Polatuzumab Vedotin As a Salvage Treatment in Relapsed or Refractory DLBCL: Single Center Experience
Authors: Bin Morya Marwa , Marei Mohammed A. , Tailor Imran K. , Alrajhi Abdullah M , Alnakhli Adel , Alnajjar Foud , Alnoamani Mohammed S. , Alshehri Hassan , Motabi Ibraheem H. , AlShehry Nawal , Alfayez Mansour 
Published: November 2021

Abstract
Background: Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma, accounting for approximately 25% of all newly diagnosed patients (Swerdlow et. al. IARC, 2017). It is estimated that 40% of patients are refractory to, or relapse after treatment with chemo-immunotherapy (R-CHOP). Salvage therapy with autologous stem-cell transplantation (ASCT) can cure around 40% of those patients, nevertheless, the prognosis is poor for most patients with R/R DLBCL who are relapsed after, or ineligible for ASCT, and in those with suboptimal response to salvage chemotherapy. Polatuzumab vedotin is a CD79b-targeted antibody-drug conjugate delivering monomethyl auristatin E (MMAE), a microtubule inhibitor. It was granted accelerated approval by the US FDA on June 2019 for treatment of R/R DLBCL after at least two prior therapies, in combination with bendamustine and rituximab. We herein report our experience on the use of polatuzumab in patients with R/R DLBCL.
Methods: Retrospective-single center review on the use of polatuzumab vedotin as part of a compassionate program in patients with R/R DLBCL between June 2018 and July 2021. Inclusion criteria for the study were: age ≥ 18 years, R/R DLBCL [both de-novo and transformed lymphoma], 2 or more prior lines of therapy, and treatment with polatuzumab-based therapy for at least 1 cycle. Patients with CNS involvement were excluded. The compassionate use access program provided polatuzumab at a dose of 1.8 mg/kg, administered with or without bendamustine (up to two doses of 90 mg/m2,) and rituximab (375 mg/m2). Treatment was given every 21 days for up to 6 cycles.
Results: we identified 3 patients with R/R DLBCL who were treated with polatuzumab-based therapy. The median number of prior therapies was 2 (2 - 5). The median IPI and CNS-IPI score were 2, (1 - 4) and 2, (2 - 5), respectively (Baseline characteristics are summarized in Table). The median number of Pola-BR cycles received was 3 (2 - 6). One patient completed 6 cycles of polatuzumab with bendamustine and rituximab and achieved partial response. The other two patients were taken of treatment at the time of progression on cycles number 1 and 3. Treatment options were limited after polatuzumab-based therapy. The patient who achieved partial response after 6 cycles of Pola-BR maintained that response for 11 months without additional treatment and died due to COVID-19 associated pneumonia. One patient been screened for Glofitamab compassionate use program, and one patient elected to receive no further therapy.
Conclusions: Polatuzumab-based treatment in R/R DLBCL is a promising treatment in an otherwise difficult to treat patient population. The compassionate use program provides access in developing countries to an otherwise prohibitively expensive emerging therapeutic armamentarium in R/R DLBCL.
Figure 1 Figure 1.

Disclosures
No relevant conflicts of interest to declare.