Supplementary Figure S4. Clinical impact of CD49d bimodal expression on durability of BTKi therapy.

Supplementary Table S4. Mutations status of patients with disease progression on BTKis

Supplementary Table S9. Gene Signatures

In March 2023 and 2024, a panel of international experts convened at the first and second Intercepting Blood Cancers (IBC) Workshops, with the aim of better appreciating the diagnostic challenges, pathophysiology, and potential therapeutic interventions for precursor malignant hematology conditions. Here, we report a summary of the proceedings from the sessions focused on monoclonal B-cell lymphocytosis (MBL)/chronic lymphocytic leukemia (CLL). We highlight four main content areas: biology of MBL, clinical implications of MBL, progression of MBL and transformation from indolent CLL to aggressive disease, and opportunities for therapeutic intervention in early CLL. We additionally outline key consensus management recommendations and research goals.

Over the past decade, treatment recommendations for patients with chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL) have shifted from traditional chemoimmunotherapy to targeted therapies. Multiple new therapies are commercially available, and in many cases a lack of randomized clinical trial data makes selection of the optimal treatment for each patient challenging. Additionally, many patients continue to receive chemoimmunotherapy in the US, suggesting a gap between guidelines and real-world practice. The Lymphoma Research Foundation convened a workshop comprised of a panel of CLL/SLL experts in the US to develop consensus recommendations for selection and sequencing of therapies for patients with CLL/SLL in the US. Herein, the recommendations are compiled for use as a practical clinical guide for treating providers caring for patients with CLL/SLL, which complement existing guidelines by providing a nuanced discussion relating how our panel of CLL/SLL experts in the US care for patients in a real-world environment.

Supplemental Table 3. Frequency of BTK and PLCG2 mutations in previously untreated patients or those with relapsed/refractory disease who experienced Richter's transformation

Supplementary Figure S3. In vivo effect of acalabrutinib on the VLA-4 activation upon BCR and chemokine signaling

Monoclonal antibodies (mAbs) improve survival of patients with mature B-cell malignancies. Fcγ-receptor dependent effector mechanisms kill tumor cells but can promote antigen loss through trogocytosis, contributing to treatment failures. Cell-bound mAbs trigger the complement cascade to deposit C3 activation fragments and lyse cells. Within 24 hours after ofatumumab administration to patients with chronic lymphocytic leukemia (CLL), circulating tumor cells had lost CD20 and were opsonized with C3d. We hypothesized that C3d provides a target to eliminate residual CD20 negative tumor cells. To test this hypothesis, we generated C8xi, a mouse/human chimeric IgG1 that reacts with human but not mouse C3d. C8xi was effective in a patient-derived xenograft model against CD20 negative, C3d opsonized CLL cells from patients treated with ofatumumab. We also generated rabbit mAbs, two of which were chosen because they bound mouse and human C3d with low nanomolar affinity but were minimally cross-reactive with full-length C3. Anti-C3d rabbit/human chimeric IgG1 in combination with ofatumumab or rituximab prolonged survival of xenografted mice that model three different types of non-Hodgkin lymphoma (NHL). For example, in a diffuse large B-cell lymphoma model (SU-DHL-6), median survival with single-agent CD20 mAb was 114 days but was not reached for mAb combination treatment (P=.008). In another NHL model (SU-DHL-4), single-agent and combination mAb therapy eradicated lymphoma in most mice. In long-term survivors from both cohorts, there was no evidence of adverse effects. We propose that C3d mAbs combined with complement fixing CD20 mAbs can deliver a one-two punch and increase efficacy of mAb-based therapy.

