ALBERT

Description: Background Multiple myeloma (MM) remains incurable despite treatment advances. While passive immunotherapy such as anti-CD38 antibodies is highly effective, active immunotherapy may provide long-lasting remissions by virtue of triggering memory. A phase 1 nivolumab study, an antibody targeting programmed death-1 (PD1), was unable to yield any responses in multiply relapsed MM patients. Conversely, preliminary trial data of lenalidomide combined with pembrolizumab, a different anti-PD1 antibody, found significantly higher response rates. These two differing outcomes reflect our limited understanding of checkpoint inhibition and immunotherapy in MM. There is a paucity of preclinical models to guide therapeutic studies. Cell lines and xenografted murine models are incapable of exploring active immunotherapy due to a lack of microenvironment and endogenous immune cell signals. Furthermore, malignant cells responsive to drugs in 2-dimensional (2D) cultures are known to display a more resistance in 3D. We have previously demonstrated that B-cell malignancies can be accurately studied using a 3D culture system of patient bone marrow mononuclear cells (BMCs) and can better inform translational trials. Herein we describe an ex vivo, 3D tissue culture model of patient-derived MM samples to more accurately test therapeutics including checkpoint inhibition using ipilimumab, a monoclonal antibody targeting cytotoxic T-lymphocyte antigen 4 (CTLA) which is crucial in co-stimulatory signaling of effector T-cells. Methods A 3D extracellular matrix was created using matrigel in 12-well plates. BMCs were isolated from marrow aspirates of 5 MM patients at time of diagnosis and individually cultured. Each patient sample was tested for sensitivity against increasing concentrations of ipilimumab (1X, 3X, and 10X clinical doses) added into supportive medium. Plates were monitored visually by microscopy followed by harvest on day 21 using enzymatic degradation. Unique clonotypic heavy chain immunoglobulin rearrangement (IgH VDJ) from each sample was sequenced, validated and used for semi-quantitative PCR. Semi-QT PCR with clone-specific primers estimated malignant cell survival after harvest. Flow cytometry was used to define cell populations present in culture and to correlate with clonotypic PCR data. T-cell mediated activity was examined by reverse transcription of trizol-extracted, T-cell RNA after harvest. Results All samples were successfully cultured, followed for 21 days and harvested. Flow cytometry confirmed presence of T-cell subsets, B-cells, NK cells and dendritic cells before and after culture in 3D. Minimal depletion of clonotypic cells was observed at 3x clinical levels of drug. At 10x simulated clinical therapeutic levels, 3 MM samples demonstrated 〉90% death of clonotypic MM cells while the other 2 demonstrated 62% and 72% death, respectively, compared to untreated control cultures. The extent to which the drug diffuses into the matrigel is as yet unknown. Flow cytometry of harvested cells suggest that T-cells demonstrate a modest shift toward CD4 and CD8 effector cells. Preliminary mechanistic data from one MM sample using trizol-extracted RNA and reverse transcriptase PCR harvested at 21 days from 3D culture suggests that anti-malignant, cytotoxic T-cell effect may be driven by granzyme B expression. Expanded data from the remaining samples will be presented. Conclusions We demonstrate that an ex vivo 3D tissue culture model of MM is both feasible and informative in studying immunotherapy. By culturing unselected BMCs which include stromal cells, immune cells and malignant populations, the 3D culture more closely mimics the tumor microenvironment with both the patient's immune system present as well as stromal supportive signals. In this study, we show that in the presence of active immune effector cells, ipilimumab has activity against patient-derived MM cells. The data suggests the importance of targeted cytotoxic T-cell activation as a primary mechanism of action. We have previously studied standard MM therapeutics such as cytotoxic chemotherapy, immunomodulatory drugs, and proteasome inhibitors in the same way. Consequently, this model is well positioned to study other immunotherapies such as other checkpoint inhibitors, cellular therapy, and combinations. Further testing with therapeutics targeting PD1/PDL1, and adenosine receptors are underway. Disclosures Venner: Takeda: Honoraria; Celgene: Honoraria, Research Funding; J+J: Research Funding; Janssen: Honoraria; Amgen: Honoraria. Belch:Celgene: Honoraria; Janssen: Honoraria; Amgen: Honoraria; Takeda: Honoraria.

