Phase I and pharmacokinetic study of a low-clearance, unilamellar liposomal formulation of lurtotecan, a topoisomerase 1 inhibitor, in patients with advanced leukemia

BACKGROUND: OSI-211 is a low-clearance, unilamellar liposomal formulation of a water-soluble camptothecin analogue, lurtotecan. OSI-211 has significant activity in severe combined immunodeficient mouse models of human leukemia. METHODS: This study was conducted to define the dose-limiting toxicities (DLT) and pharmacokinetics of OSI-211 in patients with refractory myeloid leukemias. Patients with refractory acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or chronic myelogenous leukemia in blastic phase (CML-BP) were eligible. OSI-211 was given as an intravenous infusion over 30 minutes daily for 3 days. The starting dose was 1.5 mg/m2 per day (4.5 mg/m2 per course). The dose was escalated by 50% until Grade 2 toxicity was observed and then by 30-35% until the DLT was defined. Serial plasma and urine samples were collected, and drug levels were determined by high-performance liquid chromatography with fluorescence detection. RESULTS: Twenty patients (18 patients [90%] with AML, and 1 patient each [5%] with MDS and CML-BP) were treated. Mucositis and diarrhea were considered to be the DLTs. The maximum tolerated dose was 3.7 mg/m2 per day. Fourteen of 18 evaluable patients (78%) with AML or MDS achieved transient bone marrow aplasia. The mean systemic clearance of lurtotecan in plasma was 0.946 +/- 1.53 L/hour/m2. Urinary recovery of lurtotecan was 6.66% +/- 5.26% (range, 1.05-18.4%). CONCLUSIONS: Liposomal encapsulation of lurtotecan altered its metabolism significantly. There was no evident correlation between exposure, as measured by plasma pharmacokinetics of lurtotecan, and clinical response or toxicities. OSI-211 merits further study in hematologic malignancies.     

Phase I and pharmacologic study of OSI-774, an epidermal growth factor receptor tyrosine kinase inhibitor, in patients with advanced solid malignancies.

PURPOSE: To assess the feasibility of administering OSI-774, to recommend a dose on a protracted, continuous daily schedule, to characterize its pharmacokinetic behavior, and to acquire preliminary evidence of anticancer activity. PATIENTS AND METHODS: Patients with advanced solid malignancies were treated with escalating doses of OSI-774 in three study parts (A to C) to evaluate progressively longer treatment intervals. Part A patients received OSI-774 25 to 100 mg once daily, for 3 days each week, for 3 weeks every 4 weeks. Part B patients received OSI-774 doses ranging from 50 to 200 mg given once daily for 3 weeks every 4 weeks to establish the maximum tolerated dose (MTD). In part C, patients received this MTD on a continuous, uninterrupted schedule. The pharmacokinetics of OSI-774 and its O-demethylated metabolite, OSI-420, were characterized. RESULTS: Forty patients received a total of 123 28-day courses of OSI-774. No severe toxicities precluded dose escalation of OSI-774 from 25 to 100 mg/d in part A. In part B, the incidence of severe diarrhea and/or cutaneous toxicity was unacceptably high at OSI-774 doses exceeding 150 mg/d. Uninterrupted, daily administration of OSI-774 150 mg/d represented the MTD on a protracted daily schedule. The pharmacokinetics of OSI-774 were dose independent; repetitive daily treatment did not result in drug accumulation (at 150 mg/d [average]: minimum steady-state plasma concentration, 1.20 +/- 0.62 microg/mL; clearance rate, 6.33 +/- 6.41 L/h; elimination half-life, 24.4 +/- 14.6 hours; volume of distribution, 136. 4 +/- 93.1 L; area under the plasma concentration-time curve for OSI-420 relative to OSI-774, 0.12 +/- 0.12 microg/h/mL). CONCLUSION: The recommended dose for disease-directed studies of OSI-774 administered orally on a daily, continuous, uninterrupted schedule is 150 mg/d. OSI-774 was well tolerated, and several patients with epidermoid malignancies demonstrated either antitumor activity or relatively long periods of stable disease. The precise contribution of OSI-774 to these effects is not known.     

Randomized trial of two intravenous schedules of the topoisomerase I inhibitor liposomal lurtotecan in women with relapsed epithelial ovarian cancer: a trial of the national cancer institute of Canada clinical trials group.

