ALBERT

Description: Background: Primary central nervous system lymphoma (PCNSL) is a rare type of extranodal non-Hodgkin lymphoma (NHL). Most cases occur in the immunocompetent population. Despite advances in therapy, the prognosis of PCNSL remains poor, with 5-year overall survival (OS) rates at 30-50% (Ferreri 2011). The standard of care treatment regimen includes high-dose methotrexate (HD-MTX), often in combination with other multiagent CNS penetrating chemotherapies. Although the addition of rituximab in systemic aggressive B-cell NHLs has shown improvement in OS, the benefit of this agent in PCNSL has not been confirmed in a prospective dataset (Bromberg 2017). The majority of PCNSLs are classified as diffuse large B-cell lymphomas (DLBCL), and the outcomes based on treatment and cell of origin (germinal center B-cell (GCB) vs. non-GCB subtype) have yet to be fully elucidated. In this review, we report our findings from a series of PCNSL patients based on treatment regimen and cell of origin. Methods: This is a retrospective study of patients with PCNSL diagnosed and treated at the University of Colorado Hospital from 1995 to 2017. Chart abstraction included demographics, DLBCL subtype by Hans algorithm (Hans 2004), treatment details, and outcomes. OS was examined using Kaplan Meier methods, while bootstrap resampling and a z-test was used to compare median survival times across strata. Fisher's exact test was used to determine whether treatment responses were different between those that received treatment withHD-MTX and rituximab versus HD-MTX without rituximab. A significance level of 0.05 was used for all tests. When assessing differences by subtype, treatment type, relapse, and treatment response the data was subset to include only patients without a prior HIV diagnosis. Results: 71 patients with PCNSL were identified. 13 patients were HIV positive (the HIV status of 1 patient was unknown). Of the remaining 57 immunocompetent patients, 39 patients were treated with HD-MTX, of which 29 patients received rituximab in combination therapy. The most commonly received regimen was rituximab with methotrexate, procarbazine, and vincristine (R-MPV) (43.6%, 17 of 39). Median age in the HD-MTX subgroup was 65 years, with 83% of patients with KPS〉70 at diagnosis. EBV positivity was noted in only 4 of 39 samples (10.2%), while 25 of 39 (64.1%) tested negative; the remaining patients' data was not available. Median OS was 29.9 months for all 71 patients (Figure 1). There was no significant difference in median OS between those with and without HIV (p=0.127). 22 of 29 (75.9%) patients in the HD-MTX with rituximab group achieved a complete response (CR) while no patients (0%; 0 of 10) in the HD-MTX without rituximab group achieved a CR. The number of patients with a CR was significantly higher for those that received HD-MTX with rituximab compared to those that received HD-MTX without rituximab (p

Description: Key Points Checkpoint blockade via anti–PD-1 mAbs was associated with a high overall response rate in relapsed Hodgkin lymphoma allo-HCT patients. Checkpoint blockade via anti–PD-1 mAbs after allo-HCT can be complicated by rapid onset of severe and treatment-refractory GVHD.

