Matjaz Zwitter
University of Maribor
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Featured researches published by Matjaz Zwitter.
Anti-Cancer Drugs | 2005
Matjaz Zwitter; Viljem Kovac; Uros Smrdel; I. Kocijancic; B. Segedin; Martina Vrankar
After monotherapy with gemcitabine in low dose in long infusion, promising results in a variety of advanced chemoresistant tumors have been reported. In a previous phase I trial on heavily pre-treated patients, maximum tolerated dose (MTD) of gemcitabine in a 6 h infusion was 250 mg/m2. The objective of our phase I–II trial was to test the combination of gemcitabine in a 6-h infusion and cisplatin in the treatment of advanced non-small cell lung cancer (NSCLC). Eligible patients were chemonaive, had locally advanced or metastatic NSCLC, Eastern Oncology Cooperative Oncology Group performance status 0–2 and normal organ function. Treatment consisted of gemcitabine in a 6-h infusion on days 1 and 8, and cisplatin at 75 mg/m2 on day 2 of a 3-week cycle. During phase I of the trial, the dose of gemcitabine was escalated from 130 to 170, 210 and 250 mg/m2. After establishing dose-limiting toxicity (DLT) and MTD of the combination, the trial continued as phase II. Altogether, 61 patients were enrolled, of whom 54 had stage IV disease. In phase I of the trial, groups of six, seven, eight and eight patients were treated at the four dose levels of gemcitabine. In phase II, the remaining 32 patients all received gemcitabine at 250 mg/m2. Serious toxicity included a patient with grade 5 ventricular arrhythmia and another with grade 4 cerebrovascular ischemia; four patients had grade 3 anemia. Reversible thrombocytosis with platelets over 500 was recorded in 32 patients; 42 patients had grade 2 alopecia. In general, tolerance to this treatment was good. One patient had complete response and 27 had partial responses, for a 28 of 61 (46%) response rate. Median progression-free survival, median survival and 1-year survival were 6 months, 9.5 months and 40%, respectively. We conclude that this treatment has an acceptable, yet distinct, toxicity profile; routine thromboprophylaxis is recommended. In our population of chemonaive patients, no DLT has been encountered. Due to the remarkable response rate, further research is warranted.
Radiology and Oncology | 2014
Karmen Stanic; Matjaz Zwitter; Nina Turnsek Hitij; Izidor Kern; Aleksander Sadikov; Tanja Cufer
Abstract Background. The brain represents a frequent progression site in lung adenocarcinoma. This study was designed to analyse the association between the epidermal growth factor receptor (EGFR) mutation status and the frequency of brain metastases (BM) and survival in routine clinical practice. Patients and methods. We retrospectively analysed the medical records of 629 patients with adenocarcinoma in Slovenia who were tested for EGFR mutations in order to analyse the cumulative incidence of BM, the time from the diagnosis to the development of BM (TDBM), the time from BM to death (TTD) and the median survival. Results. Out of 629 patients, 168 (27%) had BM, 90 patients already at the time of diagnosis. Additional 78 patients developed BM after a median interval of 14.3 months; 25.8 months in EGFR positive and 11.8 months in EGFR negative patients, respectively (p = 0.002). EGFR mutations were present in 47 (28%) patients with BM. The curves for cumulative incidence of BM in EGFR positive and negative patients demonstrate a trend for a higher incidence of BM in EGFR mutant patients at diagnosis (19% vs. 13%, p = 0.078), but no difference later during the course of the disease. The patients with BM at diagnosis had a statistically longer TTD (7.3 months) than patients who developed BM later (3.1 months). The TTD in EGFR positive patients with BM at diagnosis was longer than in EGFR negative patients (12.6 vs. 6.8, p = 0.005), while there was no impact of EGFR status on the TTD of patients who developed BM later. Conclusions. Except for a non-significant increase of frequency of BM at diagnosis in EGFR positive patients, EGFR status had no influence upon the cumulative incidence of BM. EGFR positive patients had a longer time to CNS progression. While EGFR positive patients with BM at diagnosis had a longer survival, EGFR status had no influence on TTD in patients who developed BM later during the course of disease.
