ALBERT

Beschreibung: Key Points NFKB2 GOF mutations are associated with CID without endocrine or ectodermal manifestations. As most autosomal-dominant primary immunodeficiencies, NFKB2 GOF changes have incomplete penetrance and variable expressivity.

Beschreibung: Pathogenic gain-of-function variants in the genes encoding phosphoinositide 3-kinase δ (PI3Kδ) lead to accumulation of transitional B cells and senescent T cells, lymphadenopathy, and immune deficiency (activated PI3Kδ syndrome [APDS]). Knowing the genetic etiology of APDS afforded us the opportunity to explore PI3Kδ inhibition as a precision-medicine therapy. Here, we report in vitro and in vivo effects of inhibiting PI3Kδ in APDS. Treatment with leniolisib (CDZ173), a selective PI3Kδ inhibitor, caused dose-dependent suppression of PI3Kδ pathway hyperactivation (measured as phosphorylation of AKT/S6) in cell lines ectopically expressing APDS-causative p110δ variants and in T-cell blasts derived from patients. A clinical trial with 6 APDS patients was conducted as a 12-week, open-label, multisite, within-subject, dose-escalation study of oral leniolisib to assess safety, pharmacokinetics, and effects on lymphoproliferation and immune dysregulation. Oral leniolisib led to a dose-dependent reduction in PI3K/AKT pathway activity assessed ex vivo and improved immune dysregulation. We observed normalization of circulating transitional and naive B cells, reduction in PD-1+CD4+ and senescent CD57+CD4− T cells, and decreases in elevated serum immunoglobulin M and inflammatory markers including interferon γ, tumor necrosis factor, CXCL13, and CXCL10 with leniolisib therapy. After 12 weeks of treatment, all patients showed amelioration of lymphoproliferation with lymph node sizes and spleen volumes reduced by 39% (mean; range, 26%-57%) and 40% (mean; range, 13%-65%), respectively. Thus, leniolisib was well tolerated and improved laboratory and clinical parameters in APDS, supporting the specific inhibition of PI3Kδ as a promising new targeted therapy in APDS and other diseases characterized by overactivation of the PI3Kδ pathway. This trial was registered at www.clinicaltrials.gov as #NCT02435173.

Beschreibung: Introduction: 18Fluoro-deoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is one of the most widely used imaging techniques to detect multiple myeloma (MM). Intracellular FDG uptake depicts in vivo metabolic activity, which can be seen in both malignant and non-malignant cells, resulting in limited sensitivity and specificity. Our group showed preclinically that tracing MM dissemination using a CD38-directed human antibody, daratumumab, that is radioconjugated with copper-64 via the chelator DOTA (64Cu-DOTA-Dara), led to improved sensitivity and specificity over that of FDG (Caserta et al, Blood 2018). Herein, we report the results of a Phase 1 trial (NCT#03311828) designed to 1) assess the safety and feasibility of 64Cu-DOTA-Dara PET/CT and 2) to evaluate and characterize the ability of 64Cu-DOTA-Dara to accurately detect or exclude MM lesions compared with FDG PET/CT. Methods: Patients with biopsy-proven MM and/or a plasmacytoma received an FDG PET/CT scan within 60 days of enrollment. On Day 0, patients were infused with unlabeled ("cold") Dara at one of four dose levels (0 mg, 10 mg, 45 mg, 95 mg) to optimize biodistribution of radioconjugated 64Cu-DOTA-Dara, especially in the liver and the spleen. Within 6 hours of unlabeled Dara administration, patients received 64Cu-DOTA-Dara at a dose of 13.63-16.68 mCi (~5 mg). Whole-body PET scans were obtained at 24 hours and at 48 hours (the latter scan encompassing known tumors). 64Cu-DOTA-Dara standardized uptake values (SUV) were evaluated in MM lesions and normal organs, which were then compared with values from standard FDG PET/CT. Biopsies were performed on accessible discordant lesions. Results: A total of 10 Dara-naïve patients were imaged. Patients were treated with 0 (n=3), 10 (n=3), 45 (n=3), or 95 mg (n=1) of unlabeled Dara. Four patients had newly diagnosed disease, one had biochemical relapse, one had a recurrent plasmacytoma by MRI, and four had possible recurrence by standard PET/CT. No significant adverse events were observed from either cold or 64Cu-DOTA-Dara. With the exception of the one patient with a recurrent plasmacytoma, radiolabeled antibody was eliminated from systemic circulation in subjects analyzed at the first three dose levels within 30 min post injection. In the patient with a recurrent plasmacytoma, the radiolabeled antibody was elevated in the blood for over two days. One newly diagnosed patient had extensive disease by FDG PET and had a biopsy-proven target lesion in the sternum, which had an SUVmax of 14.7 on 64Cu-DOTA-Dara PET/CT vs. 3.3 onFDG PET/CT. A second biopsy from the same patient was taken from a discordant iliac crest lesion (positive for 64Cu-DOTA-Dara but negative for FDG PET/CT) that showed 20-30% MM cell infiltration. In another patient, an iliac crest lesion was 64Cu-DOTA-Dara positive and FDG-negative; biopsy revealed 6% plasmacytosis in the bone. A third patient had an FDG PET/CT positive pleural lesion with an SUVmax of 8.98 and negative on 64Cu-DOTA-Dara (Figure 1A). The lesion did not show recurrence upon biopsy. Furthermore, 64Cu-DOTA-Dara PET/CT yielded superior imaging of bone lesions in the calvarium (Figure 1B). Escalating doses of unlabeled Dara decreased liver and spleen uptake by 64Cu-DOTA-Dara. Conclusions: In this ongoing study, 64Cu-DOTA-Dara PET/CT imaging is to date safe and provides whole body imaging of MM. Further dose escalation of cold Dara (145 mg, 195 mg) is planned to optimize background interference. This modality has the potential to improve sensitivity and specificity over FDG PET/CT scanning in early-stage MM as well as in recurrent disease. Disclosures Krishnan: Celgene, Janssen, Sanofi, BMS: Consultancy; Sutro BioPharma, zPredicta: Consultancy; Amgen, Takeda: Speakers Bureau; Celgene, Z Predicta: Other: Stock Ownership; Takeda: Research Funding. Palmer:Gilead Sciences: Consultancy. Rosenzweig:Celgene, Takeda: Speakers Bureau. Wu:ImaginAb, Inc.: Consultancy, Other: Board Member.