Description: Introduction Tenalisib (RP6530) is a next generation, oral, selective, PI3Kδ/g inhibitor with nanomolar inhibitory potency. Besides its apoptotic and anti-proliferative activity, Tenalisib modulates the tumor microenvironment resulting in reprogramming of tumor associated-macrophages (TAMs) from a protumor M2 phenotype to an antitumor M1 phenotype and a marked reduction of angiogenesis in pre-clinical models. Tenalisib has demonstrated activity in patients with relapsed/refractory lymphoid malignancies (Carmelo, ASH 2016 and Oki, ASCO 2018). Since there are concerns over long-term safety of PI3K δ or PI3K dual δ/g inhibitors with respect to immune-mediated toxicities (e.g. transaminitis, colitis and pneumonitis), cytopenias, and infections, a pooled safety analysis across two Phase I studies in patients treated with Tenalisib was performed. Methods Safety data was pooled from two Phase I Tenalisib monotherapy trials (NCT02017613 and NCT02567656) with similar key eligibility criteria. Patients had R/R lymphoid malignancies with ≥1 prior therapy. Responses were evaluated in lymphoid malignancies using IWG criteria (Cheson et al., 2007) and in CTCL using the modified Severity Weighted Assessment Tool (mSWAT). Adverse events were graded according to CTCAE v4.03. Results A total of 93 patients were included in the analysis. Among these patients, 34% were PTCL, 32% CTCL, 16% HL, 6% DLBCL and 12% were other lymphomas. Patients received a median of 5 prior therapies. 53 % of patients received Tenalisib for ≤ 3 months, 21% for 3-6 months and 26% for 〉 6 months. The overall incidence of related AEs and ≥G3 AEs were 58% and 29% respectively (Table 1). Very few AEs were seen with exposures 〉6 months and mainly included single cases of diarrhea, anemia, edema, and abdominal pain. There were no incidences of late onset toxicities such as colitis and pneumonitis and most of the AEs happened during the initial three months of therapy. No treatment discontinuations due to AE's were seen in patients exposed to 〉 6 months of treatment. Efficacy response assessments of the 66 evaluable patients demonstrated an ORR of 45% in TCL (44% in PTCL (8/18, 3 CR, 4 PR) & 45% in CTCL (9/20, 9 PR)), 29% (4/14; 1CR; 3PR) in HL, and 13% (1/6; 1CR) in DLBCL. Conclusion In this pooled safety analysis with long term follow-up, Tenalisib exhibited an improved safety profile when compared to other investigational/marketed PI3K inhibitors. The incidence of transaminitis was low and occurred within the first two to three cycles of therapy. In particular, there were no occurrences of pneumonitis or colitis in patients that had been on treatment for 〉 3 months and beyond. Incidence of neutropenia/thrombocytopenia and infections was limited. Tenalisib can therefore be safely combined with a diverse array of other agents active in lymphoid malignancies. Tenalisib is currently being studied in combination with Pembrolizumab and Romidepsin and as a monotherapy in a Phase II trial in indolent NHL. Disclosures Haverkos: Viracta Therapeutics: Membership on an entity's Board of Directors or advisory committees. Ramchandren:Pharmacyclics LLC an AbbVie Company: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy; Merck: Research Funding; Janssen: Consultancy, Research Funding. Devata:Affimed: Research Funding. Routhu:Rhizen Pharmaceuticals SA: Employment. Barde:Rhizen Pharmaceuticals SA: Employment. Nair:Rhizen Pharmaceuticals SA: Employment. Carlo-Stella:Boehringher Ingelheim Italia: Consultancy; Sanofi: Consultancy; MSD Italia: Speakers Bureau; Rhizen Pharmaceuticals: Research Funding; AstraZeneca: Speakers Bureau; ADC Therapeutics: Research Funding, Speakers Bureau; Janssen: Speakers Bureau; Genenta Science: Speakers Bureau; Bristol-Myers Squibb: Speakers Bureau; Amgen: Speakers Bureau.