Radiology and Oncology | 2012
Viljem Kovac; Matjaz Zwitter; Tina Zagar
Improved survival after introduction of chemotherapy for malignant pleural mesothelioma in Slovenia: Population-based survey of 444 patients Background. Malignant pleural mesothelioma is a rare tumour with increasing frequency throughout the world. Due to long latency after exposure to asbestos, restrictions in the production and use of asbestos have not yet alleviated the burden of mesothelioma. During the last decade, several trials confirmed the benefit of systemic treatment with drugs such as doublets with cisplatina and gemcitabine or pemetrexed for carefully selected patients in good performance status. The purpose of this survey was to assess the impact of systemic treatment for the whole national population of patients with mesothelioma. Patients and methods. A retrospective study included all patients in Slovenia with histologically confirmed diagnosis of malignant pleural mesothelioma in the period from 1974 till 2008. Data from the Cancer Registry of Slovenia were supplemented by review of clinical records of the Institute of Oncology in Ljubljana where virtually all non-surgical treatment for mesothelioma was performed. We analysed the incidence, treatment, and survival of patients treated in the era of infrequent chemotherapy (1974-2003, the first period) and after it (2004-2008, the second period). Results. The survey included 444 patients, of whom 325 and 119 were diagnosed in the first and second period, respectively. Joinpoint regression analysis showed that after 1995 the trend in crude incidence rates increased more rapidly; the annual change was 0.03 per 100,000 per year before 1995 and 0.06 per 100,000 per year after. There was clear male predominance (70%) throughout the period covered by the survey. The proportion of patients above 65 years of age increased from 41.8% to 54.6% for the first and second period, respectively (p = 0.02). With a total of 52 (11.7%) operated patients, surgical treatment was rare and used only for selected patients with early disease and without comorbidity, leading to their relatively long median survival of 13.6 months. Chemotherapy was applied to 56 (17.2%) and to 96 (80.7%) patients during the first and second period, respectively. While a variety of older drugs were used in the first period, the most common regimen in the second period (applied to 91 patients) was doublet of low-dose gemcitabine in prolonged infusion and cisplatin. For the whole population of patients regardless the mode of treatment, median survival was 7.4 and 12.6 months (p-value = 0.037) for the first and second period, respectively. Conclusions. Increasing incidence, male predominance and increased proportion of older patients confirm that the burden of mesothelioma persists in spite of a 15-years old ban in the production of asbestos. Modern chemotherapy, and in particular treatment with low-dose gemcitabine in prolonged infusion and cisplatin significantly prolonged median survival of patients with malignant pleural mesothelioma in Slovenia.
Radiology and Oncology | 2014
Matjaz Zwitter; Karmen Stanic; Mirjana Rajer; Izidor Kern; Martina Vrankar; Natalija Edelbaher; Viljem Kovac
Abstract Background. Pharmaco-dynamic separation of cytotoxic and targeted drugs might avoid their mutual antagonistic effect in the treatment of advanced non-small cell lung cancer (NSCLC). Patients and methods. Eligible patients were treatment-naive with stage IIIB or IV NSCLC. In addition, inclusion was limited to never-smokers or light smokers or, after 2010, to patients with activating epidermal growth-factor receptor (EGFR) mutations. Treatment started with 3-weekly cycles of gemcitabine and cisplatin on days 1, 2 and 4 and erlotinib on days 5 to 15. After 4 to 6 cycles, patients continued with erlotinib maintenance. Results. Fifty-three patients were recruited into the trial: 24 prior to 2010 (of whom 9 were later found to be positive for EGFR mutations), and 29 EGFR mutation-positive patients recruited later. Unfavourable prognostic factors included stage IV disease (51 patients - 96%), performance status 2-3 (11 patients - 21%) and brain metastases (15 patients - 28%). Grade 4 toxicity included 2 cases of neutropenia and 4 thrombo-embolic events. The 15 EGFR negative patients had 33% objective response rate, median progression-free survival (PFS) 6.0 months and median survival 7.6 months. Among 38 EGFR positive patients, complete response (CR) or partial response (PR) were seen in 16 (42.1%) and 17 (44.7%) cases, respectively. PET-CT scanning was performed in 30 patients and confirmed CR and PR in 16 (53.3%) and 9 (30.0%) cases, respectively. Median PFS for EGFR mutated patients was 21.2 months and median survival was 32.5 months. Conclusions. While patients with EGFR negative tumors do not benefit from addition of erlotinib, the intercalated schedule appears most promising for those with EGFR activating mutations
Anti-Cancer Drugs | 2012
Viljem Kovac; Matjaz Zwitter; Mirjana Rajer; Aleksander Marin; Andrej Debeljak; Uros Smrdel; Martina Vrankar
