Real-World Multicenter Experience in Tumor Debulking Prior to Blinatumomab Administration in Adult Patients With Relapsed/Refractory B-Cell Precursor Acute Lymphoblastic Leukemia

Blinatumomab is an immunotherapeutic agent with dual specificity for CD3 and CD19 that is approved for the treatment of relapsed/refractory B-cell precursor acute lymphoblastic leukemia (R/R B-ALL). A steroid based pre-treatment is recommended before administering blinatumomab to patients with a high tumor burden to minimize the risk of tumor lysis syndrome, but the optimal debulking regimen and whether it can improve responses remain unclear. The present study retrospectively evaluated real-world outcomes following tumor debulking and blinatumomab infusion in R/R B-ALL adult patients treated at 7 Italian centers. Data were collected from 34 patients. The choice of the cytoreductive therapy was made by the treating clinician on an individual patient basis; regimens included chemotherapy (n=23), steroids (n=7) and tyrosine kinase inhibitors alone or in combination (n=4). The rate of complete responses (CR) and complete minimal residual disease (MRD) responses in CR patients were 67.6% and 81% respectively, after 2 cycles of blinatumomab. Moreover, among patients with a high tumor burden 50% obtained a CR, with 89% of them also achieving a complete MRD response. Favorable responses were also obtained in patients over 50 years of age at treatment initiation. Overall, 7 of 23 patients in CR after blinatumomab underwent hematopoietic stem cell transplantation. The results of this retrospective study highlight the heterogeneity in the use of pre-blinatumomab tumor debulking in real-life clinical practice. Nonetheless, debulking pre-treatment enhanced responses to blinatumomab compared to historic studies, indicating that this strategy may help to improve outcomes for R/R B-ALL patients.

High Plus Low Dose Radiation Strategy in Combination with TIGIT and PD1 Blockade to Promote Systemic Antitumor Responses

Tumors deploy various immune-evasion mechanisms that create a suppressive environment and render effector T-cells exhausted and inactive. Therefore, a rational utilization of checkpoint inhibitors may alleviate exhaustion and may partially restore antitumor functions. However, in high-tumor-burden models, the checkpoint blockade fails to maintain optimal efficacy, and other interventions are necessary to overcome the inhibitory tumor stroma. One such strategy is the use of radiotherapy to reset the tumor microenvironment and maximize systemic antitumor outcomes. In this study, we propose the use of anti-PD1 and anti-TIGIT checkpoint inhibitors in conjunction with our novel RadScopal technique to battle highly metastatic lung adenocarcinoma tumors, bilaterally established in 129Sv/Ev mice, to mimic high-tumor-burden settings. The RadScopal approach is comprised of high-dose radiation directed at primary tumors with low-dose radiation delivered to secondary tumors to improve the outcomes of systemic immunotherapy. Indeed, the triple therapy with RadScopal + anti-TIGIT + anti-PD1 was able to prolong the survival of treated mice and halted the growth of both primary and secondary tumors. Lung metastasis counts were also significantly reduced. In addition, the low-dose radiation component reduced TIGIT receptor (PVR) expression by tumor-associated macrophages and dendritic cells in secondary tumors. Finally, low-dose radiation within triple therapy decreased the percentages of TIGIT+ exhausted T-cells and TIGIT+ regulatory T-cells. Together, our translational approach provides a new treatment alternative for cases refractory to other checkpoints and may bring immunotherapy into a new realm of systemic disease control.

Obinutuzumab plus lenalidomide (GALEN) in advanced, previously untreated follicular lymphoma in need of systemic therapy

