The addition of the proteasome inhibitor Velcade® (bortezomib) to the treatment combination Revlimid® (lenalidomide) plus dexamethasone improves survival when used as initial therapy in multiple myeloma among patients who do not intend to immediately undergo a stem cell transplant. These results were presented at the 2015 annual meeting of the American Society of Hematology in Orlando, Florida.
Multiple myeloma is a type of blood cancer that affects certain immune cells called plasma cells. Healthy plasma cells produce proteins called antibodies that are an important part of the immune system’s defense for fighting bacteria and viruses.
Cancerous plasma cells tend to replicate at a fast pace, crowding out other healthy immune cells, as well as producing malfunctioning antibodies. These antibodies tend to cause damage to the kidneys, in addition to reducing the immune system’s ability to efficiently fight infection.
A common standard treatment combination for newly diagnosed multiple myeloma includes lenalidomide and dexamethasone. Researchers continue to explore potential new combinations of therapies that improve outcomes for this group of patients.
Normal cellular processes include the breakdown of proteins that are no longer being used. The components of the protein that are broken down are then recycled into new, usable proteins. Proteasomes, structures found in healthy cells, play an important role in the breakdown and recycling of proteins.
Bortezomib is a proteasome inhibitor, meaning it prevents proteasomes from breaking down unusable proteins in a cell. These proteins then start to accumulate within the cell, ultimately causing cellular death.
Researchers recently conducted a clinical trial to evaluate the effectiveness of bortezomib in newly diagnosed multiple myeloma. The trial included 525 patients from 48 institutions: one group was treated with the addition of bortezomib to lenalidomide/dexamethasone, and the other group was treated with lenalidomide/dexamethasone only, and results were directly compared. The patients in this trial had no intention of undergoing a subsequent stem cell transplant.
- The median progression-free survival (PFS; survival without progression of cancer) was 43 months for patients treated with bortezomib/lenalidomide/dexamethasone, compared with 31 months for those treated with lenalidomide/dexamethasone only.
- Median overall survival (OS) had not yet been reached at the time of data collection for patients treated with bortezomib/lenalidomide/dexamethasone, compared to 63 months for those treated with lenalidomide/dexamethasone only.
- Side effects were similar between the two treatment groups, except those treated with bortezomib experienced more neuropathy.
The researchers stated that “The addition of bortezomib to lenalidomide dexamethasone for induction therapy in previously untreated myeloma results in a statistically significant and clinically meaningful improvement in PFS as well as better OS. [Bortezomib/lenalidomide/dexamethasone] had an acceptable safety and tolerability profile despite increased neurotoxicity and represents a potential new standard of care.”
Reference: Durie B, Hoering A, Rajkumar V, et al. Bortezomib, lenalidomide and dexamethasone vs. lenalidomide and dexamethasone in patients (pts) with previously untreated multiple myeloma without an intent for immediate autologous stem cell transplant (ASCT): results of the randomized phase III trial SWOG SO777. Proceedings from the 2015 annual meeting of the American Society of Hematology. Abstract #25.
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