Immunoglobulin heavy chain variable region (IGHV) somatic hypermutation (SHM) status is a strong prognostic marker in CLL. Previous studies in the chemoimmunotherapy era reported inferior outcome linked to specific IGHV stereotyped subsets, such as subset #2 associated with IGHV3-21 usage. The prognostic value of individual IGHV subgroups remains less well-understood in the targeted therapy setting. We performed a retrospective analysis of patients registered on the Dana-Farber Cancer Institute CLL database between 1999 and 2025. IGHV mutation rates and subgroups were assessed by PCR of gDNA or cDNA and NGS as an alternative to PCR at CLIA-certified labs. Stereotypy data were unavailable. We used Kaplan-Meier methods to estimate overall survival (OS) from time of CLL diagnosis, event-free survival (EFS, events were defined as death, histologic transformation, or treatment initiation) from time of CLL diagnosis, time to first-line therapy (TTFT) from time of CLL diagnosis, and time from first- to second-line therapy (TT2T). Cox regression models were used to compare clinical outcomes. We defined targeted therapy as regimens including Bruton's tyrosine kinase, B cell lymphoma 2 protein, and/or phosphoinositide 3-kinase inhibitors with or without CD20 monoclonal antibody, while excluding regimens containing cytotoxic agents. A total of 2,989 CLL patients with IGHV data were identified. Median age at diagnosis was 60.0 years. 1,369 (45.8%) patients had unmutated (U) IGHV. Of patients with mutated (M) IGHV, the median % of mutation compared to the consensus germline IGHV sequence was 5.7%. Borderline IGHV mutation (2.01-3.00%) was found in 146 (4.9%) of patients. 260 (8.7%) of patients had more than one productive IGHV sequence. Selected IGHV subgroups for analysis were: 1-69 (11.6%), 1-2 (4.3%), 3-21 (4.1%), and 4-39 (4.0%). Certain IGHV subgroups had a skewed representation (>2-fold) of either U (90.5% of 1-69, 69.2% of 4-39) within the group, while others had a less skewed distribution of U and M-IGHV (U-IGHV in 65.6% of 1-2, 47.5% of 3-21). With a median follow-up of 77 months, U-IGHV was associated with significantly shorter OS compared to M-IGHV (p<0.05, 10Y OS: 76.7% for U-IGHV vs 91.5% for M-IGHV). Notably, patients with IGHV3-21 usage, commonly linked with inferior OS regardless of SHM status, showed a numerically shorter OS in patients with U (10Y OS 61.6%) vs. M-IGHV (10Y OS 88.8%, p=0.055). OS of patients with U and M-IGHV within the selected subgroups (1-69, 1-2, 3-21, and 4-39) were comparable to their respective SHM groups in the overall study population. Next, we conducted further analyses of 1,218 patients with a comprehensive annotation of the status of histologic transformation and treatment course. As expected, U-IGHV was associated with shorter EFS and TTFT compared to M-IGHV (5Y EFS: 32% [27%, 38%] vs 77% [73%, 81%], 5Y TTFT: 33% [28%, 39%] vs 78% [74%, 83%]). In addition, histologic transformation predominantly occurred in the U-IGHV group (17 of 19 cases). Among 343 patients who received targeted therapy as their first-line CLL therapy (1L targeted therapy), patients with U-IGHV had comparable OS and TT2T to those with M-IGHV (5Y OS: 88% [82%, 96%] vs 93% [86%, 100%], 5Y TT2T: 63% [51%, 77%] vs 83% [71%, 97%]). We analyzed three IGHV subgroups (3-21, 4-39, and 1-2) with relatively lower U:M ratios. Prognostic impact of IGHV groups in the context of targeted therapy could not be assessed due to limited numbers of patients in each IGHV group and limited duration of follow ups. Descriptively, 1 of 9 patients with IGHV3-21 progressed to receive next-line therapy at 51 months after starting 1L targeted therapy. We observed a relatively high incidence of histologic transformation (3 of 17 patients) in the IGHV4-39 group treated with 1L targeted therapy. Two of 15 patients with IGHV1-2 usage in the 1L targeted therapy group received additional lines of therapy (2 and 74 months after initial therapy). SHM status is a robust prognostic marker in CLL associated with OS, EFS, and TTFT. Despite the lack of stereotypy information, OS by SHM status within IGHV subgroups mirrored that of the corresponding U or M-IGHV in the whole cohort. Initial treatment of CLL with targeted agents led to excellent 5-year OS of 88% for U-IGHV and 93% for M-IGHV.