Obinutuzumab and lenalidomide (GALEN) is an active immunomodulatory combination with a manageable safety profile in multiple types of lymphoma. We report efficacy and safety results for the phase 2 GALEN study in previously-untreated patients with advanced follicular lymphoma (FL). Eligible patients aged ≥ 18 years had ECOG PS ≤ 2, high-tumor burden, grade 1-3a FL. Induction treatment was obinutuzumab (1000 mg IV, days 8/15/22, cycle 1; day 1, cycles 2-6) plus lenalidomide (20 mg/day, days 1-21, cycle 1; days 2-22, cycles 2-6) for 6 cycles. Maintenance included obinutuzumab (1000 mg every 2 cycles) plus lenalidomide (10 mg, days 2-22) for ≤ 12 cycles (year 1) followed by obinutuzumab (1000 mg every 56 days) for 6 cycles (year 2). The primary endpoint was complete response rate (CRR) after induction per IWG 1999 criteria. From October 2015 to February 2017, 100 patients were enrolled. CRR after induction was 47% and overall response rate (ORR) 92%. Post-hoc analyses per 2014 Lugano classification including patients with missing bone marrow assessments identified an additional 13 patients fulfilling CRR criteria, resulting in a complete metabolic response of 80% and ORR of 94%. At a median follow-up of 3.7 years, 3-year progression-free and overall survival were 82% and 94%, respectively. The most common adverse event was neutropenia (48% any-grade; 47% grade ≥ 3) but only 2% of patients presented febrile neutropenia; others were mainly grade ≤ 2. No other specific grade ≥3 toxicity occurred at a frequency higher than 3%. Overall, these results demonstrated promising clinical efficacy for the chemo-free backbone obinutuzumab and lenalidomide in previously untreated, high tumor burden FL patients. Except for neutropenia, the safety profile of the combination is remarkable. The study was registered with ClinicalTrials.gov, number NCT01582776

Phase II Study of Venetoclax in Combination with Obinutuzumab and Bendamustine in Patients with High Tumor Burden Follicular Lymphoma As Front Line Therapy (PrECOG 0403)

