capivasertib

Drug Overview

Capivasertib is an advanced, newly approved cancer medicine. It belongs to a special group of treatments called Targeted Therapy or “Smart Drugs.” Unlike older chemotherapy that attacks all fast-growing cells in the body, capivasertib is designed to find and block a specific protein that cancer cells use to grow and survive.

This medicine is particularly important for patients whose breast cancer has stopped responding to traditional hormone therapies. It provides a new way to fight the cancer from the inside out.

• Generic Name: Capivasertib
• US Brand Names: TRUQAP™
• Drug Class: AKT Inhibitor / Serine/Threonine Kinase Inhibitor (Targeted Therapy)
• Route of Administration: Oral (taken by mouth as a tablet)
• FDA Approval Status: Fully FDA Approved (Approved in November 2023)

What Is It and How Does It Work? (Mechanism of Action)

Capivasertib works by shutting down a major communication line inside cancer cells.

To stay alive, cells rely on a chain of signals called the PI3K/AKT/mTOR pathway. Think of this pathway as a microscopic relay race where proteins pass a baton to tell the cell to divide, grow, and survive. In many breast cancers, genetic mutations (specifically in the genes PIK3CA, AKT1, or PTEN) cause this pathway to get stuck in the “ON” position. This runaway signal is what causes the tumor to grow out of control.

At the molecular level, capivasertib specifically targets the middle messenger in this relay race: a protein called AKT (specifically all three types: AKT1, AKT2, and AKT3).

1. The Blockade: The drug slips into the cancer cell and tightly binds to the “ATP-binding pocket” of the AKT protein. This acts like a key breaking off inside a lock.
2. Stopping the Signal: Because AKT is blocked, it cannot pass the baton (a process called phosphorylation) to the next proteins in the chain (like mTOR and GSK3β).
3. Cancer Cell Death: Without these vital growth signals, the cancer cell gets confused. It stops dividing and eventually goes through a natural self-destruct process called apoptosis.

FDA Approved Clinical Indications

Currently, capivasertib is approved to be used in combination with another cancer drug called fulvestrant (an injection that blocks estrogen).

Oncological Uses

• Treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative locally advanced or metastatic breast cancer.
• The tumor must have one or more specific genetic mutations (PIK3CA, AKT1, or PTEN alterations).
• It is used after the cancer has grown or spread despite prior hormone-based treatments.

Non-Oncological Uses

• There are currently no FDA-approved non-oncological uses for this drug. It is prescribed strictly for cancer.

Dosage and Administration Protocols

Capivasertib is taken at home as a pill. It follows a unique “4 days on, 3 days off” weekly schedule to give your normal cells time to rest while still keeping the cancer cells suppressed.

• 
  Dose Adjustments for Adverse Reactions: Because capivasertib can raise blood sugar and cause severe diarrhea, doctors will frequently lower the dose (e.g., to 320 mg or 200 mg) if these side effects become hard to manage.
• Renal/Hepatic Insufficiency: No starting dose adjustment is needed for mild to moderate kidney impairment. For patients with severe liver (hepatic) problems, the drug is used with extreme caution or avoided, as the liver is responsible for clearing the medicine from the body.

Clinical Efficacy and Research Results

The FDA approval of capivasertib was based on a major Phase 3 clinical trial called CAPItello-291 (published in 2023). This trial proved that capivasertib is highly effective for patients with specific genetic mutations.

• Effects on Disease Progression: In the trial, patients with PIK3CA, AKT1, or PTEN gene mutations who took capivasertib plus fulvestrant had a median Progression-Free Survival (the time the cancer stopped growing) of 7.3 months. Patients who took a placebo plus fulvestrant only saw 3.1 months of disease control.
• Risk Reduction: Taking capivasertib reduced the overall risk of the cancer growing or spreading by 50% in the biomarker-altered population.
• Tumor Shrinkage: Nearly 29% of patients with these specific gene mutations saw their tumors shrink significantly (Objective Response Rate), compared to less than 10% in the placebo group.

