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Updated: Oct 22, 2025

Molecular and Immunologic Techniques in a Genetically Engineered Mouse Model of Gastrointestinal Stromal Tumor
Published on: May 2, 2022
Molecular diagnostics and therapies for gastrointestinal tumors: a real-world experience
Sabrina Welland1, Tiago deCastro1, Melanie Bathon1
1Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
Purpose:
Several targeted agents demonstrated efficacy in early clinical trials for gastrointestinal (GI) cancers, but in many cases, phase-III trials and/or approval by the European Medicines Agency (EMA) are lacking. The primary focus of this study was to assess the regulatory processes associated with use and reimbursement of off-label treatment in precision oncology and to evaluate the benefit of targeted therapy in a real-world population in Germany.
Methods:
Our cohort comprises 137 patients with GI cancers and is biased towards cancer entities with a high frequency of known targetable alterations, such as cholangiocarcinoma. Genetic testing was used to identify molecular targets, and therapy response was evaluated based on CT scans.
Results:
A molecular target for precision oncology was identified in 53 patients and 43 requests for cost coverage were submitted to health insurance companies. 60% of the requests received approval after initial application and another 7% after appeal. Half of the rejected requests were denied despite ESCAT IA level evidence. The median time between initiation of molecular testing and start of therapy was 75 days. 35 patients received matched targeted therapies (n = 28) or, in the case of MSI, immunotherapy (IO) (n = 7). We observed a trend in favor of molecular therapy when compared to the immediate prior treatment.
Conclusion:
Relevant treatment options were identified by molecular testing in a significant subset of patients. When targeted therapies that lack EMA approval are considered, treatment initiation may be delayed by the duration of the molecular analysis and the regulatory processes.
Insights
Precision oncology in gastrointestinal cancers identified molecular targets in over half of patients. However, regulatory hurdles and molecular testing delays can significantly impede access to targeted therapies lacking European Medicines Agency (EMA) approval.
Area of Science:
- Oncology
- Genetics
- Pharmacology
Background:
- Targeted agents show promise in early trials for gastrointestinal (GI) cancers.
- Many targeted therapies lack phase-III trials or European Medicines Agency (EMA) approval.
- Off-label use and reimbursement present challenges in precision oncology.
Purpose of the Study:
- Assess regulatory processes for off-label precision oncology treatments in Germany.
- Evaluate the real-world benefit of targeted therapy in GI cancer patients.
- Analyze cost coverage and reimbursement for molecularly targeted treatments.
Main Methods:
- Retrospective cohort study of 137 GI cancer patients.
- Focus on entities with high targetable alteration frequency (e.g., cholangiocarcinoma).
- Molecular testing to identify targets; CT scans for therapy response evaluation.
Main Results:
- Molecular targets identified in 53 patients; 43 cost coverage requests submitted.
- 67% of requests approved (60% initial, 7% appeal), with rejections despite strong evidence.
- Median 75-day delay from molecular testing initiation to therapy start; trend favoring molecular therapy.
Conclusions:
- Molecular testing identifies actionable targets in a significant subset of GI cancer patients.
- Regulatory processes and testing duration can delay treatment initiation for EMA-unapproved therapies.
- Real-world data highlights challenges in accessing precision oncology treatments.
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