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Osimertinib for Uncommon EGFR Mutations: Evidence and Clinical Trials | TrialFinder
HomeResourcesOsimertinib for Uncommon EGFR Mutations: What the Evidence Shows

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Published · September 18, 2026

Osimertinib for Uncommon EGFR Mutations: What the Evidence Shows

Osimertinib (Tagrisso) is an EGFR tyrosine kinase inhibitor used in EGFR-mutated non-small cell lung cancer (NSCLC).

Its established first-line FDA indication is for tumors with EGFR exon 19 deletions or exon 21 L858R substitutions, confirmed by an FDA-approved test. Other FDA-approved uses of Tagrisso also name those two mutations. A separate later-line indication covers EGFR T790M-positive metastatic NSCLC after prior EGFR TKI therapy. T790M is not the same topic as the uncommon variants people often search for.

A search for an uncommon EGFR mutation needs a more specific answer. Uncommon EGFR mutations are not one group. The evidence, and what is considered standard treatment, can differ by the exact variant, the stage of the cancer, prior treatment, and the country where care is given.

What counts as an uncommon EGFR mutation?

In EGFR-mutated NSCLC, the most common changes are exon 19 deletions and the exon 21 L858R substitution. Those are the mutations named in the first-line FDA indication for osimertinib.

Uncommon EGFR mutations include other changes in the same gene. Three that come up often in this search are:

G719X. A change at position 719 of EGFR. The "X" means more than one amino-acid substitution can appear there, such as G719A, G719S, or G719C.

S768I. A change at position 768, from serine to isoleucine.

A change at position 861, from leucine to glutamine.

L861Q.

A report may list one of these alone, or together with another EGFR change. Compound mutations are often treated and studied as a separate question, because the combination can behave differently from a single variant.

EGFR exon 20 insertions are also less common than exon 19 deletions and L858R. They still belong in a different bucket. They are biologically and clinically distinct, and they should not be folded into the same conclusion as G719X, S768I, or L861Q.

Does osimertinib work for G719X, S768I, or L861Q?

The FDA first-line indication for Tagrisso names exon 19 deletions and L858R. It does not name G719X, S768I, or L861Q as a group.

Researchers have studied osimertinib in some people with these variants, including in clinical studies and registry reports. That kind of record can support a careful discussion with an oncologist. It is not the same as a labeled indication, and it is more limited than the evidence behind the exon 19 deletion and L858R approvals.

No page can predict whether osimertinib will help one person. Response can depend on the exact variant, whether it sits alone or with another mutation, the stage of the cancer, what treatment has already been given, and where care is delivered. A statement from a study or registry should be read as evidence from that setting, not as a guarantee.

If a molecular report lists one of these variants, the useful next step is to bring the exact result to the oncologist rather than assuming that "EGFR-positive" and "osimertinib" automatically go together.

What about EGFR exon 20 insertions?

EGFR exon 20 insertions are not interchangeable with G719X, S768I, or L861Q. They change the protein in a different way, and the usual treatment discussion is different.

Standard-dose osimertinib is not the usual standard treatment for this group. That does not mean every exon 20 insertion is identical, or that osimertinib is never studied in this setting. It does mean that "EGFR-positive, so Tagrisso" is the wrong shortcut.

Other targeted options exist, including amivantamab-based treatment. In the United States, the FDA has approved amivantamab-vmjw (Rybrevant) for EGFR exon 20 insertion-mutated NSCLC in specified settings, as detected by an FDA-approved test. Approvals, combinations, and access vary by country and by line of treatment.

A clinical trial can be worth discussing. It is not automatically preferable to standard care. The listing, the exact insertion, prior therapy, and local options all matter.

What should I ask my oncologist?

A short list is often enough:

  • What is the exact EGFR variant on the molecular report?
  • Is it a single mutation or a compound mutation?
  • What is approved or considered standard for this stage and treatment line where I live?
  • Has the cancer been tested broadly enough for other actionable changes?
  • Are there recruiting trials matched to this exact variant and prior treatment history?

