ALBERT

Description: Graft rejection (GR) following an allo-SCT occurs in 10-20% of patients with β thalassemia major (TM). The reported clinical outcome following second transplants have been associated with a high incidence of graft rejection, treatment related mortality, and graft versus host disease [Haematologica 2009; 94(9)]. There is limited data on the clinical profile and long term outcome of patients who have had a graft rejection. We undertook a retrospective analysis of patients who had a graft failure post allogeneic SCT for TM at our center. From October, 1991 to June 2016, 506 HLA matched related transplants for TM were done at our center. Of these 55 (11%) patients had a graft failure. An additional 7 patients with graft failure following an allo-SCT done at other centers were referred to us for a second transplant. Of the 62 patients with graft failure 32 (52.4%) were primary graft failures (PGF; 15 with aplasia and 17 with autologous recovery) while 30 (47.6%) were secondary graft failures (SGF; 5 with aplasia and 25 with autologous recovery). The median age of the patients who had graft failure was 8 years (range:1-19) and there were 38 (60.3%) males. On conventional risk stratification 40 (63.5%) were Class III. Eighteen (54.5%) cases with PGF and 16 (53.3%) with SGF did not receive a second transplant. From Oct 2009, at our center, a reduced toxicity myeloablative (MAC) treosulfan based conditioning regimen with a PBSC graft was offered to all high risk patients and for second transplants at the treating physician's discretion. Twenty nine (46%) of the patients with GR underwent a second allo-SCT. With the exception of one patient (first allo-SCT with an unrelated cord blood product) the donor for the second transplant was the same as the first transplant. Conditioning regimen for second SCT was busulfan based MAC in 7 (24%), treosulfan based MAC in 12 (41.3%) and the remaining received non-myeloablative conditioning regimens (fludarabine based, low dose TBI, OKT3, Cy-OKT3) often in view of pancytopenia and perceived inability to tolerate a MAC. All patients receiving a treosulfan based regimen had a PBSC graft. A BM graft was used in 7 (41%) of the remaining cases. None of the patients conditioned with a treosulfan based regimen had a graft rejection though one patient died of Grade IV acute GVHD. Of the remaining 17 patients 10 died following a second GR, 3 died of regimen related toxicity. Four are alive of which one has recurrent TM and the rest are well and transfusion independent at 55, 80 and 204 months from second transplant (all busulfan based MAC). The baseline characteristics and clinical outcomes of patients who received a treosulfan based MAC regimen versus the rest is summarized in table 1 and figure 1. On a univariate analysis a non-treosulfan based conditioning regimen and time from GR to second transplant of

Description: Among transplant related complications, graft versus host disease (GvHD) significantly affects survival among patients undergoing allogeneic hematopoietic stem cell transplantation (aHSCT). There is limited data on GvHD and its impact on outcomes of aHSCT in patients with thalassemia major (TM). We have reviewed the incidence and outcome of GVHD among patients with TM who underwent aHSCT at our center. All patients with TM undergoing their first aHSCT between January 2007 and December 2017 were included in this analysis. Till 2009, all patients received conditioning with busulfan (16mg/kg over 4 days) with cyclophosphamide (200mg/kg over 4 days). From 2010, most patients received treosulfan (42 G/m2 over 3 days) with thiotepa (8mg/Kg for one day) and fludarabine (160mg/m2over 4 days) based conditioning regimen. All patients receiving busulfan conditioning received bone marrow (BM) as the graft while most patients receiving treosulfan conditioning received mobilized peripheral blood stem cells (PBSC). GvHD prophylaxis was with short-course methotrexate (10mg/m2 on day +1, and 7mg/m2 on days 3, 6 and 11) with cyclosporine. Thymoglobulin was added for matched unrelated donors (MUD). GvHD was prospectively recorded and graded according to the Glucksberg classification. Between January 2007 and December 2017, 363 first transplants were done for patients with TM with HLA identical donors. There were 12(3.3%) class 1, 105(28.9%) class 2 and 246(67.8%) class 3 (Pesaro risk stratification), with 115(46.7%) of the latter being high risk (Vellore risk stratification - BBMT, 2007; 13: 889). The median age was 8 years (range: 1-25) with a male predominance (60%). 