Avapritinib in the Treatment of Unresectable or Recurrent Metastatic GIST Non-exon18 Mutations of PDGFRA

February 24, 2025 updated by: Xinhua Zhang, MD

Avapritinib in the Treatment of Unresectable or Recurrent Metastatic Gastrointestinal Stromal Tumors Non-exon18 Mutations of PDGFRA:A Real-world Study

This is a prospective, multicenter, observational real-world study to explore the Avapritinib therapy in GIST patients who definited Non-exon18 Mutations of PDGFRA.

Study Overview

Status

Recruiting

Conditions

Detailed Description

INTRODUCTION AND RATIONALE Gastrointestinal stromal tumors (GIST) are thought to develop from the interstitial cells of Cajal or their stem cell precursors. They are the most common mesenchymal tumors occurring in the gastrointestinal (GI) tract. The annual incidence of GIST is about 1/100,000 ~ 2/100,000 globally. Biological behavior can range from benign to malignant, and immunohistochemical staining is usually positive for CDs 117 and DOG-1, showing Cajal cell differentiation. Eighty-five percent of GISTs is caused by activating mutations in the receptor tyrosine kinase KIT or platelet-derived growth factor receptor alpha (PDGFRA) gene. Targeted therapy for KIT and PDGFRA alters metastatic or unresectable GISTs without effective drug therapy, allowing tumor control and significantly prolonging patient survival.

Following the marketing application approved in March 2021 for Avapritinib and Repaitinib (the indication for the former is GIST with PDGFRA exon18 mutation and the latter is the standard four-line therapy for GIST), five targeted drugs are currently available for treatment of unresectable or recurrent metastatic GIST. The first, second and third-line treatments were imatinib, sunitinib and regorafenib, respectively. Different targeting drugs can inhibit the activation of GIST- or PDGFRA--encoded transmembrane tyrosine kinases by binding to GIST- driven genes to induce apoptosis. There were differences in molecular structure and mechanism of action among the five targeted drugs, which led to different mutations in different exons of GIST, and the sensitivity to targeted drugs was different. KIT protein is a common type III receptor tyrosine kinase (RTK), which is a transmembrane receptor protein. PDGFRA protein is highly homologous and has similar functions. KIT proteins are predominantly extracellular (encoded by exon 9), transmembrane, near-membrane (encoded by exon 11), kinase domains (further divided into kinase binding domains encoded by exon 13/14, and activation loops encoded by exon 17/18). KIT protein has two kinds of three-dimensional spatial conformation (type I-activated conformation and type II-non-activated conformation), which can be transformed and dynamically balanced under normal conditions. The first-line targeted drug imatinib can competitively bind to ATP in the kinase-binding domain of RTK, and the mechanism of action of imatinib is that after the ATP-binding site of the kinase domain is occupied by it, it blocks substrate phosphorylation and signal transduction, inhibits the proliferation of tumor cells and promotes apoptosis. More than 80% of all GISTs in the advanced stage of treatment present as KIT single-gene driven types, and therefore, the clinical benefit rate of first-line imatinib is more than 84%. One of the reasons for primary resistance to first-line therapy is that tumors derive from primary mutations in the activated loop, such as PDGFRA exon 18 D842V mutations, which cause the kinase to tend to an activated conformation for most of the time, whereas imatinib, sunitinib, and regorafenib belong to the same type II TKIs (tyrosine kinase inhibitors), which theoretically can only bind to kinase in a non-activated conformation and are therefore primary resistant to this mutant GIST. In addition, secondary resistance occurs after first-line treatment is effective, with a median of PFS 24 months. The most common cause of resistance is mutations in the KIT gene at the secondary site. The most common secondary mutations are almost concentrated in the exon 13/14 and exon 17/18 regions. Mutations encoding binding domains (exon 13 and 14) prevented the binding of imatinib to RTKs; Mutations that encode activated rings (exon 17 and 18) cause KIT to tend to activate the conformation, preventing most TKIs, including imatinib, from binding to it. Avapritinib is the only type I TKI that has been approved for the treatment of GIST compared to the other 4 targeted agents. Previous studies have found that this compound has a strong inhibitory effect on KIT exon17 D816V mutants that cause mast cell hyperplasia. The mutant is located in the activation ring. Mutations that are highly similar in structure and function are multidrug resistant PDGFRA exon18 D842V mutations accounting for around GIST 5%. Preclinical studies showed broad-spectrum inhibition of KIT or PDGFRA, including KIT exon 11,17,18, and PDGFRA exon 18 mutations, weak affinity for wild-type KIT and PDGFRA, PDGFRB, CSF1R, and FLT3. In the Phase 1 clinical study in patients with metastatic or unresectable PDGFRA D842V-mutant GISTs, the objective response rate (ORR) for Avapritinib was 91%, with a complete response rate of 13%, median duration of efficacy (DOR) of 27.6 m (95% CI 17.6-N%), and median progression-free survival (PFS) of 34 m (95% CI 22.9-N%), with an estimated overall survival (OS) of 61% at 36months. In patients with KIT or non-D842V PDGFRA mutations treated more than three lines, atorvastatin ORRs were 17%, all in partial response (PRs), median DORs were 10.2 m (95% CI 7.% -10.2), clinical benefit rate (CBRs) were 38%, median PFSs were 3.7 m (95% CI 2.% -4.6), and median OSs were 11.6 m (95% CI 9.% -12.6). These studies indicate that Avapritinib is effective in PDGFRA exon 18, especially in the D842V mutant GISTs, and that some of the remaining KIT mutations can also be treated with Avapritinib for tumor control. In vitro studies suggest that KIT activating ring mutations GISTs are sensitive to Avapritinib, but there are no clinical studies evaluating the exact efficacy of Avapritinib in this type of patient population. In addition, on the surface of the preliminary study, secondary resistance to the PDGFRA exon 18 mutation GIST following the benefit of Avapritinib was due to secondary mutations in the PDGFRA gene; However, the causes of secondary resistance to KIT-mutant GISTs that have been shown to be effective in the treatment of Avapritinib and changes in the driver gene are unknown.