If it helps to plan the appointment, How to Talk to Your Doctor About Clinical Trials walks through how to raise the topic and what to bring.

Are there active clinical trials for osimertinib and uncommon EGFR mutations?

The list below is built from TrialFinder's live trial data. It keeps studies that are recruiting, using the same recruiting filter as the main search, and then keeps lung/NSCLC studies that mention EGFR plus osimertinib and/or a named uncommon variant (G719X, S768I, L861Q, or an exon 20 insertion) in the title, conditions, summary, or inclusion criteria. Mentions that appear only as exclusion criteria, and broad solid-tumor studies that are not lung-focused, are left out.

To look beyond this focused list, search TrialFinder for recruiting osimertinib and EGFR studies. For the broader disease context, see the lung cancer clinical trials guide.

How do I read a trial listing?

A listing is a starting point, not a decision. The exact mutation, stage, previous treatments, performance status, age, and location can all change eligibility. Two people with "uncommon EGFR" on a report can still fail different criteria.

If terms on the listing are unclear, the plain-language clinical trial glossary explains them. When a specific study looks possible, take it to the oncologist before making any medical decision.

Sources

  • FDA prescribing information for Tagrisso (osimertinib), including the first-line indication for EGFR exon 19 deletions or exon 21 L858R mutations detected by an FDA-approved test.
  • FDA approval of amivantamab-vmjw for EGFR exon 20 insertion-mutated NSCLC.
  • Current recruiting-trial facts on this page come from ClinicalTrials.gov and are shown through TrialFinder listings.
  • NCI: Testing osimertinib as a treatment for lung cancers with an EGFR exon 20 change, which describes osimertinib as a treatment being studied in that setting.

Related conditions

Lung Cancer Clinical Trials: How Type and Biomarkers Shape Eligibility NSCLC, SCLC, and biomarkers such as EGFR, ALK, and KRAS change which lung cancer trials may fit. A plain-language guide, plus recruiting studies.

Further reading

How to Talk to Your Doctor About Clinical Trials What questions should you ask your doctor about clinical trials? A step-by-step guide for patients: when to bring it up, what to prepare, and what to do after.

Key Clinical Trial Terms Plain-language explanations of terms patients and families encounter during the clinical trial process.

Start Here: How to Search for Clinical Trials on TrialFinder A step-by-step guide to finding clinical trials on TrialFinder. Learn how to search by condition, use filters, and understand your results.

Before You Join a Clinical Trial: Screening, Informed Consent, and Red Flags What happens between finding a clinical trial and your first visit: screening, the informed consent form, the questions worth asking, common fears answered plainly, and the red flags that should make you walk away.

Clinical Trials in Mental Health: What Patients and Families Should Know Mental health clinical trials can test medications, psychotherapy, TMS devices, digital therapeutics, and psychedelic-assisted treatment. Here is how they differ from cancer trials, and how to start looking.

The Reminder Moderna and Merck's Personalized mRNA Cancer Vaccine Gives Us About Clinical Trials Moderna and Merck's personalized mRNA cancer vaccine just hit its Phase 3 endpoints in melanoma. Here's what it teaches us about the value of joining clinical trials.

Breakthrough in Pancreatic Cancer: Compassionate Use for KRAS Mutations Explained The new drug Daraxonrasib showed impressive survival results for eligible pancreatic cancer patients. It is currently available via compassionate use. Here is what you need to know.

What is a Clinical Trial? (It's More Than You Think) How clinical trials work, why they matter, and what patients should know before considering one.

Not a Perfect Match? Tips for Getting Into a Clinical Trial Anyway A rejection from a clinical trial doesn't have to be the end. Practical tips for patients and caregivers who hit a wall.

How to Talk About Clinical Trials with a Family Member A guide for caregivers on introducing clinical trials to a loved one who is hesitant, tired, or afraid.

