Low platelet counts (less than 50 x 109/L) can be caused by the MF treatment you’re currently taking, or by changes in your MF. To manage those changes, doses may have to be lowered in order to lessen the risk of making low platelet counts worse. However, with VONJO, you have a therapy that’s tailored to your type of MF from the start by treating the disease while managing low platelet counts.
MF develops when changes (mutations) take place in blood stem cells. When these mutations send more signals than normal along various signaling pathways, it causes inflammation in the bone marrow. As a result, that bone marrow becomes scarred and unable to create normal amounts of blood cells. The resulting scar tissue may lead to complications such as low red blood cells (anemia), low platelets (thrombocytopenia), weakness, and tiredness. It can also cause the spleen to enlarge as it works harder to take over blood cell production.
Some of the mutations specific to your MF may be related to Janus kinase (JAK) proteins, such as JAK1 and JAK2. The JAK2 mutation is found in more than half of people with MF (approximately 50%-60%), but there may be more mutations involved in your MF. In some people, both JAK2 and IRAK1 (interleukin-1 receptor-associated kinase 1) mutations may be changing how the body sends signals for blood cell production.
VONJO is believed to inhibit (interrupt) more than one of the overactive signals (JAK2 and IRAK1) that may be driving MF. However, VONJO does not significantly inhibit JAK1, which is important because sparing that signaling pathway may help reduce the chance of worsening platelet counts. VONJO is approved for use in people with low platelet counts.
When people have MF, overactive signaling in the JAK and IRAK pathways can cause chronic inflammation within the body and various related symptoms.
VONJO is believed to inhibit (interrupt) JAK2 and IRAK1 within these pathways to help address the inflammation and reduce MF-related symptoms, including an enlarged spleen. However, some FDA-approved therapies for MF inhibit JAK1, which may result in worsening platelet counts. VONJO is different than these therapies in that it does not inhibit JAK1.*
10x more patients (29%) had a spleen volume reduction on VONJO than those receiving best available therapy (3%).
More patients (83%) reduced spleen size on VONJO than those receiving best available therapy (56%).
In the best available therapy group, most patients (39%) were on ruxolitinib. Other options included monitoring without treatment (32% of patients) and hydroxyurea (26% of patients).
Tell your doctor if you are pregnant, plan to become pregnant, are breastfeeding, or plan to breastfeed. It is not known if VONJO will harm your unborn baby or if it passes into breast milk. You should not breastfeed during treatment and for two weeks after your last dose of VONJO. Talk to your doctor about the best way to feed your baby during this time.
VONJO may affect fertility in males. You may have problems fathering a child. Talk to your doctor if this is a concern for you.
Tell your doctor about all the medications you are taking, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Taking VONJO with certain other medicines may affect the amount of VONJO in your blood, and may increase your risk of side effects or affect how well VONJO works.
Know the medicines you take. Keep a list of the medicines you take to show your doctor and pharmacist when you get a new medicine.
If you take other kinase inhibitors (eg, ruxolitinib), carefully follow your doctor’s instructions about how to slowly decrease (taper) your dose or stop the other kinase inhibitor medicines before you begin taking VONJO.
VONJO is a prescription medicine used to treat adults with certain types of myelofibrosis (MF) who have a platelet count below 50 × 109/L.
It is not known if VONJO is safe and effective in children.
This indication is approved under accelerated approval based on spleen volume reduction. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial(s).
Bleeding. VONJO may cause severe bleeding, which can be serious and, in some cases, may lead to death. Avoid taking VONJO if you are bleeding. If you develop bleeding, stop VONJO and call your healthcare provider. Your healthcare provider will do a blood test to check your blood cell counts before you start VONJO and regularly during your treatment with VONJO. Tell your healthcare provider right away if you develop any of these symptoms: unusual bleeding, bruising, and fever. You will need to stop taking VONJO 7 days before any planned surgery or invasive procedure (such as a heart catheterization, stent placement in a coronary artery in your heart, or a procedure for varicose veins). Your healthcare provider should tell you when you can start taking VONJO again.