A drug called Blenrep (belantamab mafodotin-blmf) was recently approved by the Food and Drug Administration (FDA) for adult patients with relapsed or refractory multiple myeloma who have received at least 4 prior therapies (including an anti-CD38 monoclonal antibody, a proteasome inhibitor, and an immunomodulatory agent). The term “relapsed” refers to cancer that comes back or grows again after a period of remission, whereas “refractory” means the cancer did not respond to treatment (meaning that the cancer cells continued to grow), or the response to treatment did not last very long.
The recommended dose of Blenrep is 2.5 mg/kg given as a 30-minute intravenous (IV) infusion once every 3 weeks (your healthcare provider will decide how many treatments you need). In a clinical trial of patients with relapsed or refractory multiple myeloma who had received at least 4 prior therapies, patients who were given this dose responded well to the drug, and their responses were long-lasting—longer than 6 months for most people in the trial. Clinical trials are research studies performed on people to test the safety and effectiveness of new drugs or treatments.
Common side effects seen in the trial (in more than 20% of patients) were keratopathy (damage to the cornea due to dryness of the eyes), nausea, worsening vision, blurred vision, fever, allergic reaction to the IV fusion (characterized by chills or shaking, redness of the face, itching, or rash), and feeling tired. Although these tend to be the most common side effects associated with Blenrep, healthcare providers will monitor each of their individual patients on the drug and will decrease the dose, temporarily stop, or completely stop treatment with Blenrep if side effects are serious enough.
It is important to note that the prescribing information for Blenrep includes a boxed warning (also known as a black box warning). This is the strictest warning that can be issued for a drug by the FDA. These warnings are there to alert doctors to potentially serious side effects of a medicine, or to restrictions on the use of a medicine.
Eye problems are common with this drug, and the boxed warning for Blenrep states that the drug can cause changes in the corneal epithelium, resulting in changes to vision, including severe vision loss and corneal ulcer. It can also lead to symptoms like blurred vision and dry eyes, so regular eye exams before and during treatment, and as soon as possible in the case of any worsening symptoms, should be conducted for patients taking this drug. Patients should tell their healthcare provider if they have any vision changes or eye problems during their treatment with Blenrep.
Even if patents are not experiencing any of these symptoms and their vision seems fine, it is important that they get their eyes checked during treatment, because some of these changes can begin to occur without any symptoms and might get worse if not caught early during an eye exam. Patients on this drug should use preservative-free lubricant eye drops at least 4 times per day during treatment, and they should use caution when driving or operating machinery because their vision may be affected by the drug. Unless told otherwise by an eye specialist, patients should also avoid wearing contact lenses during treatment.
Another potentially serious side effect of Blenrep is thrombocytopenia (a decrease in the blood cells that allow blood to clot). Your doctor will check your blood cell counts before you start treatment with Blenrep and will monitor them during treatment. Patients should tell their healthcare provider if they experience bleeding or bruising during treatment.
Because of the risks of vision-related side effects, Blenrep is only available to patients through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS), called the BLENREP REMS. Before prescribing Blenrep, healthcare providers will explain the BLENREP REMS to their patients who are eligible to receive the drug. Before receiving this drug, patients must read and agree to all of the instructions outlined in the BLENREP REMS and sign the patient enrollment form.
Before taking Blenrep, patients should tell their doctor about any medical conditions, including any vision or eye problems, any bleeding problems, or any history of bleeding problems. Women who are pregnant or plan to become pregnant should not take this drug as it can cause harm to an unborn baby or result in a miscarriage. Women who can become pregnant should always use effective birth control when taking this drug, and for 4 months after their final dose. Males with female partners who can become pregnant should use effective birth control during treatment and for 6 months after the last dose. It is not known if Blenrep passes into breast milk, so patients should not breastfeed during treatment and for 3 months after the final dose. Blenrep may affect fertility in both males and females, so patients should talk with their healthcare provider about fertility preservation options if this is a concern. Patients should also tell their healthcare provider about any prescription and over-the-counter medicines they take, including vitamins and herbal supplements.
The introduction of Blenrep in the clinic represents a major advance for select patients with advanced multiple myeloma. This drug employs principles from 2 cutting-edge technologies and is only made available through a drug safety program called REMS (Risk Evaluation and Mitigation Strategy).