Description: Diagnostic criteria for multiple myeloma include abnormal plasma cell infiltration of the bone marrow plus the presence of monoclonal immunoglobulin in the serum and/or monoclonal free light chains in the urine. However, recent studies have indicated that measurement of free light chains in the serum (sFLC) is more sensitive than urine assays. Also, because of the slow clearance of IgG from serum (half-life ~20 days compared with 2–6 hours for sFLC) intact immunoglobulin assays can be slow to reflect the full extent of response to treatment. The aim of this study was to compare the relative sensitivity and specificity of serum free light chain (sFLC) measurement, urine free light chain measurement (uFLC) and serum immunofixation (sIFE) with bone marrow analysis for assessment of myeloma. All 45 patients studied were enrolled in the UK MRC Myeloma VII trial and 75 serum samples were selected for sFLC measurement and sIFE. The sera had been collected at various times before, during and after treatment but all within 4 days of a bone marrow assessment and uFLC measurement (by radial immunodiffusion assay). sFLC results were classified as abnormal if the kappa/lambda ratio was outside the normal range and for uFLC, if there was 〉40mg/L. The bone marrow assessment was called abnormal if 5% or greater plasma cell infiltration was recorded in aspirate or trephine, in accordance with the EBMT criteria. The results of the comparisons are summarised in the table. Summary of paraprotein assays Bone Marrow Normal Abnormal Serum Free Light Chains Normal 19 4 Abnormal 5 47 Urine Free Light Chains Normal 21 21 Abnormal 3 30 Serum Immunofixation Normal 10 5 Abnormal 14 46 Of the three paraprotein assays, sFLC had the highest concordance with bone marrow biopsy. Compared with the bone marrow assessment, the relative sensitivity and specificity of the sFLC assays was 92% and 79% respectively. For uFLC the values were 59% and 88%, respectively and for sIFE, 90% and 42% respectively. Of the 5 sera abnormal by the sFLC assays but with concurrent normal bone marrow results, all were abnormal by sIFE. Of the 4 patients with normal sFLC results but abnormal marrows, 3 were sIFE positive and of the 5 with negative sIFE results but abnormal marrows, 4 had abnormal sFLC ratios. Only 1 patient had an abnormal marrow with normal sFLC and sIFE results. In this comparison sFLC measurement showed a good degree of correlation with bone marrow assessments of myeloma, while uFLC assays were considerably less sensitive. Both sFLC and sIFE assays appeared to identify disease in 5 patients who had normal bone marrow assessments. This was presumably because the serum assays sample monoclonal protein produced throughout the body while distribution of the disease in the bone marrow is occasionally “patchy”. The sIFE results were positive in a much higher number (14) of bone marrow-negative patients. The 9 “extra” positives, which had normal bone marrow results and free light chain ratios, might result from a greater sensitivity for detecting tumours producing intact immunoglobulin with low levels of free light chains. Some of the 9 subsequently became sIFE negative so the slow clearance of monoclonal intact immunoglobulin is an alternative explanation for the discordant results. This could not be proven, however, as all patients had some form of treatment in the intervening period.

Description: Culture of bone marrow and/or blood cells in a semisolid agar system from 43 adults with acute nonlymphoblastic leukemia at first presentation showed two distinct growth patterns at 14 days. In 53% of patients cells failed to grow (type O), while in the remainder an abnormal growth pattern (type B) with small numbers of diffuse colonies and excessive numbers of cell clusters was seen. The response following chemotherapy was significantly better in the patients whose cells failed to grow. Serial culture studies, performed in 9 patients throughout remissions of 100–1112 days, which had been maintained by intermittent chemotherapy, showed wide fluctuations in proliferative activity. These ranged from no growth to marked proliferation with predominance of clusters and small numbers of diffuse colonies, indistinguishable from the type B pattern seen in 47% of patients at first presentation. The possibility is discussed that the periods of failure to grow, and/or those in which a type B pattern emerged, represented sporadic reactivation of leukemic cells.