Background: Chemoimmunotherapy is considered standard initial therapy for follicular lymphoma (FL) with high tumor burden (HTB). Obinutuzumab and Bendamustine (OB) with maintenance Obinutuzumab (mO) is considered a standard therapy for the frontline treatment of HTB FL (GALLIUM, Marcus et al, NEJM 2017). Venetoclax (VEN), an oral BCL2 inhibitor, is an attractive target in FL given the high BCL2 expression; though single agent activity has been disappointing (Davids et al. JCO 2017). BCL2 inhibition is thought to be synergistic with chemotherapy. Thus, the PrE0403 study evaluated the OB-VEN combination in frontline HTB FL. Here we present end of induction (EOI) outcomes. Methods: The primary objective of this Phase II study was to estimate the complete remission (CR) rate at EOI. Potential participants must have had a histologically confirmed diagnosis of FL grade 1, 2, or 3a with HTB defined by GELF or high risk defined by FLIPI-1 criteria. They must have had adequate performance status and organ function. Notably, creatinine clearance must have been ≥50 mL/min. Participants must have not had prior treatment for FL. Eligible participants were treated with Bendamustine IV 90 mg/m2 Day (D) 1 & 2, Obinutuzumab IV 100 mg D1, 900 mg D2, 1000 mg D8 and D15 of Cycle (C) 1 then D1 of each cycle, and VEN 800 mg orally daily D1-10 every 28 days for 6 total cycles. Due to a high rate of laboratory tumor lysis syndrome (TLS) during C1 in the first 21 patients, VEN was removed from C1 and given in C2-6 only. Participants with a CR at EOI were treated with mO IV 1000 mg D1 every 8 weeks for 2 years. Those with a partial response (PR) or stable disease (SD) were treated with mO as well as VEN 800 mg orally daily for 2 years. Pneumocystis jiroveci Pneumonia (PJP) and antiviral prophylaxis was required as was G-CSF support. Response was assessed via Lugano Criteria at EOI including PET/CT and bone marrow assessment. Adverse Events (AEs) were evaluated using CTCAE v5.0. To be considered promising, OB-VEN should improve the null hypothesis CR rate of 50% (OB) to 65%. With an 85% power and a one sided 15% type I error, 56 participants would be needed with an estimated 51 eligible. Support for the study was from Genentech, Member of the Roche Group. Results A total of 56 participants were enrolled and treated between 12/2017 and 11/2020; baseline characteristics are listed in Table 1. TLS was closely monitored in C1 and 8/21 participants developed TLS when VEN was administered in C1; 0/35 when it was not. However, monitoring for TLS in C1 became less stringent when VEN was not administered. Treatment related Grade ≥3 toxicities occurred in 47/56 participants (83.9%) with serious adverse events in 31 of 56 (55.5%). Atypical infections were seen; there was one treatment related death on study due to cytomegalovirus (CMV) encephalitis as well as PJP pneumonia which occurred after induction C6. Enrollment was temporarily suspended and CMV monitoring was implemented with no further occurrences. Another participant receiving mO later developed BK virus nephropathy following mO C6 and now requires ongoing hemodialysis. Another was diagnosed with Respiratory Syncytial Virus pneumonia 30 days after C6 and later PJP pneumonia after C2 of mO. Common (incidence >10%) AEs during induction are listed in Table 2. 45 of 56 (80.4%) participants were able to receive all 6 cycles of OB-VEN. CR was seen in 41 of 56 participants (73.2%, 2 sided 95% Confidence Interval (CI) 59.7-84.2%) at the EOI. 30 participants (53.5%) went onto maintenance. With a median follow up of 20.9 months, estimated 2 year Overall Survival (OS) and Progression-Free Survival (PFS) (90% CI) is 94.4% (82.4-98.3%) and 85.8% (68.8-93.9%) respectively. Conclusions This Phase II study of OB-VEN in untreated HTB FL showed high CR rate and met its primary endpoint with early signs of prolonged PFS. Laboratory TLS was identified but it was unclear if attributed solely to VEN, as baseline laboratory TLS rate for OB is unknown. The rate of Grade ≥3 AE of 83.9% (compared to 69% for OB in GALLIUM, Hiddeman JCO 2018) and the observation of opportunistic infections including CMV encephalitis, PJP pneumonia and BK nephropathy, suggests the combination is highly immunosuppressive. Therefore, while the study met its primary outcome, the combination of OB-VEN at 800 mg for 10 days, plus mO, does not have an acceptable risk/benefit profile. Participants will continue to be followed for efficacy and safety during the maintenance phase. Figure 1 Figure 1. Disclosures Portell: Acerta/AstraZeneca: Research Funding; SeaGen: Research Funding; Pharmacyclics: Honoraria; Xencor: Research Funding; Aptitude Health: Honoraria; BeiGene: Honoraria, Research Funding; Abbvie: Research Funding; TG Therapeutics: Honoraria, Research Funding; Kite: Honoraria, Research Funding; Merck: Honoraria, Research Funding; Morphosys: Honoraria; Targeted Oncology: Honoraria; Genentech: Research Funding; VelosBio: Research Funding. Nowakowski: MorphoSys: Consultancy; Incyte: Consultancy; Kymera Therapeutics: Consultancy; TG Therapeutics: Consultancy; Blueprint Medicines: Consultancy; Nanostrings: Research Funding; Roche: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Celgene/Bristol Myers Squibb: Consultancy, Research Funding; Zai Labolatory: Consultancy; Daiichi Sankyo: Consultancy; Bantham Pharmaceutical: Consultancy; Curis: Consultancy; Karyopharm Therapeutics: Consultancy; Selvita: Consultancy; Ryvu Therapeutics: Consultancy; Kyte Pharma: Consultancy. Cohen: Janssen, Adicet, Astra Zeneca, Genentech, Aptitude Health, Cellectar, Kite/Gilead, Loxo, BeiGene, Adaptive: Consultancy; Genentech, BMS/Celgene, LAM, BioINvent, LOXO, Astra Zeneca, Novartis, M2Gen, Takeda: Research Funding. Kahl: AbbVie, Acerta, ADCT, AstraZeneca, BeiGene, Genentech: Research Funding; AbbVie, Adaptive, ADCT, AstraZeneca, Bayer, BeiGene, Bristol-Myers Squibb, Celgene, Genentech, Incyte, Janssen, Karyopharm, Kite, MEI, Pharmacyclics, Roche, TG Therapeutics, and Teva: Consultancy. OffLabel Disclosure: Venetoclax is not approved for follicular lymphoma or in combination with bendamustine and obinutuzumab

Rhoa Mutation Is a Potential Biomarker Associated with Adverse Prognosis and High- Tumor Burden in Patients with Nodal Peripheral Lymphomas with T-Helper Follicular Phenotype (nPTCL-Thf): Data from a Brazilian Retrospective Cohort of Nodal PTCL

