Paraneoplastic Calmodulin Kinase-Like Vesicle-Associated Protein (CAMKV) Autoimmune Encephalitis

OBJECTIVES

To report an autoimmune paraneoplastic encephalitis characterized by immunoglobulin G (IgG) antibody targeting synaptic protein calmodulin kinase-like vesicle-associated (CAMKV).

METHODS

Serum and cerebrospinal fluid (CSF) samples harboring unclassified antibodies on murine brain-based indirect immunofluorescence assay (IFA) were screened by human protein microarray. In 5 patients with identical cerebral IFA staining, CAMKV was identified as top-ranking candidate antigen. Western blots, confocal microscopy, immune-absorption, and mass spectrometry were performed to substantiate CAMKV specificity. Recombinant CAMKV-specific assays (cell-based [fixed and live] and Western blot) provided additional confirmation.

RESULTS

Of 5 CAMKV-IgG positive patients, 3 were women (median symptom-onset age was 59 years; range, 53-74). Encephalitis-onset was subacute (4) or acute (1) and manifested with: altered mental status (all), seizures (4), hyperkinetic movements (4), psychiatric features (3), memory loss (2), and insomnia (2). Paraclinical testing revealed CSF lymphocytic pleocytosis (all 4 tested), electrographic seizures (3 of 4 tested), and striking MRI abnormalities in all (mesial temporal lobe T2 hyperintensities [all patients], caudate head T2 hyperintensities [3], and cortical diffusion weighted hyperintensities [2]). None had post-gadolinium enhancement. Cancers were uterine adenocarcinoma (3 patients: poorly differentiated or neuroendocrine-differentiated in 2, both demonstrated CAMKV immunoreactivity), bladder urothelial carcinoma (1), and non-Hodgkin lymphoma (1). Two patients developed encephalitis following immune checkpoint inhibitor cancer therapy (atezolizumab [1], pembrolizumab [1]). All treated patients (4) demonstrated an initial response to immunotherapy (corticosteroids [4], IVIG [2]), though 3 died from cancer.

INTERPRETATION

CAMKV-IgG is a biomarker of immunotherapy-responsive paraneoplastic encephalitis with temporal and extratemporal features and uterine cancer as a prominent oncologic association. ANN NEUROL 2024.

Ibrutinib-based therapy reinvigorates CD8+ T cells compared to chemoimmunotherapy: immune monitoring from the E1912 trial

ABSTRACT

Bruton tyrosine kinase inhibitors (BTKis) that target B-cell receptor signaling have led to a paradigm shift in chronic lymphocytic leukemia (CLL) treatment. BTKis have been shown to reduce abnormally high CLL-associated T-cell counts and the expression of immune checkpoint receptors concomitantly with tumor reduction. However, the impact of BTKi therapy on T-cell function has not been fully characterized. Here, we performed longitudinal immunophenotypic and functional analysis of pretreatment and on-treatment (6 and 12 months) peripheral blood samples from patients in the phase 3 E1912 trial comparing ibrutinib-rituximab with fludarabine, cyclophosphamide, and rituximab (FCR). Intriguingly, we report that despite reduced overall T-cell counts; higher numbers of T cells, including effector CD8+ subsets at baseline and at the 6-month time point, associated with no infections; and favorable progression-free survival in the ibrutinib-rituximab arm. Assays demonstrated enhanced anti-CLL T-cell killing function during ibrutinib-rituximab treatment, including a switch from predominantly CD4+ T-cell:CLL immune synapses at baseline to increased CD8+ lytic synapses on-therapy. Conversely, in the FCR arm, higher T-cell numbers correlated with adverse clinical responses and showed no functional improvement. We further demonstrate the potential of exploiting rejuvenated T-cell cytotoxicity during ibrutinib-rituximab treatment, using the bispecific antibody glofitamab, supporting combination immunotherapy approaches.

