Joffe, Erel

Abstract BACKGROUND Emavusertib, an oral interleukin-1 receptor-associated kinase 4 (IRAK4) inhibitor, targets toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling pathway in B-cell proliferation. IRAK4 forms a Myddosome complex with MYD88 adaptor protein and drives overactivation of NF-κB, causing inflammation and tumor growth. Emavusertib has been reported to be well tolerated and active as monotherapy in heavily pretreated relapsed/refractory (R/R) non-Hodgkin lymphoma (NHL). In a murine PDX model of primary CNS lymphoma (PCNSL), emavusertib crossed the blood-brain barrier, resulting in tumor response and prolonged survival. In combination with Bruton tyrosine kinase (BTK) inhibitors, emavusertib showed in vivo anti-cancer synergy in B-cell NHL. METHODS This is an ongoing open-label trial (NCT03328078) in patients with R/R NHL. Currently, we are in the dose escalation portion of combination therapy to evaluate safety and efficacy following treatment of emavusertib at dose levels of 200 or 300mg BID with ibrutinib at full prescribed dose. As of May 6th, 2022, 13 patients have been treated with emavusertib+ibrutinib combination therapy. RESULTS Among the 13 patients, two were diagnosed with R/R PCNSL and had several prior lines of anti-cancer therapy. Emavusertib in combination with ibrutinib (560 mg daily) appeared to be well tolerated in these two subjects. One patient experienced Gr3 treatment-related adverse events (thrombocytopenia, muscle weakness, pain). The preliminary efficacy data demonstrated one CR and one SD. The patient who achieved CR after the combination therapy was originally intolerant to high-dose methotrexate based chemoimmunotherapy and did not achieve complete remission after switching to ibrutinib, providing early clinical evidence of CNS penetration and anti-tumor activity of emavusertib. CONCLUSION In R/R PCNSL, these preliminary data suggest that combination therapy has a tolerable safety profile with promising anti-cancer activity and may overcome ibrutinib resistance.

7575 Background: CA-4948 is a novel oral inhibitor of interleukin-1 receptor-associated kinase 4 (IRAK4), which is essential for toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling in B cell proliferation. IRAK4 forms a Myddosome complex with MYD88 adaptor protein and drives overactivation of nuclear factor-kappa B (NF-κB), causing inflammation and tumor growth. CA-4948 has been reported to be well tolerated and active as monotherapy in heavily pretreated patients with relapsed/refractory (R/R) non-Hodgkin lymphoma (NHL). Preclinical studies demonstrated that tumor resistance and survival via IRAK4 activation could be delayed or reversed. CA-4948 crossed the blood-brain barrier in a murine PDX model of pCNS lymphoma, resulting in tumor response and prolonged survival. In combination with Bruton tyrosine kinase (BTK) inhibitors, CA-4948 showed in vivo synergy in B-cell NHL. Here we will present an update on the preliminary efficacy data of CA-4948+ibrutinib in R/R hematologic malignancies. Methods: This is an ongoing open-label trial (NCT03328078) of CA-4948 as monotherapy and in combination with ibrutinib. Part A1 (completed) dose escalation of CA-4948 as monotherapy; the recommended phase 2 dose (RP2D) is 300 mg BID with continuous oral dosing. Part A2 (dose escalation in combination with ibrutinib), and Part B (a basket design of 4 expansion cohorts of CA-4948 and ibrutinib: BTK-naïve MZL, DLBCL, or PCNSL and NHL with adaptive resistance to ibrutinib). The primary endpoints of Parts A1 and A2 include safety, tolerability, and RP2D. The primary endpoints of Part B include CR or ORR, with key secondary endpoints of DOR, DCR, PFS and OS following treatment of CA-4948 at dose levels of 200 (DL1) or 300 mg BID (DL2) with ibrutinib at full prescribed dose. Results: As of December 7th, 2021, 35 heavily pretreated NHL patients have received CA-4948 monotherapy (median age 66 years, range 50-87), of which six patients have been on CA-4948 for approximately 1 year or longer, suggesting CA-4948 has a long-term acceptable safety and tolerability profile at RP2D (dose level of 300 mg BID). In Part A2, 10 patients are treated with CA-4948+ibrutinib (median age 65 years, range 56-82). Median number of prior lines of anti-cancer therapies is 3 (range 1-8). No DLTs were observed at 200 or 300 mg dose levels to date. The preliminary efficacy data of seven evaluable patients with combination therapy showed 1 CR (MCL), 2 PR (MCL and MZL), 3 SD, and 1 PD, 3 of whom had failed prior ibrutinib. The preliminary data indicate the combination therapy may overcome ibrutinib resistance. Conclusions: CA-4948 as a monotherapy and in combination with ibrutinib is well tolerated with an acceptable long term safety profile and promising efficacy. Part A2 is transitioning to Part B basket cohorts of MZL, ABC-DLBCL, PCNSL and NHL with adaptive resistance to ibrutinib. Clinical trial information: 03328078.

7560 Background: Tafasitamab (tafa) + lenalidomide (LEN) demonstrated efficacy in adult patients (pts) with R/R DLBCL ineligible for autologous stem-cell transplant in the pivotal Phase II study L-MIND (NCT02399085) and received accelerated approval in the United States in 2020 and conditional marketing authorization in Europe and Canada in 2021 in this setting. RE-MIND2 (NCT04697160), an observational, retrospective cohort study, compared pt outcomes from L-MIND with matched pt cohorts treated with other NCCN/ESMO recommended therapies. Methods: Methodology for RE-MIND2 has been presented previously. Hypothesis-generating analyses were conducted for pt subgroups of number of extranodal sites (ENS) (0–1 vs ≥2) and elevated lactate dehydrogenase (LDH) (yes vs no) in matched cohorts of pts receiving tafa + LEN vs systemic therapies pooled (STP), polatuzumab vedotin + bendamustine + rituximab (pola-BR), rituximab + LEN (R2), and CD19 CAR-T therapies (CAR-T). The primary endpoint was overall survival (OS). Results: Of 3,454 pts enrolled, 961, 106, 106, and 149 were treated with STP, pola-BR, R2, and CAR-T, resulting in 76, 24, 33, and 37 matched pairs for pts receiving tafa + LEN, respectively. Hazard ratios (HR) for OS show a trend toward favoring tafa + LEN in most pt subgroups (Table). Conclusion: These analyses suggest that tafa + LEN may be associated with improved OS vs selected systemic therapies for certain pts with high-risk disease and may further inform physicians’ treatment choices for pts with R/R DLBCL. These analyses are not powered for statistical comparison; small sample sizes in some subgroups result in wide confidence intervals (CI) and so results must be interpreted with caution. Data for other treatment cohorts, pt subgroups, and endpoints will be presented. Funding: MorphoSys AG. Clinical trial information: NCT04697160. [Table: see text]