoxyuridine (IdUrd) before surgery for placement of a hepatic arterial catheter. Biopsy specimens were obtained at the time of surgery and incorporation of IdUrd into deoxyribonucleic acid (DNA) in tumor and normal hepatic tissue was measured by HPLC and used as an index of drug selectivity. Over a 3‐day intravenous infusion of IdUrd at 1000 mg/m2/day, substitution for thymidine in tumor DNA averaged 3.1%. Normal hepatic DNA contained < 1% substitution by IdUrd. Arterial delivery of IdUrd increased levels in DNA, whereas modulation with fluorodeoxyuridine produced mixed results. In six patients, flow cytometric analysis showed that the tumor contained a median of 32% of tumor cells that had incorporated IdUrd in 3 days, corresponding to a potential doubling time of only 10 days. Thymidylate synthetase activity in tumors was 20‐fold greater than in normal liver tissue, whereas thymidine kinase activity was twofold greater in tumors. These pharmacologie studies encourage further clinical trials of IdUrd as a cytotoxic agent or radiosensitizer.

Leukemic cell and plasma daunomycin concentrations after bolus injection and 72 h infusion

SummaryThe effect of the duration of daunomycin (DNM) infusion on leukemic cell drug concentrations was evaluated. Cellular and plasma DNM concentrations were measured in 20 patients with acute non-lymphocytic leukemia. DNM 45 mg/m2 was administered either as a bolus injection or as a 4-, 8- or 72-h constant-rate infusion during 3 consecutive days. Peak plasma DNM levels amounted to 227±116 ng/ml after bolus injection and were only 16±6 ng/ml after 72-h DNM infusions. Terminal plasma DNM half-lives were 14±4 h. Peak leukemic cell DNM concentrations at the 3rd day of administration were 16810±2580 ng/109 cells (bolus injections) and 10310±5510 ng/109 cells (72-h infusions). The areas under the cellular curve were similar and independent of the duration of the DNM infusion. Peak leukemic cell daunomycinol (DNMol) concentrations were respectively 3500 ± 1600 ng/109 cells and 2850±1720 ng/109 cells. Cellular DNM terminal half-life was 13±4 h. DNM concentrations in nucleated blood and bone marrow cells correlated well (r=0.93, n=26). Long-term infusion produced less severe side effects. Therapeutic efficacy was maintained during long-term infusion.

Plasma and human leukemic cell pharmacokinetics of oral and intravenous 4‐demethoxydaunomycin

On 3 consecutive days, 4‐demethoxydaunomycin (D‐DNM) was administered orally (30 mg/m2) as bolus injection and 4‐ or 24‐hour infusion to seven patients with acute leukemia. Cellular (nucleated blood and bone marrow cells) and plasma drug concentrations were studied. After bolus injection, peak plasma D‐DNM concentrations were about 50 mg/ml. D‐DNM plasma t½s were 0.4 ± 0.3 hours (T½α) and 16.4 ± 4.7 hours (T½β). D‐DNM concentrations in nucleated blood and bone marrow cells were on the same order of magnitude and amounted to more than 400 times the plasma concentration, whereas 4‐demethoxydaunomycinol (D‐DNMol) concentrations were about 200 times higher. Cellular D‐DNM concentrations were maximal at the end of intravenous dosing and at 2 to 4 hours after D‐DNM ingestion. D‐DNMol concentrations increased more slowly and accumulated on subsequent treatment days in cells and plasma; D‐DNM and D‐DNMol cellular t½ times were 42 and 72 hours, respectively. Antileukemic activity was observed.

Iododeoxyuridine (IdUrd) incorporation into DNA of human hematopoietic cells, normal liver and hepatic metastases in man: As a radiosensitizer and as a marker for cell kinetic studies

Iododeoxyuridine (IdUrd) was administered as a continuous infusion for 14 days to patients with glioblastoma and sarcoma, and for 3 days to patients with metastatic colorectal carcinoma. In the first group, the maximum incorporation of IdUrd into DNA was determined, taking granulocytes as parameter. In the second group, selective incorporation into DNA of normal liver and hepatic metastases of colorectal cancer was investigated. The highest dose of 675 mg/sq.m./day for 14 days produced IdUrd plasma concentrations of 1.8 +/- 0.3 microM, and a substitution of dThd by IdUrd in the range of 7.1-11.7%. Coadministration of fluorodeoxyuridine did not show significant enhancement of IdUrd-incorporation in granulocytes. Three-day intravenous infusions of IdUrd 1000 mg/sq.m./day produced 1.7-4.5% IdUrd-incorporation in hepatic metastases. Three-day intraarterial infusions (hepatic artery) produced 3.8-10.5% dThd-replacement, whereas, in 9/10 patients this was less than 1% in normal liver. In tumor tissue there was a trend towards FdUrd-modulated enhancement of IdUrd-incorporation, although there was considerable scatter. Cell kinetic studies revealed that IdUrd-incorporation in monocytes and granulocytes was very similar. In lymphocytes, a much lower fraction incorporated IdUrd. Liver tumor contained a considerably higher fraction of IdUrd-labeled cells, compared with normal liver. Potential doubling times for the tumors were estimated to be 10 days.