PURPOSE: Liposomal lurtotecan (OSI-211) is a liposomal formulation of the water-soluble topoisomerase I inhibitor lurtotecan (GI147211), which demonstrated superior levels of activity compared with topotecan in preclinical models. We studied two schedules of OSI-211 in a randomized design in relapsed ovarian cancer to identify the more promising of the two schedules for further study. PATIENTS AND METHODS: Eligible patients had measurable epithelial ovarian, fallopian, or primary peritoneal cancer that was recurrent after one or two prior regimens of chemotherapy. Patients were randomly assigned to receive either arm A (OSI-211 1.8 mg/m(2)/d administered by 30-minute intravenous infusion on days 1, 2, and 3 every 3 weeks) or arm B (OSI-211 2.4 mg/m(2)/d administered by 30-minute intravenous infusion on days 1 and 8 every 3 weeks). The primary outcome measure was objective response, which was confirmed by independent radiologic review, and a pick the winner statistical design was used to identify the schedule most likely to be superior. RESULTS: Eighty-one patients were randomized between October 2000 and September 2001. The hematologic toxic effects were greater on arm A than on arm B (grade 4 neutropenia, 51% v 22%, respectively), as was febrile neutropenia (26% v 2.4%, respectively). Of the 80 eligible patients, eight patients (10%) had objective responses; six responders (15.4%; 95% CI, 6% to 30%) were in arm A and two responders (4.9%; 95% CI, 1% to 17%) were in arm B. CONCLUSION: The OSI-211 daily for 3 days intravenous schedule met the statistical criteria to be declared the winner in terms of objective response. This schedule was also associated with more myelosuppression than the schedule of OSI-211 administered in arm B.     

Activity of oral and intravenous 9-aminocamptothecin in SCID mice engrafted with human leukemia

The intravenous (i.v.) injection of the human acute myelogenous leukemia cell line KBM-3 into severe combined immune deficient (SCID) mice results in disseminated multi-organ human disease involvement in these animals which leads to their death over a defined period of time. We utilized this model of human leukemia to investigate the in vivo therapeutic efficacy of the topoisomerase I inhibitor 9-aminocamptothecin (9-AC) given by two different routes. Mice injected with KBM-3 were divided into five groups. Group 1 received only diluent and served as control. The four remaining groups were treated with 9-AC four days a week for three consecutive weeks as follows: group 2 received 1.33 mg/kg/dose, i.v.; group 3, 1.33 mg/kg/dose, orally (p.o.); group 4, 2.0 mg/kg/dose i.v. and group 5, 2.0 mg/kg/dose p.o.. All animals in the control group died from disseminated human leukemia by day 64 from grafting, with a median survival of 59 days. Eleven out of 20 treated mice survived with no evidence of disease and were sacrificed at the termination of the experiment on day 128. PCR-assisted tissue analysis for the presence of human DNA showed no evidence of human leukemia. In conclusion, 9-AC is an active agent in SCID mice engrafted with human myelogenous leukemia and should be explored in phase I-II trials. Oral and intravenous routes are equally effective.     

A phase I study of OSI-211 and cisplatin as intravenous infusions given on days 1, 2 and 3 every 3 weeks in patients with solid cancers.

BACKGROUND: OSI-211 (also known as NX211) is a liposomal preparation of the topoisomerase I inhibitor, lurtotecan, which has shown antitumor activity in phase I and II clinical trials. Cisplatin is a widely used antineoplastic agent with activity in a broad range of tumor types. This phase I trial was conducted to determine the recommended doses of these agents, and their pharmacokinetic properties and toxicities in patients with advanced solid malignancies. PATIENTS AND METHODS: Fourteen patients with advanced and/or metastatic solid malignancies were enrolled in this trial. The first planned dose level was OSI-211 0.9 mg/m(2) with cisplatin 25 mg/m(2) administered intravenously daily for the first three consecutive days of a 21-day cycle. Patients were evaluated for hematological and non-hematological toxicities, and pharmacokinetic studies were performed on both agents. RESULTS: The recommended phase II dose was determined to be 0.7 mg/m(2) OSI-211 given with 25 mg/m(2) cisplatin. Dose-limiting neutropenia was seen in two of three patients at the starting dose level. Three of 11 patients at the second (lower) dose level experienced dose-limiting thrombocytopenia; febrile neutropenia was also seen in one patient. Non-hematological toxicities were generally manageable and included fatigue, nausea and vomiting. Considerable variability was seen in both hematological toxicities and pharmacokinetics. One complete response and three partial responses were seen. CONCLUSIONS: The recommended phase II dose for this combination is 0.7 mg/m(2) OSI-211 with 25 mg/m(2) cisplatin given as an intravenous infusion on days 1, 2 and 3 of a 21-day cycle. The main toxicity was myelosuppression. Preliminary evidence of antitumor activity was seen.     

