Targeted drugs: why your tumor's report decides this one

Most of these drugs need something to aim at. The gene results from your tumor say whether there is one. One of them works differently. What each of these drugs is for, and what it asks of you. And the question worth asking about every one of them: what would it mean to say this worked?

The short version

A targeted drug is made to act on one particular change inside tumor cells. So it needs something to aim at, and the gene results from your tumor are what say whether there is one. If your report does not show that change, the drug will not help. That is not bad luck about you. It is how those drugs work. One drug here is the exception, and it is aimed at the swelling rather than at a gene change. There are several of these drugs now. They are used at very different points, and the one question worth asking about every one of them is what it would mean to say it worked.

What is a targeted drug?

It is a drug built to act on one specific thing inside tumor cells.

Chemotherapy works in a broader way. It goes after cells that are dividing, wherever they are, which is why it affects healthy parts of you that divide quickly too. Chemotherapy: the drugs, your blood counts, and the fever rule covers those drugs.

A targeted drug is narrower. It is made to block one protein, or one change in one gene. Some are pills you take at home. One of the ones used for brain tumors is given as an infusion, into a vein through an IV line.

Narrower does not mean gentler. These drugs have real side effects, and they are different from chemotherapy's rather than smaller. There is a section on them below.

Why does my tumor's report decide this?

Because the drug has to have something to act on, and the report is what says whether it is there.

When your tumor was taken out or sampled, the laboratory looked at its genes. The National Cancer Institute puts the general rule plainly: most of the time your tumor has to be tested to see whether it carries a target that a drug exists for. The words on your gene results goes through those words one at a time.

So there are two separate questions, and people often merge them. The first is whether your tumor carries the change. The second is whether a drug for that change is a good idea for you now. A yes to the first is not a yes to the second, and your team will have reasons either way.

If your report shows no target, that is information rather than a door closing. It means the drugs matched to a gene change are not the route. It says nothing about bevacizumabbevacizumab: A drug that acts on the blood vessels a tumor builds. In brain tumors it is used mainly for two things. One is to control symptoms from swelling. The other is to cut down how much steroid someone needs. See the glossary, which is not matched to one, and nothing about surgery, radiation, chemotherapy, or a trial. Clinical trials: is this for me? is worth reading either way, because a trial is one of the routes a new targeted drug reaches people.

Which drug goes with which result?

Here is the shape of it. Where you sit in it is a question for your team.

• A change in IDH1IDH gene change: A small change in a tumor's IDH gene. It is the first thing your team looks at when naming an adult glioma, and it can affect which treatments are offered. Your pathology report says whether your tumor has it. See the glossary or IDH2, in a grade 2 astrocytoma or oligodendroglioma, after surgery. The drug is vorasidenibvorasidenib: A medicine approved in 2024 for some people with a grade 2 glioma. The glioma has to have an IDH change. The medicine acts on that change itself. It is taken after surgery. See the glossary, a tablet. Your own tumor page has the decision: low-grade glioma and astrocytoma.
• A BRAF V600EBRAF: A gene in a pathway that tells cells to divide. Some tumors carry a change in it. There are drugs made to target that change, so your team may test for it. See the glossary change. There are several pairs of pills here. For children with a low-grade gliomaglioma: A tumor that starts in the glial cells. Those are the support cells of the brain and spinal cord. Gliomas are given a grade from 1 to 4. The grade says how the tumor is expected to act. See the glossary, dabrafenib with trametinib is approved as the first drug treatment. For adults, the American Cancer Society says these are usually an option after other treatments have been tried. Which of those you are is a question for your team.
• Swelling around a fast-growing glioma, or a tumor that has come back. Bevacizumab, given as an infusion. It blocks a protein that tumors use to build blood vessels, which brings the swelling down. That is its target, rather than a change on your report.
• An H3 K27MH3 K27-altered: A change in a histone. A histone is a protein DNA wraps around. A diffuse glioma can have it. If it also sits in the middle of the brain or spine, it is called a diffuse midline glioma. See the glossary change, in a diffuse midline glioma that has kept growing after other treatment. Dordaviprone, taken by mouth. Diffuse midline glioma says what its early approval does and does not show.
• A tumor called a subependymal giant cell astrocytoma that cannot be fully removed. Everolimus, a pill.
• An NTRK gene change. These are rare in brain tumors. There are three pills used when a tumor is still growing after other treatment.
• A brain or spinal cord tumor caused by von Hippel-Lindau disease, in an adult. The drug is belzutifan, a pill. For a brain or spinal cord tumor, it is only for people with that inherited condition. It is used when a tumor needs treating and surgery is not the next step. Hemangioblastoma is the tumor page. It carries the warnings for this drug, including that it must not be taken in pregnancy.

