Diaz, Paula A Lengerke

Chimeric antigen receptor (CAR) T-cell therapy is an effective treatment for hematologic malignancies. However, it is limited by high costs, risk of severe toxicities such as cytokine release syndrome and neurotoxicity, and heterogeneous patient responses. The current therapy monitoring depends largely on subjective symptom assessment, routine laboratory tests, and basic vital signs, without real-time, quantitative evaluation of CAR T-cell expansion or activation in clinical practice. This lack of timely immune monitoring hampers individualized care and contributes to increased treatment costs. To address this need, we present a proof-of-concept, label-free rapid optical imaging (ROI) biosensor with automated machine learning analysis for direct quantification of CAR T-cells from whole blood. This microfluidic platform integrates red blood cell (RBC) removal, CAR T-cell capture, and imaging-based quantification on a single chip, eliminating the need for centrifugation, staining, and operator-dependent interpretation. For validation, 50 μL whole blood samples spiked with Jurkat cells expressing CD19 CARs underwent RBC depletion by agglutination and microfiltration. The remaining blood components were then incubated on a sensor chip functionalized with recombinant CD19 protein. Captured CAR T-cells were imaged by brightfield microscopy and automatically enumerated using a machine learning algorithm trained on fluorescence-validated cells. The CD-19 cells’ capture performance was validated by flow cytometry and fluorescence imaging. The trained machine learning model validated at 88% sensitivity and 96% specificity. Buffer and whole blood calibration curves were established across clinically relevant concentrations (1–1000 cells/µL) with triple replicates. The results showed high correlation (0.975 and 0.990 R2) between the spiked concentration and the detected CAR T-cells, with a 95% certainty limit of detection (LOD) and quantification (LOQ) of 0.6 and 1.1 cells/µL for spiked buffer, and 14 and 67 cells/µL for spiked whole-blood, respectively.

Abstract BackgroundAlternative splicing (AS) is a fundamental process in eukaryotes contributing to the diversity of mRNA isoforms with variable ratios of intron/exon. SF3B1 is a pivotal protein of the spliceosome machinery. Mutations in the SF3B1 gene have prognostic value in Chronic Lymphocytic Leukemia (CLL). Our previous studies have shown that SF3B1 inhibition with macrolides induces apoptosis specifically in CLL compared with normal cells. SF3B1 inhibition is associated with a widespread increase in intron retention (IR) on most transcripts, suggesting that IR can be used as a marker of spliceosome inhibition in CLL cells. However, it is unknown how the activity of SF3B1 contributes to the spliceosome activity and the poor clinical prognosis in CLL.MethodsTo better understand this process, we performed a comprehensive analysis to quantify the abundance of individual exonic and intronic mapped reads on annotated RNA-Seq transcripts derived from the B cells of 98 CLL patients and nine healthy volunteers (Normal B cells – NBC). We calculated ratios for intron and exon abundance for each transcript and use this as a measure of intron retention (IR) and a surrogate for alternative splicing (AS).ResultsWe found that 66% of CLL B-cells transcripts had significant IR elevation compared to NBC and that transcripts with high IR were associated with low expression levels and mRNA downregulation. The IR increase in CLL B-cells was independent of prognostic factors such as IgVH or SF3B1 mutations. Transcripts with the highest IR levels belonged to biological pathways associated with gene expression and RNA splicing. Also, we observed a >2-fold increase of active pSF3B1 in CLL B-cells compared to NBC. Additionally, when the CLL-B cells were treated with macrolides (pladienolide-B), a significant decrease in pSF3B1, but not total SF3B1 protein was observed. ConclusionsOur findings suggest that IR/ARS is increased in CLL and that this process is associated with SF3B1 phosphorylation and susceptibility to SF3B1 inhibitors. These data provide additional support to the relevance of AS in carcinogenesis and evidence of pSF3B1 participation in this process.

Ibrutinib-based therapies are costly and require continuous administration. We hypothesized combining BTK inhibition with anti-CD20 monoclonal antibodies would yield deep remissions allowing discontinuation. We enrolled 32 therapy-naïve CLL patients to receive ibrutinib plus obinutuzumab, followed by single-agent ibrutinib. Patients could discontinue ibrutinib after 36 months with sustained complete response (CR). We evaluated treatment safety, efficacy, and outcomes after ibrutinib discontinuation. The overall response rate was 100%, 28% achieved a CR, and 12.5% achieved bone marrow undetectable minimal residual disease. At a three-year median follow-up, 91% remain in remission with 100% overall survival. Five patients in sustained CR stopped ibrutinib and have not progressed. Eight non-CR patients discontinued for other reasons, with only two progressing. The treatment was safe, with a lower IRR rate. All patients responded to treatment with longer time-to-progression after discontinuation of ibrutinib. Our data support the evaluation of ibrutinib discontinuation strategies in more extensive clinical trials (https://Clinicaltrials.gov Identifier https://clinicaltrials.gov/ct2/show/NCT02315768).