Schedule-dependent variations in the response of murine P388 leukemia to cyclophosphamide in combination with interferons-alpha/beta

Positive therapeutic effects of interferons (IFNs) in combination with other therapies will depend on defining modalities, doses, and timing of treatment in the setting of varied tumor burdens. When 10(4) P388 leukemia cells were inoculated i.p. on day 0 in BALB/c x DBA/2 F1 mice, all mice died within 18 days if left untreated. Murine IFN-alpha/beta (5 x 10(5) units) injected daily i.p. on days 5-9 resulted in 20% increase in life span (ILS) (P less than 0.0001). Cyclophosphamide (CY) (100, 33, or 15 mg/kg) was injected i.p. once 2 days before start (day 3), simultaneously with start (day 5), or 2 days after cessation of IFN treatment (day 11). When 100 mg/kg CY alone were injected on day 3 or 5, all mice survived more than 90 days and were considered cured. When IFN was given after this curative dose of CY, more tumor deaths occurred; up to 100% of the mice died when 100 mg/kg CY on day 3 were combined with IFN on days 5-9. Increased mortality with the combination was not due to added toxicity of CY and IFN since the mice developed abdominal tumors and ascites. Mice not inoculated with tumor cells and treated similarly suffered only a transient weight loss, had only moderate white count depression, and did not die. When IFN was injected before CY on days 1-5 (instead of days 5-9), IFN did not alter the effectiveness of CY (100 mg/kg on day 5). In contrast to these results, when CY (100 mg/kg) was administered on day 11, after IFN (days 5-9), an augmented survival occurred with 119% ILS and 40% cures (CY alone on day 11 resulted in 69% ILS but no cures). In addition, when CY at a lower dose of 15 mg/kg was injected in combination with IFN, survival was consistently augmented by IFN; e.g., CY alone on day 3 caused 40% ILS and with IFN (days 5-9) 60% ILS (P less than 0.0001). Qualitatively similar findings were obtained when P388 leukemia cells were inoculated s.c. and the drugs delivered i.p. Inhibition by IFN of antitumor effects of a second alkylating agent, 1,3-bis(2-chloroethyl)-1-nitrosourea, was also identified. Thus, IFN-alpha/beta potentiated suboptimal CY effects for P388 leukemia, had neutral effects when injected before CY treatment, and inhibited antitumor activity of curative CY or nitrosourea schedules.     

Antitumor and toxicity evaluation of free doxorubicin and doxorubicin entrapped in cardiolipin liposomes

Summary The antitumor activity of free doxorubicin and doxorubicin entrapped in cardiolipin liposomes was evaluated in P388 ascitic leukemia, disseminated Gross leukemia, and advanced mammary carcinoma. In P388 leukemia, free drug and drug entrapped in liposomes demonstrated equivalent antitumor activity at doses of 2.2 and 4.4 mg/kg, demonstrating 52% and 69% ILS (increase in life-span), respectively. Free doxorubicin at a dose of 10 mg/kg was superior, producing a 185% ILS against 82% with liposomal doxorubicin. With an increase in administered dose the antitumor response with liposomal doxorubicin was much more pronounced; at doses of 20 and 25 mg/kg the ILS was in excess of 376%, with five of ten mice surviving tumor-free. In Gross leukemia, the optimum dose of free doxorubicin, 10 mg/kg, brought about 186% T/C (median survival in treated mice over that in controls, x100), whereas with liposomal doxorubicin the optimum dose was 16.9 mg/kg, which yielded 214% T/C. In advanced mammary carcinoma, the maximum tumor regression with free doxorubicin was at a dose of 7.5 mg/kg, with two of six mice dying of toxicity. Liposomal doxorubicin caused maximum tumor regression at 10.8 mg/kg dose with no toxic deaths. Doxorubicin entrapped in cardiolipin liposomes was much less toxic than free drug at high doses in normal mice.This work was supported by a grant from the American Heart Association (82-922) and by PHSCA 5P30 CA 1-4626     

Plasma and cerebrospinal fluid pharmacokinetics of erlotinib and its active metabolite OSI-420.

