A phase II study of active specific immunotherapy and 5-FU/Leucovorin as adjuvant therapy for stage III colon carcinoma.

Active specific immunotherapy, using vaccines with autologous tumour cells and BCG, significantly reduces the rate of tumour recurrence in stage II colon cancer patients, while no clinical benefit has yet been observed in stage III patients. Adjuvant treatment with 5-Fluorouracil/Leucovorin is now considered standard therapy for stage III colon carcinoma and results in an absolute survival benefit of approximately 10%. Yet, the 5-year overall survival rate of stage III colon cancer patients is only 40-50%. Combining chemotherapy and immunotherapy might improve prognosis for stage III patients, especially when considering that active specific immunotherapy and chemotherapy have shown synergistic effects in pre-clinical tumour models. We performed a phase II study with 56 patients, using the combination of active specific immunotherapy and chemotherapy as an adjuvant therapy in stage III colon cancer patients to assess the influence of 5-Fluorouracil/Leucovorin on anti-tumour immunity induced by autologous tumour cell vaccinations. Anti-tumour immunity was measured before and after chemotherapy by means of delayed type hypersensitivity reactions, taken 48 h after the third and the fourth vaccination. We also investigated the toxicity of this combined immuno-chemotherapy treatment. Delayed type hypersensitivity reactions before chemotherapy had a median size of 20.3 mm, while after chemotherapy delayed type hypersensitivity size was 18.4 mm (P=0.01), indicating that chemotherapy hardly affected anti-tumour immunity. The severity of ulcers at the BCG vaccination sites was comparable to previous studies. In 30% of the patients grade III or grade IV chemotherapy related toxicity was seen; this is comparable to what is normally observed after adjuvant chemotherapy alone. This study shows that the active specific immunotherapy-induced anti-tumour immune response is only minimally impaired by consecutive chemotherapy and that the combined treatment of stage III colon cancer patients with active specific immunotherapy and 5-Fluorouracil/Leucovorin does not cause unexpected toxicity.

Skin tests predict survival after autologous tumor cell vaccination in metastatic melanoma: experience in 81 patients.

BACKGROUND: Currently there is no standard adjuvant treatment following surgical resection of metastatic melanoma. We investigated whether surgery followed by autologous tumor cell-BCG vaccination was beneficial for malignant melanoma patients. In this study we focus on the prognostic value of DTH response following vaccination therapy. PATIENTS AND METHODS: Eighty-one patients with AJCC stage III and IV melanoma were selected. Whenever feasible, radical metastasectomy was performed. ASI was initiated by the administration of three weekly intra-cutaneous vaccinations with 10(7) irradiated autologous tumor cells, starting four weeks after surgery. Depending on the size of DTH response to the first three injections, subsequent vaccinations were planned. The first two vaccines also contained 10(7) BCG organisms as an immune stimulatory adjuvant. RESULTS: Induration as well as erythema correlated strongly with survival (P < 0.0001 and P = 0.0004). After radical metastasectomy in stage III melanoma patients a five-year survival of 48% was observed. In stage IV disease, a five-year survival of 34% was seen, after radical surgery had been performed. When macroscopic disease was present at start of vaccination treatment, no clinical responses occurred. Apart from transient skin ulceration at the site of BCG-containing vaccinations, no serious side effects were observed. CONCLUSIONS: This study shows that large-scale preparation of autologous melanoma cell vaccines is feasible. while vaccination results in DTH responses that correlate significantly with survival. ASI seemed to be beneficial in stage III and stage IV melanoma when given in the adjuvant setting, while causing only very mild side effects.

Pharmacokinetics and pharmacodynamics of lobaplatin (D-19466) in patients with advanced solid tumors, including patients with impaired renal of liver function.