331 (91.2%) patients had matched related donors (MRD) and 32 (8.8%) had MUDs. Donor gender was mismatched in 207 (57%) of which 129 (35.5%) were female to male transplants. The graft was obtained from the bone marrow in 137 (37.7%) of whom 53 (38.7%) were class III, and from mobilized peripheral blood in 226 (62.3%) of whom 193 (85.4% were class III. 149 (41%) patients developed GvHD - acute GvHD (aGvHD) in 115 (31.7%) and chronic GvHD (cGvHD) in 80 (22%). aGvHD was grade I in 32 patients (27.8%), grade II in 36patients (31.3%), grade III in 16 patients (13.9%) and grade IV in 25 patients (21.7%), while 6 patients (5.2%) had features of overlap GvHD only (oral lichen planus). First line treatment was with steroids in all patients with grade II and above aGvHD (n=83) with 43 (51.8%) of them responding adequately. There were 37 patients (44.5%) who required various second line agents for aGvHD with 20 (24%) receiving more than one immunosuppressive agent. 20 patients (24%) with persistent aGvHD went on to develop cGvHD. Out of the total of 80 patients with cGvHD, 13 (16.3%) had limited and 67 (83.7%) had extensive cGvHD. 26 patients (32.5%) developed de novo cGvHD, 8 (10%) of them after donor lymphocyte infusion (DLI) for potential rejection. The other 46 patients (57.5%) had chronic overlap GvHD following previous aGvHD. Among the different variables evaluated for association with aGvHD (patient/donor age, gender mismatch, MUD vs MRD), none were significant. Among those with MRD, aGVHd occurred in 36/135 patients (26.7%) of patients receiving BM grafts compared to 65/196 patients (33.2%) who received PBSC grafts (p=ns). cGvHD occurred in 23/106 patients (21.7%) in those receiving BM grafts vs 52/171 patients (30.4%) receiving PBSC (p=ns). 30 patients (8.3%) persisted to have cGvHD at last follow-up but only 20 (5.2%) required treatment. Mortality of the whole cohort was 66 (18.2%), out of which 32 (8.8%) were related to GvHD - 24 (6.6%) due to aGvHD and 8 (2.2%) due to cGvHD. At a median follow up of 41 months (range: 0-148), the 5-year and 10-year overall survival (OS) was 81.1±2.1% each for the whole cohort. The 5-year OS of those with grade 2-4 aGvHD was significantly lower than those with grade 0/1 aGvHD (65.7±5.3% vs 85.7±2.2%, p=0.000) [figure 1]. The 5 year OS of those with cGvHD was 88.9% ± 3.8% as compared to those without cGVHD was 96.9% ± 1.2% (P=0.009) [figure 2]. There was no significant difference in OS among those with limited and extensive cGvHD (90.9±3.6% vs 88.4±4.2% (p=ns). Our data shows that, as expected, severe aGvHD and extensive cGvHD significantly lowers survival in patients with TM undergoing aHSCT. However, PBSC graft did not result in higher acute or chronic GVHD compared to BM. Disclosures No relevant conflicts of interest to declare.

Description: An allogeneic stem cell transplant (SCT) remains the only curative option for patients with β thalassemia major (TM). Conventional pre-transplant risk stratification is limited by its subjective nature of definition of hepatomegaly, adequacy of chelation therapy and also the need for an invasive liver biopsy. We have previously reported on the significant limitations in applying this risk stratification in our population (developing country) where the majority will fall into the high risk Class III group and further there is significant heterogeneity within this Class III subset that is not recognized by the conventional risk stratification (BBMT 2007;13:889). The major determinant of pre-transplant risk in patients with TM is related to iron overload, in organs such as the liver and heart. T2* magnetic resonance imaging (T2*MRI) has been widely utilized as a non-invasive measure of iron overload in these organs and has been reported to predict organ dysfunction and to guide adequacy of therapy. There is however no data available on the role of T2*MRI in pre-transplant risk assessment of patients with TM. From Jan 2014 to June 2016, in 69 patients with TM undergoing an allo-SCT a pre-transplant a T2*MRI cardiac and hepatic value was generated using standard techniques and validated software. The median age of this cohort was 7 years (range: 2-20) and there were 43 (62.3%) males. Twenty four (34.8%) were Lucarelli Class I/II while 45 (65.2%) were Class III. Of the Class III patients 15 (33.3%) were Class III high risk (Class III-HR) as previously defined by us. All Class III patients received a treosulfan based reduced toxicity myelo-ablative conditioning regimen. In this cohort 5 (7.2%) had graft failure, 12 (17.4%) had acute GVHD, 10 (14.5%) had sinusoidal obstruction syndrome (SOS) and 5 (7.2%) patients died. The cause of death was related to GVHD in 4 and in one it was due to uncontrolled sepsis. The 3 year KM estimate of OS and TFS for this cohort was 91.4±4.0% and 84.7±4.9% respectively. The