Therefore, it is necessary to conduct a multicenter observational study in patients with unresectable or relapsed/metastatic GISTs other than PDGFRA exon 18 mutations in order to explore the benefit of Avapritinib in addition to PDGFRA exon 18 mutations, and to investigate changes in the status of primary and secondary resistance mutations of Avapritinib in order to provide evidence for individualized treatment of advanced GISTs.

Study Type

Observational

Enrollment (Estimated)

74

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • China
      • Guangzhou, China, 510080
        • Recruiting
        • The First Affiliated Hospital, Sun Yat-sen University
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Sampling Method

Probability Sample

Study Population

Approximately 74 patients with metastatic or unresectable advanced gastrointestinal stromal tumors from tier-3 hospitals who meet the criteria will be enrolled in the study.

Description

Inclusion Criteria:

  • Patients who are aged ≥ 18 years.
  • Gastrointestinal stromal tumors confirmed by histopathological examination, and CD- and/or DOG-1-positive by immunohistochemistry.
  • Presence of mRECIST v1.1-compliant lesions with at least one measurable lesion (non-lymphadenopathy ≥1.0 cm or ≥2-fold scan slice thickness).
  • Treatment with Avapritinib.
  • Patients with an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 to 2 at screening.
  • Patient informed consent and signed written consent form.
  • The patient was compliant and voluntarily scheduled for follow-up, treatment, laboratory tests, and other study procedures.

Exclusion Criteria:

