J. H. M. Schellens

Bioavailability and pharmacokinetics of oral topotecan: a new topoisomerase I inhibitor

The results of preclinical and clinical studies indicate enhanced antineoplastic activity of topotecan (SKF 104864-A) when administered as a chronic treatment. We determined the apparent bioavailability and pharmacokinetics of topotecan administered orally to 12 patients with solid tumours in a two-part crossover study. The oral dose of 1.5 mg m-2 was administered as a drinking solution of 200 ml on day 1. The i.v. dose of 1.5 mg m-2 was administered as a 30 min continuous infusion on day 2. The bioavailability was calculated as the ratio of the oral to i.v. area under the curve (AUC) calculated up to the last measured time point. The oral drinking solution was well tolerated. The bioavailability revealed moderate inter-patient variation and was 30% +/- 7.7% (range 21-45%). The time to maximum plasma concentration after oral administration (Tmax) was 0.78 h (median; range 0.33-2.5). Total i.v. plasma clearance of topotecan was 824 +/- 154 ml min-1 (range 535-1068 ml min(-1)). The AUC ratio of topotecan and the lactone ring-opened hydrolysis product (hydroxy acid) was of the same order after oral (0.34-1.13) and i.v. (0.47-0.98) administration. The bioavailability of topotecan after oral administration illustrates significant systemic exposure to the drug which may enable chronic oral treatment.

Phase I and pharmacologic study of oral topotecan administered twice daily for 21 days to adult patients with solid tumors.

PURPOSEnTopotecan is a specific inhibitor of topoisomerase I. Recently bioavailability of an oral formulation of approximately 30% with limited variability was reported. We conducted a phase I and pharmacokinetic study of the oral formulation of topotecan to characterize the maximum-tolerated dose (MTD), toxicities, pharmacokinetics, and antitumor effects in patients with refractory malignancies.nnnPATIENTS AND METHODSnPatients were treated with oral topotecan given twice daily for 21 days, with cycles repeated every 28 days. In subsequent cohorts, the dose was escalated from 0.15 to 0.6 mg/m2 twice daily. Pharmacokinetics were performed on day 1 and 8 of the first course using a validated high-performance liquid chromatographic assay and noncompartmental pharmacokinetic methods.nnnRESULTSnThirty-one patients entered the study; one patient was not assessable for toxicity and response as therapy was prematurely interrupted on request of the patient who had not experienced toxicity. Thirty patients received a total of 59 courses. The dose-limiting toxicity (DLT) was reached at a dose of 0.6 mg/m2 twice daily and consisted of diarrhea, which started subacutely at a median onset on day 15 (range, 12 to 20) and resolved after a median of 8 days (range, 7 to 16). Other toxicities were mild, including leukocytopenia, thrombocytopenia, nausea, and vomiting. The MTD was 0.5 mg/m2 twice daily. No responses were observed. Pharmacokinetics showed a substantial variation of the area under the plasma concentration-time curve at time point t [AUC(t)] of topotecan and ring-opened product hydroxyacid. A significant correlation was observed between the percentage of decrease in WBC count versus the AUC(t) of topotecan (r = .75), which was modeled by a sigmoidal maximal effect concentration (Emax) function.nnnCONCLUSIONnThe DLT in this phase I study for chronic oral topotecan for 21 days was diarrhea. The recommended dose for phase II studies is 0.5 mg/m2 twice daily.

Five days of oral topotecan (hycamtin®), a phase I and pharmacological study in adult patients with solid tumours

Topotecan is a specific inhibitor to topoisomerase I. An oral formulation of topotecan is available with a bioavailability of 32-44% in humans. A phase I and pharmacological study of the oral formulation of topotecan administered daily for 5 days every 21 days was performed in adult patients with solid tumours to determine the maximum tolerated dose (MTD). Adult patients with a WHO performance status < or = 2 adequate haematological, hepatic and renal functions, with malignant solid tumours refractory to standard forms were entered into the study. Pharmacokinetics were performed on days 1 and 4 of the first course using a validated high performance liquid chromatographic assay. 29 patients entered the study, all patients were evaluable for toxicity and response. The doses studied in the 29 patients were 1.2, 1.8, 2.3, 2.7 mg/m2/day and a fixed dose of 4 mg/day without surface area adjustment. A total of 109 courses were given. Dose limiting toxicity (DLT) was reached at a dose of 2.7 mg/m2/day and consisted of CTC (NCI-Common Toxicity Criteria) grade IV granulocytopenia. The regimen was well tolerated. Non-haematological toxicities were mild, including fatigue, anorexia, nausea, vomiting and diarrhoea. A significant correlation was observed between the percentage decrease in white blood cells versus the area under the curve (AUC(t)) of topotecan lactone (R = 0.76 P < 0.01) which was modelled by a sigmoidal Emax function. The correlation coefficient between the absolute topotecan dose administered and the AUC(t) was R = 0.52 (P = 0.04). Pharmacokinetics of the fixed dose of 4 mg/day were comparable to the 2.3 mg/m2/day dose. DLT in this phase I study of five daily doses of oral topotecan every 21 days was granulocytopenia. The recommended dose for phase II studies is 2.3 mg/m2/day or alternatively, a fixed dose of 4 mg/day.