Safety Profile and Side Effects

Because capivasertib changes how cells process energy and signals, it comes with specific side effects that require careful monitoring. Currently, capivasertib does not have an FDA “Black Box Warning.”

Common Side Effects (>10%)

• Diarrhea: This is very common and can be severe or watery.
• Hyperglycemia: High blood sugar. The AKT pathway normally helps control insulin; blocking it causes sugar to build up in the blood.
• Cutaneous Reactions (Skin Rash): Red, itchy, or bumpy skin rashes.
• Fatigue: Feeling unusually tired or lacking energy.
• Nausea and Vomiting: Mild to moderate stomach upset.
• Stomatitis: Mouth sores.

Serious Adverse Events

• Severe Hyperglycemia: Dangerously high blood sugar that can lead to a life-threatening condition called ketoacidosis, even in people who do not have diabetes.
• Severe Dehydration: Caused by uncontrolled diarrhea, which can damage the kidneys.
• Erythema Multiforme: A severe, painful skin reaction that requires immediate medical attention.

Management Strategies

• For High Blood Sugar: Doctors will check your fasting blood sugar frequently. If it spikes, they may prescribe daily diabetes medication (like metformin) to safely control it while you stay on your cancer treatment.
• For Diarrhea: Keep over-the-counter anti-diarrheal medicine (like loperamide) at home. Drink plenty of clear fluids. If diarrhea lasts more than a day, call your doctor.
• For Skin Rashes: Use gentle, alcohol-free moisturizers. Your doctor may prescribe steroid creams or antihistamines to calm the skin.

Research Areas

While capivasertib is currently approved for advanced breast cancer, it is a major focus in broader Targeted Therapy research. Because the PIK3CA/AKT/PTEN pathway is a very common “engine” that drives many types of tumors, scientists are testing capivasertib in prostate cancer, ovarian cancer, and blood cancers. Researchers are also exploring how to combine capivasertib with modern immunotherapy to see if blocking the AKT pathway can help immune cells better recognize and destroy stubborn tumors that resist standard treatments.

Patient Management and Practical Recommendations

Pre-Treatment Tests to be Performed

Before you start capivasertib, your healthcare team will perform:

• Tumor Genetic Testing: An FDA-approved test on your tumor tissue to confirm you have the specific PIK3CA, AKT1, or PTEN mutations.
• Fasting Blood Glucose and HbA1c: To check your baseline blood sugar levels.
• Pregnancy Test: For women who can become pregnant, as this drug can severely harm an unborn baby.

Precautions During Treatment

• Monitor Your Blood Sugar: If your doctor asks you to, you will need to check your blood sugar at home using a finger-prick monitor.
• Watch for Diabetes Symptoms: Tell your doctor right away if you feel extremely thirsty, need to urinate very often, or feel confused, as these are signs of dangerous blood sugar levels.

“Do’s and Don’ts” list

• DO take the pills at the same times every day (e.g., morning and evening) during your 4 “on” days.
• DO use highly effective birth control during treatment and for at least 1 month after your last dose.
• DON’T eat grapefruit or drink grapefruit juice, as it can dangerously increase the amount of the drug in your blood.
• DON’T take a double dose to make up for a missed one. If you vomit after taking a pill, just wait and take your next dose at the regularly scheduled time.
• DON’T stop taking the medicine just because you feel better. Always talk to your oncologist before changing your schedule.

Legal Disclaimer

The information provided in this guide is for educational and informational purposes only and does not constitute medical advice. Capivasertib (TRUQAP) is a prescription medication, and treatment protocols, dosages, and side effects vary by individual. Patients should always consult with their primary oncologist or a qualified healthcare professional regarding diagnosis, treatment options, and the management of medical conditions. Do not disregard professional medical advice or delay in seeking it because of something you have read in this material.