However, more sensitive methods of detecting urinary and serum light chain myeloma proteins using enzyme-linked immunosorbent assays indicate that >60% of cases initially diagnosed as non-secretory multiple myeloma had abnormal levels of either a clonal κ or λ light chain in their urine or serum and therefore were better diagnosed as having light chain multiple myeloma. Based on the latter definition, non-secretory multiple myeloma represents ~1% of all multiple myeloma cases with formerly diagnosed non-secretory myelomas considered to be cases primarily of light chain multiple myeloma but on occasion "false non-secretors", i.e. cases in which there is evidence of myeloma protein secretion such as renal myeloma protein deposits.A Mayo Clinic study of 124 patients initially diagnosed as having non-secretory multiple myeloma were later found to be composed of 65% free light chain secretors and 35% true non-secretors. As a group, these patients response to therapy, time to disease recurrence, and overall survival were similar to typical myeloma patients. However, in a subset of patients diagnosed after 2001 and therefore treated with more effective therapy that included autologous stem-cell transplantation, prognosis was significantly better in non-secretory multiple myeloma patients (median survival 8.3 years) compared to typical myeloma patients (median survival 5.4 years). In addition, non-secretory patients exhibited a better prognosis than light chain-secretory patients.
Tisotumab vedotin, sold under the brand name Tivdak, is an antibody-drug conjugate used to treat cervical cancer. It is a combination of tisotumab, a monoclonal antibody against tissue factor, and monomethyl auristatin E (MMAE), a potent inhibitor of cell division. Tisotumab vedotin was approved for medical use in the United States in September 2021. It is administered by infusion into a vein every 3 weeks.Tisotumab vedotin is the international nonproprietary name (INN). Adverse effects
In the United States, Tivdak carries a black box warning for ocular toxicity, which occurs in up to 60% of treated patients. In clinical trials, the most common forms of ocular toxicity were dry eye, conjunctivitis, corneal damage, and blepharitis.To prevent eye damage, premedication with three different types of eye drops—a topical corticosteroid, a vasoconstrictor,  and artificial tears—is recommended before each infusion, as well as the use of cold packs over the eyes.Other very common adverse effects include bleeding (occurring in approximately 60% of patients, most often nosebleed) and peripheral neuropathy (42% of patients). Like all drugs containing MMAE, tisotumab vedotin can cause inflammation of the lungs. Mechanism of action
The antibody portion of tisotumab vedotin (tisotumab) binds to and forms a complex with tissue factor, a molecule expressed on the surface of cancer cells. This complex is then taken up into the cell, where tisotumab vedotin is broken down by proteolytic cleavage, releasing MMAE, which stops the cell cycle and kills the cell by apoptosis.