Phase I and pharmacologic study of docetaxel and cisplatin in patients with advanced solid tumors

PURPOSEnThis phase I study was performed to assess the feasibility of the combination of docetaxel and cisplatin and to determine the maximum-tolerated dose (MTD) and the side effects with an emphasis on sequence-dependent side effects.nnnMATERIALS AND METHODSnPatients who were not pretreated with taxanes or cisplatin derivatives and who had received no more than one prior combination chemotherapy regimen or two single-agent regimens were entered. Treatment consisted of docetaxel given as a 1-hour infusion followed by cisplatin as a 3-hour infusion (schedule A), or cisplatin followed by docetaxel (schedule B). Docetaxel doses ranged from 55 to 100 mg/m2 and cisplatin doses from 50 to 100 mg/m2.nnnRESULTSnLeukocytopenia and granulocytopenia were common (overall, 90%; grade 3 or 4, 87%), short-lasting, and docetaxel dose-dependent. Infections and neutropenic fever occurred in 10% and 4.5% of courses, respectively. Nonhematologic toxicities were mild to moderate and included alopecia, nausea, vomiting, diarrhea, mucositis, neurotoxicity, fluid retention, and skin and nail toxicity. There were no significant differences in pharmacokinetic parameters between schedules A and B. Tumor responses included one complete response (CR) and nine partial responses (PRs).nnnCONCLUSIONnThe dose levels docetaxel 100 mg/m2 plus cisplatin 75 mg/m2 and docetaxel 85 mg/m2 plus cisplatin 100 mg/m2 appeared to be manageable. At these dose levels, the median relative dose-intensity was high and 81% and 88% of all cycles, respectively, could be given at full dose. Schedule A is advocated for further treatment.

The effect of dexamethasone on the uptake of cisplatin in 9L glioma and the area of brain around tumor

The negative influence of dexamethasone (Dex) on the uptake of cisplatin in brain tumors was investigated in rats bearing 9L glioma. Dex or saline was given intraperitoneally prior to intravenous administration of cisplatin 5 mg/kg. Total Platinum (Pt) concentration was quantified with atomic absorption spectroscopy (AAS) in tumor, brain around tumor (BAT), normal brain and plasma. In the second experiment DNA-adducts of cisplatin were determined in tumor and BAT by AAS. In tumor, there was no difference in the Pt concentration and in the DNA-adduct level between the two treatment groups. In BAT, the Pt level in the Dex group was 0.20 µg/g (SD = 0.10 µg/g), which was significantly lower than in the controls (0.53 µg/g (SD=0.21 µg/g); p < 0.001). In addition, the DNA-adduct level in BAT was 23% lower in the Dex treated rats (p=0.05). In normal brain the Pt concentration was 10-fold lower than in tumor tissue. Thus, Dex did not significantly limit the uptake of cisplatin in brain tumor nor did it influence the uptake in normal brain parenchyma. In contrast, in BAT that has a partially disrupted BBB, the concentrations of Pt and DNA-adduct formation were significantly decreased following pretreatment with Dex. The influence of Dex on limiting the effects of chemotherapy for brain tumors needs further study.