Introduction: BTK inhibitors are effective treatments for CLL/SLL; however, treatment intolerance and resistance to BTK inhibitors are major clinical challenges for many patients. BGB-16673 is an orally available protein degrader that blocks BTK signaling by tagging BTK for degradation through the cell's proteasome pathway, leading to tumor regression. CaDAnCe-101 (BGB-16673-101; NCT05006716) is an ongoing open-label, phase 1/2 study evaluating BGB-16673 monotherapy in patients with B-cell malignancies. Here, updated phase 1 safety and efficacy data are reported for patients with relapsed/refractory (R/R) CLL/SLL. Methods: Eligible patients must have confirmed R/R CLL/SLL (≥2 prior therapies), an ECOG performance status of 0-2 (0-1 in the EU), and adequate organ function. In the US, EU, and Australia, patients must have previously received a covalent BTK inhibitor (cBTKi). Patients received BGB-16673 once daily orally. The primary phase 1 objectives were to assess safety/tolerability (NCI-CTCAE v5.0; iwCLL hematologic toxicity criteria) and to establish the maximum tolerated dose and recommended dose for expansion. A secondary objective was to assess overall response rate (ORR) per iwCLL 2018 criteria with partial response with lymphocytosis (PR-L) modification and per 2014 Lugano criteria for SLL, with the first response assessment after 12 weeks of treatment. Results: As of May 23, 2025, 67 patients with CLL/SLL were enrolled and treated (50 mg, n=1; 100 mg, n=22; 200 mg, n=17; 350 mg, n=15; 500 mg, n=12). Patients had a median age of 70 years (range, 47-91 years) and a median of 4 prior lines of therapy (range, 2-10), including cBTKis (n=63 [94.0%]), BCL2is (n=55 [82.1%]), and noncovalent BTK inhibitors (ncBTKis; n=14 [20.9%]). At study baseline, 65.7% (44/67) of patients had CLL/SLL with del(17p) and/or TP53 mutation, 77.6% (38/49) with unmutated IGHV, 38.1% (24/63) with BTK mutation, and 15.9% (10/63) with PLCG2 mutation. Median study follow-up was 18.0 months (range, 0.3-31.0 months); 39 patients (58.2%) remained on treatment at the data cutoff. Overall, 95.5% of patients had any-grade treatment-emergent adverse events (TEAEs); any-grade TEAEs in ≥25% of patients were fatigue (37.3%), contusion/bruising (31.3%), diarrhea (28.4%), and neutropenia (28.4%). Grade ≥3 TEAEs occurred in 62.7% of patients; grade ≥3 TEAEs in ≥5% of patients were neutropenia (23.9%), pneumonia (10.4%), and thrombocytopenia (6.0%). Eight patients (11.9%) had a TEAE leading to dose reduction. TEAEs led to treatment discontinuation in 12 patients (17.9%), three (4.5%) of whom had treatment-related TEAEs (subdural hemorrhage, maculopapular rash, and disseminated aspergillosis). Four patients (6.0%) had TEAEs that led to death (all due to infections, including 1 fungal infection); no deaths were deemed related to treatment. In 66 response-evaluable patients (1 patient on treatment did not reach the first assessment by the data cutoff), ORR (PR-L or better) was 86.4% (n=57), with a 4.5% (n=3) complete response (CR)/CR with incomplete marrow recovery rate. At 200 mg, ORR was 93.8% (15/16), including 1 CR. The median time to first response was 2.8 months (range, 2.0-19.4 months). Thirty-three patients (49.3%) remained on treatment for ≥12 months. Responses deepened over time: of 22 patients with initial PR-L, 15 transitioned to partial response (PR); of 16 patients with initial stable disease, 1 transitioned to PR-L and 10 to PR. Responses were seen in patients previously treated with a cBTKi (53/62 [85.5%]) or ncBTKi (10/14 [71.4%]), with double (cBTKi and BCL2i; 39/42 [92.9%]) and triple exposure (cBTKi, BCL2i, and ncBTKi; 9/12 [75.0%]), with (18/24 [75.0%]) and without (36/39 [92.3%]) BTK mutations, with del(17p) and/or TP53 mutation (35/43 [81.4%]), and with PLCG2 mutation (9/10 [90.0%]). The 12-month progression-free survival rate was 79.2%; 15 patients (22.4%) had progressive disease (2 associated with Richter transformation to diffuse large B-cell lymphoma), and 4 (6.0%) died. Further exploratory analyses will be presented at the meeting.Conclusions: Data from the ongoing CaDAnCe-101 study demonstrate that the novel BTK degrader BGB-16673 has a tolerable safety profile and shows robust and deepening responses in patients with heavily pretreated R/R CLL/SLL, including those with prior BTK inhibitor treatment and BTK mutations. The 200-mg dose of BGB-16673 is being evaluated in phase 2 and 3 studies in patients with R/R CLL/SLL.