median T2*MRI cardiac and hepatic value was 17.3 msec (range: 0.06-65) and 3 msec (range: 0.44-27) respectively. The correlation coefficient between T2*MRI cardiac and liver values was 0.169; P-value=0.164 (Fig 1A). It was of biological interest to note that there were patients in whom there was preferential hepatic or cardiac iron overloading as seen in Figure 1A. There was a trend to correlation with age and T2*MRI cardiac values (Fig 1C) similarly there was a significant though weak correlation between T2*MRI cardiac values and conventional risk stratification (Fig 1B). There was no significant correlation between either T2*MRI cardiac or hepatic values on graft rejection, SOS, GVHD or death nor did either of this parameters stand out as significant on linear regression analysis. In conclusion, with currently used reduced toxicity regimens, in the absence of organ dysfunction there is limited prognostic values of T2*MRI cardiac and hepatic readings on immediate peri-transplant events. Its impact on long term follow up post-transplantation on organ function and its role in directing post-transplant chelation therapy remains to be analyzed. Further evaluation is also required to understand the genetic and environmental factors that favor iron over load in one over the other organ as clearly seen in a proportion of cases. Disclosures No relevant conflicts of interest to declare.

Description: The standard of care for patients with acute promyelocytic leukemia (APL) relapsing after frontline treatment with arsenic trioxide (ATO) based regimens remains to be defined. Available data on response and survival outcomes in patients who had received ATO as part of upfront therapy suggests that there is a high incidence of resistance to ATO and ATRA resulting in inferior response and survival (Zhu HH et al. N Engl J Med. 2014). We present our experience on management of relapse in APL patients treated with frontline ATO based therapy. Data on all consecutive patients with relapsed APL diagnosed and treated in the Depatment of Haematology, Christian Medical College, Vellore, from January, 1998-December, 2015 were included in this retrospective analysis. One hundred and four (29%) out of the total 358 APL patients diagnosed during the study period had relapsed. Out of these 73 (70%) patients received upfront ATO based therapy. Six out of 73 refused treatment and got discharged at request following the diagnosis of relapse, the remaining 67 (91.8%) were included in the analysis. Median age of patients was 28 years (range: 4-54), 44 (65.7%) were males. Median time to relapse from initial diagnosis was 19.6 months (range: 6 - 128). Relapses were isolated molecular in one, isolated CNS in 6 [9%], bone marrow + CNS in 13 [19.4%] and medullary only in 47 [70.1%] patients. All 67 patients received ATO based therapy (ATO ± ATRA +/- Anthracycline/Bortezomib) as re-induction. 63/67 (94%) achieved molecular remission post re-induction, while 3 (4.5%) died during re-induction and one discontinued treatment. An autologous SCT was offered to all patients who achieved molecular remission, however only a proportion of cases opted for SCT due to financial constraints. Those that did not opt for an autologous SCT were given ATO+ATRA maintenance therapy. 35/63 (55.6%) opted for autologous SCT while 28 (44.4%) continued on maintenance therapy alone. Median time to autologous SCT from relapse was 5.8 months (range: 2 - 32). There were no treatment related deaths following autologous SCT. At a median follow up of 46 months (range: 1-224), the 5 year estimate of OS and EFS (Fig 1) of the whole cohort (n=67) was 73.6% ± 5.7% and 67% ± 6.1%. The 5 year estimate of OS and EFS (Fig 2) of those who received autologous SCT vs those who were on chemotherapy were 90.3% ±5.3 vs 58.6±10.4 %, (P=0.004) and 87.1% ±6.0% vs. 47.7% ±10.3%, (P=0.001) respectively. In unadjusted analysis, those who received chemotherapy as post relapse consolidation had 5.73 (95%CI: 1.86 - 17.65) times risk of relapse as compared to those who received autologous SCT, which was statically significant (P=0.002). In the adjusted analysis (Table 1) those who received chemotherapy the risk of relapse was 7.6 (95%CI: 1.98 - 28.87) times compared to those who received autologous SCT, which was statically significant (P=0.003) after adjusting for age, total WBC at relapse and duration of CR1. Remission induction with ATO based regimens followed by an autologous SCT in patients with relapsed APL who were treated with frontline ATO based regimens is associated with excellent long term survival and should be considered the standard of care even in this setting. Disclosures No relevant conflicts of interest to declare.