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This article was written by a patient advocate based on personal experience, not by a medical professional. It is not medical advice. Consult your doctor before making any medical decisions.

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Trial data from ClinicalTrials.gov. For information only.

Trials that mention osimertinib and an uncommon EGFR variant

  • Testing Osimertinib as a Treatment for Lung Cancers With an EGFR Exon 20 Change

    Advanced Lung Non-Small Cell Carcinoma · Recurrent Lung Non-Small Cell Carcinoma · Stage IIIB Lung Non-Small Cell Cancer AJCC v7

    United StatesRecruitingPhase 2
    Simple summary·Eligibility check·Doctor guide
    Anchorage, United States · Anchorage, United States

Other recruiting trials for uncommon EGFR mutations or exon 20 insertions

  • Adjuvant EGFR-TKI Therapy After Surgery for EGFR-Mutant High-Risk Stage IA2-IIB NSCLC

    Non-Small Cell Lung Cancer

    ChinaRecruiting
    Simple summary·Eligibility check·Doctor guide
    Wuhan, China

Open the full TrialFinder search for osimertinib and EGFR · Search recruiting lung cancer trials

  • A Study of Zipalertinib in Patients With Advanced Non-Small Cell Lung Cancer With Epidermal Growth Factor Receptor (EGFR) Exon 20 Insertions or Other Uncommon Mutation.

    Advanced or Metastatic NSCLC Harboring Epidermal Growth Factor Receptor (EGFR) Exon 20 Insertion (ex20ins) Mutations

    12 countriesRecruitingPhase 2
    Simple summary·Eligibility check·Doctor guide
    Birmingham, United States · Duarte, United States

  • First-In-Human Study of STX-721/PFL-721 in Participants With Locally Advanced or Metastatic Non-Small Cell Lung Cancer Harboring EGFR or HER2 Exon 20 Insertion Mutations

    Non-Small Cell Lung Cancer · NSCLC · EGFR/HER2 Exon 20 Insertion Mutation

    7 countriesRecruitingPhase 1/2
    Simple summary·Eligibility check·Doctor guide
    Duarte, United States · Huntington Beach, United States

  • Assessing an Oral EGFR Inhibitor, DZD9008 in Patients With Advanced Non-small Cell Lung Cancer(NSCLC) With EGFR Mutations (WU-KONG15)

    Non Small Cell Lung Cancer

    ChinaRecruiting
    Simple summary·Eligibility check·Doctor guide
    Beijing, China

  • Study to Evaluate Efficacy and Safety of Firmonertinib Compared With Investigator's Choice of EGFR Inhibitor as First-Line Treatment in Participants Who Have Locally Advanced or Metastatic NSCLC With EGFR P-Loop and Alpha C-Helix Compressing (PACC) Uncommon Mutations

    Non-Small-Cell Lung Cancer · Metastatic Non-Small-Cell Lung Cancer · Advanced Non-Small-Cell Lung Cancer

    17 countriesRecruitingPhase 3
    Simple summary·Eligibility check·Doctor guide
    Fullerton, United States · Los Angeles, United States

  • OSIREAL - Osimertinib RWE on EGFRm NSCLC in Spain

    Non-small Cell Lung Cancer

    SpainRecruiting
    Simple summary·Eligibility check·Doctor guide
    A Coruña, Spain · Alicante, Spain

  • Study of BEBT-109 in Subjects With Non-Small Cell Lung Cancer Carrying EGFR Exon 20 Insertion Mutations

    Non Small Cell Lung Cancer

    ChinaRecruitingPhase 2
    Simple summary·Eligibility check·Doctor guide
    Guangzhou, China

  • A Phase 1/2, Open-label, Multicenter, FIH Study to Evaluate Safety, Tolerability, PK and Anti-tumor Activity of YH42946

    NSCLC (Non-small Cell Lung Cancer) · Solid Tumor

    2 countriesRecruitingPhase 1/2
    Simple summary·Eligibility check·Doctor guide
    Fairfax, United States · Seongnam-si, South Korea