Description: BACKGROUND Outcomes in multiple myeloma have improved dramatically over the last decade however, optimal sequencing of therapy remains unknown. Specifically, in an era where post-transplant lenalidomide (L) maintenance is now as established standard of care, questions remain around the utility of full dose L-based regimens in second line therapy. In this series, we sought to evaluate the impact of different regimens used at first relapse in patients who received autologous stem cell transplant (ASCT) in the frontline setting treated with and without lenalidomide maintenance (LM). We focused on the impact of L-based therapies in patients relapsing on LM. METHODS Using our prospectively maintained institutional MM database we retrospectively analyzed patients treated at the Cross Cancer Institute from January, 2005 to January, 2016 to ensure 2 years of follow-up for surviving patients. 4 categories were identified based on 2 variables: receipt of LM following 1st line therapy (yes or no) and receipt of L-based 2nd line therapy (yes or no). The primary endpoint was 2nd PFS defined as time of initiation of second line therapy to relapse, death or last follow-up. OS was defined as time of initiation of first line induction therapy to death or last follow-up. Second OS was defined as time of initiation of second line therapy to death or last follow-up. Survival statistics were determined using the Kaplan-Meier method with SPSS software. A p - value of

Description: Specific tyrosine kinase inhibition (TKI) of the bcr-abl fusion protein in Philadelphia chromosome positive chronic myelogenous leukemia (CML) was introduced into general use in 2000 after a plenary abstract presentation to ASH in December 1999. Here we report the impact of the use of TKI on survival of all patients with CML in a total population based registry in the province of Alberta in Canada where BMT has been in use since 1980, α interferon +/− cytarabine since 1990 and TKI since 2000. All therapies have been fully funded by the public health care system in Alberta. Alberta’s population in 2000 was 2.97 million. Prior to 2000, allogeneic stem cell transplant (BMT) was the only curative therapy available but its application was limited to a minority of patients with CML. Alpha interferon induced a cytogenetic remission in some CML and alpha interferon plus cytarabine prolonged survival in CML. CML AML n 5 yr survival % BMT n 5 yr survival % BMT *59% of deaths occurred in the first year after diagnosis in the 2000–06 cohort 1980–89 303 40% NA 540 13% NA 1990–99 276 48% 25 692 15% 13 2000–06 216 83%* 8 680 25% 16 p

Description: Imatinib mesylate (IM) is the standard therapy for Philadelphia chromosome positive chronic myelogenous leukemia (CML). It is generally well tolerated with most non-hematologic toxicities being mild to moderate in severity. Muscle cramps and/or myalgia may occur in up to half of patients (pts) treated, particularly with doses of IM 〉 400 mg/day. Prompted by a case of rhabdomyolysis, we began to monitor creatine kinase (CK) levels in CML patients on IM in 2005. 71 patients with chronic phase CML (diagnosed between 1994 and 2007 and treated with IM between 2000 and 2007) had CK levels done every 3 months. Elevated CK occurred in 33/71 (47%) of patients (30% grade 1; 11% grade 2; 4% grade 3 and 2% grade 4); the majority (91%) (including those with ≥ grade 3 toxicity) were taking ≤ 400 mg/day of IM. Of these 33 patients, 21 had a normal baseline CK. The mean and median duration of IM exposure at the time of first documented CK elevation in these 21 patients was 82.5 weeks and 53 weeks respectively (range 4 – 300 weeks). 36% (12/33) of the patients with elevated CK levels reported associated symptoms (muscle cramps, muscle spasms and/or myalgia): the majority of the adverse events were ≤ grade 2 in severity, with some pts reporting more than 1 symptom. CK elevation was documented once in 8 patients, continuously in 9 patients and intermittently in 16 patients. 7 patients required dose modification; all subsequently had a reduction in CK levels to ≤ grade 1. Of the 38/71 who had normal CK levels, 24% (9/38) reported either grade 1 or 2 muscle cramps and/or myalgia: only 1 of these pts required dose reduction due to muscle related toxicity. Possible factors contributing to CK elevation included hypothyroidism (9 pts), vigorous physical activity (7 pts), antipsychotics (7 pts), cholesterol lowering agents (6 pts), alcohol use (2 pts), beta blockers and infection (1 pt each). Conclusions: hyperCKemia is common in patients on IM for CML (1);hyperCKemia is not correlated with myalgia or muscle cramps;many patients had multiple potential etiologies for increased serum CK;hyperCKemia responds to IM dose modification.

