Vitrakvi, the brand name for larotrectinib, is a targeted cancer medication with a rather unusual job description. Instead of focusing on where a cancer startedsuch as the lung, thyroid, colon, or salivary glandit targets a specific genetic change called an NTRK gene fusion.
That makes Vitrakvi a tumor-agnostic treatment. In plain English, the tumor’s molecular wiring matters more than its ZIP code. The medication may be used in adults and children whose solid tumors have the qualifying genetic alteration, have spread or would be difficult to remove safely, and have no satisfactory treatment alternative.
The FDA initially granted Vitrakvi accelerated approval in 2018 and converted the indication to traditional approval in 2025 after reviewing additional evidence. Although responses can be meaningful and long-lasting for some patients, Vitrakvi is not appropriate for every cancer, and genetic testing is essential before treatment.
What Is Vitrakvi?
Vitrakvi is an oral kinase inhibitor that contains larotrectinib. It is considered a precision or targeted therapy rather than traditional cytotoxic chemotherapy.
The medication inhibits TRKA, TRKB, and TRKC proteins, which are produced by the NTRK1, NTRK2, and NTRK3 genes. When one of these genes fuses with another gene, it may create an abnormal TRK fusion protein that continuously tells cancer cells to grow. It is essentially a stuck accelerator pedal, except the vehicle is a tumor and nobody asked it to go anywhere.
Larotrectinib blocks signaling from the abnormal protein. In responsive tumors, that may slow cancer growth or cause tumors to shrink.
What Is Vitrakvi Used For?
Vitrakvi is FDA-approved for adult and pediatric patients with solid tumors that meet all of the following conditions:
- The tumor has an NTRK gene fusion without a known acquired resistance mutation.
- The cancer is metastatic, or surgery would probably cause severe medical complications or disability.
- No satisfactory alternative treatment is available, or the cancer has progressed after treatment.
An FDA-approved diagnostic test is generally used to determine whether an NTRK fusion is present. Depending on the cancer and available tissue, testing may involve next-generation sequencing, RNA-based testing, fluorescence in situ hybridization, or another validated molecular method.
Which cancer types may have NTRK fusions?
NTRK fusions are uncommon overall but have been detected in many solid tumors. Examples include certain thyroid, lung, colorectal, pancreatic, breast, salivary gland, soft-tissue, central nervous system, and pediatric tumors. They occur especially often in a few rare cancers, including infantile fibrosarcoma and secretory cancers.
Finding an NTRK mutation is not automatically enough. The alteration must be a qualifying gene fusion, and the oncology team must consider the full clinical situation. Molecular reports can resemble alphabet soup printed during an earthquake, so interpretation by an experienced clinician is important.
How effective is Vitrakvi?
The evidence supporting full FDA approval included 339 evaluable adults and children with NTRK fusion-positive solid tumors. The pooled overall response rate was approximately 60%, including complete and partial responses. The reported median duration of response was longer than three years.
These results do not predict exactly how one individual will respond. Cancer type, fusion partner, previous treatment, disease burden, resistance mechanisms, and general health can all influence the outcome.
Vitrakvi Dosage and Administration
Vitrakvi is available as capsules and an oral solution. It is usually taken twice a day, approximately 12 hours apart, with or without food. Treatment generally continues until the cancer progresses or side effects become unacceptable.
| Patient group | Typical recommended dose |
|---|---|
| Adults and pediatric patients with a body surface area of at least 1 square meter | 100 mg by mouth twice daily |
| Pediatric patients with a body surface area below 1 square meter | 100 mg per square meter by mouth twice daily |
Body surface area is calculated using height and weight. Parents should not try to calculate or round a child’s dose at home unless specifically trained by the oncology team.
How to take Vitrakvi capsules
- Swallow each capsule whole with water.
- Do not crush or chew the capsule.
- Take doses at approximately the same times each day.
- Do not share the medication with anyone else.
How to use the oral solution
The oral solution contains 20 mg of larotrectinib per milliliter. Measure it only with the supplied oral syringe and bottle adapter. A kitchen teaspoon is suitable for cereal, not precision oncology.
The liquid should be stored in a refrigerator and must not be frozen. Depending on the bottle configuration, unused solution may need to be discarded either 31 or 90 days after opening. Follow the pharmacy label and the instructions supplied with the specific package.
What if a dose is missed?
Take the missed dose when remembered unless the next scheduled dose is less than six hours away. In that situation, skip the missed dose and resume the regular schedule. Do not take two doses together to compensate.
If vomiting occurs after a dose, do not immediately repeat it. Take the next dose at the normally scheduled time.