Supplementary Table S5: CD49d samples used for the RNAseq analysis

Background: The CLL-International Prognostic Index (IPI) is a weighted scoring system that combines 5 factors (age, clinical stage, unmutated immunoglobulin heavy chain variable region [U-IGHV], elevated beta-2 microglobulin [B2M], and TP53 aberrations [TP53ab, defined as TP53 mutations and/or del(17p)]). The CLL-IPI predicted overall survival (OS) in patients treated with chemoimmunotherapy (Hallek et al. Lancet Oncol. 2016) and progression-free survival (PFS) in patients primarily treated with venetoclax-based targeted therapy (Langerbeins et al. Blood. 2024). The 4-factor model (CLL4) was developed using data from patients receiving the BTK inhibitor (BTKi) ibrutinib and identified risk groups with distinct PFS and OS based on 4 variables (TP53ab, relapsed/refractory [R/R] disease, elevated B2M, and elevated lactate dehydrogenase [LDH]; Ahn et al. J Clin Oncol. 2021). To characterize the clinical impact of prognostic factors included in the CLL-IPI and the CLL4, as well as complex karyotype, in the context of zanubrutinib therapy, we analyzed data from the SEQUOIA and the ALPINE studies. Methods: SEQUOIA (NCT03336333) is a phase 3 study comparing zanubrutinib (Arm A) versus bendamustine and rituximab (Arm B) in patients with treatment naïve (TN) CLL without del(17p), and, in a separate cohort, investigating zanubrutinib monotherapy in patients with del(17p) (Arm C). ALPINE (NCT03734016) is a phase 3 trial comparing zanubrutinib to ibrutinib in R/R CLL. TP53 mutations, fluorescence in situ hybridization (FISH), IGHV, and cytogenetic status were assessed following the European Research Initiative on CLL guidelines. Specifically, we utilized centralized testing of baseline TP53 mutations by next-generation sequencing at a Clinical Laboratory Improvement Amendments (CLIA)-certified lab (Predicine, CA, USA; reporting threshold: variant allele frequency [VAF] ≥1%) and Vysis CLL FISH for del(17p) (reporting threshold: abnormality >7%). Complex karyotype, defined as ≥3 abnormalities (CKT3), was assessed according to the International System for Human Cytogenomic Nomenclature criteria. We conducted univariable and multivariable Cox regression analyses of baseline factors among patients treated with zanubrutinib monotherapy. Results:In this retrospective biomarker analysis, patients treated with zanubrutinib from SEQUOIA (Arms A and C, n=350) and ALPINE (zanubrutinib arm, n=327) were included. Univariable analyses demonstrated that the following variables were associated with shorter PFS in both TN and R/R CLL: elevated B2M (≥5 mg/L), elevated LDH (>250 U/L), elevated Eastern Cooperative Oncology Group performance status (≥1), and bulky disease (≥5 cm) (all P<.05). CKT3 and U-IGHV were associated with shorter PFS in R/R but not TN CLL. TP53ab was not associated with shorter PFS in TN or R/R CLL. In multivariable analyses, of the factors found to be associated with shorter PFS in univariable analyses in TN and/or R/R CLL patients, only LDH was an independent prognostic marker for shorter PFS in TN CLL (P<.05). Notably, TP53ab did not independently predict PFS. Conclusion: In patients with TN and R/R CLL treated with zanubrutinib in the SEQUOIA and ALPINE studies, LDH was the sole independent prognostic marker associated with PFS, and its predictive value is for patients with TN CLL only. TP53ab was not associated with inferior PFS in TN or R/R CLL in this post-hoc analysis. New risk-stratification tools may be warranted in the context of zanubrutinib therapy in CLL.