Description: Introduction: Cyclophosphamide, bortezomib and Dexamethasone (CyBorD) has become the standard frontline approach for the treatment of multiple myeloma (MM) in many centers across Canada. In the non-transplant eligible setting, recently a randomized controlled trial reported on the impact of Lenalidomide and Dexamethasone (LD), showing that this doublet-therapy is a feasible and efficacious combination. Based on the above-mentioned success of the LD combination, we aimed to compare the effect of CyBorD and LD for the treatment of non-transplant eligible MM (NTE) patients in the Alberta Myeloma and Dysproteinemia Program (AMDP). Patients and Methods: The primary objective was to assess ORR and PFS for NTE MM patients treated with CyBorD and LD. The recommended CyBorD regimen was as follows: bortezomib 1.3-1.5 mg/m2 SC or IV days 1, 8, 15 of a 28 day cycle (as of August, 2013 we adopted the a strategy whereby bortezomib can also be given on day 22), cyclophosphamide 300 mg/m2 PO days 1, 8, 15 and 22 and dexamethasone 20-40 mg PO days 1, 8, 15 and 22 with an aim to deliver a minimum of 9 cycles of treatment. LD was given at 25 mg days 1-21 of a 28-day cycle with Dexamethasone 20-40 mg PO days 1, 8, 15 and 22. Dose adjustments were at the discretion of the treating physician. Two-sided Fisher exact test was used to test for differences between categorical variables. A p value of

