Favorable results from a phase 2 trial have prompted further development of polatuzumab vedotin in non-Hodgkin lymphoma.
In the ROMULUS trial, polatuzumab vedotin plus rituximab (R-pola) produced more durable responses than did pinatuzumab vedotin plus rituximab (R-pina) in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) or follicular lymphoma (FL).
Researchers also observed a more favorable benefit-risk profile with R-pola.
Franck Morschhauser, MD, of Centre Hospitalier Régional Universitaire de Lille, France, and his colleagues described these findings in the.
Thetrial included 81 DLBCL patients and 42 FL patients. They were randomized to receive R-pola or R-pina (rituximab at 375 mg/m2 plus either antibody-drug conjugate at 2.4 mg/kg) every 21 days until disease progression or unacceptable toxicity for up to 1 year.
Among DLBCL patients, the median age was 69 years in the R-pina arm and 68 years in the R-pola arm. Among FL patients, the median age was 59 years in the R-pina arm and 67 years in the R-pola arm.
Seventy-six percent of DLBCL patients randomized to R-pina were refractory to their last treatment, as were 80% of DLBCL patients assigned to R-pola, 52% of FL patients assigned to R-pina, and 35% of FL patients assigned to R-pola.
The median number of prior systemic therapies was three in the R-pina DLBCL arm, the R-pola DLBCL arm, and the R-pina FL arm. The median number of prior therapies was two in the R-pola FL arm.
Response and survival
Among the DLBCL patients, R-pina produced an objective response rate (ORR) of 60% and a complete response (CR) rate of 26%. R-pola produced an ORR of 54% and a CR rate of 21%. The median duration of response was 6.2 months in the R-pina arm and 13.4 months in the R-pola arm.
The median progression-free survival in the DLBCL cohort was 5.4 months for the R-pina arm and 5.6 months for the R-pola arm. The median overall survival was 16.5 months and 20.1 months, respectively.
In the FL cohort, R-pina produced an ORR of 62% and a CR rate of 5%. R-pola produced an ORR of 70% and a CR rate of 45%. The median duration of response was 6.5 months in the R-pina arm and 9.4 months in the R-pola arm.
The median progression-free survival in the FL cohort was 12.7 months for the R-pina arm and 15.3 months for the R-pola arm. The 2-year overall survival rate was 90.5% and 87.8%, respectively. The median overall survival was not reached in either arm.
“Patients treated with R-pola tended to have longer durations of response than those receiving R-pina (particularly those with relapsed or refractory diffuse large B-cell lymphoma), and the results for R-pola compared favorably with other novel antilymphoma agents,” Dr. Morschhauser and his colleagues wrote.
Among DLBCL patients, serious adverse events (AEs) occurred in 50.0% of those in the R-pina arm and 35.9% of those in the R-pola arm. Among FL patients, serious AEs occurred in 28.6% of those the R-pina arm and 35.0% of those in the R-pola arm.