The purpose of this study was to determine the influence of impaired renal and liver function on the pharmacokinetics and pharmacodynamics of lobaplatin in cancer patients. A total of 25 patients with advanced solid tumors not amenable for standard treatment entered the study. Patients had normal organ function or an impaired liver or renal function (two levels). The starting dose of lobaplatin was 50 mg/m2 i.v. given every 3 weeks. The blood and urine of all patients were sampled for the determination of (ultrafilterable) platinum, intact lobaplatin, creatinine, and blood cell counts. No objective responses were recorded. Five patients experienced no change and received 4-10 cycles (median, 6 cycles) of lobaplatin. The extent and duration of hematological toxicity were worse in patients with impaired renal function. Thrombocytopenia was most prominent; grade 4 toxicity was observed in 15 patients in the first two cycles of treatment. The concentration-time curves of ultrafilterable platinum and intact lobaplatin revealed almost identical patterns. The elimination of ultrafilterable platinum [final half-life (t1/2 final) = 131+/-15 min; clearance (Cl) = 125+/-14 ml/min/1.73 m2] was much faster than that of total platinum (t1/2 final = 6.8+/-4.3 days, CI = 34+/-11 ml/min/1.73 m2). No pharmacokinetic differences were observed between patients with normal organ function and those with an impaired liver function within the investigated range. An impaired renal function resulted in an increase of the t1/2 final due to a decrease of the total body Cl that resulted in a higher exposure of the body to the drug. The calculated creatinine Cl was linearly correlated with the total body clearance of ultrafilterable platinum (r = 0.91), which resulted in the dosage formula D = AUCinfinity (1.1 Cl(CrU) + 16), in which D represents dose, AUC represents area concentration-time curve, and Cl(CrU) represents creatinine Cl. The thrombocyte surviving fraction correlated well with the AUC value of ultrafilterable platinum (r = 0.72). It can be concluded that the hematological toxicity and the pharmacokinetics of lobaplatin are strongly affected by renal function. The total body Cl of ultrafilterable platinum correlated well with the creatinine Cl and the thrombocyte surviving fraction. In patients with renal function, represented by a creatinine clearance > or =30 ml/min/1.73 m2, the derived dosage formula will enable us to calculate the dose that is expected to lead to an acceptable extent of thrombocytopenia in a patient with a given renal function. Prospective studies with larger groups of patients are needed to prove the value of this dosage formula.

Active specific immunotherapy for stage II and stage III human colon cancer: a randomised trial.

BACKGROUND: Colon cancer is curable by surgery, but cure rate depends on the extent of disease. We investigated whether adjuvant active specific immunotherapy (ASI) with an autologous tumour cell-BCG vaccine with surgical resection was more beneficial than resection alone in stage II and III colon cancer. METHODS: In a prospective randomised trial, 254 patients with colon cancer were randomly assigned postoperative ASI or no adjuvant treatment. ASI was three weekly vaccinations starting 4 weeks after surgery, with a booster vaccination at 6 months with 10(7) irradiated autologous tumour cells. The first vaccinations contained 10(7) BCG organisms. We followed up patients for time to recurrence, and recurrence-free and overall survival. Analysis was by intention to treat. FINDINGS: The 5.3 year median follow-up (range 8 months to 8 years 11 months) showed 44% (95% CI 7-66) risk reduction for recurrence in the recurrence-free period in all patients receiving ASI (p=0.023). Overall, there were 40 recurrences in the control group and 25 in the ASI group. Analysis by stage showed no significant benefit of ASI in stage III disease. The major impact of ASI was seen in patients with stage II disease, with a significantly longer recurrence-free period (p=0.011) and 61% (18-81) risk reduction for recurrences. Recurrence-free survival was significantly longer with ASI (42% risk reduction for recurrence or death [0-68], p=0.032) and there was a trend towards improved overall survival. INTERPRETATION: ASI gave significant clinical benefit in surgically resected patients with stage II colon cancer. ASI has minimal adverse reactions and should be considered in the management of stage II colon cancer.

Influence of amifostine on the pharmacokinetics of cisplatin in cancer patients.

The pharmacokinetics of cisplatin was investigated in 13 patients receiving 18 courses of cisplatin alone or in combination with amifostine to investigate the influence of amifostine (WR 2721; Ethyol) on the pharmacokinetics of cisplatin. Cisplatin was administered as a 1-h i.v. infusion, whereas amifostine was given i.v. over 15 min just before the cisplatin infusion. An increase in the final half-life of ultrafilterable platinum was observed after treatment with cisplatin and amifostine (t1/2, 0.77 +/- 0.10 h; n = 8), compared to cisplatin alone (t1/2, 0.57 +/- 0.15 h; n = 8). This might be caused by an influence of amifostine on the kidney function, because an increase in the serum creatinine levels was also observed 24 h after treatment with cisplatin and amifostine (13.8 +/- 12.6%; n = 9), which was not observed after treatment with cisplatin alone (-0.1 +/- 6.8%; n = 9). Surprisingly, the final half-life of unchanged cisplatin did not increase, but even showed a slight decrease after treatment with amifostine. In vitro data would suggest that this might be due to a chemical interaction between cisplatin and amifostine. Because the AUC values of ultrafilterable platinum and unchanged cisplatin did not change significantly and no change in Pt-DNA adduct (Pt-GG) levels in leukocytes was observed upon addition of amifostine in the treatment schedule, the change in the pharmacokinetics of cisplatin is most probably of minor importance and has no significant impact on the efficacy of cisplatin, as already confirmed by clinical studies.