Description: BACKGROUND: Primary central nervous system post-transplant lymphoproliferative disorder (PCNS-PTLD) is a rare complication of solid organ transplant, with no standard therapy. Epstein-Barr virus (EBV) is ubiquitous making the virus a candidate therapeutic target. For virus targeted therapy to be effective, antiviral agents must be phosphorylated by lytic-phase kinases BXLF1 and BGLF4. We hypothesized that lytic kinases would be constitutively expressed in PCNS-PTLD and that antiviral therapy would prove an attractive therapeutic alternative to high dose methotrexate-based regimens in patients who often have impaired organ function and poor performance status. METHODS: We investigated the safety and efficacy of EBV-kinase targeted therapy with zidovudine (AZT), ganciclovir (GCV), rituximab, and dexamethasone in patients with PCNS-PTLD. Patients with biopsy-proven PCNS-PTLD following solid organ transplantation were eligible for treatment. Immune suppression was reduced in all patients prior to treatment. Induction therapy consisted of 14 days of AZT 1500 mg IV BID, GCV 5 mg/kg IV BID, dexamethasone 10 mg IV BID and rituximab 375 mg/m2 once weekly for four weeks. Maintenance antiviral therapy was initiated on day 15 with valganciclovir 450 mg and AZT 300 mg, both twice daily. Responses were evaluated by serial brain MRIs beginning 4 weeks after initiation of treatment. Brain biopsy specimens were evaluated for expression of BGLF4 and BXLF1 by in situ hybridization or immunohistochemistry. To test the hypothesis that expression of EBV kinases conferred sensitivity to antiviral therapy, 293T cells were transfected with cDNAs (or control vectors) encoding for full length BXLF1 and/or BGLF4. Transiently transfected cells were tested for expression by immunoblot and drug sensitivity to AZT/GCV was performed by MTS and flow cytometry assays. RESULTS: Twelve patients (7 M, 5 F) with a median age of 49 were treated from 1998-2014. Transplant history included kidney (N=11), pancreas (N=2), and liver (N=1). Histology data included diffuse large B-cell lymphoma (N=7) and grade III lymphomatoid granulomatosis (N=5). EBV positivity (EBER-ISH) and CD20 expression were documented in all cases. All patients completed induction therapy. Median follow-up time and median duration of maintenance therapy were 28 months (range 2 - 143). The mean progression free survival (PFS) was 33.8 months. Overall response rate (ORR) was 83.3%. Eight patients achieved a complete response (CR) within a median time of 2 months (range 0.75 – 6 months). Two patients had a partial response (PR) with an average time to response of 1.25 months. Two patients (2/12) had progressive disease (PD). Causes of death included septic shock (n=3), pulmonary embolism (n=1), and poor functional status requiring hospice (n=1). One patient had PD at the time of death. Median overall survival (OS) was 29 months (range 2 – 143 months). Grade 3-4 toxicity was primarily hematologic, including anemia (N=4), thrombocytopenia (N=2), and neutropenia (N=5). Toxicity in the maintenance phase was generally reversible with holding therapy. Three patients required discontinuation of AZT during maintenance treatment for transfusion-dependent anemia persisting after holding AZT for 7 days or neutropenia coinciding with systemic infection. One patient had AZT discontinued due to nausea and vomiting that led to acute kidney injury. Evaluation of BXLF1, BGLF4 and LMP1 was completed in 7 patients and found to be positive in all cases. LMP1 and kinase expression occurred in mutually exclusive regions of the tumor. Expression of BXLF1 and BGLF4 led to enhanced sensitization of 293T cells to antiviral-induced growth inhibition and apoptosis. CONCLUSIONS: EBV-kinase targeted therapy with AZT, GCV, rituximab and dexamethasone appears to be effective treatment for patients with EBV+ PCNS-PTLD. We demonstrated durable responses without disease recurrence and minimal toxicity. Expression of BXLF1 and BGLF4 kinases provides a mechanistic rationale for an antiviral approach to this disease and an attractive option to replace high dose chemotherapeutic regimens with less toxic targeted therapy in patients with compromised transplant organ function. A multi-center phase II trial is in development to further investigate this regimen in patients with immune deficiency-related CNS EBV-LPD. Figure 1 Figure 1. Disclosures Porcu: Infinity: Research Funding; Seattle genetics: Research Funding; Actelion: Honoraria; Celgene: Honoraria; United States Cutaneous Lymphoma Consortium: Membership on an entity's Board of Directors or advisory committees; Cutaneous Lymphoma Foundation: Membership on an entity's Board of Directors or advisory committees.

