Tumour Lysis Syndrome Associated with Lenvatinib: an Investigator-Initiated, Retrospective Observational Post-Authorisation Safety Study (TELSTAR)

Study type

• Study topic:
  Human medicinal product
• Study type:
  Non-interventional study
• Scope of the study:
  Safety study (incl. comparative)
• Data collection methods:
  Secondary use of data

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Medicinal product name:
  LENVIMA

  KISPLYX
• Study drug International non-proprietary name (INN) or common name:
  LENVATINIB
• Anatomical Therapeutic Chemical (ATC) code:
  (L01EX08) lenvatinib

  lenvatinib
• Medical condition to be studied:
  Tumour lysis syndrome

Population studied

• Age groups:
  • Adult and elderly population (≥18 years)

    • Adults (18 to < 65 years)

      • Adults (18 to < 46 years)
      • Adults (46 to < 65 years)
    • Elderly (≥ 65 years)

      • Adults (65 to < 75 years)
      • Adults (75 to < 85 years)
      • Adults (85 years and over)

Study design details

• Study design:
  Retrospective, single-centre observational cohort PASS using real-world EHR data to estimate the incidence of tumour lysis syndrome in adults treated with lenvatinib, with descriptive subgroup analyses and pharmacovigilance reporting.
• Main study objective:
  To estimate the incidence proportion of TLS, including both laboratory TLS and clinical TLS, ; defined according to Cairo–Bishop criteria, among patients treated with lenvatinib at ULSSJ during the ; study period
• Setting:
  This single-centre study is conducted at ULS São João (Porto, Portugal) using routinely collected electronic health record and pharmacy data. The study population includes all adult patients (≥18 years) treated with lenvatinib for any oncologic indication between 28 May 2015 and 30 November 2025. Patients are identified through hospital pharmacy dispensing records and cross-checked with prescribing and oncology consultation systems.; ; Inclusion requires documented lenvatinib exposure and availability of baseline and on-treatment laboratory data sufficient to assess tumour lysis syndrome (TLS). Patients enrolled in interventional trials with lenvatinib or lacking adequate laboratory data are excluded from the evaluable cohort (though recorded for coverage assessment).; ; The study follows a single exposed cohort (no external comparator), with follow-up from treatment initiation (index date) until treatment discontinuation or last recorded contact. Subgroup analyses are planned according to clinically relevant variables, including treatment indication, baseline renal function, tumour burden (e.g. LDH), and combination therapy (e.g. with pembrolizumab).
• Comparators:
  The study uses a single exposed cohort (lenvatinib-treated patients) without an external comparator group.
• Outcomes:
  The primary outcome is the incidence proportion of tumour lysis syndrome (TLS) among patients treated with lenvatinib, defined according to Cairo–Bishop criteria and including both:; Laboratory TLS (LTLS); Clinical TLS (CTLS); ; Secondary outcomes include:; Clinical characterization of TLS cases (e.g. tumour type, renal function, tumour burden); Severity grading (CTCAE v5.0); Causality assessment (WHO-UMC); Clinical outcomes (recovery, sequelae, death); Subgroup incidence estimates (e.g. by indication, renal function, combination therapy)
• Data analysis plan:
  The primary analysis will estimate the incidence proportion of tumour lysis syndrome (TLS) among evaluable lenvatinib-exposed patients, calculated as the number of patients with at least one TLS event during treatment divided by the number of evaluable exposed patients. Exact 95% binomial confidence intervals (Clopper–Pearson) will be calculated.; ; Secondary analyses will estimate incidence separately for laboratory TLS (LTLS) and clinical TLS (CTLS), and will also describe laboratory data coverage using all exposed patients as the denominator. Exploratory subgroup analyses will be performed according to clinically relevant variables such as indication, baseline renal function, LDH, and combination therapy. These comparisons will be presented descriptively using risk ratios with 95% confidence intervals and assessed with Fisher’s exact test. No imputation of missing data is planned; exclusions from the evaluable cohort and reasons for missingness will be summarized. All analyses will be performed in R (version 4.3 or higher)