Pharmacokinetics of amifostine and its metabolites in the plasma and ascites of a cancer patient.

The pharmacokinetics of amifostine, a protector against chemotherapy and radiation-induced toxicities, was investigated in the plasma and ascites of a cancer patient. A high-performance liquid chromatography (HPLC) procedure with electrochemical detection was used to measure amifostine, its active metabolite, WR 1065, and the disulfides (symmetrical plus mixed disulfides). Both amifostine and WR 1065 were rapidly cleared from the plasma (95% and 50% of the peak concentration within 1 h, respectively). The disulfides, which were rapidly formed from WR 1065, were cleared much more slowly (final half-life 13.6 h). Multiple dosing resulted in a tendency toward increasing peak levels of WR 1065 and decreasing peak levels of the disulfides. Only 1% of the delivered dose appeared in the ascites. Therefore, it is not plausible that the presence of ascites or other third spaces would have an impact on the pharmacokinetics of amifostine.

Safe handling of antineoplastic drugs. Results of a survey.

As research continues to highlight the risks involved in handling antineoplastic drugs, the health services are giving increased attention to safety measures. In order to establish what protective measures nursing staff employ and what they know about antineoplastic drugs, a survey was carried out in The Netherlands. The questions were based on the self-study modules by Dunne and the (American) Oncology Nursing Society. A total of 1,373 questionnaires were distributed in 10 hospitals. Of these, 824 were returned, which represents a response rate of 60%. Over two-thirds (68%) of the nursing staff reported that they were involved, on a daily or weekly basis, in caring for patients being treated with antineoplastic drugs. In the view of 94% of the nurses, protective measures are effective. While administering antineoplastic drugs, 91% of the respondents said that they wore gloves, 21% said that they wore a gown, 18% wore a mask, and 3% used goggles. While handling excreta, fewer nurses applied safety measures. Thirty-nine percent of the respondents knew that latex gloves offer a greater degree of protection than PVC gloves. It appeared that there was not one Dutch hospital whose guidelines for the safe handling of antineoplastic material were completely up-to-date and that nurses do not always follow the guidelines established.

A double-blind randomized crossover study to compare the antiemetic efficacy of 250 mg with 500 mg methylprednisolone succinate (Solu-Medrol) as a single intravenous dose in patients treated with noncisplatin chemotherapy.

A double-blind randomized crossover study was performed in 56 chemotherapy-naive patients, all receiving non-cisplatin-based chemotherapy, to compare the antiemetic effects of 2 doses of a single administration of methylprednisolone succinate (Solu-Medrol): 250 versus 500 mg. Among the 39 patients who satisfactorily completed both parts of the study, complete and major protection from emesis (0 and 1 emetic episode or only retching) was observed in 79% during the first course and in 69% during the second course. Treatment failure (> or = 6 episodes of vomiting) was observed in 18% during the first course and 21% during the second course. There was no significant difference between the two dose levels neither in terms of antiemetic protection nor in terms of the occurrence of side effects nor in patient preference. Most important side effects were facial flushing (45%), headache (22%) and facial edema (18%). It is concluded that, although a comparison with lower dosages cannot be made, within the dose range studied no clear dose-response relationship could be found.

Comparison of two different high doses of metoclopramide in the prevention of chemotherapy-induced emesis.

A randomized double-blind study was conducted to compare the anti-emetic efficacy of 1 mg/kg vs 2 mg/kg metoclopramide, administered 5 times over a period of 8.5 h in 50 cancer patients treated with platinum-containing regimens (cisplatin, ethylenediamine platinum II malonate or spiroplatin). Twenty-six patients were treated with combination chemotherapy, mainly consisting of cisplatin and 5-fluorouracil. No statistically significant differences were observed with respect to the protection against nausea and vomiting between the two dose levels of metoclopramide. However, in the group of patients who received a high dosage of cisplatin (70-100 mg/m2), or ethylenediamine platinum II malonate (800-900 mg/m2), there was a significant difference in nausea and vomiting between patients who had and those who had not received prior chemotherapy, most probably due to anticipation. No difference in the severity of the side effects was observed with the 2 metoclopramide dose levels. Considerable interpatient variation was present in serum metoclopramide levels. No clear correlation was observed between serum metoclopramide levels and prevention of platinum-induced emesis. We conclude that 1 mg/kg of metoclopramide is just as effective as 2 mg/kg as an anti-emetic agent in patients receiving platinum-based chemotherapy, and that metoclopramide serum levels are not related to the anti-emetic effect.