If your cancer started somewhere else and spread to the brain, the drug is usually chosen from that first cancer's own test results, not from the brain tumor's. Cancer that has spread to the brain covers how those two teams work together.

What happens, step by step

There are two shapes, and which one you get depends on the drug.

If it is a pill or capsule:

1. Your tumor is tested, if it has not been already.
2. You have blood tests before you start, and every other medicine and supplement you take is gone through. Bring the list rather than the memory.
3. You collect the drug and take it at home. Some are once a day. One is once a week.
4. You come back for blood tests and appointments on a rhythm your team sets.
5. Scans continue on whatever schedule your team has you on.

If it is an infusion:

1. The same tests and medicine review first.
2. You come in for the infusion. Bevacizumab is usually given every couple of weeks.
3. Your blood pressure is usually checked, because this drug can raise it.

Nobody starts a drug aimed at a gene change without the testing being done. Bevacizumab is the exception, because it is not matched to one. If you are told a targeted drug is being considered, it is fair to ask whether the test result is back and whether you can have a copy.

How long does it take?

Usually for as long as it is helping and you are tolerating it, with no end date set at the start. That is different from a course of radiation or a set number of chemotherapy cycles, and it takes people by surprise.

• A pill carries on at home until something changes it.
• An infusion runs on a repeating rhythm rather than to a finish line.

Ask what your own stopping point would look like, and what would make your team change course. Those two answers make an open-ended treatment something you can plan around.

What is it like to be on one?

Quieter than people expect, and open-ended in a way the other treatments are not.

On a pill, most days feel like nothing at all. You take it and get on with your day. There is no hospital visit attached to the treatment itself, which is a relief for some people and oddly unsettling for others, because it does not feel like being treated.

The blood tests are the rhythm of this, not the drug. They are frequent early on and usually settle into a pattern. That pattern, rather than the pill, is what you end up planning around.

The open end is the part people find hardest. There is no set number of weeks written down at the start, so there is no countdown and no last day to aim at. Some people find that easier than a course with an end. Some find it much harder. Both are ordinary, and it is worth saying out loud to somebody rather than carrying it.

An infusion is a different shape of day, closer to an appointment: you come in, you are checked over, it goes in, you go home.

What would it mean to say this worked?

This is the most useful question on the page, and the answer is genuinely different for each of these drugs.

It is worth asking because "it works" can mean several different things. A drug can shrink a tumor on a scan. It can hold a tumor still. It can delay the next treatment. It can make you feel better. It can help people live longer. Those are five different things, and a drug can do one and not the others.

Bevacizumab is the clearest example, and its own page says it plainly. It can make scans look better and cut down the need for steroids. But in the trials in newly diagnosed glioblastomaglioblastoma: A glioma that is given grade 4. Grade 4 is the highest grade there is. The tumor grows fast. Treatment usually starts soon after it is found. It often means surgery, and then radiation and chemotherapy. See the glossary it did not help people live longer. Glioblastoma carries that in full. Reducing swelling is worth having on its own terms. It is just not the same claim.

Vorasidenib was measured on time, not on living longer. The trial that led to its approval looked at how long people went before the tumor grew, and at how long before they needed the next treatment. Living longer was not one of the things it measured. That is not a criticism of the drug. It is what the trial was built to answer, and it is worth knowing which question got answered.

That trial also left out anyone who had already had chemotherapy or radiation. Everyone in it had had surgery and nothing else. So if you have already had either, you are not the person the trial studied, and what the drug would do for you is a genuinely open question rather than a settled one. It is worth asking your team about directly, because the answer is theirs and not this page's.

Dordaviprone has what is called an accelerated approval. That means it was allowed onto the market on early results, with a trial still running to find out whether it helps people live longer. That trial has not reported. A reader offered this drug should know it is genuinely new ground.