Beschreibung: Introduction: Despite significant progress in the treatment of multiple myeloma (MM), the disease remains incurable and typically follows a pattern of multiple responses and relapses. In the relapsed/refractory MM setting (RRMM), outcomes for patients may be particularly discouraging. New treatments that are safe and effective are therefore of urgent need for this population. Since its FDA approval in 1998 for the treatment of rheumatoid arthritis, leflunomide has been used in over 300,000 patients worldwide. Leflunomide is hepatically cleared and has a favorable toxicity profile even when given over long periods. Its primary mechanism of action is inhibition of pyrimidine synthesis by targeting dihydroorotate dehydrogenase, thus achieving anti-proliferative effects on B and T lymphocytes. The anti-neoplastic potential of this agent has been studied in a number of pre-clinical tumor models. Leflunomide's immunoregulatory action may be related to functional inhibition of CD4+ effector T cells, including Th17 cells as well as dysregulation of T regulatory cells (Tregs). We found that leflunomide-treated C57BL/KaLwRij mice engrafted with 5TGM1 cells had more robust expansion of CD8+ cytotoxic T cells and subsequent decrease of CD4+ Tregs compared to untreated mice. We have also noted that leflunomide impairs growth of MM cells at least partly through inhibition of PIM kinases and c-Myc signaling. We present here final results from a phase 1 study of leflunomide in patients with RRMM. Methods: This single center, single agent, phase 1 dose-escalation trial was designed to determine the maximum tolerated dose of leflunomide in patients with RRMM. The trial implemented a modified rolling six phase 1 dose escalation design. The primary objectives were as follows: 1) to determine the maximum tolerated dose and recommended phase 2 dose of leflunomide; 2) to assess the safety and tolerably of leflunomide at each dose level by evaluation of toxicities. Leflunomide was administered at a loading dose of 100 mg daily for the first three days, then daily in 28-day cycles. The starting dose of daily leflunomide was 20 mg daily, with dose escalation in increments of 20 mg/day, up to 60 mg/day. Dose de-escalation in decrements of 10mg/day was planned. Results: A total of 12 patients have been enrolled starting in December 2015 and treated. The median age is 68 (range 48 - 85), and the median number of prior therapies is 5 (range: 3 - 14). Nine patients had prior autologous stem cell transplant. Double refractory (lenalidomide/bortezomib) disease was noted in 9 patients. High-risk cytogenetics were observed in 5 patients including 2 patients with del17p. All 12 subjects were evaluable for toxicity. One subject was not evaluable for response because of non-compliance. Of the eleven patients evaluable for response, the median number of cycles was 3 (range 1- 15). The median follow up was 177 days (range: 42 - 602). Three patients were treated on DL 1 (20 mg) and three on DL3 (40 mg) without incidence of DLT. At DL5 (60 mg), one patient had a DLT with grade III elevation of alanine aminotransferase; an additional three patients were enrolled at this dose level without further DLTs. One out of 12 subjects remains on treatment, 8 patients were removed from study due to disease progression, two due to adverse events (bacteremia at 60 mg, possibly related to study drug and angioedema at 40 mg, not related to study drug) and one from noncompliance. The most common toxicities were hematologic. There were 4 patients with grade 1 or 2 neutropenia on the 20 and 40 mg dose levels and 1 patient with grade 4 lymphopenia on the 40 mg dose. Except for the DLT, all non-hematologic toxicities were ≤ grade 2. Response: Although not all patients were treated at the 60 mg dose, a clinical benefit rate of 90% has been seen, with 9/10 achieving stable disease (SD). The median duration of SD among 9 patients thus far is 56 days (range: 27-401). In the five evaluable patients with high risk cytogenetics, four of them achieved a clinical benefit. Two subjects had SD lasting nearly one year or longer. In this small cohort, no association between dose and benefit was observed. Conclusion: Leflunomide is a safe and well-tolerated oral option for patients with RRMM, with a clinical benefit from single agent dosing. On the basis of our preclinical work showing synergistic inhibition of MM using leflunomide, pomalidomide, and dexamethasone, we plan clinical testing of this drug combination. Disclosures Rosenzweig: Celgene: Speakers Bureau. Krishnan:Janssen: Consultancy, Speakers Bureau; Sutro: Speakers Bureau; Onyx: Speakers Bureau; Takeda: Speakers Bureau; Celgene: Consultancy, Equity Ownership, Speakers Bureau. Forman:Mustang Therapeutics: Other: Licensing Agreement, Patents & Royalties, Research Funding.