Progression and survival of MBL: a screening study of 10 139 individuals

Monoclonal B-cell lymphocytosis (MBL) is a common hematological premalignant condition that is understudied in screening cohorts. MBL can be classified into low-count (LC) and high-count (HC) types based on the size of the B-cell clone. Using the Mayo Clinic Biobank, we screened for MBL and evaluated its association with future hematologic malignancy and overall survival (OS). We had a two-stage study design including discovery and validation cohorts. We screened for MBL using an eight-color flow-cytometry assay. Medical records were abstracted for hematological cancers and death. We used Cox regression to evaluate associations and estimate hazard ratios and 95% confidence intervals (CIs), adjusting for age and sex. We identified 1712 (17%) individuals with MBL (95% LC-MBL), and the median follow-up time for OS was 34.4 months with 621 individuals who died. We did not observe an association with OS among individuals with LC-MBL (P = .78) but did among HC-MBL (hazard ratio, 1.8; 95% CI, 1.1-3.1; P = .03). Among the discovery cohort with a median of 10.0 years follow-up, 31 individuals developed hematological cancers with two-thirds being lymphoid malignancies. MBL was associated with 3.6-fold risk of hematological cancer compared to controls (95% CI, 1.7-7.7; P < .001) and 7.7-fold increased risk for lymphoid malignancies (95% CI:3.1-19.2; P < .001). LC-MBL was associated with 4.3-fold risk of lymphoid malignancies (95% CI, 1.4-12.7; P = .009); HC-MBL had a 74-fold increased risk (95% CI, 22-246; P < .001). In this large screening cohort, we observed similar survival among individuals with and without LC-MBL, yet individuals with LC-MBL have a fourfold increased risk of lymphoid malignancies. Accumulating evidence indicates that there are clinical consequences to LC-MBL, a condition that affects 8 to 10 million adults in the United States.

Abstract 5256: Incidence of squamous cell carcinoma (SCC) in a large screening cohort of monoclonal B-cell lymphocytosis (MBL)

MBL is a common pre-malignant condition characterized by circulating clonal B-cells with an absolute B-cell count &lt;5x109/L and no lymphadenopathy, organomegaly, or cytopenias. MBL is the precursor to CLL. The incidence of cutaneous SCC in CLL is significantly higher compared to controls. The incidence of SCC in MBLs has not yet been determined. Study participants from the Mayo Clinic Biobank who had no prior history of hematologic malignancy, were 40 years or older, and were Olmsted County residents completed a health questionnaire and provided blood samples between 7/2009 and 12/2020. Stored peripheral blood mononuclear cells were screened for MBL using flow cytometry. We defined three MBL immunophenotypes: CLL-like MBL (CD5+, CD20dim), atypical MBL (CD5+, CD20+), and non-CLL-like MBL (CD5-, CD20+). MBL individuals were also classified by cell count into low-count MBL (LC-MBL) and high-count MBL (HC-MBL), with HC-MBL having a percent clonal B-cell count ≥85%. Data on newly diagnosed SCC was abstracted from the medical records, and prior history of skin cancer before sample collection was ascertained from patient questionnaires. Individuals were followed from sample date to the earliest of SCC, death, loss to follow-up, progression, or 12/31/2020. Cumulative SCC incidence was adjusted for competing risk of death. Cox regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CIs) adjusted for age and sex. A total of 5,470 participants were screened for MBL and included 949 (17%) with LC-MBL, 63 (1%) with HC-MBL, and 4,458 (81%) controls (negative for MBL). Individuals with HC-MBL (median age 75 years) or LC-MBL (median age 73 years) were significantly older (P&lt;0.001) than controls (median age 66 years). There were 41 (65%) males among HC-MBL, 447 (47%) among LC-MBL, and 1,551 (35%) among controls. Prior skin cancer history was highest among HC-MBLs (N=17, 27%) or LC-MBLs (N=236, 25%) compared to controls (N=767, 17%). After a median follow-up of 18 months (range 0-138), 154 of the 5,470 individuals were identified to have incident SCC following MBL screening. At least one SCC was observed in 3 individuals with HC-MBL, 33 individuals with LC-MBL, and 118 controls. The 5- and 10-year cumulative incidence of SCC in individuals with MBLs was 7% and 16%, respectively; control estimates were 4% and 8%, respectively. However, after adjusting for age and sex, we observed no evidence of an association between MBL and risk of incident SCC (HR=0.95, CI=0.65-1.40, P=0.80), nor when we stratified individuals by age or by sex (all P&gt;0.05). In the largest MBL screening cohort to date, individuals with MBL do not have an increased risk of incident SCC compared to controls. In contrast to individuals with CLL, these individuals with screening MBL do not need increased dermatologic examination for skin cancer, which is important given the high prevalence of MBL (18% of the population above age 40).