Pharmacokinetics of free and total platinum species after rapid and prolonged infusions of aqua (1,1-bis(aminomethyl)cyclohexane) sulfatoplatinum (II) (spiroplatin) during a phase I trial.

The pharmacokinetics of the second generation platinum complex aqua(1,1-bis-(aminomethyl)cyclohexane)sulphatoplatinum(II) (spiroplatin, TNO-6) were studied during a phase I evaluation. Thirty patients received 49 cycles of spiroplatin by short term (less than or equal to 10-min), 1-, 3- or 6-h infusion. Dosages given ranged from 5 to 40 mg/m2. Platinum determinations were performed by atomic absorption spectrometry. Up to 5 days after administration platinum concentrations in plasma decayed triexponentially. Pharmacokinetic parameters of total platinum in plasma after short-term and prolonged infusion were similar in terms of terminal half-life (3.7 +/- 1.1 and 3.6 +/- 0.5 days), AUC/dose (548 +/- 106 and 616 +/- 278 min.m2/l), volume of distribution (20 +/- 6 and 27 +/- 81) and total body clearance (2.9 +/- 1.0 and 3.4 +/- 1.8 ml/min), whereas peak plasma concentrations were two times lower after prolonged infusion. The cumulative urinary platinum excretion after short-term infusion was 20 +/- 6%, 30 +/- 6% and 47 +/- 7% of the administered dose after 6, 24 and 120 h, respectively. These values are comparable to those after administration of cisplatin. The half-life of ultrafilterable platinum was 4.4 +/- 0.7 min. The curves of free and total platinum diverged rapidly, reflecting the high reactivity of spiroplatin towards plasma proteins. This high reactivity, most likely caused by the abundant presence of aquated compounds in the injection fluid, may also account for severe and unpredictable nephrotoxicity induced by spiroplatin.

Pharmacokinetics of carboplatin after i.v. administration.

Pharmacokinetics of the cisplatin analog carboplatin were studied in ovarian cancer patients who received short-term iv infusions of 290-370 mg/m2. Platinum (Pt) was determined by atomic absorption spectrometry in plasma ultrafiltrate up to 24 hours and in plasma and urine up to 5 days following infusion. Carboplatin was determined in plasma ultrafiltrate and in urine by high-performance liquid chromatography with electrochemical detection. The final half-life of total Pt in plasma was 5.8 +/- 1.6 days. Pharmacokinetics of carboplatin and ultrafilterable Pt (free Pt) were similar with respect to alpha-half-life (16 +/- 6 and 23 +/- 8 mins), beta-half-life (118 +/- 15 and 120 +/- 11 mins), area under curve/dose (18 +/- 5 and 17 +/- 4 min/m2/L), total-body clearance (101 +/- 21 and 107 +/- 19 ml/min), and volume of distribution Vss (9.9 +/- 1.3 and 10.0 +/- 1.4 L/m2). After 6 hours the cumulative urinary excretion of carboplatin and Pt was 41% +/- 14% and 68% +/- 7% of the dose, respectively. After 5 days the cumulative urinary excretion of Pt was 84% +/- 6%. Renal and metabolic clearances of free Pt from plasma were 81 +/- 17 and 26 +/- 11 ml/minute, respectively. The first-order rate constant for metabolic elimination of free Pt (KM = CLM/Vss) was 1.5 X 10(-3) +/- 0.6 X 10(-3) min-1, which is ten times lower than the value calculated from literature data for cisplatin (15 X 10(-3) +/- 1 X 10(-3) min-1). This means that the overall in vivo reactivity of carboplatin is ten times lower than that of cisplatin.

Pharmacokinetics of ethylenediaminemalonatoplatinum(II) (JM-40) during phase I trial.