The bioavailability of oral GI147211 (GG211), a new topoisomerase I inhibitor

Topoisomerase I inhibitors are new compounds of interest for cancer chemotherapy. We performed a study with GI147211, a new semisynthetic camptothecin analogue, to determine the absolute bioavailability of the drug given orally. Patients with a histologically confirmed diagnosis of a solid tumour refractory to standard forms of therapy were eligible for the study. GI147211 was given orally on day 1 and as a 30-min infusion daily on days 2-5. The treatment course was repeated every 3 weeks. In subsequent patient cohorts, the dose of the oral formulation was escalated from 1.5 mg m(-2) to 6.0 mg m(-2); the dose for i.v. administration was fixed at 1.2 mg m(-2). Plasma pharmacokinetics was performed on day 1 and 2 of the first course and on day 1 of the second course using a validated high-performance liquid chromatographic assay. Nineteen patients were entered into the study; one patient was not evaluable because the treatment course was stopped prematurely. Eighteen patients received a total of 47 treatment courses. The absolute bioavailability of GI147211 averaged 1.3 +/- 5.2%. Drug appeared quickly in plasma with a median Tmax at 0.5 h. Fasting or fed state had no significant influence on the bioavailability of GI147211. The terminal half-life after administration of oral GI147211 was 6.85 +/- 3.13 h, similar to the half-life after intravenous administration. The major toxicities were neutropenia and thrombocytopenia. Nadirs for neutropenia and thrombocytopenia occurred on day 8 and day 15 respectively. Other toxicities predominantly consisted of mild and infrequent nausea and vomiting, and fatigue. The oral administration of the drug is well tolerated. Oral administration of topoisomerase I inhibitor GI147211 results in a low bioavailability with relatively wide interpatient variation. The intravenous route of administration is advised for further development of this promising topoisomerase I inhibitor.

Phase I study on docetaxel and ifosfamide in patients with advanced solid tumours

Docetaxel and ifosfamide have shown significant activity against a variety of solid tumours. This prompted a phase I trial on the combination of these drugs. This phase I study was performed to assess the feasibility of the combination, to determine the maximum tolerated dose (MTD) and the side effects, and to propose a safe schedule for further phase II studies. A total of 34 patients with a histologically confirmed solid tumour, who were not pretreated with taxanes or ifosfamide and who had received no more than one line of chemotherapy for advanced disease were entered into the study. Treatment consisted of docetaxel given as a 1-h infusion followed by ifosfamide as a 24-h infusion (schedule A), or ifosfamide followed by docetaxel (schedule B) every 3 weeks. Docetaxel doses ranged from 60 to 85 mg m(-2) and ifosfamide doses from 2.5 to 5.0 g m(-2). Granulocytopenia grade 3 and 4 were common (89%), short lasting and ifosfamide dose dependent. Febrile neutropenia and sepsis occurred in 17% and 2% of courses respectively. Non-haematological toxicities were mild to moderate and included alopecia, nausea, vomiting, mucositis, diarrhoea, sensory neuropathy, skin and nail toxicity and oedema. There did not appear to be any pharmacokinetic interaction between docetaxel and ifosfamide. One complete response (CR) (soft tissue sarcoma) and two partial responses (PRs) were documented. A dose of 75 mg m(-2) of docetaxel combined with 5.0 g m(-2) ifosfamide appeared to be manageable. Schedule A was advocated for further treatment.

Abstract CT103: Clinical safety and efficacy of pembrolizumab (MK-3475) in patients with malignant pleural mesothelioma: Preliminary results from KEYNOTE-028

Background: The programmed death receptor 1 (PD-1) pathway is implicated in evasion of the antitumor immune response. Pembrolizumab is a potent, highly selective humanized monoclonal antibody against PD-1 designed to block interaction with its ligands, PD-L1 and PD-L2, thus removing inhibition of T-cell activation against cancer. PD-L1 is overexpressed in malignant pleural mesothelioma (MPM) and associated with poor prognosis. We assessed the safety and efficacy of pembrolizumab in patients with PD-L1-positive MPM. Methods: KEYNOTE-028 (ClinicalTrials.gov, NCT02054806) is a nonrandomized, multicohort, phase Ib trial of pembrolizumab for PD-L1-positive advanced solid tumors. Key eligibility criteria for the MPM cohort were measurable disease, PD-L1 expression in ≥1% of cells in tumor nests or PD-L1-positive bands in stroma as determined by a prototype immunohistochemistry assay at a central laboratory, failure of standard therapy, Eastern Cooperative Oncology Group performance status (ECOG PS) 0-1, adequate organ function, and no autoimmune disease or interstitial lung disease. Pembrolizumab 10 mg/kg was given every 2 weeks for up to 2 years or until confirmed progression or unacceptable toxicity. Primary end points are safety, tolerability, and preliminary efficacy. Response was assessed per RECIST v1.1 by investigators every 8 weeks for the first 6 months and every 12 weeks thereafter. Results: Of the 84 patients with MPM who were screened, 38 (45%) had PD-L1-positive tumors. Between March 2014 and December 2014, 25 patients with MPM were treated (68% men; median age, 65 years; 64% ECOG PS 1). 36% of patients had epithelioid histology. 88% of patients received ≥1 prior therapy (28% ≥2); 80% received a platinum and pemetrexed. Fifteen patients (60%) experienced a drug-related adverse event (DRAE); only 3 (12%) had grade ≥3 DRAEs. DRAEs with incidence >25% were nausea (40%), fatigue (32%), and decreased appetite (28%). Four patients (16%) experienced immune-related AEs, but only 2 patients required dose interruption (1 because of ALT increased, 1 because of uveitis). There was no treatment-related mortality, and no patients discontinued because of DRAEs. Preliminary overall response rate (confirmed and unconfirmed) was 24% (n = 6); 13 patients (52%) had stable disease, resulting in a disease control rate of 76%. Four patients (16%) had progressive disease, and 2 patients had no assessment at the time of analysis. 16 patients (64%), including all responders, remain on treatment (duration 8+ to 24+ weeks). Conclusion: Pembrolizumab is generally well tolerated and provides robust antitumor activity in patients with advanced PD-L1+ MPM. The 76% disease control rate in this previously treated MPM population is unprecedented and warrants further study. Citation Format: Evan W. Alley, L. Rhoda Molife, Armando Santoro, Kim Beckey, Sammy Yuan, Jonathan D. Cheng, Bilal Piperdi, Johannes H.M. Schellens. Clinical safety and efficacy of pembrolizumab (MK-3475) in patients with malignant pleural mesothelioma: Preliminary results from KEYNOTE-028. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT103. doi:10.1158/1538-7445.AM2015-CT103

