POLARIX: A phase 3 study of polatuzumab vedotin (pola) plus R-CHP versus R-CHOP in patients (pts) with untreated DLBCL.

Abstract

TPS7571 Background: Rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) remains the standard of care in pts with previously untreated diffuse large B-cell lymphoma (DLBCL) but outcomes remain poor in pts with high-risk disease. Pola is an antibody–drug conjugate targeting CD79b; it delivers the antimitotic agent monomethyl auristatin E. Addition of pola to bendamustine and R in pts with transplant-ineligible DLBCL resulted in improved OS (Sehn et al, 2018). In front-line treatment of DLBCL, pola is being evaluated as a replacement for vincristine within the R-CHOP regimen. In a phase Ib/II study in pts with higher risk DLBCL, pola + R-CHP demonstrated promising efficacy and a safety profile similar to that observed in the R-CHOP arm of the GOYA study (Tilly et al, 2017; Vitolo et al, 2017). The phase 3 POLARIX study investigates pola + R-CHP in untreated DLBCL. Methods: POLARIX is an ongoing, international, randomized, double-blind, active-placebo-controlled, phase 3 study in pts with previously untreated DLBCL. Pts aged 18–80 years with CD20-positive DLBCL (including DLBCL not otherwise specified, GCB, and ABC subtypes), ECOG performance status 0–2, and IPI score 2–5, are stratified by IPI score (2 vs 3–5), bulky disease and geographical region and randomized (1:1). Pts receive 6 cycles of either: pola 1.8 mg/kg on Day 1 plus R-CHP (standard dosing schedule) plus vincristine placebo; or pola placebo plus R-CHOP (standard dosing schedule). R monotherapy is administered in cycles 7 and 8 (both arms). PET-CT and CT scans are obtained at screening, after 4 cycles (planned interim assessment), and 6–8 weeks after end of study treatment. Follow-up will continue for 5 years after treatment. Primary endpoint: investigator-assessed progression-free survival (PFS; Lugano classification). Secondary endpoints: independent review committee-assessed PET-CT complete response rate at end of treatment, event-free survival, 2-year PFS rate, and OS. Enrolment began Nov 2017. This trial is currently recruiting, and plans to enrol 875 patients in 24 countries. Clinical trial information: NCT03274492.