After a favorable experience with gemcitabine at a low dose in a prolonged infusion in combination with cisplatin for advanced non-small-cell lung cancer, here, we present the results from a phase II trial for patients with malignant pleural mesothelioma. Eligible patients had biopsy-proven malignant pleural mesothelioma, were chemo-naive, Eastern Cooperative Oncology Group performance status 0–2, had normal hematopoietic liver and renal function, and gave informed consent. Treatment consisted of gemcitabine 250 mg/m2 in a 6-h infusion on days 1 and 8 and cisplatin at 75 mg/m2 on day 2 of a 3-week cycle for four cycles, followed by two additional cycles without cisplatin. Seventy-eight patients (58 men, 20 women; age 33–82 years, median 58) were recruited into the trial. The histologic types were as follows: epitheloid 56 (71.8%); four sarcomatoid (5.1%); mixed 15 (19.2%); and mesothelioma, three not otherwise specified (3.8%). Grades 3–4 toxicity included two (2.6%) patients with anemia, 18 (23.1%) with neutropenia, and one with nausea/vomiting. Reversible thrombocytosis with platelets over 1000–109/l was recorded in 10 (12.8%) patients and grade 2 alopecia in 60 (76.9%). Four (5.1%) patients showed a complete response and 35 (44.9%) showed a partial response with a response rate of 39/78 (50%). Minimal response or stable disease was seen in 35 (44.9%), whereas only four (5.1%) patients progressed during treatment. Most patients reported symptomatic improvement with a higher or a stable quality of life score in 70 (89.7%) cases. The median progression-free survival was 8.0 months (confidence interval 6.9–9.0). The median overall survival was 17.0 months (confidence interval 14.7–19.2). One-year, two-year, and three-year survival rates were 67.3, 32.7, and 19.8%, respectively. Epitheloid histological type was the only statistically significant favorable prognostic factor for progression-free survival and overall survival. Because of the acceptable toxicity, remarkable activity, and reasonable cost, this treatment should be further explored.
Journal of Thoracic Oncology | 2009
Matjaz Zwitter; Viljem Kovac; Uros Smrdel; Martina Vrankar; Vesna Zadnik
Objective: Gemcitabine in low dose in prolonged infusion is a treatment with documented activity against a variety of tumors. We here report the first randomized trial to compare standard brief and low-dose prolonged infusion of gemcitabine. Patients and Methods: Eligible patients had non-small cell lung cancer in stage IIIB (wet) or IV, Karnofsky performance status 100 to 70 (Eastern Cooperative Oncology Group 0–2), measurable disease, were chemonaïve and fulfilled the standard criteria for chemotherapy. In arm A (standard treatment), gemcitabine was given at 1250 mg/m2 in 20 to 30 minutes and in arm B (prolonged infusion) at 250 mg/m2 in 6 hours infusion. All patients received gemcitabine on days 1 and 8 and cisplatin at 75 mg/m2 on day 2 of a 3-week cycle for four cycles, followed by two cycles of gemcitabine as monotherapy. Results: A total of 249 patients (188 men and 61 women, median age 58 years) were randomized between arm A (125 patients) and arm B (124 patients). Adenocarcinoma (53.9%) was the predominant histologic type; 92% of patients were in stage IV. The two groups were balanced for prognostic factors; however, group A had fewer patients with significant weight loss and no patient with lung cancer as a second malignancy or after radiotherapy for brain metastases. Grade 3 or greater toxicity was rare: anemia in 0.8 and 3.2%, neutropenia in 21.6 and 22.6%, thrombocytopenia in 0 and 1.6%, and nausea/vomiting in 4 and 8.1% for arms A and B, respectively. Alopecia was seen in 54.5% of patients in arm B, as compared with 9.7% in arm A. No patient died of treatment-related toxicity. During cycle 5, 47.7% of patients in arm A and 60.7% in arm B reported improved well-being, as compared with the status before chemotherapy. Patients in arm A had no complete remission, 32.8% partial responses, 48% minimal responses or stable disease, 13.6% progressions, and 5.6% were not evaluable. For arm B, the corresponding figures are as follows: complete remission 0.8%, partial responses 46% (for overall response rate of 46.8%), minimal responses or stable disease 36.3%, progression 12.1%, and not evaluable 4.8%. Median progression-free survival was 5.5 and 6.0 months, median overall survival was 10.1 and 10.0 months, and 1-year survival was 46.6 and 41.1% for arms A and B, respectively. For the 71 patients with squamous carcinoma, arm B seems superior to arm A, as seen by the higher overall response rate (51.3 versus 35.5%), longer median progression-free survival (6.2 versus 4.9 months), and longer median survival (11.3 versus 8.5 months). However, because of the small number of patients, these differences did not reach the level of statistical significance. Conclusion: In the treatment of advanced non-small cell lung cancer, gemcitabine in low dose in prolonged infusion in combination with cisplatin has low toxicity and has activity comparable with gemcitabine in higher dose in standard brief infusion. Low-dose gemcitabine may be preferred for incurable cancer among economically deprivileged patients. In addition, apparent superior activity against squamous carcinoma opens new perspectives and deserves further research.