Beschreibung: Introduction: Multiple Myeloma (MM) cell survival strictly depends on the interaction with multiple cell types in the bone marrow (BM), collectively referred to as the MM microenvironment (MM-ME). CD84 (SLAMF5) belongs to the signaling lymphocyte activation molecule family of immunoreceptors; previous data from our group have shown that CD84 mediates malignant B cells and their ME (Marom et al. 2017); however, its role within the MM-ME has not yet been investigated. Results: Using the MMRF CoMMpass IA9 dataset, we found that CD84 mRNA expression is low or absent in CD138+MM cells isolated from 660 newly diagnosed patients. In agreement with these data, flow analysis showed an absence of CD84 expression in all MM cell lines tested (n=9) and minimal surface expression (5.5-13%) in primary cells (n=3). However, a significantly higher expression of CD84 was detected on the surface of BM and peripheral blood (PB) monocytic fractions (CD14+) (76-97%) compared to that of matched CD14 negative fractions (2-9%) obtained from 16 different MM patients (p

Beschreibung: Introduction: Daratumumab (Dara) is a human monoclonal antibody targeting the highly expressed multiple myeloma (MM) surface receptor CD38, with significant activity in relapsed MM. However, resistance to Dara develops in virtually all patients (pts). Thus, in order to maximize its clinical activity and prevent resistance, it is imperative to understand why pts stop responding. Our group recently reported that, in addition to the malignant cells, several immune-effector cells also express CD38. Thus, we hypothesized that the expression of CD38 or lack of it on non-cancer immune cell-subsets may also play a role in both clinical response and resistance to Dara. Results: To address our hypothesis, we analyzed CD38 surface expression in CD138+ MM cells isolated from 5 Dara-naïve (D-naïve) pts and from 8 Dara progressing pts (D-prg) who had discontinued Dara therapy for at least 4 weeks prior to analysis. We observed that the CD138+ MM-cells of D-prg displayed a lower median fluorescence intensity (MFI) of CD38 compared to the MFI of MM cells isolated from the D-naïve (p=0.04); no significant difference was however observed in the percentage of CD38+ MM cells between the two groups. In fact, all of the MM cells expressed CD38 in both D-naïve and D-prg, supporting the hypothesis that resistance to Dara was not mediated by loss of CD38 expression on MM cells. Next, we looked at whether CD38 on the surface of MM cells from D-prg was still recognizable by Dara. Thus, we treated MM cells ex-vivo with Dara at the clinically achievable concentration of 100 μg/ml. We showed that Dara was still able to bind CD38 on the surface of the D-prg CD138+ MM cells, since, after Dara treatment, no CD38+ signal was detected upon staining with a CD38 monoclonal antibody sharing the same targeting CD38 epitope (clone IB6) (Fig.1a). Conversely, we detected a CD38+ signal when a different anti-human CD38 multi-epitope antibody was used in a similar experiment (Cytognos) (Fig.1b). CD38 mRNA expression was observed in all MM cells isolated from D-prg, and we were not able to identify any missense mutations in CD38 mRNA from MM cells of D-prg for whom material was available for analysis. Thus, having demonstrated that resistance to Dara was not related to the expression of CD38 on the MM-cells, we turned our attention to the MM bone marrow (BM) microenvironment (ME). We performed RNA-sequencing of the BM-ME depleted of the CD138+ MM cells obtained from the D-prg (n=5) and D-naïve (n=5). A gene expression signature differentiated the two groups. In D-prg, we observed a significant downregulation (fold-change