For everolimus, the American Cancer Society says it out loud: it may shrink the tumor or slow it down for a while, and it is not clear whether it helps people with these tumors live longer.

So ask your team this, about whatever drug is on the table: what are we hoping this does, and how will we know? It is a fair question, it has an answer, and the answer changes what the next scan means to you.

Side effects

Different from chemotherapy's, and different between the drugs. Ask for the written list for the drug you are actually on. In general:

Bevacizumab. High blood pressure, tiredness, bleeding, low white cell counts, headaches, mouth sores, less appetite and diarrhea.

It has a shorter list of serious ones, and those are the ones to know what to do about. They are blood clots, bleeding inside the body, heart problems, and a hole in the bowel.

• Chest pain, or trouble breathing, is an ambulance call. 911, or your local emergency number. That is where the rest of this site files it too.
• Sudden bad pain in your belly, blood in your stool, or bleeding that will not stop, means calling your team the same day.

Those two lines are the same answer brain surgery and chemotherapy give for the same symptoms.

Vorasidenib. Tiredness, headache, feeling sick to your stomach, aching muscles, diarrhea, and seizures. The one that needs watching is the liver, which is why the blood tests are regular.

Call your team if your eyes or skin turn yellow, your urine goes dark, you lose your appetite, or you get pain in the upper right of your belly. Those can be signs of a liver problem.

The BRAF and MEK pills. Skin changes, rash, itching, burning easily in the sun, headache, fever, chills, aching joints, tiredness, cough, hair loss, feeling sick to your stomach, diarrhea and high blood pressure.

Fever is common enough with these that it is worth expecting, and it needs a plan rather than a guess. Ask your team, before you start, what temperature they want to hear about and what number to call after hours. Write it down. A fever on one of these drugs is not the same event as a fever during chemotherapy, which has its own rule on the chemotherapy page. So ask for the rule that applies to the drug you are actually on.

The BRAF and MEK pills also ask for your skin to be watched. Some people on these drugs get skin cancers. Your skin should be checked regularly while you are on them, so ask how often, and tell your team right away about any new spot or any patch that looks different.

Dordaviprone. Tiredness, headache, feeling sick to your stomach, throwing up, and aching muscles, joints and bones. It can lower your blood counts and affect the liver.

Everolimus. Mouth sores, more infections, feeling sick to your stomach, less appetite, diarrhea, rash, tiredness, swelling in the legs, and rises in blood sugar and cholesterol.

The NTRK pills. Dizziness, tiredness, feeling sick to your stomach and throwing up, constipation, weight gain and diarrhea.

Whichever of these you are on, keep that written list somewhere you will find it again.

If you are having surgery, bevacizumab has its own rule

This is the part people most often do not know about, and it is the least explained.

Bevacizumab slows down wound healing. So it usually cannot be given in the weeks around an operation.

There is no one number that fits everybody. The gap depends on the operation and on you. What is agreed is that it usually cannot be given within a few weeks of surgery.

So ask for your own dates, and ask both ways. How long before the operation does it stop, and how long after it do you wait. Write the answers down. If any operation is being planned, including a dental one, tell whoever is planning it that you are on this drug. Getting ready for surgery covers the rest of what happens before an operation.

What you need first

Before any of these starts, expect:

• The gene results from your tumor. This is the gate for every drug on this page except bevacizumab, which is not matched to a gene change. The words on your gene results explains what is being looked for and how long it takes. Ask for a copy of the report.
• Blood tests, including liver tests for several of these drugs.
• Blood pressure checks, for bevacizumab. Ask what else will be monitored while you are on it, because the answer is your team's rather than this page's.
• A full list of everything you take, including things you buy yourself and anything herbal. Some of these drugs are affected by other medicines, and this is the appointment to get that sorted rather than later.
• Your surgery plans, if you have any, for the reason in the section above.

For the person alongside them

If you are the one driving to the appointments, keeping track of the pills, and lying awake at night worrying about them, this part is for you.

You are allowed to ask questions. In one study, families said they were afraid of annoying the doctor by asking too much. One of them was told by a doctor to stop playing doctor. Ask anyway. Write your questions down before you go, and bring a notepad. Two people in the room hear more than one.