Introduction: Nodal PTCL constitute a rare group of aggressive malignancies with heterogeneous clinical-biological presentation and outcomes. In the last decade, its pathophysiological knowledge has been improved, with descriptions of gene mutations associated with epigenetic phenomena (IDH2, TET2 and DNMT3A) and of the RHOA G17V mutation playing a fundamental role in the lymphomagenesis. However, the prognostic impact of these alterations is still controversial, and particularly, in the case of the RHOA mutation, it has never been previously accessed in the literature. Our group has described and validated biomarkers with potential prognostic impact in nPTCL patients, including overexpression of the genes CCNA2, GATA3 and monocytosis in peripheral blood [1,2,3]. The identification of new potential molecular biomarkers can refine the prognostic stratification of these tumors and allow identification of targets for future specific therapies. The aim of this study was to evaluate the frequency and prognostic impact of mutations in the IDH2, TET2, DNMT3 and RHOA genes in Brazilian patients with nPTCL. Methods: In this observational, retrospective and unicentric study, we analyzed the clinical-epidemiological characteristics, outcomes and mutational profile of 59 Brazilian patients with nPTCL treated at the HC-FMUSP, from January 2000 to December 2017. All cases were submitted to centralized histopathological review and were classified according to the criteria proposed by WHO-2008. Cases initially categorized as PTCL/NOS were later reclassified according to WHO-2016 criteria. FFPE-tumor samples from patients with PTCL/NOS, AITL, ALK+/ALCL and ALK-/ALCL were submitted to DNA extraction using QIAmp DNA FFPE kit. For amplification of specific products of target-genes primers flanking the hot spots regions were designed. After this step, the PCR products were submitted to first generation sequencing in 3500 Genetic Analyzer. Absolute and relative frequencies of mutations were accessed for the total cohort and its pathological subtypes. OS and PFS curves were constructed using the Kaplan-Meier method. Log-rank test was used to estimate the prognostic impact of mutations. Results: The clinical-epidemiological characteristics of the 59 Brazilian-patients with nPTCL are summarized in Table 1. With a median follow-up of 3.70 years (0.90-12.4 years), the estimated 2-years OS and PFS were 59.1% and 47.2%, respectively. ORR was 55.9% (33/59), with early relapse rate (< 12 months) of 14.3% (5/59) and global death rate of 52.5% (31/59). In the total cohort, we found a mutation frequency of 3.4% (2/59) for the IDH2 gene, 62.7% (37/59) for DNMT3A, 23.7% (14/59) for RHOA and 50.8% (30/59) for TET2. There was no statistically significant difference in the frequency distribution of IDH2, DNMT3A and TET2 mutations between the different histological subtypes of nPTCL. However, there was a statistical trend towards a higher occurrence of the RHOA mutation in the AITL and PTCL/NOS subtypes (3/9-33.3% and 7/16-43.7%, respectively; p=0.07). Among 7 cases with RHOA mutation classified as PTCL/NOS according WHO-2008 criteria, 6/7 (85.7%) expressed the PD-1 marker in immunohistochemistry, being reclassified as nPTCL with THf phenotype according to WHO-2016 criteria. So, the mutation RHOA was predominantly found in THf cell-derived neoplasms in our cohort. The mutational status of DNMT3A, RHOA and TET2 genes had no prognostic impact on OS, with p=0.85, p=0.13 and p=0.95, respectively. The same was observed in relation to PFS for the DNMT3A (p=0.70) and TET2 (p=0.52) mutations. However, the presence of the RHOA mutation was associated with the unfavorable PFS in our cohort (HR:1.98, p=0.05). We observed 2-year PFS of 28.6% (95% CI: 8.8-52.4%) for mutated-RHOA cases versus 52.9% (95% CI: 37.3-66.3%) for wild-type-RHOA patients (p=0.05) [Figure 1]. We also demonstrated that RHOA mutation was a predictor of lower ORR to first-line therapy (p=0.01) and was associated with high tumor burden (p=0.03) [Figure 2]. Conclusion: In this study, for the first time was demonstrated the unfavorable prognostic impact of the RHOA mutation in patients with nPTCL-Thf (AITL and nPTCL-THf), making it a potential molecular biomarker predictor of poor-PFS, associated with resistance to primary therapy and with high tumor burden. Such results are preliminary and will need to be validated in series with a larger number of cases. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

European Multicenter Study on Degradable Starch Microsphere TACE: The Digestible Way to Conquer HCC in Patients with High Tumor Burden