PURPOSE: To report cerebrospinal fluid (CSF) penetration of erlotinib and its metabolite OSI-420. EXPERIMENTAL DESIGN: Pharmacokinetic measurements were done in plasma (days 1, 2, 3, and 8 of therapy) and, concurrently, in plasma and CSF (before and at 1, 2, 4, 8, and 24 h after dose on day 34 of therapy) in an 8-year-old patient diagnosed with glioblastoma who received local irradiation and oral erlotinib in a phase I protocol. CSF samples were collected from a ventriculoperitoneal shunt, which was externalized because of infection. Erlotinib concentrations were determined by liquid chromatography/mass spectrometry. CSF penetration of erlotinib and OSI-420 were estimated by a compartmental model and by calculating the ratio of CSF to plasma 24-h area under concentration-time curve (AUC(0-24)). RESULTS: This patient was assigned to receive erlotinib at a dose level of 70 mg/m(2), but the actual daily dose was 75 mg (78 mg/m(2)). Erlotinib and OSI-420 plasma pharmacokinetic variables on days 8 and 34 overlapped to suggest that steady state had been reached. Whereas erlotinib and OSI-420 AUC(0-24) in plasma on day 34 were 30,365 and 2,527 ng h/mL, respectively, the correspondent AUC(0-24) in the CSF were 2,129 and 240 ng h/mL, respectively. Erlotinib and OSI-420 CSF penetration were 7% and approximately 9%, respectively, using both estimate methods. The maximum steady-state CSF concentration of erlotinib was approximately 130 ng/mL (325 nmol/L). CONCLUSIONS: The plasma pharmacokinetics of erlotinib in this child overlapped with results described in adults. Oral administration of erlotinib achieves CSF concentrations comparable with those active against several cancer cell lines in preclinical models.     

In vivo activity on murine tumors of a novel antitumor compound,N-β-dimethylaminoethyl 9-carboxy-5-hydroxy-10-methoxybenzo[a]phenazine-6-carboxamide sodium salt (NC-190)

Summary A novel antitumor compound, N--dimethylaminoethyl 9-carboxy-5-hydroxy-10-methoxybenzo[a]-phenazine-6-carboxamide sodium salt (NC-190) was evaluated for its antitumor activity in experimental murine tumor systems. In the initial studies with P388 leukemia (i.p.-i.p.), NC-190 led to an increase of >200% in life span (ILS), and 75% of the mice were alive on day 30, when the optimal dose (50 mg/kg, days 1–5) was given. Additionally, the compound had significant activities against i.p. inoculated mouse L1210 leukemia, B16 melanoma, M5076 reticulum cell sarcoma, sarcoma 180, mouse hepatoma MH134, and rat Yoshida sarcoma and Yoshida ascites hepatoma AH130. The optimal dose resulted in a >280% ILS with a 30-day survival of 50% in mice with L1210 leukemia (100 mg/kg, days 1–5), a 156% ILS in mice with B16 melanoma (50 mg/kg, days 1–5), a 98% ILS with a 90-day survival of 25% in mice with M5076 reticulum cell sarcoma (25 mg/kg, days 1, 5, 9, and 13), a >300% ILS with a 60-day survival of 50% in mice with sarcoma 180 (50 mg/kg, days 3–10), a 148% ILS with a 60-day survival of 25% in mice with MH134 (25 mg/kg, days 1–5), a 129% ILS with a 60-day survival of 12.5% in rats with Yoshida sarcoma (12.5 mg/kg, day 3–10), and a >161% ILS with a 60-day survival of 50% in rats with AH130 (6.3 mg/kg, days 3–10). In the experiments with s.c. inoculated tumors, NC-190 not only inhibited tumor growth, but also increased the life span of mice with Lewis lung carcinoma or B16 melanoma. The 60-day survivors accounted for 60% and 30% in mice with Lewis lung carcinoma and B16 melanoma, respectively. The compound significantly inhibited the spontaneous lung metastasis of Lewis lung carcinoma by more than 90% when eight daily i.v. injections were given. NC-190 was active by the i.p., s.c., and i.v. routes. Five consecutive daily i.p. doses (days 1–5) were more effective than a single dose (day 1), two doses (days 1 and 5), or three doses (days 1, 5, and 9). NC-190 warrants further study as a potential antineoplastic agent against human neoplasms, as it has a broad spectrum of antitumor activity and inhibits metastasis.Abbreviations ILS increase in life span - MST median survival time - MMC mitomycin C - ADM adriamycin - CPA cyclophosphamide - 5-FU 5-fluorouracil     

Phase II study of OSI-211 (liposomal lurtotecan) in patients with metastatic or loco-regional recurrent squamous cell carcinoma of the head and neck. An EORTC New Drug Development Group study

The purpose of this study was to evaluate the activity and safety of OSI-211, the liposomal form of lurtotecan, in patients ineligible for curative surgery or radiotherapy and with metastatic/locoregional recurrent squamous cell carcinoma of the head and neck (SCCHN) and target lesions either within a previously irradiated field (“within”) or outside a previously irradiated field (“outside”). OSI-211 was given intravenously over 30 min on days 1 and 8 at 2.4 mg/m²/day, repeated every 21 days (1 cycle). From July 2001 to March 2002, 32 patients from 14 institutions were enrolled in the “within” arm and 18 in the “outside” arm. In the “within” arm, two patients were ineligible because their tumour site was not allowed in the protocol (nasopharynx, skin) and two other patients never started treatment. Of the 46 eligible patients who started treatment, there was one objective response (response rate: 2.2% (95%Confidence Interval (CI): [0–11.5%]). Twelve patients in the “within” arm and 6 in the “outside” arm had stable disease, with a median duration of 18 weeks, 95% CI (12.7–25.7). The median time to progression was 6 weeks (95%CI: [5.9–12.7] weeks). Haematological toxicity was moderate in both arms. The most common haematological toxicity was grade 1–2 anaemia in 79% of patients. Non-haematological toxicity was mild in both arms. The most common grade 3–4 non-haematological toxicity was infection in 8.5% of patients. OSI-211 administered on d1 and d8, every 3 weeks, is well tolerated, but shows only minimal activity in locally advanced/metastatic SCCHN.     