Pharmacokinetics of the cis-platin analog ethylenediaminemalonatoplatinum(II) (JM-410) was studied in 28 cycles of 19 patients during the phase I study of this drug. The drug was administered intravenously by short-term (10-60 min) infusion. Doses ranged from 20 to 1,200mg m-2. JM-40 was determined in plasma ultrafiltrate and urine by HPLC. Platinum (Pt) concentrations were determined in plasma, plasma ultrafiltrate, urine and red blood cells by atomic absorption spectrometry up to 5 days after administration of the drug. Ultrafilterable Pt could be determined up to 45 days after the infusion in one patient sampled over such a long period. Pharmacokinetics of JM-40 showed a linear behaviour. The final half-life of total Pt in plasma was 4.1 +/- 0.9 days. The disposition of JM-40 was similar to that of ultrafilterable Pt in respect to t1/2 alpha (10 and 13 min), t1/2 beta (44 and 57 min), volumes of distribution Vc (11 and 121) and Vss (17 and 201), systemic clearance (256 and 223 ml min-1), renal clearance (69 and 73 ml min-1) and metabolic clearance (183 and 154 ml min-1). During the first 6 h 27 +/- 9% of the administered dose was excreted as JM-40. Cumulative platinum excretion in the urine amounted to 29 +/- 13% and 60 +/- 13% over the first 6 h, 24 h and 5 days, respectively. The uptake of platinum in red blood cells was limited, comprising only 0.24 +/- 0.12% of the administered dose. Although JM-40 and carboplatin are structurally closely related, pharmocokinetics and toxicity of JM-40 were more similar to cis-platin than to carboplatin.

Phase I and pharmacokinetic study of 5-aza-2'-deoxycytidine (NSC 127716) in cancer patients.

A phase I trial and pharmacokinetic study of 5-aza-2'-deoxycytidine (5-aza-dCyd) were conducted in 21 patients with advanced solid tumors. The drug was given as three 1-h infusions, separated by intervals of 7 h. Treatment was repeated every 3-6 weeks. Forty-six cycles of 5-aza-dCyd were administered at 7 dose levels ranging from 25 to 100 mg/m2 in three infusions. The dose-limiting toxicity was myelosuppression, with a delayed white blood cell nadir, occurring at Day 22. Other toxicities included a mild, reversible elevation of serum creatinine in three patients, minimal nausea and vomiting in six patients, and transient fatigue in three patients. In this study one partial response in a patient with an undifferentiated carcinoma of the ethmoid sinus was observed. Plasma and urinary concentrations of 5-aza-dCyd were measured using a bioassay based on growth inhibition of L1210 leukemia cells in vitro. For 75 and 100 mg/m2 given as 1-h infusions, mean peak plasma concentrations of 0.93 and 2.01 microM, respectively, were attained. In seven of nine courses at doses of 25-60 mg/m2, plasma 5-aza-dCyd concentration was less than 0.01 microM. In one case at 30 mg/m2 and another at 60 mg/m2, peak plasma drug concentrations were determined to be 0.244 and 0.409 microM, respectively. Following cessation of the infusion rapid disappearance of drug from plasma was observed with a t1/2 alpha and t1/2 beta of 7 and 35 min, respectively. High clearance values and a total urinary excretion of less than 1% of the administered dose suggest that 5-aza-dCyd is eliminated rapidly and largely by metabolic processes. For the present schedule studied, a dose of 75 mg/m2 in three infusions, every 5 weeks, is recommended for phase II trials in solid tumors.

Phase I study of ethylenediamine platinum(II) malonate (NSC 146 068), a second generation platinum analogue.

Ethylenediamine platinum(II) malonate [JM-40 (NSC 146 068)] has been selected for clinical studies because of its favorable preclinical toxicity profile as a "second generation" platinum analogue. When compared to cisplatin, JM-40 was less emetic in the ferret and less nephrotoxic in the dog, while its antitumor activity approached that of cisplatin. Twenty-nine patients received 86 courses of JM-40 as a single dose every 3-4 wk. After 13 dose escalation steps the maximum tolerable dose was reached at 1200 mg/m2. The dose limiting toxicities were nausea, vomiting, and nephrotoxicity. The renal damage seemed reversible up to a dose level of 1000 mg/m2 and consisted of a glomerular and tubular dysfunction. JM-40 did not cause any other dose related side effect or myelo-suppression. Pharmacokinetic studies at a dose of 1000 mg/m2 revealed mean terminal half-lives of 5.0 and 1.9 days for platinum in plasma and plasma ultrafiltrate, respectively. The mean cumulative excretion of platinum in urine accounted for 57% of the dose up to day 5. Two partial responses were observed in a patient with a large cell carcinoma of the lung and in one with a carcinoma of the lacrimal gland. Limited evaluation of JM-40 in phase II studies is warranted. The recommended dose is 1000 mg/m2 every 4 wk and 800 mg/m2 for patients pretreated with platinum analogues.

