Defining a target population
R-CHOP – rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone – has been the first-line standard of care for DLBCL for 2 decades, but it cures only about 60%-70% of patients. Researchers have tried for years to improve the cure rate by adding novel agents and other means, but outcomes haven’t been clinically meaningful, the investigators explained.
Polatuzumab, the antibody component of PV, zeroes in on a ubiquitous target on mature B-cell lymphomas, delivering vedotin, a potent microtubule inhibitor, directly to tumor cells.
Study subjects were treatment naive and a median of 65 years old with intermediate-risk or high-risk DLBCL. About a third had activated B-cell–like DLBCL, and almost two-thirds had baseline International Prognostic Index (IPI) scores between 3 and 5.
Each arm of the trial underwent six treatment cycles, plus two cycles of rituximab monotherapy.
On subgroup analysis, PFS benefit clustered among higher risk patients, namely patients older than 60 years, those with IPI scores between 3 and 5, and patients with the activated B-cell–like subtype.
Younger patients, subjects with lower IPI scores, patients with bulky disease, and those who had germinal-center B-cell–like DLBCL “did not show a clear [PFS] benefit,” the study team said.
Ongoing trial in the elderly
Adverse events in POLARIX were in line with the component drugs’ known toxicity profiles, with no new safety signals identified.
The most common grade 3/4 adverse events were neutropenia (28.3% in the pola-R-CHP group and 30.8% in the R-CHOP group), febrile neutropenia (13.8% and 8.0%, respectively), and anemia (12.0% and 8.4%). A bit over 6% of subjects in both arms discontinued because of adverse events.
The higher incidence of febrile neutropenia with pola-R-CHP “did not translate into a higher overall incidence of infection, treatment discontinuation, or dose reductions,” the investigators said.
They noted that patients with lymphoma arising from previously diagnosed indolent lymphoma, those with a primary mediastinal lymphoma, and people older than 80 years were not included in the study. A phase 3 trial in patients 75 years and up is recruiting.
The work was funded by PV maker Genentech/Roche. Many of the investigators disclosed ties to the companies, including Dr. Tilly, an adviser and speaker for Roche, and Dr. Salles, an adviser for Genentech. Three investigators were Genentech employees. Dr. Gopal is a consultant for Genentech/Roche. Dr. Winter did not have any ties to the companies.