Antitumor activity of 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxy-camptothec in, a novel water-soluble derivative of camptothecin, against murine tumors

The search for new water-soluble analogues of camptothecin (CPT) with higher activity and less toxicity has led to the development of a novel compound, 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxy-camptothecin (CPT-11), which showed significant antitumor activity against a broad spectrum of experimental tumor models by i.p., i.v., or oral administration. When its activity against L1210 was compared with that of CPT and known derivatives, CPT-11 was most effective, giving the highest maximum increase in life span (ILS) and showing good activity over a wide dose range. The antitumor activity of CPT-11 was shown against tumors not only in the ascites form but also in the solid form. Included among the more susceptible murine tumors are S180, Meth A fibrosarcoma, Lewis lung carcinoma, Ehrlich carcinoma, MH134 hepatoma, mammary carcinoma of C3H/HeN mice, L1210, and P388 leukemia. Probable cures of these tumors were induced frequently by CPT-11. The antitumor activity of CPT-11 against i.p.-implanted L1210 was superior to that of Adriamycin in maximum ILS, the number of cured mice, and the therapeutic ratio. CPT-11 at a dose of 100 mg/kg produced an ILS in excess of 300% with five of six mice surviving tumor free, and effected 100% tumor regression at 200 mg/kg, whereas the optimum dose of Adriamycin, 12.5-25 mg/kg, brought about 114-129% ILS with one of six mice surviving. The acute toxicity of CPT-11 was extremely low, particularly in the case of oral administration. CPT-11 is expected to be clinically useful.     

Effect of concurrent calcium leucovorin infusion on 5-fluorouracil cytotoxicity against murine L1210 leukemia

Summary We examined the effect of concurrent SC infusion of calcium leucovorin (LV) on the action of 5-fluorouracil (FUra) against mouse L1210 leukemia implanted either SC or IP. Mice bearing the SC tumor treated with FUra (100 mg/kg, IP, day 1) plus infusion with either LV (11.5 mg · kg^-1 · day^-1, days 1–4), or 0.9% NaCl (days 1–4) resulted in an identical increase in median lifespan (ILS) of 28%. Similar experiments with FUra (100 mg/kg) plus LV infusion (115 mg · kg^-1 · day^-1) or FUra (200 mg/kg) plus LV infusion (115 mg · kg^-1 · day^-1) resulted in 50% and 59% ILS, respectively, which were not different from that obtained with the same doses of FUra plus 0.9% NaCl infusion. Mice bearing the IP tumor treated with FUra (100 mg/kg, IP, day 1) plus infusion with either LV (11.5 mg · kg^-1 · day^-1, days 1–4) or 0.9% NaCl (days 1–4) had an identical 56% ILS. Similar experiments with FUra (100 mg/kg) plus LV infusion (115 mg · kg^-1 · day^-1) or FUra (200 mg/kg) plus LV infusion (115 mg · kg^-1 · day^-1) resulted in 67% and 94% ILS, respectively, which were not different from those obtained with the same doses of FUra plus 0.9% NaCl infusion. Treatment of normal mice with FUra (200 mg/kg, IP, day 0) plus LV infusion (115 mg · kg^-1 · day^-1, days 0–3) was no more toxic than FUra plus 0.9% NaCl infusion, judging by similar transient decreases in body weight and no mortality. The data indicate that concurrent infusion with the LV failed to enhance the action of FUra against the mouse L1210 leukemia.     

The topoisomerase I inhibitor DX-8951f is active in a severe combined immunodeficient mouse model of human acute myelogenous leukemia.