Objective/background: Despite the success of chimeric antigen receptor (CAR) T-cell therapy in patients with aggressive non-Hodgkin lymphoma (aNHL), some patients still fail treatment, and their prognosis is dismal. Methods: We performed a retrospective study of aNHL patients treated with axicabtagene ciloleucel (axi-cel) at two Mayo Clinic centers between 2018 and 2020. We evaluated predictive factors, toxicities, and responses to salvage regimens after CAR T-cell therapy. Results: Thirty-four patients received axi-cel with a median length of hospitalization of 14 days. Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome of any grade occurred in 91% and 41% of patients, respectively. Furthermore, 71% of patients responded to therapy, with 53% achieving a complete response (CR). The CRS grade and absolute lymphocyte count at leukapheresis (ALC Leuk ) correlated with CR and overall survival (OS), respectively. After a median follow-up of 6.8 months (interquartile range [IQR] 4.6–14.9), 15 patients (44%) showed progressive disease (PD). Most patients (60%) progressed during the first 3 months and had persistent CD19 tumor expression. Elevated C-reactive protein at baseline increased the risk of PD, whereas elevated ferritin increased PD and mortality risk. Twelve patients received salvage therapy, but only three responded. Median OS of relapsed/refractory patients to axi-cel was 3 months (IQR 1.3–5.1). Conclusion: The grade of CRS and ALC Leuk correlated with better outcomes to axi-cel therapy. In addition, elevated inflammatory markers at baseline were associated with PD and shorter survival. Relapses after treatment frequently occur within months after axi-cel infusion; they confer a poor prognosis and create an urgent need for novel and effective treatment options in this patient population.

Abstract Ibrutinib-based therapies are costly and require continuous administration. We hypothesized combining BTK inhibition with anti-CD20 monoclonal antibodies would yield deep remissions allowing discontinuation. We enrolled 32 therapy-naïve CLL patients to receive ibrutinib plus obinutuzumab, followed by single-agent ibrutinib. Patients could discontinue ibrutinib after 36 months with sustained complete response (CR). We evaluated treatment safety, efficacy, and outcomes after ibrutinib discontinuation. The overall response rate was 100%, 28% achieved a CR, and 12.5% achieved bone marrow undetectable minimal residual disease. At a three-year median follow-up, 91% remain in remission with 100% overall survival. Five patients in sustained CR stopped ibrutinib and have not progressed. Eight non-CR patients discontinued for other reasons, with only two progressing. The treatment was safe, with a lower IRR rate. All patients responded to treatment with longer time-to-progression after discontinuation of ibrutinib. Our data support the evaluation of ibrutinib discontinuation strategies in more extensive clinical trials.

AbstractIntroductionHypoalbuminemia is a known adverse prognostic factor in lymphomas. Yet, it is unknown if axicabtagene ciloleucel (axi‐cel) overcomes the adverse prognostic impact of hypoalbuminemia in relapsed/refractory large B‐cell lymphoma.MethodsWe conducted a retrospective analysis across three Mayo Clinic centers to assess the relationship of hypoalbuminemia (defined as a serum albumin (SA) levels ≤ 3.5 g/dL) on outcomes of patients treated with axi‐cel.ResultsThis analysis included 81 patients. Two patients had no available SA levels preceding axi‐cel infusion. Eighteen patients (22.8%) had hypoalbuminemia with a median SA of 3.3 g/dL. Patients with normal SA had a statistically higher ORR than those without hypoalbuminemia (P = .018). There was no difference in 1‐year PFS and OS between the group with hypoalbuminemia and the group with normal SA levels (48% vs 49%, P = .81) and (74% vs 73%, P = .97), respectively. There was no difference in the severity or median duration of cytokine release syndrome or neurotoxicity between the two groups.ConclusionNotwithstanding the limitations related to the relatively small sample size, axi‐cel therapy appears to overcome the adverse effect of hypoalbuminemia on OS and PFS. Large multicenter clinical studies are certainly needed to validate these findings.

Abstract Background Infective endocarditis (IE) secondary to Staphylococcus aureus bacteremia (SAB) has high morbidity and mortality. The systematic use of echocardiography in SAB is controversial. We aimed to validate VIRSTA and Predicting Risk of Endocarditis Using a Clinical Tool (PREDICT) scores for predicting the risk of IE in Colombian patients with SAB and, consequently, to determine the need for echocardiography. Methods Cohort of patients hospitalized with SAB in 2 high complexity institutions in Medellin, Colombia, between 2012 and 2018. The diagnosis of IE was established based on the modified Duke criteria. The VIRSTA and PREDICT scores were calculated from the clinical records, and their operational performance was calculated. Results The final analysis included 922 patients, 62 (6.7%) of whom were diagnosed with IE. The frequency of IE in patients with a negative VIRSTA scale was 0.44% (2/454). The frequency of IE in patients with a negative PREDICT scale on day 5 was 4.8% (30/622). The sensitivity and negative predictive value (NPV) of the VIRSTA scale was 96.7% and 99.5%, respectively. For the PREDICT scale on day 5, the sensitivity and NPV were 51.6% and 95.1%, respectively. The discrimination, given by the area under the receiver operating characteristic curve, was 0.86 for VIRSTA and 0.64 for PREDICT. Conclusions In patients with negative VIRSTA, screening echocardiography may be unnecessary because of the low frequency of IE. In PREDICT-negative patients, despite the low frequency of IE, it is not safe to omit echocardiography.