Docetaxel and paclitaxel inhibit DNA-adduct formation and intracellular accumulation of cisplatin in human leukocytes

Abstractu2002The purpose of this study was to determine the mechanism of the pharmacodynamic interaction between docetaxel/paclitaxel and cisplatin. Cisplatin-induced DNA-adducts and cisplatin accumulation were quantitated in peripheral blood leukocytes (WBC). The WBC were obtained from patients treated with docetaxel or paclitaxel in phase I/II studies and were incubated in vitro with cisplatin. In addition, blank whole-blood samples were obtained from patients and healthy subjects and incubated in vitro with cisplatin or docetaxel/paclitaxel and cisplatin. The cisplatin-induced DNA-adduct levels measured in WBC after treatment with docetaxel or paclitaxel were significantly lower than those determined in non-pretreated WBC. Docetaxel and paclitaxel reduced the intracellular accumulation of cisplatin in WBC by 46–47%. If the pharmacodynamic interaction between docetaxel/paclitaxel and cisplatin also occurs in other normal tissues such as bone marrow, it may well contribute to the sequence dependent toxicity that has been observed in clinical studies.

A phase II study of weekly high-dose cisplatin combined with oral etoposide in advanced non-small-cell lung cancer

Abstractu2003As a dose-response relationship has been suggested for cisplatin, it appeared attractive to explore high-dose-intensity regimens in non-small-cell lung cancer. In a phase I study of weekly administration of cisplatin combined with oral etoposide we achieved a cisplatin dose intensity of 52.5u200a–u200a60 mg/m2 per week in most patients. We subsequently explored this regimen in advanced non-small-cell lung cancer. Patients were treated with cisplatin infused at 70 mg/m2 on days 1, 8, 15 and 29, 36, 43 in combination with oral etoposide given at 50 mg on days 1u200a–u200a15 and 29u200a–u200a43. Patients showing stable disease or a better response were continued on treatment with oral etoposide given at 50 mg/m2 per day on days 1u200a–u200a21 every 28 days for a maximum of four cycles. In all, 22 patients with stage III disease and 31 patients with stage IV disease entered the study. The median number of cisplatin administration was 6 per patient; 17 patients reached the planned cisplatin dose intensity of 60 mg/m2 per week, 11 patients achieved 52.5 mg/m2 per week, and 7 patients reached 47 mg/m2 per week. Overall, 11 of 21 stage III patients had a partial response [response rate 51%, 95% confidence interval (CI) 36u200a–u200a81%], as did 9 of 28 patients with stage IV disease (32%; 95% CI 15u200a–u200a49%). Toxicity was mainly hematologic, with leukocytopenia being the most frequent cause of treatment delay. Nephrotoxicity of grade 1 was observed in seven patients. Two patients developed clinical hearing loss. With this schedule a high median cisplatin dose intensity of 52.5u200a–u200a60 mg/m2 per week was reached. The 51% response rate achieved in stage III disease makes this schedule attractive for further exploration; however, it is not recommended for routine use in stage IV disease.