Abstract 2129
Background
We present a pharmacodynamic model that describes the tumor volume evolution during and after treatment with radiation and in combination with a radiosensitizing agent. A key contribution is the inclusion of a long-term radiation effect, which allows the model to describe distinct tumor behaviors including tumor eradication and tumor regrowth with different growth rates. Additionally, we introduce the concept of TSE (Tumor Static Exposure), the exposures of one or multiple compounds that result in tumor stasis and provide an example of its utility for optimizing drug combinations in oncology.
Methods
The model was challenged with data from four treatment groups (Vehicle, radiation, radiation + radiosensitizer 25 or 100 mg/kg) in xenograft study using a clinically-relevant administration schedule (6 weeks treatment, 5 days on/2 days off) and a mixed-effects approach was used for model-fitting. The model incorporated a permanent inhibition of the natural growth rate. This step was required to capture the complete tumor eradication and the observed tumor regrowth with different rates with animals having slower regrowth compared to control animals. The presence of a radiosensitizer will lead to the same tumor evolution as if a higher dose of radiation had been administered. The model was applied to predict exposure combinations that result in tumor eradication using the TSE.
Results
The developed model captured experimental data from all treatment groups adequately, with the parameter estimates taking biologically reasonable values. Model simulation showed that tumor eradication is observed at total radiation dose of 110 Gy, which is reduced to 80 or 30 Gy with co-administration of 25 or 100 mg/kg of a radiosensitizer.
Conclusions
The new model can describe different tumor dynamics including tumor eradication and tumor regrowth with different rates. The proposed model can be expanded for radiation in combination with chemical interventions or immunotherapy. The model and TSE can be applied to generate treatment predictions for different dosing schedules or determining drug synergies. The translational utility of the TSE concept is currently under investigation.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Merck Healthcare KGaA.
Funding
Tim Cardilin was supported by an education Grant from Merck Healthcare KGaA, Darmstadt, Germany. This work was also partially funded by the Swedish Foundation for Strategic Research (Grant no. AM13-0046).
Disclosure
S. El Bawab: Full / Part-time employment: Merck Healthcare KGaA. A. Zimmermann: Full / Part-time employment: Merck Healthcare KGaA. F. Lignet: Full / Part-time employment: Merck Healthcare KGaA. All authors have declared no conflicts of interest.
Resources from the same session
5822 - Greek nursing students experience facing death in clinical practice
Presenter: Maria Dimoula
Session: Poster Display session 3
Resources:
Abstract
2866 - HOPEVOL: Hospice care appropriate to the wishes and needs of patients in the palliative terminal phase.
Presenter: Merel van Klinken
Session: Poster Display session 3
Resources:
Abstract
829 - Mindfulness-based stress reduction in early palliative care for advanced cancer patients : an italian single-centre study. MINDEEP
Presenter: Emilia Gianotti
Session: Poster Display session 3
Resources:
Abstract
2702 - Optimising Inpatient Oncology Care
Presenter: Lisa Judge
Session: Poster Display session 3
Resources:
Abstract
1527 - Analysis on the Implementation Results of Family Sickbed for Oncology Patients in Dongshi Township Health Centers from 2015 to 2017
Presenter: Yayu Huang
Session: Poster Display session 3
Resources:
Abstract
2054 - Exploring needs for palliative care and quality of life for oncology patients with advanced disease who undergo radiotherapy
Presenter: Foteini Antonopoulou
Session: Poster Display session 3
Resources:
Abstract
5605 - Cytotoxic contamination in cancer care settings – Risks and safety awareness among cancer nurses
Presenter: Sandra Lundman Vikberg
Session: Poster Display session 3
Resources:
Abstract
5769 - Understanding Chemotherapy - group education sessions prior to commencing chemotherapy
Presenter: Aileen McHale
Session: Poster Display session 3
Resources:
Abstract
2620 - Estimation of HPQ-based absenteeism and presenteeism in cancer patients via ResearchKit
Presenter: Shunsuke Kondo
Session: Poster Display session 3
Resources:
Abstract
4705 - Identifying falls-related variables and risk factors in hospitalised cancer patients
Presenter: Maria Montserrat Martí Dillet
Session: Poster Display session 3
Resources:
Abstract