Dose reductions
For serious side effects other than certain liver abnormalities, clinicians may temporarily withhold treatment and restart it at a lower level after symptoms improve. Standard reductions for patients with a body surface area of at least 1 square meter are generally:
- 75 mg twice daily
- 50 mg twice daily
- 100 mg once daily
Pediatric reductions are calculated by body surface area. Vitrakvi may be permanently stopped when a serious reaction does not resolve, severe liver injury develops, or the patient cannot tolerate treatment after three dose reductions.
What Does Vitrakvi Look Like?
Official U.S. labeling describes both capsule strengths as opaque white hard gelatin capsules with blue printing:
- 25 mg capsule: white, size 2, printed with the Bayer cross and “25 mg.”
- 100 mg capsule: white, size 0, printed with the Bayer cross and “100 mg.”
- Oral solution: a clear liquid that may range from colorless or yellow to orange, reddish, or brownish, depending on the package.
Packaging and labeling can change, and lighting can make colors look different in photographs. Never identify a cancer drug solely from an online picture. Confirm the medication, strength, expiration date, and instructions with the dispensing pharmacy.
Common Vitrakvi Side Effects
Side effects vary considerably. Some patients experience only mild problems, while others need a treatment interruption or dose reduction. Common clinical reactions reported in studies included:
| Side effect | Approximate frequency in clinical trials |
|---|---|
| Musculoskeletal pain | 41% |
| Fatigue | 31% |
| Vomiting | 30% |
| Cough | 29% |
| Constipation | 27% |
| Fever | 26% |
| Diarrhea | 26% |
| Nausea | 25% |
| Abdominal pain | 24% |
| Dizziness | 22% |
| Rash | 21% |
Blood tests may also reveal elevated liver enzymes, anemia, low albumin, low calcium, or reduced white blood cell, lymphocyte, and neutrophil counts. A person may feel completely normal while laboratory values are changing, which is why scheduled blood work is not optional paperwork invented to decorate a calendar.
Serious Warnings and Precautions
Central nervous system effects
Vitrakvi can affect the brain and nervous system. Reported problems include dizziness, confusion, memory impairment, difficulty concentrating, mood changes, agitation, depression, hallucinations, insomnia, and drowsiness.
Across clinical studies, central nervous system effects of any grade were reported in about 40% of patients, while severe Grade 3 or 4 effects were much less common. Patients should avoid driving, climbing ladders, or operating dangerous equipment when dizziness, confusion, sleepiness, or other neurologic symptoms occur.
Contact the treatment team promptly for new confusion, hallucinations, marked personality changes, speech difficulties, severe dizziness, or problems with attention and memory.
Bone fractures
Fractures occurred in approximately 7% of patients in the clinical safety population, including both adults and children. Some followed only minimal or moderate trauma.
New bone pain, tenderness, swelling, reduced mobility, or a visible deformity should be evaluated promptly. Patients with osteoporosis, previous fractures, bone metastases, or other skeletal risks should discuss monitoring and fall-prevention strategies with their clinicians.
Liver injury
Vitrakvi can cause elevated liver enzymes and, less commonly, serious drug-induced liver injury. Liver testsincluding ALT, AST, alkaline phosphatase, and bilirubinshould be obtained before treatment, every two weeks during the first two months, and monthly afterward unless more frequent monitoring is needed.
Call the oncology team for yellow skin or eyes, dark urine, persistent nausea, unusual bruising, severe fatigue, loss of appetite, or pain in the upper-right abdomen. Significant abnormalities may require treatment interruption, dose reduction, or permanent discontinuation.
Pregnancy, contraception, and breastfeeding
Larotrectinib can harm a developing fetus. Pregnancy testing may be performed before treatment. Females who can become pregnant should use effective contraception during treatment and for one week after the final dose. Males with female partners who can become pregnant should follow the same timeline.
Breastfeeding is not recommended during treatment or for one week after the last dose. Animal findings also suggest that Vitrakvi may reduce female fertility, although the effect in humans is not fully known.
Vitrakvi Drug and Food Interactions
Larotrectinib is processed largely through the CYP3A4 enzyme system. Medicines or foods that strongly alter this enzyme can dramatically change the amount of drug in the bloodstream.
Substances that may increase Vitrakvi levels
Strong CYP3A4 inhibitors can raise larotrectinib exposure and increase side-effect risks. Examples include itraconazole and certain other antifungal, antiviral, or antibiotic medications. Grapefruit and grapefruit juice should be avoided. Moderate inhibitors, such as fluconazole, may require closer monitoring.
Substances that may reduce Vitrakvi levels
CYP3A4 inducers can lower larotrectinib exposure and potentially make treatment less effective. Examples include rifampin and the herbal product St. John’s wort. Strong inducers should generally be avoided, and moderate inducers may also require a physician-directed dosage adjustment.