Pharmacokinetics of free and total platinum species after rapid and prolonged infusions of cisplatin.

Pharmacokinetic studies were performed in 51 patients who received cisplatin infusions. Two treatment regimens (single-day or daily for 5 days) and three infusion schedules (for 4 to 15 minutes, 2 to 3 hours, or 24 hours) were used. The daily dose of cisplatin varied from 20 to 120 mg/m2. The kinetics of total platinum studied up to day 5 revealed differences only during the initial period after the infusion. Peak levels were both dose and schedule dependent and initial t1/2 values in the decay curves were only schedule dependent (mean values: 13 minutes for rapid infusions, 40.3 minutes for 2 to 3-hour infusions, and 220.5 minutes for 24-hour infusion). The t1/2 values between days 1 and 5 were neither dose nor schedule dependent (mean 5.0 to 7.3 days). Concentrations of free platinum declined biexponentially after the rapid and 2 to 3-hour infusions, but they declined monoexponentially after 24-hour infusions. Final t1/2 values ranged from 26.0 to 78.8 minutes. In patients with normal renal and hepatic function, the free platinum AUC was identical for cisplatin infusions of different duration when equal doses were given. Free platinum clearance correlated with creatinine clearance (P = 0.017). The uptake of platinum in red blood cells was rapid, and peak concentrations correlated with the free platinum AUC (P = 0.0006), independent of the infusion schedule. The decay of platinum levels in red blood cells was biphasic. The mean terminal t1/2 for the interval between days 5 and 15 was 29.8 days. This suggests a breakdown of red blood cells that results from cisplatin dosing.

Pharmacokinetic comparison of cisplatin in solution with common lyophilized cisplatinum (Platinol).

Total platinum kinetics were studied after the administration of two formulation products of cisplatin: the lyophilized form and a ready-to-use solution. Twelve patients received both preparations during two successive cycles in a randomized crossover study. Platinum concentrations in plasma and urine were measured by atomic absorption spectrometry. Data were analyzed by means of a mixed-effect analysis of variance. Areas under the concentration-time curves up to 96 h were increased (p = 0.026) and slopes of the elimination phase were decreased (p = 0.035) during cycle 2 when compared with cycle 1. However, no difference in these two parameters was observed when comparing the two formulations. Three-day urinary platinum excretion was not related to either the treatment cycle or the formulation used. Because of its convenience of use and reduced risk of aerosolization, the ready-to-use formulation seems preferable.

Pharmacokinetics of free and total platinum species after short-term infusion of cisplatin.

Pharmacokinetic studies were performed in ten patients who received short-term (4-15-min) infusions of cisplatin. Computerized nonlinear least-squares analysis (NLIN) and an adapted curve-stripping approach (CSTRIP) were used to characterize total-platinum concentration-time curves. The overall curves showed a rapid initial phase and a prolonged terminal phase, separated by a phase with secondary peaks attributed to the existence of an enterohepatic recirculation. Up to Day 5, NLIN analysis revealed three exponential phases, with half-lives of 14.4 mins, 273.7 mins, and 5.3 days, respectively. However, a significant consistent divergence (P less than 0.005) was found between the observed and predicted curves during the intermediate phase, not justifying the use of an exponential function during this phase. The shape of the intermediate curve was strongly suggestive of a second influx in the plasma compartment, the amount of which was estimated by the CSTRIP approach (1.4% +/- 0.5% of the administered dose). Free-platinum levels declined in a biphasic manner (half-lives: 9.7 +/- 0.2 and 40.4 +/- 2.5 mins; n = 3). After administration of 100 mg/m2 of cisplatin, maximum platinum levels in rbcs ranged from 0.51 to 0.58 micrograms/ml and were reached within 90-150 mins. Thereafter, rbc platinum levels declined in a biphasic fashion, with a terminal half-life, for the interval Days 5-15, of 36-47 days. The binding of platinum to both plasma and proteins and rbcs in vitro (using patients' own blood) was slow, biphasic, and irreversible.