Tamara Knezevic Ivanovski

Dr. Tamara Knezevic Ivanovski


Research Focus & Metrics

Academic Career Length

3Years (2024-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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23 December 2024 in Pharmaceutics
Verified
Journal Article
Open access
PDF file
SMSrdjan Markovic
Srdjan Markovic
DKDjordje Kralj
Djordje Kralj
PSPetar Svorcan
Petar Svorcan
TITamara Knezevic Ivanovski
Tamara Knezevic Ivanovski
OGOlga Golubovic
Olga Golubovic
Katarina M VučićevićKatarina M Vučićević
Katarina M Vučićević
Background/Objectives: Vedolizumab (VDZ) is approved in the treatment of patients with moderate to severe ulcerative colitis (UC) or Crohn’s disease (CD). VDZ exhibits considerable variability in its pharmacokinetic (PK) profile, and its exposure-response relationship is not yet fully understood. The aim was to investigate the variability in VDZ trough levels and PK parameters, to assess the relationship between VDZ PK and biochemical response, as well as clinical and endoscopic outcomes. Methods: We included 61 UC and 45 CD patients. Patients’ data and trough VDZ concentrations were retrospectively obtained. Population PK analysis was performed using non-linear mixed-effects modelling with NONMEM (version 7.5). Graphs and statistical analyses were performed using R (version 4.1.3). Results: In total, 116 trough VDZ concentrations from 106 patients were described by a two-compartment model. For a typical patient, clearance (CL) was estimated at 0.159 L/day, while in patients previously treated with anti-TNFα agents, VDZ CL increased by 26.4% on average. In univariate binary logistic regression, VDZ trough concentration was not statistically significant predictor of remission, whereas CL was. Moreover, combined CL and faecal calprotectin (FCP) were a statistically significant predictors of remission. The hazard ratio (HR) for CL above 0.1886 L/day was 0.35 (p = 0.05) and for FCP below 250 µg/g was 2.66 (p = 0.02) in a time-to-event analysis. Conclusions: Our population PK model incorporates the effect of prior anti-TNFα agents on CL, suggesting its association with more severe forms of IBD. VDZ CL emerged as a more robust and clinically relevant predictor of remission in IBD patients than trough concentration.

14 February 2025 in Medicina
Verified
Journal Article
Open access
PDF file
SMSrdjan Markovic
Srdjan Markovic
DKDjordje Kralj
Djordje Kralj
TITamara Knezevic Ivanovski
Tamara Knezevic Ivanovski
PSPetar Svorcan
Petar Svorcan
Background and Objectives: On 11 March 2020, our hospital adapted to the COVID-19 pandemic by becoming a temporary COVID-19 facility, leading to the suspension or delegation of non-COVID-19 services. Among the international IBD community, there were significant concerns regarding the neglect of immunocompromised IBD patients and their increased vulnerability to COVID-19. To address these challenges, the COVID-19 ECCO Taskforce recommended the implementation of telehealth. Following this recommendation, our hospital’s IT department integrated audiovisual hardware and software solutions to facilitate virtual consultations. This approach enabled patients and their local physicians to receive formal reports comparable to those issued during standard in-person care. Materials and Methods: We retrospectively analyzed data from patients diagnosed with Crohn’s disease and ulcerative colitis who participated in telemedicine consultations. Average distances and time saved were calculated using Google Maps, while carbon emissions and carbon footprint reductions were determined. Results: Between 11 August 2021 and 15 June 2023, 107 telehealth consultations were completed. Patients benefited from reduced travel distances, with an average saving of 168.28 km per consultation and a total reduction of 18,006 km. Travel time savings averaged 2 h and 22 min per consultation, amounting to a total of 252 h saved. The reduction in carbon emissions was calculated at 3.26 tons, equivalent to the annual absorption capacity of 109 fully grown trees, considering that an individual tree absorbs approximately 21.77 kg of CO2 annually. These findings underscore telemedicine’s role in reducing environmental impact while enhancing patient convenience. Conclusions: The adoption of telehealth successfully optimized outpatient clinic operations, maintaining high-quality patient outcomes while contributing to environmental sustainability.

