Drug Detail:Promacta (Eltrombopag [ el-trom-boe-pag ])
Drug Class: Platelet-stimulating agents
1. How it works
- Promacta is a brand (trade) name for eltrombopag olamine which is a platelet booster that may be given as part of the management of persistent or chronic immune thrombocytopenia (ITP), severe aplastic anemia, or chronic hepatitis C.
- Promacta (eltrombopag olamine) works in the same way as TPO (thrombopoietin). TPO is a hormone that helps create platelets in the body. Promacta resembles TPO and can interact with TPO receptors on bone marrow progenitor cells to initiate signaling cascades that induce the proliferation and differentiation of platelets from these cells. This increases the number of platelets in the blood.
- Promacta belongs to the class of medicines known as thrombopoietin receptor agonists or TPO agonists.
2. Upsides
- May be given to treat low platelet counts (thrombocytopenia) in adults and children aged 1 year and older with persistent or chronic ITP at increased risk for bleeding who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy.
- Can be used to treat thrombocytopenia in patients with chronic hepatitis C to allow the initiation and maintenance of interferon-based therapy.
- Used in combination with standard immunosuppressive therapy (IST) for the first-line treatment of adult and pediatric patients 2 years and older with severe aplastic anemia who have had an insufficient response to immunosuppressive therapy.
- Taken by mouth and available as a film-coated tablet and an oral suspension. Given once daily.
- Tablets come in four different strengths: 12.5mg (white), 25mg (orange), 50mg (blue), and 75mg (pink).
- The suspension is available in two strengths: 12.5mg and 25mg. Each suspension is packaged in a kit with a 40-cc reconstitution vessel and 30 single-use oral dosing syringes.
- Covered by Medicare with a low (less than $10) to no co-pay.
- The objective is to keep the platelet count about 50,000 per microliter to lower the risk of bleeding. Use the lowest dose necessary and adjust the dose according to the response.
- Works like TPO and tells the body to make more platelets.
- May be used in adults and children who are at least 1 year old.
3. Downsides
If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:
- Nausea, diarrhea, upper respiratory tract infections, vomiting, urinary tract infection, increases in liver enzymes (such as ALT or AST), muscle pain, sore throat, back pain, influenza, paresthesias (abnormal sensations of the skin such as tingling, pricking, chilling, burning, or numbness), and a rash are the most common side effects reported. Children may be more likely to experience upper respiratory tract infections, nasopharyngitis, cough, diarrhea, fever, or pain.
- New cataracts or a worsening of existing cataracts has been reported in patients who have received Promacta. Perform a baseline eye examination before the administration of Promacta and monitor patients regularly for signs and symptoms of cataracts.
- May cause thromboembolic complications as a result of increases in platelet counts. Portal vein thrombosis has been reported in people with chronic liver disease receiving Promacta.
- Does not treat low platelets (thrombocytopenia) caused by myelodysplastic syndrome (MDS). Research has shown that there is a risk of progression of MDS to acute myelogenous leukemia with Promacta. Promacta is not indicated for the treatment of thrombocytopenia due to MDS.
- Reserve use for patients whose platelet level and clinical condition increases the risk for bleeding.
- The aim of Promacta. is to keep the platelet count about 50,000 per microliter, not to normalize it. Trying to normalize it increases the risk of thromboembolic complications.
- The dosage of Promacta needs to be individualized. Discontinue Promacta if after 4 weeks at the maximum dose (75mg daily) the platelet count does not increase to a level sufficient enough to avoid clinically important bleeding.
- Perform laboratory monitoring, such as a complete blood count (CBC) (including platelets) weekly during the dosage adjustment phase of Promacta and then monthly following the establishment of a stable dose of Promacta. Continue CBCs weekly for at least 2 weeks following discontinuation of Promacta.
- The initial dosage of Promacta may need reducing in those with mild to moderate and severe liver disease. The half-life of Promacta may be prolonged at least 2-fold in these patients. No dosage adjustment is recommended in those with chronic hepatitis C and liver impairment. Monitor liver function tests before starting Promacta then regularly thereafter. Discontinue Promacta if the ALT or AST increases to more than six times the upper limit of normal. The risk of liver toxicity is high in patients with chronic hepatitis C when Promacta is used in combination with interferon and ribavirin.
- People of Asian ancestry (such as Chinese, Japanese, Taiwanese, Korean, or Thai) may need a lower dose of Promacta.
- May not be suitable for some people including those with MDS, blood cancer, with a blood clot, cataracts, who have had surgery to remove their spleen, or with bleeding problems.
- Platelet counts should be assessed weekly for 2 weeks when switching from the oral suspension to the tablets or vice versa, then continue monitoring monthly thereafter.
- Not indicated for the treatment of patients with myelodysplastic syndromes (MDS).
- The safety and efficacy of Promacta for the treatment of chronic hepatitis C infection in combination with direct-acting antiviral agents without interferon has not been established.
- May cause fetal harm when administered to a pregnant woman. Advise women of reproductive potential not to become pregnant while being administered Promacta. There is no data about Promacta during breastfeeding, and women should be advised not to breastfeed during treatment with Promacta.
- No generic is available.
Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects
4. Tips
- Swallow tablets whole do not split, chew, crush, cut in half, or mix with foods or liquids.
- If you are administering the suspension to yourself or a child, read the instructions for mixing the Promacta powder to make the suspension. Once mixed with 20mL of water, the suspension should be taken right away and stored for no more than 30 minutes between 68°F to 77°F (20°C to 25°C). Throw away the mixture if not used within 30 minutes. Use a new oral dosing syringe for each dose and throw away the syringe after use. If the suspension comes into contact with your skin, wash the skin right away with soap and water.