In vivo cellular adriamycin concentrations related to growth inhibition of normal and leukemic human bone marrow cells.

Inhibition of clonogenicity of normal and leukemic human hematopoietic progenitor cells was studied after in vivo and in vitro exposure of bone marrow to adriamycin (ADM). Flow cytometric determination of cellular ADM concentrations in blast cells, expressed in fluorescence units/cell (FU/cell), correlated well with the extent of cytotoxicity. After 2 h in vitro exposure to 500 ng ADM/ml, the ADM concentration of leukemic (n = 7) and normal (n = 4) bone marrow blast cells amounted to 231 +/- 180 and 249 +/- 53 FU/cell respectively, producing moderate decreases in clonogenicity by 44 +/- 30 and 54 +/- 27%. Exposure to 2000 ng/ml produced ADM concentrations of 1184 +/- 472 FU/cell for leukemic blast cells and 1024 +/- 281 FU/cell for normal blast cells. Inhibition of clonogenicity was 96 +/- 7% in leukemic blasts and 99 +/- 1% in normal blasts. In vivo ADM concentrations in leukemic blast cells at 1-2 h after administration were 216 +/- 98 FU/cell (n = 8 patients). This implies that inhibition of clonogenicity after administration of conventional dosages of ADM will be approx. 60-70% for both leukemic and normal bone marrow progenitor cells. Such values were noted in four patients of whom bone marrow was cultured, which was obtained shortly after ADM monotherapy.

Cellular and plasma pharmacokinetics of weekly 20-mg 4′-epi-adriamycin bolus injection in patients with advanced breast carcinoma

SummaryWeekly low-dose injections of 20 mg 4′-epiadriamycin (E-ADM) were given to 12 patients with advanced postmenopausal breast cancer for at least 8 weeks. In advance, all patients were given hormonal therapy and polychemotherapy not containing anthracyclines. E-ADM concentrations in plasma and urine and in blood and bone marrow cells were determined during 8 consecutive weeks. Plasma concentrations in the range of a few nanograms per milliliter were seen up to 72–96 h. Cellular concentrations, and were 190±66 ng/109 cells on day 8, before the next injection was given. Nevertheless, no serious bone marrow toxicity was observed. In two patients with an increased plasma bilirubin concentration, cellular E-ADM concentrations were 20%–40% higher than those observed in the other patients. Plasma concentrations of E-ADM and 4′-epi-adriamycinol showed terminal half-lives 2–3 times longer and could be followed throughout the week. In three patients biopsies of skin metastases were examined. In two patients E-ADM could be demonstrated in the tumor tissue up to 7 days after the last injection. Although the number of patients investigated is too small to relate the drug kinetics to clinical response, it is of interest that the two patients with the highest cellular E-ADM concentrations responded better than the others.

Determination of amsacrine in human nucleated hematopoietic cells

A new method has been developed for the determination of amsacrine (AMSA) in human nucleated hematopoietic cells. In order to prevent efflux during the cell separation procedure, white blood cells (WBCs) were separated from red blood cells by dextran sedimentation, leaving the WBCs in their natural environment. After cell counting, pelletting the cell suspension and correcting for the admixture of supernatant, AMSA was extracted from the WBCs and determined by high-performance liquid chromatography. Linearity of extraction was observed up to 40.10(6) cells. The inter-assay variation was 4.7%. Plasma and cellular concentrations were measured in five patients at the end of a 3-h infusion of 100 mg/m2 AMSA. A pharmacokinetic study of plasma and cellular AMSA concentrations up to 19 h after infusion was carried out. AMSA concentrations in WBCs correlated well with the plasma levels (n = 20, r = 0.967) with an accumulation factor compared to the plasma concentration of 2.6-9.8 in the patients studied. The method described is useful for studying cellular pharmacokinetics of AMSA in man.