What targeted therapy actually targets

Targeted medicines interfere with proteins or pathways that help cancer grow. Small molecules can act inside cells; antibodies may recognize structures on their surface. “Targeted” describes a mechanism, not freedom from side effects or automatic superiority to chemotherapy.

Matching requires the exact alteration, cancer type, disease setting and evidence for a medicine. A gene name alone is not a prescription.

Source [1]

Making sense of a biomarker report

Testing should answer a clinical question: which findings could change treatment now? Establish the diagnosis and decision first; a larger panel does not necessarily produce a useful option.

Similar-sounding findings can have different treatment implications
Finding	What it describes	What to check
Mutation or fusion	A specific DNA or RNA alteration	The exact variant, its significance and evidence in this cancer and setting.
Gene amplification	Extra copies of a gene	Test method, thresholds and whether the treatment requires this finding.
Protein expression	For example, HER2 assessed by immunohistochemistry	The score and cancer-specific criteria; expression is not the same as mutation.
Variant of uncertain significance (VUS)	A change whose clinical meaning is unclear	A VUS alone should not drive treatment or be interpreted as confirmed inherited risk.

Tissue and liquid biopsy have different limitations

Tissue can provide pathology and molecular information. Blood-based circulating tumor DNA (ctDNA) may help when tissue is difficult to obtain. A negative blood result can reflect low DNA shedding rather than absence of a target; whether tissue testing is needed depends on the situation.

A tumor mutation is not necessarily inherited

Tumor profiling and germline testing address different questions. A suspected inherited finding may need separate confirmation and genetic counseling before drawing conclusions for relatives.

Source [2][3][4]

Global treatment frontiers

The frontier is increasingly specific to the alteration. In February 2026, FDA expanded accelerated approval of zongertinib for adults with unresectable or metastatic nonsquamous NSCLC carrying activating HER2 tyrosine-kinase-domain mutations. This differs from HER2 pathways based on protein expression in other cancers.

For the difficult EGFR exon 20 insertion subgroup, sunvozertinib was approved in China in 2023 and received US accelerated approval in 2025 for the corresponding population progressing after platinum chemotherapy. Its development illustrates how an option can emerge in one region and then expand through international evidence and regulatory review.

An international comparison should align the alteration, cancer and treatment line before comparing evidence, approvals and practical access. Accelerated approval also makes subsequent confirmatory evidence important; it is not a declaration that a medicine is best for every patient.

Source [8][9][10]

Choosing treatment after a target is found

A target is the starting point. The decision also depends on cancer type, disease stage, treatment line and previous resistance. Reducing recurrence after surgery, controlling advanced disease and selecting a combination are different treatment settings.

The same gene does not mean the same treatment

Keep the precise alteration on the report, not just “HER2 positive” or “EGFR positive.” For example:

HER2: an activating mutation in lung cancer differs from protein overexpression in breast cancer.
EGFR: common mutations and exon 20 insertions may require different treatment pathways.

Tumor-agnostic approvals still have conditions

Some medicines have biomarker-based indications across cancer types, with requirements concerning testing, age, previous treatment or alternatives. An exploratory basket-trial result does not establish routine use for every tumor with that target.

Compare benefit, risk and sequence

Ask the team to address three separate questions:

Expected benefit: tumor shrinkage, longer disease control and longer overall survival are different outcomes; one headline number does not describe all three.
Risk and burden: why choose a single drug or combination, and what are the tradeoffs?
Treatment sequence: why use this option now, and what are the main alternatives?

Source [1][7][8][10]

PARP inhibitors: BRCA, HRD and treatment setting

PARP inhibitors exploit weaknesses in DNA repair in selected cancers. A BRCA alteration, a finding in another homologous-recombination repair gene and an HRD test result are not interchangeable. Their usefulness depends on the drug, cancer and indication.

Maintenance differs from treating progression

Maintenance aims to extend control after an initial response. For example, US olaparib labeling includes first-line ovarian maintenance for BRCA-mutated disease and a separate HRD-positive indication with bevacizumab. These should not be merged into a claim that every ovarian cancer qualifies.