Supplementary Table S6. DEGs for Baseline Comparison of CD49d+ and CD49d

Background Combination therapy with bendamustine and rituximab (BR) is a safe and effective front-line regimen in patients with follicular lymphoma (FL) (Rummel, Lancet 2013; Flinn, Blood 2014). Long-term data regarding the outcomes of FL patients treated with BR have largely been limited to randomized trials, and there is limited insight into the outcomes and prognostic factors of patients treated off of clinical trials with this regimen. Methods We retrospectively identified consecutive adult patients with FL (grades 1-3A) who were treated at Dana-Farber Cancer Institute with front-line BR from January 1, 2013 to June 1, 2024. Baseline demographic, clinical and radiographic characteristics were collected from the medical records. Progression free survival (PFS), overall survival (OS), and cumulative incidence of histological transformation (CIHT) were calculated using standard definitions from time of treatment start, with death considered a competing cause for CIHT. Response outcomes and other categorical variables were tested for association with continuous and other categorical baseline variables using Wilcoxon rank-sum (or Kruskal-Wallis for three or more groups) or Fisher's exact tests, respectively. Results A total of 194 patients were identified. The median age of the cohort was 61 years (range 27-91), and 52% of patients were male. More than half (54%) of patients presented with stage IV disease (37% with stage III), and 86% of patients had grade 1-2 FL. The median Ki-67 and largest SUVmax at diagnosis were 15% (interquartile range [IQR] 10-30%) and 10.0 (IQR 7.5-15.1), respectively. 33 patients (17%) had a reduction in bendamustine dosing with advanced patient age being noted as the most common reason for modification. Among patients receiving dose modifications for advanced age, 10/13 (77%) were empirically given reduced-dose bendamustine in cycle 1. N patients (86%) received all 6 planned cycles of BR. 167 pts (36%) received growth factor support during treatment of which 84% was given as primary prophylaxis. Patients receiving primary prophylaxis were generally older with a median age of 66 years. 22% of patients received maintenance rituximab (median of 10 maintenance cycles). At the end of treatment, 151 patients (78%) underwent repeat PET/CT evaluation. Among these patients, the overall (ORR) and complete response (CR) rates were 89% and 80%, respectively. Among 33 patients who underwent evaluation with CT, the ORR and CR were 90% and 70%, respectively. With a median follow-up of 65.1 months, the median PFS was 66.9 months, the median time-to-next-treatment (TTNT) and the median OS were not reached. The 6-year TTNT and OS were 56% (95% confidence interval [95% CI] 48-64%) and 78% (95% CI 70%-84%), respectively. There were 5 deaths potentially related to treatment, all due to infection. 42 patients (22%) experienced disease progression within 24 months (POD24), of whom 27 (64%) had biopsy-proven evidence of histologic transformation at the time of progression.The CIHT for total cohort at 2 years and 6 years were 13% and 17%, respectively. In univariate analysis, factors associated with worse PFS included age (hazard ratio [HR] 1.24 per 10-year increase, 95% CI 1.02-1.49), elevated LDH (HR 4.69, 95% CI 2.64-8.33), SUVmax (HR 1.04 per 1-unit increase, 95% CI: 1.01-1.07), and reduction in cycle 1 bendamustine dose (HR 3.05, 95% CI: 1.85 to 5.02) by Cox regression. Elevated LDH (HR 2.72, 95% CI: 1.05 to 6.70) was associated with increased risk of transformation. We additionally examined the impact of elevated SUVmax at baseline with a cutoff of 15 based on prior literature (Rossi, Haematologica 2020), which was associated with numerically shorter PFS (median 33.3 months vs. 83.8 months, p=0.20), shorter time-to-next-treatment (median 34.1 months vs. 103.9 months, p=0.04), and increased CIT at 2 years (23% vs 6%) and 6 years (37% vs 11%) in comparison to patients with SUV≤15 at baseline (p<0.01). Conclusions This represents one of the largest real-world analysis of outcomes of patients with FL treated with frontline BR. These data redemonstrate BR is an effective first-line regimen with favorable long-term results. Notably, an elevated baseline SUVmax was associated with shorter PFS and increased risk of transformation in line with prior analysis of FL patients (Strati, Haematologica 2019), which suggest a subset of patients that may benefit from consideration of alternative therapeutic strategies.