Description: INTRODUCTION: Acute graft-versus-host disease (aGVHD) remains a significant cause of morbidity and mortality following allogeneic stem cell transplantation (allo-SCT). CD74, also known as the HLA class II invariant chain, is expressed on the surface of antigen presenting cells (APCs) and involved in pro-survival signaling. Milatuzumab is a humanized IgG1K monoclonal antibody that interacts with CD74 leading to rapid internalization and cytotoxicity independent of antibody crosslinking. Milatuzumab, therefore, has potential to inhibit APC-mediated T-cell proliferation and decrease the risk of aGVHD. In a xenogeneic SCID mouse model, milatuzumab administered prior to SCT prevented the development of GVHD, suppressed circulating cytokines, and reduced the mortality of the SCID mice (Chen, BBMT, 2013). METHODS: We are performing an open-label, single-center phase 1 dose escalation trial to determine the maximum tolerated dose of milatuzumab when added to standard GVHD prophylaxis in the setting of reduced-intensity conditioning (RIC) for HLA matched (≥8/8) sibling or unrelated donor SCT. Patients are premedicated with dexamethasone and receive milatuzumab intravenously on Days -7, -4, -1, and +7. The initial starting dose was 8 mg/kg with continued dose escalation to 16 mg/kg and 20 mg/kg in cohorts of 3-6 until unacceptable toxicity. Dose limiting toxicities are defined as graft failure, any ≥ grade 4 organ toxicities, or ≥ grade 4 infusion reactions attributable to milatuzumab (CTCAE v4.0). Expected hematologic toxicities from SCT were excluded from this definition. Acute and chronic GVHD was recorded according to Consensus and NIH criteria, respectively. RESULTS: Seven patients have been treated on trial with median follow up of 53 days post SCT (average 105 days; range 13-234). The median age is 59 years (range 26-70). Patients had a variety of hematologic malignancies (3 AML, 1 MDS, 1 ALL, 1 HD, & 1 MCL). Median Sorror comorbidity score (CMI) was 1 (range 0-8). Patients were in complete remission prior to SCT except for one MCL patient with partial response to prior therapy. Recipients received RIC with fludarabine (30 mg/m2 days -7 to -3) and busulfan (0.8 mg/kg Q6 hours days -4 & -3 x8 doses) along with standard GVHD prophylaxis including tacrolimus and methotrexate (D+ 1, 3, 6, & 11). Donors were 8/8 HLA-matched siblings (UPNs 2, 4, & 7) or matched unrelated (UPNs 1, 3, 5, & 6). All patients received four doses of milatuzumab. Three individuals were initially treated with 8 mg/kg (DL1) and 3 received 16 mg/kg (DL2). At DL2, two of 3 patients had grade 5 sepsis with one having grade 4 respiratory failure. As a result, three more patients will be enrolled to DL1 to further assess safety; one has been treated thus far. The most common toxicities attributable to milatuzumab were grade 1-2 including GI complaints, nasal congestion, fever, parathesia, and urticaria. One patient had grade 1-2 infusion reactions on two occasions. Four of 7 patients had cutaneous aGVHD with 2 of 4 experiencing grade 1, one with grade 2, and one with grade 4 (table 1). One patient experienced grade 1 GI aGVHD. The grade 4 aGVHD (UPN 6) was histologically and phenotypically indistinguishable from toxic epidermal necrolysis/Stevens-Johnson syndrome and that patient was treated with brentuximab for steroid-refractory cutaneous GVHD. He subsequently died due to polymicrobial sepsis. Two other patients died, one from relapsed AML (UPN 4) and one from staphylococcal aureus sepsis (UPN 5). CONCLUSIONS: While the grade 5 events in DL2 (16 mg/kg) were not considered specifically attributable to milatuzumab, DL1 has been expanded to further evaluate safety of this dose. Four patients have been enrolled at DL1 with only grade 1 and 2 aGVHD reported, either cutaneous or upper GI. We will continue to accrue at DL1 and pending tolerability may amend the protocol to test an intermediate dose of 12 mg/kg. Milatuzumab remains an intriguing potential agent to prevent aGVHD. Abstract 1168. Table 1: Matched RIC allo-SCT recipients treated prophylactically with milatuzumab for prevention of aGVHD UPN Age Disease CMI Dose Level aGVHD Follow up 1 59 AML 4 1 D+20 (grade 2/stage 3 cutaneous) Alive D+234 2 70 AML 0 1 D+22 (grade 1/stage 2 GI & cutaneous) Alive D+181 3 26 HD 1 1 D+35 (grade 1/stage 1 cutaneous) Alive D+186 4 51 AML 1 2 none Relapse D+26 (Death D+53) 5 66 MDS 8 2 none Death D+13 6 57 ALL 0 2 D+16 (grade 1/stage 2); D+34 (grade 4/stage 4) cutaneous Death D+48 7 59 NHL (MCL) 0 1 none Alive D+22 Disclosures Goldenberg: immunomedics: Employment. Wegener:immunomedics: Employment.