Other cancers require their own assessment

Breast, pancreatic and prostate uses differ in setting and prior-treatment requirements. A BRCA result starts the assessment; it does not settle the regimen. Confirm whether the finding is germline or somatic and whether the proposed use is adjuvant, maintenance or treatment of advanced disease.

Older indications may no longer be valid

Some ovarian PARP uses were withdrawn or narrowed following longer-term survival findings. That does not invalidate the whole class, but it makes current indication checks essential. A historical drug list is not evidence that the same use remains appropriate today.

Source [5][6]

Managing treatment after it starts

Oral treatment still requires active cancer care. Give the team a complete medicines and supplements list, and clarify food instructions, interactions and missed doses. Do not take extra tablets to make up a dose or change treatment yourself.

Monitoring is drug-specific

Rash, diarrhea, liver changes, hypertension, cardiac problems and pneumonitis are not equally likely with every drug. Follow the monitoring plan for the prescribed medicine and your own risk factors.

Blood counts matter with PARP inhibitors

Anemia and other cytopenias need monitoring; persistent abnormalities may require further investigation, including consideration of the uncommon but serious MDS/AML risk. New breathlessness, fever or severe diarrhea should prompt contact with the team, not be dismissed as an expected reaction.

Symptoms and objective assessments both count

Keep planned imaging and safety checks. An isolated tumor-marker change usually does not decide a switch on its own, and feeling well is not a reason to skip monitoring.

Source [1][5]

Why testing may be repeated at progression

Resistance may involve changes in the original target, alternative growth pathways or expansion of different cancer-cell populations. A treatment stopping working does not necessarily mean the original test or treatment choice was wrong.

A new sample should answer a new question

After confirming progression, the team considers whether tissue or liquid biopsy could identify an actionable mechanism. An older sample remains useful but may not fully represent the treated cancer. Balance biopsy safety against whether the result could change care.

The next option may use a different mechanism

Depending on the resistance mechanism, options may include a supported next-generation medicine, a combination, a different treatment class or a clinical study. The review should distinguish available treatments from investigational combinations and assess the additional monitoring needed.

Source [1][2][11]

Estimated total treatment cost

Oral targeted treatment and antibody combinations have different care requirements. These ranges cover selected oral treatments and the HER2 combination shown below.

Estimated total medical costs by treatment plan
Treatment plan	Estimated total cost
Selected oral targeted medicines or PARP inhibitors	US$4,000–28,000
Trastuzumab + pertuzumab with chemotherapy	US$20,000–63,000

What’s included

These are estimates of total medical treatment costs for the listed treatment plans. In addition to the named medicines, they include specialist consultations and assessment, pretreatment tests, routine laboratory and imaging follow-up as needed, treatment administration and nursing where applicable, necessary hospitalization and monitoring, and routine supportive care. Travel and accommodation are not included.

Your individual treatment costs

Many targeted treatments do not have a fixed treatment duration, while some have a defined course. Costs accumulate with actual treatment and vary with the medicine, dose, combination therapies and care needs. Other targeted medicines and combinations require a separate estimate. This range is indicative only; your individual costs may fall outside it. Contact us for a personalized cost estimate based on your medical needs and specialist assessment.

Turning the report into a treatment discussion

Bring full pathology and molecular reports, a treatment timeline, current medicines and recent assessments. The aim is to understand the matching evidence and management plan, not simply obtain a drug name.

Questions to resolve at the consultation

Which exact finding changes the recommendation, and is the evidence from my cancer type or a tumor-agnostic study?
Is this locally approved, off-label or investigational? Does previous treatment affect eligibility or expected benefit?
Why use this option now, and what are the tradeoffs of single-drug, combination and alternative approaches?
How will response and side effects be assessed, and what would trigger repeat sampling or a change in treatment?

Source [2]

Evidence & sources

Prepared by Chirona’s content team from the sources below. This guide supports a discussion with your treating team; it does not determine an individual treatment plan.