The severe combined immunodeficient (SCID) mouse model of human acute myelogenous leukemia (AML) is a unique system for preclinical in vivo evaluation of the activity and toxicity of new agents. The topoisomerase I (topo I) inhibitor topotecan is active in patients with AML and myelodysplastic syndromes. DX-8951f is a novel topo I inhibitor with more potent antitumor effects than topotecan or CPT-11 in vitro. To study the in vivo activity of DX-8951f, 6-week-old female SCID mice received injections into the tail vein with 2 x 10(7) exponentially growing KBM-3 cells. In each experiment, three to five sets of five mice were treated with DX-8951f doses ranging from 7.5 to 80 mg/kg and at schedules of 1, 3, and 5 days; a control set of five mice was treated with the drug vehicle alone. One group received DX-8951f on day 7 of the inoculation with KBM-3 (early-treatment group). To study the activity of DX-8951f in advanced disease, a second group was treated 1 month after the inoculation, when the animals were developing symptoms (late-treatment group). The study end point was the duration of survival until death from leukemia, which was assessed clinically and by the presence of the human DQ alpha gene in tissue samples by PCR. Six experiments were conducted with 170 animals. Survival was higher in both the early- and late-treatment groups than in untreated controls, and the treated groups had significantly less central nervous system disease. Significantly improved survival was observed in animals treated early with 60 and 80 mg/kg as a single injection, with 15 and 20 mg/kg over 3 days, and with 7.5 and 10 mg/kg over 5 days. In the late-disease model (treatment starting on days 28-35), improved survival was observed with a single dose of 80 or 20 mg/kg over 5 days. Dose escalation was limited by dilution problems at the 1-day schedule and by toxicity (mainly gastrointestinal) of the prolonged schedules. Both efficacy and toxicity were dose schedule dependent, increasing with higher doses and prolonged exposure. By establishing the antileukemic activity of DX-8951f against human AML transplanted into SCID mice at doses below the LD10, our data provide a rationale for clinical evaluation of the drug in patients with AML and favor the use of prolonged administration.     

Radiation potentiating effect of ethyl bis(2,2-dimethyl-1-aziridinyl) phosphinate (AB-163)

Ethyl bis(2,2-dimethyl-i-aziridinyl) phosphinate (AB-163), a new tris(aziridinyl) phosphine oxide (TEPA) analogue, was tested in a murine P389 lymphocytic leukemia combination radiotherapy chemotherapy model. In this system, the combination was synergistic with results rivaling the best previously reported radiation drug combination results in this model. Three time intervals between the two modalities were tested. The optimum combination utilized AB-163 120 mg/kg four hours before 400 rad whole-body γ-radiation; this resulted in 50% survival at 100 days and a 330°10 increased life span (ILS) for the remainder. Drug alone produced a maximum of 188% ILS (120 mg/kg) with one survivor while radiation alone gave 48% ILS (optimum 400 rad) with no survivors. These findings make AB-163 attractive for further investigation including clinical combined modality trials.     

Additive action of gemcitabine (2',2'-difluorodeoxycytidine) and 2-chlorodeoxyadenosine on murine leukemias L1210 and P388

The influence of 2-chlorodeoxyadenosine (2-CdA) and 2',2'-difluorodeoxycytidine (Gemcitabine, dFdC) on the survival time of mice bearing L1210 and P388 leukemias was investigated. Seventy-two male CD2F1 strain mice were used in the experiment. They were given 2-CdA (20 mg/kg) on days 1-5 after inoculation with leukemic cells (day 0) i.p. or dFdC (20 mg/kg) on days 1, 4, 7, and 10 i.p. The drugs were administered alone and in combination (sequential therapy) according to the following schedules: 2-CdA and dFdC at the same time at the doses given above; 2-CdA before dFdC, sequential therapy (2-CdA on days 1-5, then dFdC on days 6, 9, 12, 15); dFdC before 2-CdA, sequential therapy (dFdC on days 1, 4, 7, 10 and then 2-CdA on days 11-15). The animals were observed daily for survival for a minimum of 60 days. The efficacy of the therapy against leukemia (defined as the increase in lifespan, ILS) was assessed as the percentage of the median survival time (MST) of the treated group (T) to that of the control group (C): ILS = [(MSTc/MSTT-1] x 100. The survival time of mice bearing L1210 or P388 leukemia treated with dFdC before 2-CdA was significantly prolonged as compared with the animals receiving these agents separately. The prolongation of the survival time of the treated mice (ILS) compared with the untreated was 300% in case of L1210 and 241% in case of P388 leukemia. The combinations 2-CdA before dFdC and simultaneous injections of both drugs were not more effective than the treatment with dFdC alone. In case of L1210 leukemia, mice treated with these regimens showed a survival time similar to those treated with dFdC alone, although the survival time of mice bearing P388 leukemia treated with these regimens was shorter than that of mice given dFdC singly. Our study revealed that the most effective treatment schedule in both leukemias was dFdC given before 2-CdA. The results confirm the additive action of dFdC and 2-CdA.     

Plasma and cerebrospinal fluid pharmacokinetics of intravenous oxaliplatin, cisplatin, and carboplatin in nonhuman primates.