Description: Introduction: With the widespread adoption of novel agents (NA) in all lines of therapy patients are being exposed to both proteosome inhibitors (PIs) and immunomodulatory drugs (IMiDs) early in their treatment course. This has lead to marked improvements in survival in the frontline setting. Data is limited with respect to patient outcomes after exposure to both these drug classes in the real world setting. Here we present our experience examining outcomes after each line of therapy whereby bortezomib-based induction followed by lenalidomide-based therapy at first relapse has become the standard of care. We further explored the outcomes of patients who were exposed to both active classes of drugs within their first 2 lines of therapy. Patients and methods: This series includes patients seen through the provincial Alberta Myeloma and Dysproteinemia Program in Canada. Only patients treated between 2005-2013 were included to allow at least 2 years of follow-up beyond first line therapy. Only those treated with a NA-containing regimen as part of their first line treatment were examined. The cohort was split based on eligibility for autologous stem cell transplant (ASCT). Double exposed patients were those who had been treated with, but were not necessarily refractory to both an IMiD and PI within the first 2 lines of treatment. Outcomes were measured after first, second and third line therapy. Survival outcomes were measured in months (m). OS was measured from the start of each line of therapy until death or last follow-up. PFS was from the start of each line of therapy to relapse, death or last follow-up. Response was measured as per the most recent International Myeloma Working Group criteria. Near complete response (nCR) was used when the monoclonal protein disappeared on protein electrophoresis but was not confirmed by immunofixation. Results: Two hundred forty eight patients had received upfront therapy (non-ASCT = 113 and ASCT = 135). One hundred twenty seven had received second line therapy (non-ASCT = 62 and ASCT = 65). Sixty-four had received third line therapy (non-ASCT = 31 and ASCT = 33). The median OS and PFS after each line of therapy are shown in table 1. After first line therapy the OS (p 〈 0.001) and PFS (p〈 0.001) were significantly better in the ASCT cohort. There were no significant differences in survival outcomes based on transplant eligibility in subsequent lines of therapy (figure 1A and B). The overall response rate to third line therapy was 45% (VGPR = 14% and nCR = 7%) for non-ASCT patients and 52% (VGPR = 15% and nCR = 6%) for ASCT patients. Fifty-five percent of non-ASCT patients failed to respond during third line therapy (34% with progressive (PD) and 21% with stable disease (SD)). Forty-eight percent of ASCT patients failed to respond (PD = 27% and SD = 21%). Forty-seven patients were double exposed within the first 2 lines of therapy (non-ASCT = 26 and ASCT = 21). In this cohort, the OS and PFS after double exposure (i.e. third line therapy) was 15m and 5m respectively with no significant difference based transplant eligibility (figure 1C and D). The response rate to third line therapy was 46% (VGPR = 17% and nCR = 8%) for ASCT patients and 43% (VGPR = 14% and nCR = 5%) for non-ASCT patients. Fifty-five percent failed to respond (PD = 38% and SD = 17%) in the non-ASCT group. Fifty-seven percent failed to respond (PD = 38% and SD = 19%) in the ASCT group. Summary: The introduction of NAs earlier in the management of patients with myeloma has improved OS. This is driven by improvements in PFS to frontline therapy and after first relapse. However, with current therapeutic approaches patients will be exposed to both IMiDs and PIs much earlier in their disease. In many jurisdictions, the limited treatment options in third line and beyond, especially in double exposed patients, poses a significant therapeutic challenge. Durable responses are limited in this setting with most patients relapsing after only 6 months. In addition, approximately a third of patients have overtly progressive disease. Interestingly, front-line ASCT eligibility had no impact on outcome with subsequent relapses, emphasizing the fact that ASCT only improves the outcome for the line in which it is employed. Further study regarding resistant mechanism and clonal evolution after exposure to both IMiDs and PIs will be important in developing rationally designed therapeutic regimens for this population. Disclosures Venner: J&J: Honoraria, Research Funding; Amgen: Honoraria; Celgene: Honoraria, Research Funding. Off Label Use: Some patients in this series will have received frontline lenalidomide which is not yet an approved indication for this drug in Canada.. Bahlis:Johnson & Johnson: Speakers Bureau; Johnson & Johnson: Consultancy; Amgen: Consultancy; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Johnson & Johnson: Research Funding. Neri:Celgene: Research Funding. Sandhu:Amgen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Duggan:Jansen: Honoraria; Celgene: Honoraria. Belch:Janssen-Cilag: Consultancy. Jimenez-Zepeda:Celgene: Honoraria; J&J: Honoraria; Amgen: Honoraria.

Description: Introduction: Pomalidomide is an IMiD that was recently approved for the use of relapsed MM failing lenalidomide and bortezomib. In the present study, we aimed to evaluate the efficacy of pomalidomide-containing regimens (PCR) for heavily-pretreated relapsed or refractory MM (RRMM) at Tom Baker Cancer Center and the Cross Cancer Institute in Alberta. Methods: We retrospectively reviewed the records of all patients with RRMM treated with PCR at our Institutions between 01/10 and 04/15. Patients received oral pomalidomide 2-4mg/d on days 1-21/28, and dexamethasone 20 mg or 40 mg on a weekly schedule, few cases were treated with PD in addition to bortezomib or cyclophosphamide. Definitions of response and progression were used according to the EBMT modified criteria. A p-value was considered statistically significant if