Citation Format: Ahmed Nadeem Ansari, Sara J. Achenbach, Sameer A. Parikh, Geffen Kleinstern, Aaron D. Norman, Kari G. Rabe, Connie E. Lesnick, Timothy G. Call, Janet E. Olson, James R. Cerhan, Neil E. Kay, Celine M. Vachon, Esteban Braggio, Curtis A. Hanson, Tait D. Shanafelt, Christian L. Baum, Susan L. Slager. Incidence of squamous cell carcinoma (SCC) in a large screening cohort of monoclonal B-cell lymphocytosis (MBL) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5256.

Measurable residual disease does not preclude prolonged progression-free survival in CLL treated with ibrutinib

E1912 was a randomized phase 3 trial comparing indefinite ibrutinib plus 6 cycles of rituximab (IR) to 6 cycles of fludarabine, cyclophosphamide, and rituximab (FCR) in untreated younger patients with CLL. We describe measurable residual disease (MRD) levels in E1912 over time and correlate them with clinical outcome. Undetectable MRD rates (<1 CLL cell per 104 leukocytes) were 29.1%, 30.3%, 23.4%, and 8.6% at 3, 12, 24, and 36 months for FCR, and significantly lower at 7.9%, 4.2%, and 3.7% at 12, 24, and 36 months for IR, respectively. Undetectable MRD at 3, 12, 24, and 36 months was associated with longer progression-free survival (PFS) in the FCR arm, with hazard ratios (MRD detectable/MRD undetectable) of 4.29 (95% confidence interval [CI], 1.89-9.71), 3.91 (95% CI, 1.39-11.03), 14.12 (95% CI, 1.78-111.73), and not estimable (no events among those with undetectable MRD), respectively. In the IR arm, patients with detectable MRD did not have significantly worse PFS compared with those in whom MRD was undetectable; however, PFS was longer in those with MRD levels <10-1 than in those with MRD levels above this threshold. Our observations provide additional support for the use of MRD as a surrogate end point for PFS in patients receiving FCR. In patients on indefinite ibrutinib-based therapy, PFS did not differ significantly by undetectable MRD status, whereas those with MRD <10-1 tended to have longer PFS, although continuation of ibrutinib would very likely be necessary to maintain treatment efficacy.

A randomized phase II trial comparing chemoimmunotherapy with or without bevacizumab in previously untreated patients with chronic lymphocytic leukemia

Bevacizumab is a monoclonal antibody targeting vascular endothelial growth factor (VEGF) with in vitro pro-apoptotic and antiangiogenic effects on chronic lymphocytic leukemia (CLL) cells. As monotherapy in patients with CLL, it has no clinical activity. Here we report the results of an open-label, randomized phase II trial comparing the combination of pentostatin, cyclophosphamide and rituximab (PCR) either without or with bevacizumab (PCR-B) in previously untreated CLL patients. A total of 65 evaluable patients were enrolled, 32 receiving PCR and 33 PCR-B. A higher rate of grade 3-4 cardiovascular toxicity was observed with PCR-B (33% vs. 3%, p < 0.003). Patients treated with PCR-B had a trend for a higher complete remission (CR) rate (54.5% vs 31.3%; p = 0.08), longer progression-free survival (PFS)(p = 0.06) and treatment-free survival (TFS)(p = 0.09). No differences in PFS and TFS by IGHV mutational status were observed with the addition of bevacizumab. A significant post-treatment increase in VEGF levels was observed in the PCR-B arm (29.77 to 57.05 pg/mL); in the PCR-B arm, lower baseline CCL-3 levels were significantly associated with achievement of CR (p = 0.01). In conclusion, the addition of bevacizumab to chemoimmunotherapy in CLL is generally well-tolerated and appears to prolong PFS and TFS.