PURPOSE: Describe and compare the central nervous system pharmacology of the platinum analogues, cisplatin, carboplatin, and oxaliplatin and develop a pharmacokinetic model to distinguish the disposition of active drug from inert platinum species. EXPERIMENTAL DESIGN: Oxaliplatin (7 or 5 mg/kg), cisplatin (2 mg/kg), or carboplatin (10 mg/kg) was given i.v. Serial plasma and cerebrospinal fluid (CSF) samples were collected over 24 hours. Plasma ultrafiltrates were prepared immediately. Platinum concentrations were measured using atomic absorption spectrometry. Areas under the concentration x time curve were derived using the linear trapezoidal method. CSF penetration was defined as the CSF AUC(0-24)/plasma ultrafiltrate AUC(0-24) ratio. A four-compartment model with first-order rate constants was fit to the data to distinguish active drug from inactive metabolites. RESULTS: The mean +/- SD AUCs in plasma ultrafiltrate for oxaliplatin, cisplatin, and carboplatin were 61 +/- 22, 18 +/- 6, and 211 +/- 64 micromol/L hour, respectively. The AUCs in CSF were 1.2 +/- 0.4 micromol/L hour for oxaliplatin, 0.56 +/- 0.08 micromol/L hour for cisplatin, and 8 +/- 2.2 mumol/L hour for carboplatin, and CSF penetration was 2.0%, 3.6%, and 3.8%, respectively. For oxaliplatin, cisplatin, and carboplatin, the pharmacokinetic model estimated that active drug accounted for 29%, 79%, and 81% of platinum in plasma ultrafiltrate, respectively, and 25%, 89%, and 56% of platinum in CSF, respectively. The CSF penetration of active drug was 1.6% for oxaliplatin, 3.7% for cisplatin, and 2.6% for carboplatin. CONCLUSIONS: The CSF penetration of the platinum analogues is limited. The pharmacokinetic model distinguished between active drug and their inactive (inert) metabolites in plasma and CSF.     

Serum erythropoietin and thrombopoietin levels in patients with essential thrombocythaemia

In 40 patients with essential thrombocythaemia (ET) serum erythropoietin (EPO) and thrombopoietin (TPO) concentrations were determined and compared with the EPO and TPO values of a healthy control group. The mean EPO serum concentration for 24 control patients was 9.4 mU/ml +/- 3.7 (range 2-17.9), for 32 untreated ET patients at diagnosis 6.6 mU/ml +/- 7.6 (range 0.5-44.3) and for 8 ET patients treated with cytoreduction 14.1 mU/ml +/- 8.0 (range 4.5-26.1). Serum EPO levels in untreated ET patients at diagnosis were significantly lower compared with serum EPO levels in healthy control patients (p=0.002). Serum EPO levels in treated ET patients were not different from serum EPO levels in healthy controls (p=0.13) but were significantly higher compared with untreated ET patients (p=0.003). Serum TPO levels were determined in 18 of 40 ET patients, the mean TPO serum concentration was 211 pg/ml +/- 109 (range 62,5-345). The mean TPO serum concentration for 10 untreated ET patients at diagnosis was 162 pg/ml +/- 87 (range 62,5-302) and for 8 ET patients who had received cytoreductive treatment 272 pg/ml +/- 106 (range 96-345), respectively (p=0.04). Both serum TPO levels for treated and untreated ET patients were significantly higher (p<0.001) compared with serum TPO levels for healthy controls. The results of our study suggest a difference in the regulation of serum EPO and TPO in patients with ET. While the mean serum EPO level is decreased in untreated ET patients, the corresponding mean serum TPO level is increased. Treatment with cytoreduction, results in normalisation of the mean serum EPO level, whereas the mean TPO serum level remains elevated.     

Evaluation of beta-tethymustine, a new anticancer compound, in murine tumour models

beta-Tethymustine, 1-[2- {bis(2'-chloroethyl)amino}ethyl]spiro[imidazolidine-4,2'-(1'H),3',4'-dihydronaphthalene]-2,5-dione, has been synthesised and LD50 value determined in Swiss male mice, which was found to be 100.00 mg/kg by single i.p. injection. The following three criteria, namely ascites cell count, ascites fluid measurement and increase in median survival times (MST) of drug-treated (T) over untreated control (C) mice, were studied for evaluation of its antitumour efficacy in vivo in three murine ascites tumours, namely Ehrlich ascites carcinoma (EAC), sarcoma-180 (S-180) and Dalton's lymphoma (DL). At the optimum dose range of 8.0 mg/kg (higher) to 4.0 mg/kg (lower) for 1-7 days treatment following tumour transplantation on day 0, it exhibited a very high percentage of inhibition of both the ascites cell and fluid in these models and displayed excellent ILS(max) value of 80 in EAC, 224 in S-180 and 240 in DL, respectively, showing 'curative' effect (2-3/6 mice having 90 days survival rate). It also demonstrated a high ILS value of 150 with one cure/six mice bearing S-180 for 6 days prior to drug therapy. Screening results were compared with two clinical drugs, cyclophosphamide and 5-fluorouracil, serving as positive controls. Its chemical alkylating activity was compared with nor-HN2 (NSC 10873) and spiromustine (NSC 172112). The results indicate that it possesses greater alkylating activity than nor-HN2 and comparable activity with spiromustine.     