Single oral targeted therapies have emerged as a standard of care in chronic lymphocytic leukemia (CLL). However, accessibility, side effects, and financial burden associated with long term administration limit their clinical use. Mainly, it is unclear in what clinical situation discontinuation of oral therapy can be recommended. The combination of type II anti-CD20 antibody obinutuzumab-Gazyva® with ibrutinib (GI) has shown a significant progression-free survival benefit in patients (pts) with CLL, including those with high-risk genomic aberrations. We conducted a phase 1b/2, single-arm, open-label trial to evaluate the safety and efficacy of GI as first-line treatment in 32 CLL pts. We report the outcome in pts that discontinued ibrutinib (either after 3 years of sustained complete response (CR) as stipulated in the clinical protocol, or due to other reasons). CLL pts enrolled in this protocol were ≥65 years old, or unfit/unwilling to receive chemotherapy. Pts received GI for six cycles, followed by daily single-agent ibrutinib. The protocol was designed to ensure that pts with a sustained CR after 36 months were allowed to discontinue ibrutinib. The median age was 66 years (IQR 59-73), and 6% of the evaluated pts had 17p deletion. All pts were able to complete the six planned cycles of obinutuzumab. The combination regimen was well-tolerated, and the most common adverse events (>5% CTCAE grade 3-4) were neutropenia, thrombocytopenia, and hyperglycemia. The rate and severity of infusion-related reactions (IRR) were much lower than expected (Grade≥ 3, 3%), and pts without IRR had lower serum levels of cytokines/chemokines CCL3 (P=0.0460), IFN-γ (P=0.0457), and TNF-α (P=0.0032) after infusion. The overall response rate was 100%, with nine pts (28%) achieving a CR, and four pts (12.5%) with undetectable minimal residual disease (uMRD) in the bone marrow, defined as <10-4 CLL cells on multicolor flow cytometry. At a median follow-up of 35.5 months (IQR 24.5-42.7) after starting treatment, 91% of the enrolled pts remain in remission with a 100% overall survival. Sixteen pts have completed a long-term follow-up of 36 months. Six pts showed CR, with three of them achieving uMRD in the bone marrow. Ten of these pts were in PR, and only one had disease progression and started treatment for symptomatic stage I disease with obinutuzumab plus venetoclax. In total, thirteen pts (41%) have stopped ibrutinib, with a median time on treatment prior to discontinuation of 35 months. Five (16%) of these pts had CRs and discontinued after 36 months. Eight additional pts (25%) had PRs and discontinued ibrutinib without being eligible: three pts discontinued prior to 36 months due to toxicities, and five pts discontinued after 36 months (3 due to side effects, and 2 due to financially driven decision). One patient eligible to discontinue ibrutinib, decided to remain on treatment despite sustained CR. After a median follow up time following ibrutinib discontinuation of 8 months (IQR 3.5-17), only two out of 13 pts have progressed (10 and 17 months after Ibrutinib discontinuation). None of the pts that stopped ibrutinib after achieving a CR have shown signs of disease progression. Of note, the pharmaceutical sponsor provided ibrutinib for the first 36 months, after which pts or their insurer became financially responsible. This particular scenario could bias the discontinuation pattern compared to a real world experience. It also provided us with a perspective about diverse factors affecting the treatment choices of pts. In summary, the obinutuzumab plus ibrutinib combination therapy was well-tolerated, with a much lower IRR rate. Efficacy compares favorably with historical controls with all pts responding to therapy, no deaths associated with treatment or disease progression, and a longer than expected time-to-progression after discontinuation of ibrutinib. The rate of ibrutinib discontinuation was higher than reported in the literature, most likely influenced by the protocol design and financial decisions driven by the switch from sponsor-provided ibrutinib to insurance or self-paid medication. Our observations regarding safety, efficacy and lack of disease progression after ibrutinib discontinuation are encouraging, and warrant confirmation in long-term prospective studies. Clinicaltrials.gov Identifier NCT02315768. Funding: Pharmacyclics LLC. Disclosures Choi: AbbVie: Consultancy, Speakers Bureau. Amaya-Chanaga:AbbVie: Ended employment in the past 24 months, Other: Research performed while employed as an investigator of this study at UCSD.. Kipps:Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Castro:Kite Pharma: Research Funding; Pharmacyclics: Research Funding; Fate Therapeutics: Research Funding.