Background With the advent of effective targeted therapy, there is growing interest in chemotherapy-free regimens in patients (pts) with mantle cell lymphoma (MCL). Triplet combinations of the BTK inhibitors ibrutinib or zanubrutinib, venetoclax (V), and obinutuzumab (O) have demonstrated efficacy in MCL, including TP53-aberrant disease (Le Gouill, Blood 2021; Kumar, Blood 2024). We hypothesized that acalabrutinib (A), in combination with VO (AVO) would be safe and effective in relapsed/refractory (R/R) and treatment naïve (TN) MCL. Methods In this investigator-sponsored, multicenter, phase I/II trial (NCT04855695), pts eligible for cohort A had R/R MCL after at least one anti-CD20 mAb-based therapy, cohort B had TN MCL ineligible for aggressive induction or TP53-aberrant MCL (TP53 mutation or >50% p53 expression on IHC). If safety and efficacy criteria were met in cohorts A or B, Cohort C would enroll TN TP53 wild-type pts eligible for aggressive induction. Pts were treated with A (100 mg po bid) starting cycle 1 (C1), O in C2 (100 mg IV D1, 900 mg IV D2, 1000 mg IV D8, D15) and D1 of C3-7, and V ramp-up in C3 to a target 400 mg daily. In all cohorts, O maintenance is given every 2 Cs between C9-C31. AV is continued indefinitely in cohort A, discontinued after achieving MRD negative (<1 in 106 cells by ClonoSEQ®) complete remission (CR) in peripheral blood (PB) for 3 months in cohort B, and optionally discontinued after MRD- CR in PB for 3 months in cohort C. Earliest discontinuation of AV was after 10 Cs in cohorts B and C. AV can be resumed at molecular or clinical relapse. Patients unevaluable for MRD received AV for 24 Cs. Primary endpoints were safety and tolerability for cohort A, CR rate after 7 Cs for cohort B, and MRD- CR rate after 7 Cs for cohort C. Results As of July 25, 2025, the study is fully enrolled (n=56). 20/20 pts in R/R cohort A, 24/24 pts in TN cohort B, and 11/12 pts in TN cohort C were evaluable for response. Median age was 65 (range 36-81). In cohort A, median number of prior therapies was 1, 20% relapsed after autologous stem cell transplant, 10% after CAR T cell therapy, and 30% had primary refractory disease. In cohort B, 79% pts (19/24) were TP53-aberrant, 71% (17/24) TP53 mutated, and 96% pts had advanced stage. MIPI score was 13% low, 21% intermediate, and 67% high risk. Ki67 ≥ 30% in 50%, Ki67 ≥ 50% in 29%, 54% complex karyotype, and 8% blastoid variant. In cohort C, 92% pts had stage IV, MIPI score was 33% low, 50% intermediate, and 17% high risk. Ki67 ≥ 30% in 33%, 25% complex karyotype, and 100% classic variant. In all pts, most common toxicities were headache (57%; all G1/2), bruising (41%; all G1), diarrhea (29%; 2% G3), and nausea (25%; all G1/2). ≥ G3 infections in 11% pts. Hematologic toxicity included neutropenia (46%; 30% G3/4), thrombocytopenia (32%; 9% G3/4), and anemia (29%; 5% G3). There was 2% febrile neutropenia, 2% atrial fibrillation, and 2 (4%) fatal toxicities due to COVID-19 and aspiration. No tumor lysis syndrome or ≥ G2 hemorrhage. Cohort A median follow-up was 24 months (range 7.3-39.4). Best ORR was 86% and CR rate 75%. 2-year progression-free survival (PFS) and overall survival (OS) were 75% (95% CI: 58, 97) and 86% (95% CI: 69, 100). Cohort B median follow-up was 20 months (range 0-26). Primary endpoint was met with CR rate 83% (ORR 88%). CR rate in TP53 mutated pts was 82%. 2-year PFS and OS were 78% (95% CI: 63, 97) and 96% (95% CI: 88, 100). Estimated 2-year PFS and OS for the 17 TP53 mutated TN pts were 82% (95% CI: 65, 100) and 94% (95% CI: 84, 100). 19/24 pts had evaluable MRD data. 15 pts (79%) achieved MRD- CR and 14 pts discontinued AV. 1 pt relapsed 4 months after discontinuing AV in MRD- CR and did not respond to AV retreatment. Median follow-up after AV discontinuation was 9 months. Cohort C median follow-up was 9 months (range 2-14.2). Best ORR and CR rate are both 100% (11/11). Estimated 12-month OS and PFS are both 100%. All 8 pts with evaluable MRD data achieved MRD- CR and 4 pts discontinued AV, with no relapses after a median follow-up of 3.5 months. Conclusions AVO is a well-tolerated and effective regimen in pts with R/R and TN MCL, with high rates of MRD- CR in TN MCL, allowing for MRD-guided time-limited therapy. The primary endpoint of TN cohort B was met, and the estimated 2 yr PFS and OS in the 17 TP53 mutated pts compare favorably with alternative regimens. Based on this data, the study will expand to include an additional 16 TP53 mutated pts.