Combination chemotherapy of UFT, etoposide and CDDP in advanced gastric cancer

Eleven patients with advanced unresectable gastric cancer were treated with a combination of UFT, etoposide and CDDP (FFP). FEP regimen was given every 4 weeks as follows: UFT 400 mg/m2 (p.o.) everyday, etoposide 50 mg/m2 (i.v.), and CDDP 30 mg/m2 (i.v.) on day 1, 8, and 15. The subjects were 3 males and 8 females with an average of 64 (ranging from 44 to 84 yrs). None had had prior chemotherapy. One patient was in performance status (P.S.) 1, 6 were in PS 2, and 4 were in PS 3. Partial responses (PR) were obtained in 5 out of 11 patients. The durations of the response were over 3 months in all patients with PR. No side effects were observed except for mild myelosuppression and nausea. In BALB/C mice with lymphoid leukemia L1210, the effects of each drug and the combination of the two or three drugs on the increase in life span (ILS) were studied. The combination of the three drugs showed the highest effect on ILS. In conclusion, it is suggested that FEP chemotherapy is useful for advanced gastric cancer.     

Pharmacodynamic evaluation of the epidermal growth factor receptor inhibitor OSI-774 in human epidermis of cancer patients.

BACKGROUND: OSI-774 is an inhibitor of the epidermal growth factor receptor tyrosine kinase (EGFR-TK) currently in clinical development. In preclinical models, the antitumor activity of OSI-774 was directly related to its ability to inhibit the EGFR-TK. On the basis of these data, we hypothesized that inhibition of the EGFR-TK will be required for this agent to be effective in the clinic. This study evaluated the pharmacodynamic effects of OSI-774 in normal skin tissues collected from patients treated with the agent in a Phase I study. METHODS: Patients with advanced cancer who were treated in a Phase I study of OSI-774 underwent a biopsy of normal skin epidermis at baseline and after the last dose of drug in the first course of treatment. The expression and activation of the EGFR, downstream signaling extracytoplasmatic-regulated kinase (Erk), and cell cycle regulator p27 were determined in paraffin-embedded skin tissues using an immunohistochemical method (IHC). The IHC data were analyzed using both a semiquantitative scoring system and an automatic absorbance quantitative IHC method. The number of cells with nuclear staining of p27 per 500 cells was determined. Plasma samples were collected to quantitate OSI-774 plasma concentrations. RESULTS: A total of 56 skin specimens was collected from 28 patients treated with OSI-774 at doses ranging from 25 to 200 mg/day. There was a significant decrease in phospho-EGFR (Tyr 1173) expression as determined semiquantitatively with OSI-774 treatment [2.75 +/- 0.51 (mean +/- SD) pretreatment versus 2.36 +/- 0.76 after treatment, pair comparison P = 0.01]. The quantitative ratio [(phopho-EGFR/EGFR) x 100] of phospho-EGFR (Tyr1173) decreased from 64.16 +/- 36.58 pretreatment to 48.87 +/- 35.37 post-treatment (pair comparison, P = 0.02). No significant differences were observed in phospho-Erk (Thr202/Tyr204) expression. The mean number of cells with nuclear staining for p27 increased from 185 +/- 101 (mean +/- SD) pretreatment to 253 +/- 111 post-treatment (pair comparison P = 0.02). A total of 12 (42.8%), 7 (25%), and 14 (50%) patients had >25% variation in the ratio of phospho-EGFR (Tyr1173), phospho-Erk (Thr202/Tyr204), and p27 expression, respectively. Only changes in p27 expression were related to the administered dose of OSI-774. CONCLUSIONS: OSI-774 exerted pharmacodynamic effects in skin tissues of 30-50% of patients treated with the agent. Up-regulation of p27, which is a downstream effect of EGFR inhibition, was dose related. Although there was a significant decrement in phospho-EGFR (Tyr1173), it was not related to the administered dose of OSI-774. On the basis of these findings and the relatively simple and reliable method to measure p27 expression, this biomarker appears to be the most promising and is being evaluated in Phase II studies as a predictor of clinical outcome.