- Take Promacta exactly as directed by your doctor. Do not increase or decrease the dosage without your doctor's advice. If you miss a dose, wait and just take your next scheduled dose. Do not take more than one dose in a day.
- Take on an empty stomach (an hour before food or two hours after) or with food or a meal that is low in calcium (50mg or less). If eating foods high in calcium such as dairy products, soy milk, canned fish, cheeses, fortified juices, or certain fruits and vegetables (such as green leafy vegetables, figs, broccolli, oranges) take Promacta either two hours before or four hours after eating these foods.
- Take Promacta at least 2 hours before or 4 hours after mineral supplements and antacids that contain polyvalent cations, such as iron, calcium, aluminum, magnesium, selenium, and zinc.
- The goal of Promacta for ITP is to keep platelet counts above 50 x 109/L to reduce the risk of bleeding, not to normalize platelet counts.
- On discontinuation of Promacta, you may be at increased risk of bleeding or thrombocytopenia that is worse than that experienced during Promacta treatment. Monitor yourself for bleeding, and if you experience significant bleeding then contact your healthcare provider immediately. Avoid situations or medications that increase your risk of bleeding.
- Talk to your doctor immediately if you experience abdominal pain, skin yellowing or yellowing of the eyes, unusual tiredness, confusion, vision problems, or any other side effects of concern.
- Talk to your doctor or pharmacist before you take any other medication with Promacta, including supplements or medicines bought from a drugstore or supermarket.
- Store Promacta tablets at room temperature between 68°F to 77°F (20°C to 25°C).
- If you are a woman of childbearing age you should use adequate contraception to ensure you do not become pregnant while you are being administered Promacta. Do not breastfeed.
5. Response and effectiveness
- Increases in platelet counts were detectable 1 week after starting treatment with Promacta in trials (Studies 773B and 773A) conducted in adults with chronic immune thrombocytopenia. Maximum response was seen after 2 weeks of therapy. An initial response during the first 2 weeks of treatment was observed in 62% of the 26 pediatric patients who responded to treatment with Promacta - achieved a platelet response (≥ 50 x 109/L without rescue) for 6 out of 8 weeks (between weeks 5 and 12) of the Petit2 trial.
- For patients with thrombocytopenia with hepatitis C, two weeks was the median time to achieve the target platelet count of ≥ 90 x 109/L in patients enrolled in the Enable 1 and 2 trials. A total of 95% of the patients were able to receive antiviral therapy after treatment with Promacta. The purpose of the trial was to treat thrombocytopenia in patients with chronic hepatitis C to allow the initiation and maintenance of interferon-based therapy.
- Promacta has also been used in combination with standard immunosuppressive therapy for the first-line treatment of severe aplastic anemia. It is unclear exactly how quickly Promacta + combination immunosuppressive therapy works in previously untreated patients with severe aplastic anemia. However, 87% (95% CI 75-100) of patients treated with Promacta once daily for the first 6 months of their treatment plan (cohort 3 Study US01T) had either a complete or partial response to Promacta + combination immunosuppressive therapy at 3 months. A total of 24 of the 25 pediatric patients in cohort 3 also had a complete or partial response at 6 months, which was a key outcome measured by the trial.
- Promacta has also been used to treat patients with severe aplastic anemia who have had an insufficient response to immunosuppressive therapy. It is unclear exactly how quickly Promacta works in patients with severe aplastic anemia who have not responded to previous immunosuppressive therapy. However, 44% (11 of 25) of patients had at least some hematologic response to therapy at 12 weeks, with 9 of the 11 patients no longer needing platelet transfusions at that time.
6. Interactions
Medicines that interact with Promacta may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with Promacta. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.
Over 140 medicines or supplements interact with Promacta, for example:
- aluminum, calcium, chromium, copper, iron, magnesium, selenium, and zinc in antacids, foods, and supplements (Promacta chelates (binds) with these polyvalent cations and its absorption is significantly reduced)
- berotralstat
- cannabidiol
- cyclosporine
- eluxadoline for irritable bowel syndrome
- ezetimibe
- glyburide
- herbals, such as black cohosh or echinacea
- HIV medications, such as didanosine
- interferon alfa (significantly), peginterferon alfa (significantly) and interferon beta (moderately), but no dosage adjustments are recommended
- kaolin
- leflunomide or teriflunomide
- lomitapide
- medications that also may cause liver toxicity, such as brentuximab,
- medications that may also increase the risk of blood clots, such as carfilzomib
- mipomersen
- naltrexone
- ozanimod
- statins, such as atorvastatin, pravastatin, or simvastatin
- sulfasalazine
- ubrogepant
- valsartan.
Take Promacta at least 2 hours before or 4 hours after any medications or products containing polyvalent cations (for example, aluminum, calcium, iron, magnesium, selenium, or zinc), such as antacids, dairy products, and mineral supplements.
Be cautious when administering Promacta with substrates of OATP1B1 (such as atorvastatin, bosentan, ezetimibe, fluvastatin, glyburide, olmesartan, pitavastatin), breast cancer resistance protein (such as imatinib, irinotecan, methotrexate, sulfasalazine). Monitor patients for excessive exposure to these drugs and consider dosage reduction of the substrate if necessary.
No dosage adjustment is recommended when Promacta is administered with HIV protease inhibitors such as lopinavir/ritonavir or HCV Protease Inhibitors such as boceprevir or telaprevir.
Refer to the product information for Promacta for any new interactions.