The Clinical Benefits of the DiviTum® TKa Test

Using a small blood sample, the DiviTum® TKa test can aid in prognosis and monitoring post-menopausal women with HR+ advanced breast cancer.

The DiviTum® TKa test measures TK activity as a surrogate for cell proliferation and tumor growth.

Consideration may be given to spacing out imaging and using the DiviTum® TKa test as monitoring tool in-between imaging.

It is interesting to learn that the DiviTum® TKa test can identify progression many months ahead of imaging.
Luca Malorni, MD, PhD Medical Oncologist, Prato Hospital, Italy

Validated to be prognostic for disease progression and overall survival1-3*

  • Lower DiviTum TKa levels are associated with lower likelihood of disease progression*

Helps health care providers determine...

which patients are—or are not—responding optimally to CDK4/6 inhibitor therapy and who may benefit from continuing therapy4,5

*In the randomized, phase III, SWOG S0226 clinical trial, DiviTum TKa demonstrated a negative predictive value (NPV) of 97% and 94% within 30 and 60 days post testing, respectively.  This clinical validation study assessed data from 1546 banked blood samples from 454 women with HR+ mBC who were treated with first-line endocrine therapy (anastrozole alone or anastrozole plus fulvestrant).


1. Bergqvist M, et al. Thymidine kinase activity levels in serum can identify HR+ metastatic breast cancer patients with a low risk of early progression (SWOG S0226). Biomarkers January 2023

2. Paoletti C, et al. Evaluating serum thymidine kinase 1 in patients with hormone receptor-positive metastatic breast cancer receiving first-line endocrine therapy in the SWOG S0226 trial. Clin Cancer Res. 2021;27(22):6115-6123.

3. Krishnamurthy J, et al. A phase II trial of an alternative schedule of palbociclib and embedded serum TK1 analysis. NPJ Breast Cancer. 2022 Mar 21;8(1):35. doi: 10.1038/s41523-022-00399-w.

4. Malorni L, et al. International Breast Cancer Study Group; Breast International Group and PYTHIA Collaborators. Serum thymidine kinase activity in patients with hormone receptor-positive and HER2-negative metastatic breast cancer treated with palbociclib and fulvestrant. Eur J Cancer. 2022;164:39-51.

5. Malorni L, et al. Serum thymidine kinase activity in patients with HRpositive/HER2-negative advanced breast cancer treated with ribociclib plus letrozole: Results from the prospective BioItaLEE trial. Eur J Cancer. 2023; 186: 1–11. Eur J Cancer 2023; 186: 1–11.


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