28 July 2025 in Pharmaceuticals
Verified
Journal Article
Open access
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BMBojana Milasinovic
Bojana Milasinovic
SKSandra Vezmar Kovačević
Sandra Vezmar Kovačević
SMSrdjan Markovic
Srdjan Markovic
Marija JovanovicMarija Jovanovic
Marija Jovanovic
TITamara Knezevic Ivanovski
Tamara Knezevic Ivanovski
Katarina M VučićevićKatarina M Vučićević
Katarina M Vučićević
Background/Objectives: Vedolizumab is a gut-selective anti-integrin monoclonal antibody approved for the treatment of inflammatory bowel disease (IBD). While clinical trials have demonstrated a favorable safety profile, real-world studies are essential for identifying rare adverse events (AEs) and evaluating post-marketing safety. This study assessed vedolizumab’s safety in a real-world cohort and supported the detection of potential safety signals. Methods: A retrospective chart review was conducted on adult IBD patients treated with vedolizumab at a tertiary center in the Republic of Serbia between October 2021 and August 2022. Data included demographics, AEs, and newly reported extraintestinal manifestations (EIMs). Exposure-adjusted incidence rates were calculated per 100 patient-years (PYs). Disproportionality analysis using the FDA Adverse Event Reporting System (FAERS) was performed to identify safety signals, employing reporting odds ratios (RORs) and proportional reporting ratios (PRRs) for AEs also observed in the cohort. Prior IBD therapies and reasons for discontinuation were evaluated. Results: A total of 107 patients (42.1% Crohn’s disease, 57.9% ulcerative colitis) were included, with a median vedolizumab exposure of 605 days. There were 92 AEs (56.51/100 PYs), most frequently infections (23.95/100 PYs), gastrointestinal disorders (4.30/100 PYs), and skin disorders (4.30/100 PYs). The most frequently reported preferred terms (PTs) included COVID-19, COVID-19 pneumonia, nephrolithiasis, and nasopharyngitis. Arthralgia (12.90/100 PYs) was the most frequent newly reported EIM. No discontinuations due to vedolizumab AEs occurred. FAERS analysis revealed potential signals for events not listed in prescribing information but observed in the cohort: nephrolithiasis, abdominal pain, diarrhea, malaise, cholangitis, gastrointestinal infection, blood pressure decreased, weight decreased, female genital tract fistula, respiratory symptom, and appendicectomy. Most patients had received three prior therapies, often stopping one due to AEs. Conclusions: Vedolizumab demonstrated a favorable safety profile in the IBD cohort. However, FAERS-identified signals, such as nephrolithiasis, gastrointestinal infections, and decreased blood pressure, warrant further investigation in larger, more diverse populations.

27 December 2024 in Biomedicines
Verified
Journal Article
Open access
PDF file
Marija JovanovicMarija Jovanovic
Marija Jovanovic
AIAna Homšek Ilić
Ana Homšek Ilić
SMSrdjan Markovic
Srdjan Markovic
DKDjordje Kralj
Djordje Kralj
PSPetar Svorcan
Petar Svorcan
Katarina M VučićevićKatarina M Vučićević
Katarina M Vučićević
Background/Objectives: Several population pharmacokinetic models of vedolizumab (VDZ) are available for inflammatory bowel disease (IBD) patients. However, their predictive performance in real-world clinical settings remains unknown. This study aims to externally evaluate the published VDZ pharmacokinetic models, focusing on their predictive performance and simulation-based clinical applicability. Methods: A literature search was conducted through PubMed to identify VDZ population pharmacokinetic models. A total of 114 VDZ concentrations from 106 IBD patients treated at the University Medical Center “Zvezdara”, Republic of Serbia, served as the external evaluation cohort. The predictive performance of the models was assessed using prediction- and simulation-based diagnostics. Furthermore, the models were utilized for Monte Carlo simulations to generate concentration–time profiles based on 24 covariate combinations specified within the models. Results: Four published pharmacokinetic models of VDZ were included in the evaluation. Using the external dataset, the median prediction error (MDPE) ranged from 13.82% to 25.57%, while the median absolute prediction error (MAPE) varied between 41.64% and 47.56%. None of the models fully met the combined criteria in the prediction-based diagnostics. However, in simulation-based diagnostics, pvcVPC showed satisfactory results, despite wide prediction intervals. Analysis of NPDE revealed that only the models by Rosario et al. and Okamoto et al. fulfilled the evaluation criteria. Simulation analysis further demonstrated that the median VDZ concentration remains above 12 μg/mL at week 22 during maintenance treatment for approximately 45–60% of patients with the best-case covariate combinations and an 8-week dosing frequency. Conclusions: None of the published models satisfied the combined criteria (MDPE, MAPE, percentages of prediction error within ±20% and ±30%), rendering them unsuitable for a priori predictions. However, two models demonstrated better suitability for simulation-based applications.

