Methods: Patients with R/R DLBCL, ineligible for autologous stem cell transplantation, who had received up to 3 prior lines of therapy, including at least one anti-CD20 therapy, and had adequate organ function were eligible. Treatment comprised up to 12, 28-day (d) cycles (C) of MOR208, 12 mg/kg IV, q1w C1–3 (loading dose on d4 of C1), and q2w C4–12 plus LEN 25 mg PO d1–21, C1–12. Pts progression-free after C12 received MOR208 q2w until progression. The primary endpoint was independent review committee (IRC)-assessed overall response rate (ORR) as per Cheson 2007 criteria. Secondary endpoints included investigator (INV)-assessed ORR, as well as overall survival (OS), progression-free survival (PFS), duration of response (DoR), and safety.

Results: As of June 5, 2018, recruitment was complete (n= 81 pts). At baseline, median age was 72 years (range 41–87), median number of prior therapies was 2 (range 1–4), 23% of pts had early relapse (≤ 12 months from initial diagnosis), 40% were rituximab-refractory (no response or progression during or within 6 months of a prior rituximab therapy), 42% were refractory to their last therapy, and 52% had an International Prognostic Index (IPI) of 3–5. MOR208 plus LEN therapy was well tolerated, and 58 (72%) pts stayed on a LEN dose of≥ 20 mg/day. The most common grade≥ 3 treatment-emergent adverse events were neutropenia in 43% of pts, thrombocytopenia in 17%, febrile neutropenia in 12%, anemia in 9%, leukopenia in 7%, and hypokalemia in 6% of pts. Investigator (INV)-assessed complete response (CR) and partial response rates were 33% and 25%, respectively; as a result, ORR was 58%(n= 81). IRC-assessed ORR and CR rates were 54% and 32%, respectively (n= 76). At a median follow-up of 12 months, the INV-assessed median PFS, OS and DoR (intention-to-treat analysis) were 16.2 months (95% CI: 6.3 months–NR), not reached (95% CI: 18.6 months–NR), and not reached (95% CI: NR–NR), respectively. Thirty-seven (46%) pts were ongoing in the study.

Conclusions: The combination of MOR208 and LEN was well tolerated and has shown encouraging activity and long lasting responses in pts with RR DLBCL, who have poor prognosis and urgently need effective therapies. Primary analysis results of the study with a recent cut-off (November 30, 2018) and a longer follow-up will be presented at this conference.