ALBERT

Description: Background: Primary cutaneous diffuse large B-cell lymphoma, leg-type (LT-DLBCL) is an extremely aggressive DLBCL subtype typically occurring at lower extremities and with very poor prognosis due to early relapses and refractory (R/R) disease. Previous studies have shown increased BCR dependence in DLBCL being observed in association with the mutation status of BCR associated genes and MYD88. Aim: Primary goal was to assess the clinical course in patients with primary cutaneous DLBCL and to elucidate the potential of alternative treatments with regard to molecular characteristics. Methods: We identified 16 patients with cutaneous DLBCL treated at our center of which 8 patients had typical localization and were histologically confirmed as LT-DLBCL. The other 8 patients showed cutaneous DLBCL at other anatomic sites (DLBCL-OS) and were classified as DLBCL/DLBCL NOS. Three R/R patients received ibrutinib as off-label individual treatment attempt (420 mg daily). We extended the clinical and molecular analysis for the ibrutinib exposed DLBCL by 1 R/R oropharyngeal DLBCL. Specimen from R/R ibrutinib exposed and 3 other patients were analyzed for CD79B, MYD88, CARD11 and BTK mutations by targeted resequencing analysis. PD-1/PD-L1 expression was assessed in 2 cases with relapse after ibrutinib. Treatment was initiated after signed informed consent. Results: The median age at diagnosis was 51 years in DLBCL-OS and 80 years in LT-DLBCL (total range 37-91). Patients received a median of 2 (0-7) treatments and response to last chemotherapy was different for DLBCL-OS (6 complete remissions (CR), 2 R/R) and LT-DLBCL (2CR, 5R/R). One LT-DLBCL patient showed stable disease (SD) without treatment. LT-DLBCL patients showed a significantly shorter median overall survival (OS) (21,5 months vs. not reached, p=0.009). After ibrutinib treatment we observed 1 ongoing CR for 10 months till date for a DLBCL-OS with CD79B p.Y197S and MYD88 L273P mutation and 1 CR for 6 months in a LT-DLBCL being WT for all sequenced genes. However, this patient relapsed with a highly proliferative disease and died shortly after. The 3rd patient with LT-DLBCL had an isolated MYD88 L265P mutation and showed a PR for 1 month. Samples from patients with indolent clinical course showed a MYD88 p.S251N and BTK p.P385S mutation (LT-DLBCL with SD) or were WT for all sequenced genes (2 patients with DLBCL-OS and ongoing CR). The patient with R/R oropharyngeal DLBCL had a MYD88 L265P and CD79B c.587A mutation, 4 prior treatment regimen and fulminant progression during the last 2 treatments. Initial response to ibrutinib was rapid with a drop of LDH levels from 2200 U/L to 620 U/L within 7 days and consecutive decrease to 323 U/L. However, this patient relapsed after 30 days of treatment. Immunomodulatory effects of ibrutinib and potential synergistic treatment with checkpoint inhibitors have previously been suggested. We specifically investigated PD-1/PD-L1 expression in tissues obtained from the two patients progressing after ibrutinib treatment. Remarkably, we observed increased expression for PD-1 (moderate) and PD-L1 (strong) in non-tumor bystander cells. Treatment with nivolumab was initiated in 1 patient with early clinical benefit. However, the patient refused the continuation of this treatment. Conclusion: Patients with LT-DLBCL are older and show a poor clinical course compared to cutaneous DLBCL at other anatomic sites. MYD88 L265P mutations were observed only in chemo-refractory cases with extranodal DLBCL. Ibrutinib can induce complete remissions and sustained responses in chemo-refractory extranodal DLBCL but relapses may be more aggressive and disseminated. Mutational patterns and ibrutinib response were in line with previous hypothetical models for sensitivity to BCR inhibition. Combining ibrutinib and checkpoint inhibitors may be considered in future trials for LT-DLBCL patients. Disclosures Weissinger: Bristol-Myers Squibb: Research Funding. Viardot:Roche: Consultancy, Honoraria; Amgen: Consultancy; Gilead Kite: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria.

Description: Background: Chemotherapy-free treatment with arsenic trioxide and all-trans retinoic acid (ATO/ATRA) of patients with acute promyelocytic leukemia (APL) with presenting white blood counts (WBC) 〈 10 G/l has been shown to be at least equivalent or even better with regard to survival and quality of life compared to standard treatment according to the AIDA scheme which includes idarubicin, mitoxantrone in combination with ATRA followed by a two-year maintenance therapy with 6-mercaptopurin, methotrexate and ATRA (Lo Coco F et al., N. Engl. J. Med. 2013;369(2):111-21; Efficace F et al J Clin Oncol. 2014 accepted). Aims: To evaluate costs in relation to benefits in a cost-effectiveness analysis comparing ATO/ATRA to standard treatment with AIDA in newly diagnosed APL with WBC