To evaluate the safety and efficacy of transarterial chemoembolization with degradable starch microspheres (DSM-TACE) for the treatment of hepatocellular carcinoma (HCC) with a high tumor burden ineligible for or failing other palliative therapies, 121 patients from three European centers were included. Kaplan–Meier analysis was used for median overall survival (OS) and time to progression (TTP, mRECIST criteria) in months with a 95% confidence interval (95% CI). Uni- (UVA) and multivariate (MVA) analyses were performed using the Cox Proportional Hazard Model. The median OS of the study cohort was 15.5 (13.3–18.7) months. The UVA identified HCC lesions ≤10 cm, unilobar involvement, lower Child–Pugh class and Barcelona Clinic Liver Cancer (BCLC) stage, absence of vascular invasion, and extrahepatic metastases as factors for prolonged survival. MVA confirmed lesions of ≤10 cm and unilobar disease as independent OS factors. Median TTP was 9.5 (7.6–10.3) months. The best response was achieved after a median of 3 (range: 1–6) treatments with CR/PR/SD/PD in 13.5%/44.5%/25.2%/16.8%, respectively. DSM-TACE was well tolerated with no major clinical adverse events and only limited major laboratory events. Preserved liver function was observed after repetitive DSM-TACE treatments. Repetitive DSM-TACE is a safe, well-tolerated and effective treatment option for HCC patients with high tumor burden ineligible or failing other palliative therapies.

Reducing Hinge Flexibility of CAR-T Cells Prolongs Survival In Vivo With Low Cytokines Release

Chimeric antigen receptor (CAR)-modified T cells targeting CD19 demonstrate unparalleled responses in B cell malignancies. However, high tumor burden limits clinical efficacy and increases the risk of cytokine release syndrome and neurotoxicity, which is associated with over-activation of the CAR-T cells. The hinge domain plays an important role in the function of CAR-T cells. We hypothesized that deletion of glycine, an amino acid with good flexibility, may reduce the flexibility of the hinge region, thereby mitigating CAR-T cell over-activation. This study involved generating a novel CAR by deletion of two consecutive glycine residues in the CD8 hinge domain of second-generation (2nd) CAR, thereafter named 2nd-GG CAR. The 2nd-GG CAR-T cells showed similar efficacy of CAR expression but lower hinge flexibility, and its protein affinity to CD19 protein was lower than that of 2nd CAR-T cells. Compared to the 2nd CAR-T cells, 2nd-GG CAR-T cells reduced proinflammatory cytokine secretion without diminishing the specific cytotoxicity toward tumor cells in vitro. Furthermore, 2nd-GG CAR-T cells prolonged overall survival in an immunodeficient mouse model bearing NALM-6 when tumor burden was high. This study demonstrated that a lower-flexibility of CD8α hinge improved survival under high tumor burden and reduced proinflammatory cytokines in preclinical studies. While there is potential for improved safety and efficacy, yet this needs validation with clinical trials.

Association of tumor burden with outcome in first-line therapy with nivolumab plus ipilimumab for previously untreated metastatic renal cell carcinoma

Objectives To investigate the prognostic impact of tumor burden in patients receiving nivolumab plus ipilimumab as first-line therapy for previously untreated metastatic renal cell carcinoma (mRCC). Methods We retrospectively evaluated 62 patients with IMDC intermediate- or poor-risk mRCC, treated with nivolumab plus ipilimumab as first-line therapy at five affiliated institutions. Tumor burden was defined as the sum of diameters of baseline targeted lesions according to the RECIST version.1.1. We categorized the patients into two groups based on the median value of tumor burden (i.e., high vs. low). The association of tumor burden with progression-free survival (PFS), overall survival (OS) and objective response rate (ORR) with nivolumab plus ipilimumab treatment was analyzed. Results The median tumor burden was 63.0 cm (interquartile range: 34.2–125.8). PFS was significantly shorter in patients with high tumor burden (n = 31) than in those with low tumor burden (n = 31) (median: 6.08 [95% CI: 2.73–9.70] vs. 12.5 [4.77–24.0] months, P = 0.0134). In addition, OS tended to be shorter in patients with high tumor burden; however, there was no statistically significant difference (1-year rate: 77.3 vs. 96.7%, P = 0.166). ORR was not significantly different between patients with high and low tumor burden (35 vs. 55%, P = 0.202). Multivariate analysis of PFS further showed that tumor burden was an independent factor (HR: 2.22 [95% CI: 1.11–4.45], P = 0.0242). Conclusions Tumor burden might be a useful factor for outcome prediction, at least for PFS prediction, in patients receiving nivolumab plus ipilimumab for mRCC. Further prospective studies are warranted to confirm our findings.