What Is Imdelltra, and Why Does It Matter?
Imdelltra (tarlatamab-dlle) is a first-of-its kind targeted cancer medicine called a bispecific T-cell engager approved for treating adults with extensive-stage small-cell lung cancer (ES-SCLC) that has gotten worse on or after chemotherapy with platinum-based cancer drugs.
Imdelltra works by helping your immune system find and attack cancer cells. It binds to CD3, a protein on T cells (a type of immune cell), and to DLL3, a protein present on most SCLC cells. By creating this connection, Imdelltra helps your immune system target and destroy the cancer cells more effectively.
ES-SCLC is one of the fastest growing and most aggressive forms of lung cancer. While many people get results from their first round of chemotherapy, the cancer often returns quickly, and treatment options become very limited once their chemotherapy stops working.
Imdelltra is the first medicine in its class to help people live longer than standard chemotherapy. It’s now listed in national guidelines as the preferred treatment option for people with ES-SCLC in whom platinum-based chemotherapy did not work or is no longer working.
Why Was It Approved?
Imdelltra was granted full (traditional) approval by the FDA because it helped people with relapsed ES-SCLC live longer and respond better to treatment than those who received standard chemotherapy.
In studies involving 509 patients with ES-SCLC that had progressed on or after one line of platinum-based chemotherapy, those who took Imdelltra lived about 5 months longer on average than those who received standard chemotherapy (13.6 months vs. 8.3 months). It also helped delay the worsening of cancer and lowered the risk for death by 40%.
About 40% of patients saw their tumors shrink, with a median duration of response of 9.7 months, and 68% of responders maintained the benefit for at least six months. Patients also reported improved breathing (dyspnea) at week 18 while on this medicine.
Imdelltra caused fewer serious side effects than chemotherapy. A common immune reaction called cytokine release syndrome (CRS) happened in more than half the people, but most cases were mild or moderate. Some people also had nervous system problems, including confusion, dizziness, seizures, headache, numbness, sleeplessness, or immune effector cell-associated neurotoxicity syndrome.
The most common side effects of Imdelltra included flu-like symptoms (CRS), tiredness, loss of appetite, anemia, changes in taste (bad or metallic taste in the mouth), fever, constipation, muscle or joint pain, and nausea. Blood test results also sometimes showed changes, including low white blood cell and neutrophil counts, low sodium levels, and high uric acid, liver enzyme, and bile pigment levels. In some cases, it also caused severe allergic reactions or infections involving the lungs (pneumonia) or the urinary or upper respiratory tracts.
What Do I Need to Know?
Imdelltra is given as an intravenous (IV) infusion at a health care facility. The first two doses are given one week apart using a step-up approach, which means you start with a smaller dose to help lower the risk for side effects like CRS. After that, you’ll get the full dose every two weeks.
You’ll need to stay at the health care facility for 22 to 24 hours after each of the first two doses. For 48 hours after each of those doses, you should stay within an hour of medical care and have someone with you. This is to help manage any serious side effects that may happen early in treatment.
Before starting each dose, your health care provider will do blood tests to check your blood counts and liver enzymes and bilirubin levels. They will also monitor you during treatment for any signs and symptoms of CRS and neurologic problems.
Contact your health care provider right away if you notice symptoms like fever, a fast heartbeat or dizziness; trouble breathing; dark urine; yellowing of your skin or eyes; blood clots; unusual or prolonged bleeding; confusion; restlessness; anxiety; trouble walking or maintaining balance; changes in taste, personality, and sleep patterns; memory loss; or tremors. These could be signs of serious side effects.
Imdelltra may harm a fetus. If you can become pregnant, use effective birth control while taking this medicine and for two months after your last dose. You should also avoid breastfeeding during this time.
Because of the risk for nervous system side effects, don’t drive, use heavy machinery, or attempt risky activities if you feel confused, dizzy, or have trouble thinking clearly during treatment.