Ribociclib was approved by the US FDA in Mar. 2017 for the treatment of certain breast cancers
in combination with an aromatase inhibitor.
The European Medicines Agency (EMA) also approved ribociclib for the same indication in Aug. 2017.
Ribociclib belongs to a class of medications called kinase inhibitors; it inhibits the cyclin-dependent kinase (CDK) 4 and 6.
It is used for treating hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer in post-menopausal women.
It is used along with another anticancer drug belonging to the aromatase inhibitor group such as letrozole.
Ribociclib acts by blocking the action of an abnormal protein which eventually interferes with the cell multiplication, and thereby results in either slowing down or stopping the spread of cancer cells.
Ribociclib is not recommended in the following conditions:
Allergy or hypersensitivity to ribociclib Pregnant women (as it causes harm to the fetus or may result in birth defects). Pregnancy should be avoided for at least three weeks after stopping the treatment. Currently, the drug is approved for use only in postmenopausal women.
Uncontrolled or significant heart disease such as heart attack, unstable angina, congestive heart failure and abnormally slow heart rhythms
The recommended adult dose of ribociclib tablets is 600mg (3 tablets of 200 mg each) taken orally once a day in the morning for the first 21 days followed by 7 days off in a 28-day treatment cycle.
In addition, the patient is also administered the aromatase inhibitor letrozole 2.5mg once daily throughout the 28-day cycle.
Dosage modification when adverse reactions are reported:
The first dose reduction is 400mg/day (2 tablets of 200mg) which can be reduced to further 200mg/day (1 tablet of 200mg) in case the adverse reactions are prolonged.
Drug treatment should be discontinued if adverse reactions occur even at the dose of 200mg once daily.
Ribociclib comes in a tablet form and should be taken by mouth either with or without food.
The tablets should not be chewed or crushed but to be swallowed as a whole with sufficient quantity of water.
If vomiting occurs after taking the medicine, do not take another dose immediately. The next dose should be taken only on the following day.
Serum electrolytes such as potassium, magnesium, calcium, and phosphorous should be monitored closely before initiating the ribociclib therapy.
ECG, complete blood cell counts and liver function must be assessed both before and during the ribociclib treatment.
Ribociclib may affect the fertility in men.
Common: Headache, weakness, low white blood cell counts, gastrointestinal disturbances, QT interval prolongation in the heart
Gastrointestinal: Nausea, vomiting, diarrhea, stomach pain, constipation, stomatitis, loss of appetite, increase in liver enzymes
Skin: Alopecia (loss of hair), itching, rashes
Central nervous system: Headache, difficulty in falling asleep, syncope (temporary loss of consciousness), increase in body temperature
Respiratory: Difficulty in breathing, sorethroat
Blood: Decreased counts of hemoglobin, leukocytes, platelets, neutrophils and/or lymphocytes
Others: Back pain, urinary tract infection, peripheral edema
Avoid excess dose.
Do not use either a broken or a damaged tablet.
The antiviral drugs such as ritonavir, saquinavir, and boceprevir should be avoided with ribociclib as they may increase the concentration of ribociclib.
The concomitant administration of ribociclib with the antifungal drugs itraconazole, posaconazole, and ketoconazole should be avoided because of the possibility of increased concentrations of ribociclib in the blood.
Drugs such as nefazodone, clarithromycin and conivaptan should not be taken together with ribociclib tablets. If required to be taken together, the dose of ribociclib should be reduced 400mg once a day.
Rifampin, phenytoin and carbamazepine should be avoided with ribociclib therapy as these drugs could reduce the concentration of ribociclib.
The co-administration of antiarrhythmic drugs such as quinidine, amiodarone, procainamide and disopyramide, or other drugs like chloroquine, halofantrine and clarithromycin with ribociclib should be avoided as it may result in QT interval prolongation.
Grapefruit juice and pomegranate or pomegranate juice increase the concentration of ribociclib while St. Johns Wort decreases the ribociclib concentration and therefore, the combinations should be avoided.
Ribociclib may increase the levels of drugs like midazolam, fentanyl, alfentanil, cyclosporine, ergotamine, everolimus, pimozide, quinidine, tacrolimus and sirolimus.
Store at room temperature between 20°C and 25°C.
Ribociclib tablets should be stored in the original package away from moisture and heat.