  • KIT or PDGFRA wild type.
  • Failure to complete continuous atorvastatin for at least 15 days due to intolerability or disease progression.
  • Other serious acute or chronic physical or mental problems, or laboratory abnormalities, may increase the risk associated with participation in the study or use of drugs, or interfere with the judgment of the study results and, in the judgment of the investigator, are not considered appropriate for participation in the investigator.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Objective Response Rate
Time Frame: 2 years
To evaluate objective response rate (ORR,CR+PR) determined by radiology assessment per mRECIST(Response Evaluation Criteriain Solid Tumours), version 1.1 in patients with Metastatic or Unresectable Gastrointestinal Stromal Tumors.Complete response is the disappearance of all lesions with nodes measuring < 10 mm and normal tumour markers.A decrease in the sum of target disease of ≥ 30% represents partial response.
2 years
Clinical Benefit Rate
Time Frame: 2 years
To evaluate clinical benefit rate(CBR,CR+PR+>16 weeks continuation SD) determined by radiology assessment per mRECIST, version 1.1 in patients with Metastatic or Unresectable Gastrointestinal Stromal Tumors.Complete response is the disappearance of all lesions with nodes measuring < 10 mm and normal tumour markers.A decrease in the sum of target disease of ≥ 30% represents partial response.Stable disease lies between partial response and progressive disease.
2 years
Duration Of Response
Time Frame: 2 years
To evaluate duration of response (DOR) determined by radiology assessment per mRECIST, version 1.1 in patients with Metastatic or Unresectable Gastrointestinal Stromal Tumors.Complete response is the disappearance of all lesions with nodes measuring < 10 mm and normal tumour markers.A decrease in the sum of target disease of ≥ 30% represents partial response.Stable disease lies between partial response and progressive disease.If a lesion reappears after disappearing in a patient with complete response, progressive disease is declared. However, if such a lesion behaves in this manner in a patient with stable disease or partial response, it is the change in sum of target disease that defines the response or progression.
2 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Progression-free survival
Time Frame: 2 years
To evaluate PFS determined by radiology assessment per mRECIST, version 1.1 in patients with Metastatic or Unresectable Gastrointestinal Stromal Tumors.Complete response is the disappearance of all lesions with nodes measuring < 10 mm and normal tumour markers.A decrease in the sum of target disease of ≥ 30% represents partial response.Stable disease lies between partial response and progressive disease.If a lesion reappears after disappearing in a patient with complete response, progressive disease is declared. However, if such a lesion behaves in this manner in a patient with stable disease or partial response, it is the change in sum of target disease that defines the response or progression.
2 years
Treatment-emergent adverse events
Time Frame: 2 years
To evaluate treatment-emergent adverse events determined in patients with Metastatic or Unresectable Gastrointestinal Stromal Tumors.
2 years
adverse events of special interest
Time Frame: 2 years
To evaluate adverse events of special interest determined in patients with Metastatic or Unresectable Gastrointestinal Stromal Tumors.
2 years
serious adverse events
Time Frame: 2 years
To evaluate serious adverse events determined in patients with Metastatic or Unresectable Gastrointestinal Stromal Tumors.
2 years
overall survival
Time Frame: 2 years

To evaluate OS determined in patients with Metastatic or Unresectable Gastrointestinal Stromal Tumors.

To evaluate OS determined in patients with Metastatic or Unresectable Gastrointestinal Stromal Tumors.Complete response is the disappearance of all lesions with nodes measuring < 10 mm and normal tumour markers.A decrease in the sum of target disease of ≥ 30% represents partial response.Stable disease lies between partial response and progressive disease.If a lesion reappears after disappearing in a patient with complete response, progressive disease is declared. However, if such a lesion behaves in this manner in a patient with stable disease or partial response, it is the change in sum of target disease that defines the response or progression.
2 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Xinhua Zhang, MD

Collaborators

Xijing Hospital
Chongqing University Cancer Hospital
Xiangya Hospital of Central South University
Peking University People's Hospital
Sun Yat-sen University
Fudan University
Shanghai Zhongshan Hospital
Chinese PLA General Hospital
West China Hospital
Peking University Cancer Hospital & Institute
Shengjing Hospital
Shanghai Jiao Tong University School of Medicine
Jiangsu Cancer Institute & Hospital
Sixth Affiliated Hospital, Sun Yat-sen University
Wuhan Union Hospital, China
Fujian Medical University Union Hospital
Peking University Shenzhen Hospital
First Affiliated Hospital of Chongqing Medical University
Cancer Hospital of Guangxi Medical University
Liaoning Cancer Hospital & Institute
Nanfang Hospital, Southern Medical University

Investigators

  • Principal Investigator: Xinhua Zhang, PhD, First affiliated hosptial,Sun Yat-sen university

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 10, 2022

Primary Completion (Estimated)

December 31, 2025

Study Completion (Estimated)

December 31, 2025

Study Registration Dates

First Submitted

July 9, 2022

First Submitted That Met QC Criteria

July 15, 2022

First Posted (Actual)

July 18, 2022

Study Record Updates

Last Update Posted (Actual)

March 25, 2025

Last Update Submitted That Met QC Criteria

February 24, 2025

Last Verified

February 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • No.[2022]107

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Gastrointestinal Stromal Tumors

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Albania

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe