Diffuse large B-cell lymphoma (DLBCL) made headlines earlier this year with the high-profile case of prominent U.S. Congressman Jamie Raskin (D-MD). Yet, until very recently, progress in treating this most common form of lymphoma has been stalled for more than 2 decades.
Significant breakthroughs have come in just the past few weeks and months, through the use of CAR T-cell and immunotherapies and with the approval in April by the Food and Drug Administration of polatuzumab for frontline DLBCL.
"Until the publishing of data from the POLARIX study (NCT03274492), which led to the approval of polatuzumab vedotin plus rituximab-cyclophosphamide, doxorubicin, and prednisone (pola + R-CHP), we had not had a breakthrough in frontline DLBCL therapies since the addition of rituximab 22 years ago," said Dr. Charalambos Andreadis, MD, of the University of California at San Francisco's Helen Diller Family Comprehensive Cancer Center.
"Pola + R-CHP is an improvement over the standard-of-care treatment, R-CHOP (rituximab-cyclophosphamide, doxorubicin, vincristine, and prednisone), giving treatment naive patients an increase in PFS without an increase in side effects," Dr. Andreadis said.
R-CHP-polatuzumab was approved only for patients with an International Prognostic Indices score between 2 and 5, leaving patients with IPI scores of 0 or 1 with the frontline standard of care (SoC) treatment of R-CHOP, which has a cure rate of between 60% and 70%.
"The highest likelihood of relapse is in the first year following treatment. After 2 years in remission, patients' chance of relapsing is the same as the general populations' chance of getting DLBCL for the first time. This is why even a slight increase in the progression-free survival rate with the addition of pola is so significant," Dr. Andreadis noted.
Historically, patients with relapsed or refractory (RR) DLBCL who did not respond to R-CHOP or who experienced disease relapse less than a year after primary intervention were treated with alternative chemotherapy regimens, often followed by autologous stem cell transplants (ASCT). Randomized control studies have shown that CAR T-cell therapies yield higher success rates than chemotherapy and ASCT, leading to the SoC in RR patients being CAR-T cell therapy directly following failed primary treatment.
"There are many new CAR T-cell platforms in development, as well as novel combination strategies that aim to target critical genetic pathways," Kieron Dunleavy, MD, professor of medicine at the Lombardi Comprehensive Cancer Center at Georgetown University Hospital, said in an interview. "While access to CAR T-cell therapies is becoming easier and more feasible in many centers, fast access continues to be an issue for many patients, often depending on geography and socioeconomic factors."
Asked about the latest breakthroughs in treating DLBCL, Dr. Dunleavy said, "A significant proportion of patients with relapsed or refractory DLBCL do not have easy access to CAR T-cell therapies, so this needs to be addressed and improved. Sometimes the rapidity of clinical progression in DLBCL can make these therapies challenging to deliver, considering logistical issues like apheresis and insurance approvals, which are frequently complex. This highlights the need for alternative and 'easier to deliver' CAR-T cells and our continued prioritization of developing alternative effective agents for DLBCL.
"Currently, commercially approved CAR T-cells in DLBCL target the CD-19 marker on lymphoma cells but CAR T-cells targeting other and more than one antigen as well as alternative anti CD19 agents like loncastuximab and tafasitamab are similarly FDA approved and available for patients," Dr. Dunleavy concluded.
Dr. Dunleavy is affiliated with the MedStar Georgetown Lymphoma group, where Rep. Raskin publicly announced that he had completed 4 months of chemotherapy treatment for DLBCL. On April 27, in an open letter to the U.S. public, he wrote that he rang the bell at MedStar to mark his preliminary diagnosis of being "in remission," with a "90% prognosis of no relapse."
Interviewed about the latest advances in treating DLBCL, Jason Westin, MD, associate professor of lymphoma and myeloma at the MD Anderson Cancer Center in Houston, said that even with improvements in overall survival possible with CAR T-cell therapies, "usually, a clinical trial should be considered strongly, as it is often the best option for patients, both in a newly diagnosed or in a relapsed setting, as they allow access to tomorrow's breakthrough therapies today."
Dr. Westin cited the example of bispecific T-cell engagers (BITE) as a promising therapy that is available to patients in clinical trials. These agents bind to one side to the lymphoma cell, but they also have a binding arm for T-cells, so they activate a patient's own immune cells to kill lymphoma cells, in some cases offering a cure when CAR T-cell therapy has failed.
The first BITE to be approved, mosunetuzumab, is authorized only for the treatment of follicular lymphoma. However, data from a recent clinical study indicated that the agent yields complete responses in 24% of heavily pretreated patients with RR DLBCL.
Another BITE, glofitamab, was approved in Canada in March 2023 for use in RR DLBCL. Based on its high efficacy, it soon may be approved elsewhere.
Dr. Andreadis noted, "We are finally at a point where for both treatment naive and RR DLBCL patients, there are several promising options on the horizon that don't involve ASCT. Furthermore, these breakthroughs reinforce each other, as there are studies in which therapies like BITE are being brought to the front line and pola to RR cases."
The growing field of new frontline and RR DLBCL therapies lend credence to the optimism of specialists who treat DLBCL — and to the sanguine note that Congressman Raskin struck in published comments about his treatment for DLBCL.
Dr. Andreadis reported ties with BMS, Novartis, Roche, Genmab, Merck, Gilead, AbbVie, and J&J. Dr. Dunleavy disclosed relationships with ONO Pharmaceuticals, Kymera, Merck, Genentech, AstraZeneca, Amgen, ADC Therapeutics, MorphoSys and Incyte, Kite/Gilead, Cellectar. Dr. Westin reported ties with Kite/Gilead, BMS, Novartis, Genentech, AstraZeneca, Morphosys/Incyte, ADC Therapeutics, Kymera, Nurix and MonteRosa.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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Cite this: DLBCL: Major New Treatment Breakthroughs - Medscape - May 18, 2023.