Effects on other medications
Vitrakvi may increase blood levels of certain sensitive CYP3A4 substrates. Depending on the second drug, this could intensify sedation, heart rhythm effects, low blood pressure, or other toxicities.
Give the oncology pharmacist a complete list of prescription medicines, over-the-counter products, vitamins, supplements, teas, powders, and herbal remedies. “Natural” does not mean “metabolically invisible.” Do not start, stop, or adjust another medicine without professional review.
Who May Need Additional Monitoring?
Tell the prescribing team about neurological disorders, balance problems, osteoporosis, previous fractures, liver disease, pregnancy plans, and all current medications.
Patients with moderate or severe hepatic impairment generally require a 50% reduction in the starting dose. No adjustment is recommended in the official labeling for mild hepatic impairment or renal impairment, although clinicians still consider the complete medical picture.
Older adults did not show major overall differences in safety or effectiveness compared with younger adults in the clinical studies. Nevertheless, medication interactions, fall risk, frailty, and organ function may require especially careful review.
Practical Treatment Experience: What Daily Life May Look Like
The following examples describe common practical situations rather than promises about an individual patient’s experience.
Getting through the first weeks
The first month often involves more scheduling than drama: two daily doses, frequent laboratory visits, pharmacy calls, and the occasional hunt for an oral syringe that was “definitely right here five minutes ago.” A written medication calendar or phone alarm can help keep doses approximately 12 hours apart.
Because liver tests are checked every two weeks during the first two months, patients may initially feel that the laboratory staff have become part of the extended family. These appointments matter even when treatment feels easy. Liver enzyme changes can develop before obvious symptoms appear.
A simple daily log can record dose times, nausea, bowel movements, appetite, pain, sleep, dizziness, mood, and temperature. This gives the care team more useful information than “I felt weird sometime around Tuesday.” It may also reveal patterns, such as nausea occurring shortly after the morning dose or dizziness becoming worse when standing quickly.
Handling fatigue, stomach symptoms, and dizziness
Mild fatigue may be managed by spreading activities through the day, prioritizing sleep, and accepting help with errands. Patients should still report worsening fatigue because anemia, infection, liver abnormalities, dehydration, or cancer itself may contribute.
For nausea or vomiting, the oncology team may recommend an anti-nausea medication and smaller meals. Diarrhea and constipation require different strategies, so guessing with random over-the-counter products is not ideal. The pharmacist should check each product for interactions before it is used.
Dizziness deserves particular attention. Getting up slowly, maintaining safe hydration when permitted, installing night-lights, and removing loose rugs may reduce falls. A caregiver may notice subtle confusion, irritability, unusual sleepiness, or memory changes before the patient does. Those observations should be shared without delay rather than politely stored for the next holiday gathering.
Using Vitrakvi in children
For a child taking the oral solution, caregivers usually develop a routine: refrigerate the bottle, measure the exact dose, administer it toward the inside of the cheek, and document the time. If the child spits out an uncertain amount, another dose should not be given unless the oncology team provides specific instructions.
Weight and height should be measured regularly because pediatric dosing depends on body surface area. Caregivers should also report limping, reduced play, persistent bone pain, unusual falls, behavioral changes, or developmental concerns.
Traveling during treatment
Travel requires planning, especially with refrigerated oral solution. Patients can ask the specialty pharmacy how to transport it safely and should carry enough medication for the trip, plus a small buffer when permitted. Vitrakvi should remain in its labeled container rather than migrating into an anonymous pill organizer that looks suspicious at airport security.
Carry a current medication list, oncology contact information, insurance details, and recent treatment summary. Confirm where laboratory testing can be completed if the trip overlaps a scheduled monitoring date.
Questions worth bringing to appointments
- Which test confirmed my NTRK fusion?
- How will we determine whether treatment is working?
- Which symptoms require an immediate call?
- How often will scans and blood tests be performed?
- Do any of my current medicines affect CYP3A4?
- What should I do if I cannot keep a dose down?
- Could my bone health or fall risk require additional monitoring?
Conclusion
Vitrakvi represents an important shift toward treating cancer according to its molecular driver rather than only its organ of origin. For appropriately selected adults and children with NTRK fusion-positive solid tumors, larotrectinib can produce substantial and durable responses.
That precision does not make the medication carefree. Central nervous system effects, fractures, liver injury, blood-count changes, pregnancy risks, and CYP3A4 interactions require careful monitoring. The safest approach is a partnership involving the patient, caregivers, oncologist, oncology pharmacist, nurses, and laboratory teamwith everyone working from the same medication list and treatment plan.
Editorial note: Drug labeling and safety recommendations may change. Review the current FDA-approved prescribing information and the instructions provided by the treating oncology team before making treatment decisions.
