New Finding: Efficacy of Osimertinib in Glioblastoma
[Press Release: OncoTarget (June 9, 2020)]
Efficacy of Osimertinib in against EGFRvIII+ Glioblastoma
Therefore, a panel of six Glioblastoma stem cells expressing EGFRv III+ was evaluated.
The EGFRv III+ GSC differed in the expression of EGFRv III and other key genes.
The GSC line D317, which expresses high levels of EGFRv III and has robust tyrosine kinase activity, was selected for assessing osimertinibs efficacy.
Herein, the authors report that osimertinib inhibits the constitutive activity of EGFRv III tyrosine kinase with high potency
Dr. Madan M. Kwatra from The Departments of Anesthesiology, Pharmacology and Cancer Biology as well as The Duke Cancer Institute at Duke University Medical Center in Durham, North Carolina said, "Glioblastoma (GBM) is the most common and deadliest primary brain tumor. It carries a median survival of 16 months for newly-diagnosed patients whose treatment aligns with the current standard of care consisting of maximal safe resection followed by radiation and chemotherapy."
At least four major molecular forms have been identified:
- wild-type EGFR with gene amplification;
- EGFR with a large deletion in the extracellular domain;
- EGFR with kinase domain duplication, and
- EGFR fused with SEPT-14.
There are two central reasons why these agents may have been ineffective in treating Glioblastoma patients:
- All four FDA-approved EGFR-TKIs that have been tested so far in GBM patients do not cross the blood-brain barrier effectively; and
- The extreme molecular and functional heterogeneity of EGFR, as mentioned above, could not be taken into account at the time these clinical trials were performed because this information was not yet understood.
Also, while it spares the wild-type EGFR it inhibits EGFRv III tyrosine kinase with high potency.
The ability of osimertinib to inhibit EGFRv III tyrosine kinase with high potency makes it an attractive candidate to target EGFRv III, a driver of Glioblastoma growth that is present in over 20% of Glioblastoma patients.
"The ability of osimertinib to inhibit EGFRv III tyrosine kinase with high potency makes it an attractive candidate to target EGFRv III"
Herein, they demonstrate that osimertinib inhibits the growth of EGFRv III+ Glioblastoma expressing high EGFRv III tyrosine kinase activity.
The Kwatra Research Team concluded in their Oncotarget Research Paper, "our study establishes that osimertinib penetrates the blood-brain barrier effectively and inhibits the growth of EGFRvIII+ Glioblastomas with higher EGFRvIII tyrosine kinase activity. Additional preclinical studies are needed to define the molecular signatures of EGFRvIII+ Glioblastomas that may make these tumors sensitive to osimertinib."
Full text - https://www.oncotarget.com/article/27599/text/
Correspondence to - Madan M. Kwatra - firstname.lastname@example.org
Dr. Kwatra tells DCI: "In my opinion, this drug will be a game changer because it is the only EGFR-TKI that penetrates the brain well."
The study was funded, in part by a NIH/NCATS grant awarded in 2015 to Dr. Kwatra and his research collaborator Dr. Glenn Lesser at Wake Forest School of Medicine. MORE