Lung Cancer | 2003
Maciel Krzakowski; Miklos Wenczl; Thomas Brodowicz; Valentina Tzekova; Rodryg Ramlau; Nicolae Ghilezan; Branka Cucevic; Kalman Gyurkovits; Ulsperger Ernst; Christoph C. Zielinski; Matjaz Zwitter
7067 Background: The optimal treatment duration for NSCLC patients is still a matter of discussion. Objectives of this trial were to compare time to progressive disease (TTPD) in patients treated with single-agent gemcitabine maintenance therapy plus best supportive care (BSC) versus BSC alone following standard GC therapy, to record responses in both arms, and to compare toxicity, duration of response, and overall survival. METHODS Chemonaive patients with stage IIIB or IV NSCLC, no prior radiotherapy >60 Gy to the chest, and a Karnofsky performance status (KPS) of ≥70 received 4 cycles of gemcitabine 1250 mg/m2 (days 1 and 8) plus cisplatin 80 mg/m2 (day 1). At the end of cycle 4, patients without progressive disease (PD) per SWOG criteria were randomized to gemcitabine 1250 mg/m2 (days 1 and 8) maintenance therapy until PD plus BSC (arm A) or BSC only (arm B) in a 2:1 fashion. Radiotherapy was not permitted on both arms. Cycles were repeated every 21 days. Time-to-event endpoints were calculated using the Kaplan-Meier method, and compared between arms using the log-rank and Wilcoxon tests. The incidence of grade 3 and 4 toxicity was compared using Pearsons chi-squared test. RESULTS From Jan 2000 to Jan 2003, 206/354 patients were randomized, 138 on arm A and 68 on arm B. There were 98/40 males/females on arm A and 53/15 on arm B, while 36/102 on arm A and 16/52 on arm B had stage IIIB/IV disease (p=0.7). The median age for arm A and B, respectively, was 58 (range, 30-77) and 56 years (range, 38-74) (p=0.3). A KPS of ≥80/<80 was reported in 113/25 patients on arm A vs 57/11 patients on arm B (p=0.8). Preliminary data indicate a significant benefit in terms of TTPD for patients treated with gemcitabine maintenance therapy: 6.6 vs 5.0 months (through the study; p<0.001) and 3.5 vs 2.0 months (post randomization; p<0.001). CONCLUSIONS At the present time of analysis, maintenance chemotherapy with gemcitabine following GC chemotherapy significantly increased TTPD. Final data will be presented at the meeting. No significant financial relationships to disclose.
Anti-Cancer Drugs | 2010
Matjaz Zwitter; Viljem Kovac; Mirjana Rajer; Martina Vrankar; Uros Smrdel
We present experience from a phase II randomized clinical trial, comparing standard gemcitabine as monotherapy with low-dose gemcitabine in long infusion in a doublet with cisplatin at reduced dose for patients with non-small cell lung cancer (NSCLC) and who are unfit for standard platin-based chemotherapy. Eligible patients had microscopically confirmed NSCLC in stage IIIB (wet) or IV, were chemo-naive, and were in poor performance status or presented with significant comorbidity. Standard treatment with gemcitabine, 1250 mg/m2 in 20–30 min on days 1 and 8 as monotherapy (arm A) was compared with low-dose gemcitabine in long infusion (200 mg/m2 in 6 h on day 1) and cisplatin at 60 mg/m2 on day 2 (arm B). Both treatment schedules were repeated every 3 weeks until disease progression, unacceptable toxicity, or to a maximum of six cycles. A total of 112 patients (83 male, 29 female, median age 66 years) were randomized between arm A (57 patients) and B (55 patients). The two groups were balanced for prognostic factors. Fifty-three patients in arm A and 52 in arm B received at least one application of chemotherapy and were evaluable for toxicity and response. The median number of cycles was four and five for arms A and B, respectively. Except for grade 3 anemia (one patient in arm A and two in arm B), no other major toxicity was seen. Regarding response to treatment, arm B was superior: 1 complete response and 13 partial remissions (response rate 26.9%) as compared with five partial remissions (response rate 9.4%) in arm A (P<0.01). The median time to progression was 3.8 and 5.6 months, and the median survival was 4.3 and 6.8 months for arms A and B, respectively (P<0.05). Treatment with low-dose gemcitabine in long infusion and cisplatin at reduced dose has very low toxicity, is effective, was found to be superior to monotherapy with gemcitabine in standard doses, and is suitable for patients with NSCLC who cannot tolerate a standard platin-based doublet.
Lung Cancer | 2010
Robert Pirker; Peter Berzinec; Stephen Brincat; Peter Kasan; Gyula Ostoros; Miloš Pešek; Signe Plāte; Gunta Purkalne; Regina Rooneem; Jana Skřičková; Dana Stanculeanu; Constanta Timcheva; Valentina Tzekova; Branko Zakotnik; Christoph Zielinski; Matjaz Zwitter
Systemic chemotherapy plays the major role in the management of patients with small cell lung cancer. Cisplatin plus etoposide is the most widely used regimen and is considered as standard in patients with limited disease. Cisplatin plus irinotecan improved survival compared to cisplatin plus etoposide in a Japanese trial but failed to do so in two trials in Caucasians. Cisplatin plus topotecan had similar efficacy compared to cisplatin plus etoposide in patients with extensive disease. In the second-line setting, topotecan showed similar efficacy but better tolerability compared to cyclophosphamide, doxorubin plus vincristine. Oral topotecan was as efficacious as its intravenous formulation and was shown to improve survival compared to best supportive care alone in patients previously treated with chemotherapy. Thus topotecan is considered as the standard second-line chemotherapy in patients with small cell lung cancer.
Radiology and Oncology | 2016
Uros Smrdel; Mara Popović; Matjaz Zwitter; Emanuela Boštjančič; Andrej Zupan; Viljem Kovac; Damjan Glavač; Drago Bokal; Janja Jerebic
Abstract Background In spite of significant improvement after multi-modality treatment, prognosis of most patients with glioblastoma remains poor. Standard clinical prognostic factors (age, gender, extent of surgery and performance status) do not clearly predict long-term survival. The aim of this case-control study was to evaluate immuno-histochemical and genetic characteristics of the tumour as additional prognostic factors in glioblastoma. Patients and methods Long-term survivor group were 40 patients with glioblastoma with survival longer than 30 months. Control group were 40 patients with shorter survival and matched to the long-term survivor group according to the clinical prognostic factors. All patients underwent multimodality treatment with surgery, postoperative conformal radiotherapy and temozolomide during and after radiotherapy. Biopsy samples were tested for the methylation of MGMT promoter (with methylation specific polymerase chain reaction), IDH1 (with immunohistochemistry), IDH2, CDKN2A and CDKN2B (with multiplex ligation-dependent probe amplification), and 1p and 19q mutations (with fluorescent in situ hybridization). Results Methylation of MGMT promoter was found in 95% and in 36% in the long-term survivor and control groups, respectively (p < 0.001). IDH1 R132H mutated patients had a non-significant lower risk of dying from glioblastoma (p = 0.437), in comparison to patients without this mutation. Other mutations were rare, with no significant difference between the two groups. Conclusions Molecular and genetic testing offers additional prognostic and predictive information for patients with glioblastoma. The most important finding of our analysis is that in the absence of MGMT promoter methylation, longterm survival is very rare. For patients without this mutation, alternative treatments should be explored.