Abstract B02: The Akt inhibitor MK-2206 in combination with rituximab and bendamustine demonstrates efficacy in relapsed/refractory chronic lymphocytic leukemia: Updated results from the NCCTG N1087 Alliance study

Background: PI3K/Akt activation is downstream of the B cell receptor (BCR) signaling cascade and is critical to mediate the interactions between CLL B-cell and bone marrow stroma which support leukemic survival. MK-2206 is a potent oral allosteric Akt inhibitor and we have demonstrated in vitro synergism with bendamustine (B) to induce CLL apoptosis. MK-2206 selectively abolishes BCR-stimulated cytokines CCL3, CCL4, CCL2, and IL-2Ra and significantly inhibits the BCR signaling pathway (Ding, BJH, 2013). We sought to assess the safety, maximal tolerated dose (MTD) and efficacy of MK-2206 in combination with B-rituximab (BR) in relapsed and refractory CLL/SLL patients in a phase I/II trial (NCCTG N1087 Alliance).

Methods: Previously treated symptomatic CLL/SLL patients with up to 3 prior lines of therapy and ECOG performance status of 0-2 were eligible. Patients with 17p deletion or prior treatment with B were excluded. A standard phase I design was used to determine the MTD of MK-2206 in combination with BR (B 70mg/m2 for 2 days per cycle; R cycle 1: 375 mg/m2, cycle 2-6: 500 mg/m2). Phase II employed the MTD to evaluate safety and efficacy of the combination. Response was evaluated 2 months after the last cycle of therapy per IWCLL 2008 criteria.

Results: 13 patients with a median age of 68 years (range 44-75) and 1.2 prior lines of therapy were treated. CLL FISH showed: del(11q) in 4 (31%), trisomy 12 in 2 (15%), del(13q) in 3 (23%), del(6q) (8%), del(17cen) (8%) and normal results in 2 (15%). IGHV was unmutated in 10 (91%) and mutated in 1 patient (9%) and was missing in 2 cases. ZAP-70 was positive in 8 (73%) and negative in 3 patients (27%). CD38 was positive in 8 (62%) and negative in 5 patients (38%). 70% of patients had received prior chemoimmunotherapy. At 90 mg of MK-2206, 1/6 patients experienced a DLT of grade 3 febrile neutropenia and hemolysis. 2/6 patients on the 135 mg dose experienced a DLT. One patient had grade 3 febrile neutropenia and one patient had a grade 3 acneiform rash. MTD was determined to be MK-2206 90 mg. The most common grade 3/4 adverse events were neutropenia (46%) including febrile neutropenia (23%), diarrhea (15%) and thrombocytopenia (15%). The most common all-grade toxicities were neutropenia (69%), thrombocytopenia (62%), anemia (54%), nausea (54%), diarrhea (39%), rash (38%), and hyperglycemia (31%).

10 patients were treated at 90 mg and 3 patients were treated at the 135 mg dose. The ORR was 92% (n=12). Responses were: 3 CR (23%), 2 CR with incomplete marrow recovery (CRi) (15%), 1 clinical CR (CCR) (8%) without marrow confirmation, 1 nodular partial remission (nPR) (8%), 5 PR (38%), and 1 progressive disease (8%). Median follow-up was 20 months (6-31 months). Median PFS in the CR/CRi group was not reached (NR) with 100% of patients progression free versus 12 months (95% CI 2 months-NR) if CR/CRi was not achieved (p=0.027). Median overall survival was NR in either the CR/CRi or non-CR/CRi groups but 2 deaths occurred in the latter group (p=0.44). One patient developed Richter transformation and died at 15 months and a second patient who had achieved PR died from autoimmune hemolytic anemia and fungal infection at 27 months. Two out of five patients who achieved CR or CRi had bone marrow MRD negative status at the final response evaluation.

Conclusions: The Akt inhibitor MK-2206 administered at 90 mg once weekly in combination with BR is tolerated in patients with relapsed or refractory CLL and compares favorably to BR alone (59% ORR and 9% CR, Fischer, JCO, 2011). An ORR of 92% was observed with a 38% of patients achieving CR or CRi. The trial was terminated prematurely due to withdrawal of sponsor support, however further testing of Akt inhibition is needed given the promising results.

Citation Format: Jeremy T. Larsen, Tait D. Shanafelt, Jose F. Leis, Betsy R. LaPlant, Timothy G. Call, Clive S. Zent, Curtis A. Hanson, Charles Erlichman, Thomas M. Habermann, Craig B. Reeder, Deborah A. Bowen, Michael Conte, Justin C. Boysen, Charla R. Secreto, Connie E. Lesnick, Renee C. Tschumper, Diane F. Jelinek, Neil E. Kay, Wei Ding. The Akt inhibitor MK-2206 in combination with rituximab and bendamustine demonstrates efficacy in relapsed/refractory chronic lymphocytic leukemia: Updated results from the NCCTG N1087 Alliance study. [abstract]. In: Proceedings of the AACR Special Conference: Targeting the PI3K-mTOR Network in Cancer; Sep 14-17, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(7 Suppl):Abstract nr B02.