7 August 2025 in Biomedicines
Verified
Journal Article
Open access
PDF file
TITamara Knezevic Ivanovski
Tamara Knezevic Ivanovski
MPMarija Milic Perovic
Marija Milic Perovic
BSBojan Stopic
Bojan Stopic
OGOlga Golubovic
Olga Golubovic
DKDjordje Kralj
Djordje Kralj
SMSrdjan Markovic
Srdjan Markovic
Background and Aim: Long-term treatment with biologic therapy alongside immunomAfodulators in patients with inflammatory bowel disease (IBD) can be associated with severe side effects. The objective of this study was to determine whether discontinuing anti-TNF treatment after two years in patients who have achieved mucosal healing is associated with lower relapse rates. Materials and Methods: A total of 67 patients with IBD from a single tertiary IBD Center who had achieved mucosal healing were enrolled in this retrospective study. In this single-center retrospective study (January 2014–December 2022), we screened 67 IBD patients in deep remission (endoscopic mucosal healing after ≥2 years of anti-TNF therapy). After excluding three patients without histologic data, 64 patients (25 ulcerative colitis, 39 Crohn’s disease) were analyzed. Mayo endoscopic sub-score and SES-CD were used to evaluate endoscopic activity after two years of anti-TNF therapy. Histological activity was assessed using the GHAS (for CD) and Nancy index (for UC). Results: A total of 67 patients were screened, of whom 3 were excluded due to a lack of biopsies. Of the 64 included patients, 39.06% (25/64) had UC and 60.9% (39/64) had CD, with a mean disease duration of 11.6 ± 8.0 years. All patients were in endoscopic remission at the time of therapy de-escalation, and 60.9% (39/64) also achieved histological remission (“deep remission”). In the follow-up of 38.6 months (IQR 30–48) after biologic therapy was stopped, 57.8% (37/64) relapsed with a median time to relapse of 13.5 months (IQR 8–24) off anti-TNF—a total of 34 patients required a restarting of biologic therapy. Using Spearman’s correlation, a moderate connection was observed between histological activity at withdrawal and subsequent relapse (rho = 0.467, p < 0.001). The probability of relapsing within 4 years after anti-TNF cessation was significantly higher (OR 2.72) in patients with histologically active disease at the time of de-escalation. Conclusions: Achieving ‘deep remission’ (clinical, endoscopic, and histological healing) may be a suitable parameter for making decisions on when to de-escalate therapy; however, given that over half of patients in endoscopic remission relapse after discontinuation, any de-escalation should be approached with caution and individualized patient assessment.

28 February 2026 in Biomedicines
Verified
Journal Article
Open access
PDF file
DKDjordje Kralj
Djordje Kralj
MMMladen Maksic
Mladen Maksic
TITamara Knezevic Ivanovski
Tamara Knezevic Ivanovski
OGOlga Golubovic
Olga Golubovic
TVTijana Veljkovic
Tijana Veljkovic
SMSrdjan Markovic
Srdjan Markovic
Inflammatory bowel disease is a recognized risk factor for venous thromboembolism, whereas arterial thrombotic events remain underappreciated despite their substantial clinical consequences. We report a 45-year-old man without significant comorbidities who developed severe ulcerative colitis complicated by diffuse arterial thrombosis, including cerebral infarctions, an ascending aortic mural thrombus, iliac artery thrombosis, and multi-organ infarctions. After stabilization with supportive care and anticoagulation, remission-directed ulcerative colitis therapy and a vascular safety–oriented maintenance strategy were initiated, including vedolizumab and individualized secondary thrombosis prevention. To contextualize this presentation, we integrate current evidence on the epidemiology, clinical phenotypes, underlying mechanisms, and risk factors for arterial thrombosis in inflammatory bowel disease, highlight disease activity as a dominant trigger, and summarize therapy-specific vascular safety considerations across IBD treatment classes.