Ask who your first call is. Care comes from a lot of people at once, and it is easy to end up as the only one holding it together. Ask the team: who do I call first? Some teams have one person whose job this is, often a nurse. Get the name and the number.

Get two numbers, and know which one to use. One for work hours, one for nights and weekends. Then ask what counts as "call us today" and what counts as "call an ambulance" for this tumor, and write the answer down where you can see it. If you are not sure which it is, call. Nobody on that team will mind.

If they have seizures, read about them before you need to. What to do when someone has a seizure is the one to know by heart. Living with seizures is about the rest of the time: what is safe, what to change, and driving.

Ask to be shown anything you are sent home to do. In that same study, families were sent home to change dressings and give medicines with no training at all. That is not fair to you. Before you leave the hospital, ask someone to show you. Then do it once while they watch.

Say what you notice. You may see a change before they do. Changes in thinking, mood and behavior can show up to the people close by first. Telling the team is not going behind their back. It is something the team cannot learn any other way.

Look after yourself, and let people help. Eat, sleep, and keep your own appointments. Take a little of the day back for yourself. When someone asks what they can do, give them a real job: a meal, a ride, an hour with the kids. Most people want to help and do not know how to offer.

You can talk to somebody about all of this today. See where to get help.

A drug taken at home moves a lot of the work onto the house, and that is the part nobody warns you about.

Pills at home mean somebody has to keep track. There is no nurse handing them over. Work out together where the pills live, whether an alarm helps, and what to do about a missed one before it happens rather than after. Ask the team that last question directly, because the answer is not the same for every drug.

Ask for the blood-test pattern in advance. It is a diary problem rather than a weekly surprise once somebody has written it down.

A few things are worth telling the team about quickly rather than waiting. Yellow eyes or skin, dark urine, or pain in the upper right of the belly. A fever, which is common enough on the BRAF and MEK pills to have its own plan. A new spot on the skin, if they are on those. Most of these turn out to be nothing, and telling somebody early is what makes that true.

Ask what the drug is hoping to do. It is the question in the middle of this page, and it is often easier for the person who is not the patient to ask it out loud. It changes what every scan afterwards means.

What if it stops working?

It happens, it has a name, and it is not a failure of yours.

Tumor cells can become resistant to a targeted drug. The National Cancer Institute describes two ways. The target itself can change, so the drug no longer fits it. Or the cells find a different way to grow that does not use that target at all.

It is also why, as the National Cancer Institute puts it, these drugs may work best alongside another targeted drug or alongside chemotherapy and radiation. And it is why the scans keep coming.

If a drug stops working, that is a conversation about what is next rather than the end of the list. Ask what the options are, whether another targeted drug applies, and whether a trial does. Follow-up scans, and what the results mean covers what a changed scan does and does not settle.

Who decides, and how will I hear?

Two things have to line up, and they are decided at different moments.

Whether your tumor carries a target is the laboratory's answer, and it arrives with your gene results. Waiting for your pathology results covers that wait.

Whether a drug for it is right for you now is your team's, usually with the rest of the people who meet about your case.

Ask how you will be told, and whether the gene results land in your online records before anybody talks you through them. A gene result is a hard thing to meet by yourself on a small screen. If you would rather hear it from a person first, say so now rather than afterwards.

What to ask your team

• Has my tumor been tested for IDH and BRAF, and can I have a copy of the whole report? Some results on it are used for other decisions rather than for these drugs.
• Is there a targeted drug for my tumor's changes?
• What are we hoping this drug does, and how will we know whether it is doing it?
• Is this instead of radiation and chemotherapy, or as well as?
• What blood tests will I need, and how often?
• What should make me call you, and what can wait?
• If I need an operation, when does this drug stop and when does it start again?
• What happens if it stops working?
• If the answer is no targeted drug, what is the route instead?

Where to go next

• The words on your gene results for what is on the report that decides all of this.
• Chemotherapy: the drugs, your blood counts, and the fever rule for the broader drugs, and the fever rule.
• Clinical trials: is this for me? because a trial is one of the routes to a new targeted drug.
• Steroids for the medicine bevacizumab can reduce the need for.
• Follow-up scans, and what the results mean for what a scan on treatment does and does not settle.
• Get help now if you need to talk to a person today.