Recently, a phase 2 study (NCT02500407) demonstrated high complete response rates with the CD20/CD3 T-cell engaging bispecific antibody mosunetuzumab among patients with RR FL1. Dr Sarit Assouline (Jewish General Hospital, Canada) presented the current subgroup analysis of this study after 3 years of follow-up. All participants received mosunetuzumab in the third line or later and POD24 was observed in 52 % of patients2.
After 3 years of therapy, complete response (CR) was seen in 60 % of participants with POD24, a figure consistent with the overall study population (also 60 %). Similarly, CR rates in participants over 64 years of age (67 %) and those who received mosunetuzumab as fourth-line therapy or later (55 %) were comparable to the rates in the general trial population. In addition, the median duration of CR was not reached in participants with POD24 or older participants but was 33 months in ‘fourth-line-or-higher’ participants.
The 3-year progression-free survival rates were 44 % in the POD24 subgroup, 47 % in participants aged over 64 years, and 43 % in the overall population. In fourth-line-or-higher participants, this rate appeared lower at 36 % compared with third-line participants (54%). Finally, the safety profile of mosunetuzumab was manageable and consistent across subgroups.
“The consistent results of mosunetuzumab across subgroups of participants with RR FL and the manageable safety profile support outpatient administration of this agent,“ concluded Dr Assouline.
Medical writing support was provided by Robert van den Heuvel.