The effect of interferon induction in newborn piglets on the humoral immune response to oral vaccination with transmissible gastroenteritis virus

Groups of newborn piglets were vaccinated orally with a modified live transmissible gastroenteritis (TGE) virus vaccine at 3 days and 13 days of age, and treated with the synthetic interferon (IFN) inducer polyinosinic:polycytidylic acid (poly ICLC) at 2, 3 or 4 days of age. Control groups consisted of piglets which were vaccinated but not treated with poly ICLC, as well as piglets which were treated with poly ICLC but not vaccinated. Significantly higher mean IFN titres were produced in response to induction at 3 or 4 days of age than at 2 days, and the mean IFN titre of the vaccinated piglets treated with poly ICLC at 3 days of age was significantly higher than in the unvaccinated piglets which were treated at the same time. The mean TGE virus neutralizing antibody titres in the vaccinated piglets which were treated with poly ICLC on the day before vaccination were significantly lower than the mean titres in the untreated vaccinated piglets 10 and 14 days after the first dose of vaccine. The mean titres in the vaccinated piglets which were treated with poly ICLC at 3 or 4 days of age did not differ significantly from those in the untreated vaccinated piglets. The piglets which were treated with poly ICLC on the day after vaccination developed severe diarrhoea which persisted for 5-7 days.

Hyporeactivity to interferon induction in newborn piglets

The aim of this study was to produce sustained activation of natural killer (NK) cells in newborn piglets by interferon (IFN) induction with polyinosinic:polycytidylic acid complexed with poly-L-lysine and carboxymethylcellulose [poly(ICLC)]. When a second dose of poly(ICLC) was given 24 or 48 h after the first dose, the piglets were found to be hyporeactive, and the levels of induced IFN were insufficient to activate NK cells in vivo or in vitro. A hyporeactive factor was demonstrated in the serum of piglets 24 and 48 h after they were treated with poly(ICLC), which inhibited IFN induction in vitro with poly(ICLC) but not with Newcastle disease virus. The IFN response of hyporeactive piglets was partially restored by the administration of prostaglandin (PG) F2 alpha at the same time as the second dose of poly(ICLC); piglets treated in this way at 3 days of age showed significantly higher lymphocytic NK activity at 5 days and 7 days than the activity in untreated piglets and in those given one or two doses of poly(ICLC) in the absence of PG F2 alpha. It was concluded that piglets develop hyporeactivity to IFN induction, but the IFN and NK cell activation responses to poly(ICLC) can be restored by treatment with PG.

Activation of natural killer cells in newborn piglets by interferon induction

Natural killer (NK) cell activity in the peripheral blood lymphocytes (PBL) of newborn piglets, normally negligible, was stimulated by in vitro treatment with porcine type I interferon (IFN), and the NK activity of PBL from weaned piglets was augmented by the same treatment. Binding of the PBL to the PK-15 targets used in the single cell cytotoxicity assay for NK activity was not affected by age or by IFN treatment. When newborn piglets were treated with a single intravenous dose at 2 days of age of 0.5 mg/kg of polyinosinic:polycytidylic acid complexed with poly-L-lysine and carboxymethylcellulose (poly ICLC), a synthetic IFN inducer, their IFN levels peaked at 6 h post-induction, and NK activity in their PBL peaked at 24 h post-induction at the level normally found in weaned piglets. The NK activity then declined until 7 days post-induction, when it increased again in a similar manner to that in untreated control piglets. Target-binding of the PBL was not affected by poly ICLC treatment of the piglets. Newborn piglets treated with poly ICLC and subsequently exposed to infection with transmissible gastroenteritis (TGE) virus showed a delay in onset of clinical signs of TGE compared with untreated control piglets. It was concluded that NK cells in newborn piglets can be activated by treatment of the piglets with poly ICLC, and that the presence of active NK cells is associated with some increase in resistance to challenge with TGE virus.