Description: Patients with relapsed or refractory aggressive B-cell Non-Hodgkin lymphoma (B-NHL) have a poor outcome. Nivolumab (NV) targeting the PD-1 receptor has shown promising results in several malignancies like melanoma, renal and lung carcinoma and Hodgkin lymphoma. Data for aggressive B-NHL are just emerging. PD-L1 expression does not necessarily correlate with response. Among lymphoma subtypes, the expression of PD-L1 seems to vary. So far there are no valid data on PD-L1 expression in aggressive lymphoma under NV treatment. We retrospectively analyzed seven patients who had aggressive B-NHL with a refractory or relapsed disease after at least 3 regimens and were thereupon treated with NV 3mg/kg once a fortnight. Treatment was initiated after signed informed consent for off-label use. The histologic specimens were analyzed for PD-L1 expression by immunohistochemistry (IHC). The median age at NV treatment start was 51 years (27-71). The histopathological diagnoses were primary mediastinal B-cell lymphoma (PMBL; n=2), composite lymphoma with diffuse large B-cell (DLBCL) and Hodgkin lymphoma components (n=2), follicular lymphoma transformed into a DLCBL (n=2) and one mediastinal grey zone lymphoma (MGZL). A median of 5 (3-7) prior therapy regimens were given including hematopoietic stem cell transplantation (HSCT) for 3 patients: autologous (n=2) and allogeneic HSCT (n=1), respectively. The lymphoma status was refractory in 2 patients and relapsed in 5 patients. PD-L1 expression was detected in 5 cases, 3 of them showing a positive staining of 10%, 30%, and 50%, respectively, and 2 cases even of 100% of the lymphoma cells. NV was mostly well tolerated (1 pneumonitis completely resolved after systemic steroid therapy, 1 unrelated death caused by septic shock) with a median of 3 (1-17) cycles administered. Response assessment (clinical examination, ultrasound, CT or PET-CT scans) were performed after a median of 3 cycles (2-7), showing regressive and refractory disease in 3 patients, respectively, while 1 patient died prior to response assessment. Among the three responders (2xCR, 1xPR) MGZL and PBML their tumors had high PD-L1 expression of 30% (n=1) and 100% (n=2), respectively. Two responders (one after autologous, one after allogeneic HSCT) are still under treatment. After 14 weeks, one responding patient showed signs of progression of a previously known cerebral lesion (or pseudo progression under immunotherapy). The third responder proceeded to allogeneic HSCT without relevant complications. The PD-L1 expression among the non-responders were 0% (n=2) with progressive disease being the cause of death and 10% (n=1) for the other who is currently receiving alternative therapy. In conclusion, NV induces remission in heavily pretreated, PD-L1 high expression aggressive B-NHL. The significance of these data are limited due to the small number of patients. Therefore, future results of current phase II trials (NCT02038933) will reveal the role of PD-1 blockade in aggressive B-NHL. Disclosures Viardot: Roche: Honoraria; Takeda: Other: travel support; Pfizer: Honoraria; BMS: Consultancy; Janssen: Consultancy; Amgen: Consultancy.

Description: Hematopoietic stem cell transplantation (HSCT) associated thrombotic microangiopathy (TA-TMA) is a frequent and prognostic important complication of HSCT and may affect 20-30% of recipients. One third of these patients suffer from severe TA-TMA with a devastating prognosis. TA-TMA is a systemic small vessel disease affecting predominantly the kidney and the CNS but can affect any other organ. There is currently no accepted standard therapy for TA-TMA. The most commonly used therapeutic approaches such as plasma exchange and defibrotide are ineffective in severe TA-TMA with mortality rates of 〉80%. Recent data have suggested that TA-TMA, like most other forms of atypical Haemolytic-Uraemic Syndrome (aHUS) is caused by systemic activation of the alternative complement pathway. Given the high success rate of treatment of aHUS with the anti-C5 monoclonal antibody eculizumab (EC), this suggests that EC might be an effective treatment of TA-TMA. Initial reports in pediatric transplant patients seem to support this hypothesis, but the experience in adult patients is very limited and contradictory. Materials and Methods: We performed a retrospective analysis of 13 patients (table 1) treated with EC in our center. Inclusion criteria were diagnosis of TA-TMA according to the Choi-criteria, significant organ damage, evidence of systemic or local complement activation by measurement of serum sC5-9 levels or tissue biopsy. The patients were treated according to the approved dosing schedule of a weekly application of 900mg EC for 4-6 weeks followed by a maintenance phase with 1200mg biweekly. EC therapy was guided by monitoring CH50 activity and serum sC5-9 concentrations as proposed by Jodele et al 2015. The EC dosing schedule was thus adjusted to maintain CH50 activity below 10% and a normal sC5-9 concentration. Clinical response was defined as improvement of organ function (e.g. no neurological residues; termination of kidney dialysis) and independence of red blood cell and platelet transfusions. All patients received ciprofloxacin prophylaxis and the majority antifungal prophylaxis with posaconazole. Results: All patients were in remission of their underlying disease at the time of TA-TMA diagnosis a median of 9 months (from 2 to 29) after HSCT. At diagnosis 12 patients were receiving either tacrolimus (n=6), cyclosporine A (n=1) or sirolimus (n=5), which was withdrawn promptly. The median C5b-C9 level was 461 U/ml (127-810). Most patients presented with multiple organ involvement, combined CNS and kidney affection was the most common (n=8). In 9 patients EC was the primary therapy, in the other 4 patients EC was initiated after treatment failure of plasma exchange and defibrotide. The median time from TA-TMA diagnosis until EC initiation was 10 days (1-16). All patients showed sufficient blockade of the terminal complement pathway after the second EC application (CH50