Background: CTLA-4 and its ligand, CD86, are expressed within the classic Hodgkin Lymphoma (cHL) tumor microenvironment (TME) at even higher frequency than PD-1 and its ligands, suggesting that the CTLA-4 pathway plays a key role in immune evasion. Monotherapy with the CTLA-4 monoclonal antibody (mAb), ipilimumab (ipi), yielded responses in patients (pts) with cHL relapsing after allogeneic stem cell transplantation; however, trials combining ipi with a PD-1 mAb (+/- brentuximab vedotin) in earlier lines of therapy failed to demonstrate a clear benefit with the addition of ipi. These results suggest that ipi has therapeutic potential in cHL, but that combination treatment in unselected pts may not be a successful strategy. To further investigate the role of ipi in cHL, we conducted a phase II clinical trial testing ipi with or without nivolumab (nivo) among pts with R/R cHL who progressed after PD-1 blockade. Methods: Adult pts with R/R cHL who had received ≥ 2 prior therapies including a PD-1 mAb were eligible. The trial was initially designed with 2 cohorts - Cohort 1 for pts with a best response of stable disease (SD) or partial response (PR) after at least 18 weeks of PD-1 mAb monotherapy and Cohort 2 for pts with progressive disease (PD) on PD-1 based treatment. Cohort 1 was closed for slow accrual (no pts enrolled). In cohort 2, pts received ipi 3 mg/kg every 3 weeks for 4 doses and then underwent restaging with positron emission tomography. Ipi responders (complete response [CR] or PR) continued ipi maintenance (3 mg/kg every 12 weeks for up to 8 doses). Ipi non-responders (SD or PD) who were clinically stable received 4 cycles of ipi (1 mg/kg) and nivo (3 mg/kg) dosed every 3 weeks followed by ipi maintenance, as above. The primary endpoint was objective response rate (ORR) to ipi monotherapy, assessed using 2014 Lugano criteria. Results: 13 pts were enrolled to Cohort 2 at 3 centers. The median age was 39 (23-76) and pts had received a median of 4 (3-17) prior therapies, including a PD-1 mAb-based regimen for all pts (median 1, range 1-3). 6 pts received PD-1 monotherapy only, 2 received PD-1-based combinations, and 5 received both PD-1 monotherapy plus 1 or more PD-1 combinations. The best ORR for PD-1 monotherapy was 27% (3/11) and for PD-1 combinations 50% (5/10). A PD-1 based regimen directly preceded study treatment for 9 pts. Pts received a median of 2 cycles of ipi monotherapy (range 1-4). 3 pts achieved a PR (ORR 23%) with no CRs observed. 3 of 10 ipi non-responders received combination treatment with nivo and ipi and none experienced an objective response. The most common reasons for treatment discontinuation were PD (n=8), toxicity (n=4), and pt decision (n=1). With a median follow-up of 11.5 months, the median progression-free survival for ipi monotherapy was 3.3 months. The duration of response for individual responders was 27.8, 3.2, and 1.5 months. The 1-year overall survival was 59%. The most common treatment-related adverse events (TRAE) with ipi monotherapy were fever (n=6) (including 3 cases in the absence of an identifiable infection), ALT elevation (n=5), cough (n=4), diarrhea (n=4), anorexia (n=3), dyspnea (n=3), fatigue (n=3), headache (n=3), nausea (n=3), pneumonitis (n=3), and maculopapular rash (n=3). Grade 3+ TRAEs occurred in 6 pts and included ALT/AST elevation in 1 pt; abdominal pain, cytokine release syndrome, dyspnea, lung infection, and thrombocytopenia in 1 pt; urinary tract infection in 1 pt; colitis in 1 pt; diarrhea and hyponatremia in 1 pt; and anorexia in 1 pt. TRAEs for the 3 pts who received ipi + nivo included 1 case each of hypothyroidism, bilateral hand rash, infusion-related reaction, and peripheral sensory neuropathy (all grade 1-2). Pre-treatment biopsy samples from all pts were analyzed using multiplex immunofluorescence (to define TME features among PD-1 relapsed cHL and to describe features associated with response) and will be presented at the meeting. Conclusions: Despite strong preclinical data supporting a key role for the CTLA-4 axis in cHL, we observed limited clinical activity with ipi monotherapy in this high-risk cohort of pts with multiply relapsed cHL. The toxicity profile in this heavily pre-treated population was notable for frequent immune-related AEs and higher rates of treatment discontinuation due to toxicity than seen with ipi in other clinical settings. Correlatives studies are ongoing which may shed further light on predictors of response.