Description: Only 25-30% of patients with Thalassemia major (TM) will have a suitable HLA-matched sibling donor for an allogeneic SCT. In the absence of a HLA-matched sibling, an extended donor search within the family may yield a suitable donor, especially in societies with a high prevalence of consanguinity. We have previously reported inferior outcomes in patients who had a transplant from a non-sibling family donor. One of the criticisms of this was the issue of low resolution typing, which may have adversely impacted outcomes in some patients. We interrogated this data further to assess whether the poorer outcomes held up to scrutiny with the availability of high resolution HLA typing. Towards this we undertook a retrospective case-control study, adjusting controls for age and Lucarelli risk group (common confounders for clinical outcomes post-transplant in TM) with a 4:1 ratio of controls to cases. All consecutive patients with TM who had a stem cell transplant between the time periods 2007-2017, were included in this retrospective analysis. A total of 371 transplants were done with 281 matched sibling donor, 58 related donors (32 fully matched and 26 with 1-2 antigen mismatch), and 32 MUD donors (24 fully matched (10/10) and 8 with 1-antigen mismatch (9/10)). Subsequent to 2012, high resolution typing was done for all non-sibling related family donors. Of the 58 related donors, high resolution typing was available in 45, with twenty four 10/10 donors, nineteen 9/10 donors and two 8/10 donors. Further analysis was done in this sub-group (excluding the 8/10 donors), with rejection and death being considered as events. A control group from the fully matched sibling donor cohort was generated randomly after adjusting for age and Lucarelli Class. All patients received a myeloablative conditioning regimen (Busulphan/Treosulfan based). In-vivo T-cell depletion was done in 11 (45.8%) of matched related transplants and 54 (56.2%) of matched sibling donor transplants (P=0.359). A PBSC graft was used in 16 (66.7%) of matched related donor transplants compared with 36 (27.5%) of matched sibling donor transplants (P=0.012). There was no difference in the median CD34 cell dose achieved in both groups (Table 1). Table 1 shows baseline characteristics, transplant details and outcomes in the 10/10 matched related donors and fully matched sibling donor groups. Table 2 shows univariate and multivariate analysis for risk factors adversely affecting Thalassemia-free survival (TFS) using Cox regression analysis. The 2-year TFS in the 10/10 matched related donor group, 9/10 matched related donor group and fully matched sibling donor group was 56.8%±10.5%, 56.1%±11.9% and 81.8%±4% respectively (P=0.011) (Figure 1A). The 2-year overall survival (OS) in the 10/10 matched related donor group and 9/10 matched related donor group and the fully matched sibling donor group was 75.4%±9.9%, 64.5%±12.1% and 85.0%±3.7% respectively (P=0.168) (Figure 1B). This data on allogeneic transplants confirms our previous observations that there is a higher risk of graft rejection when the donor is a non-sibling related donor, even if fully matched on high-resolution typing (OR 4.8 ; 95% CI=1.3-18.2 : P=0.02). Transplant physicians must be aware this increased risk and counsel families appropriately. Further modifications in conditioning regimens and GVHD prophylaxis could potentially help in improving these outcomes. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Description: Targeted intravenous (IV) Busulfan (TBu) in combination with cyclophosphamide (Cy) is widely used as a preparative regimen in children with thalassemia major undergoing matched allogeneic haematopoietic stem cell transplantation (HSCT) to reduce toxicity. At our centre, we have been using TBu/Cy regimen since 2011 for very young children (Pesaro class I/II risk status) and with matched related donors. We have compared the outcome of HSCT in this group of patients with a retrospective cohort (from 1995-2009) of age and risk status matched patients receiving fixed dose oral Bu without PK monitoring. All patients with beta thalassaemia major undergoing HSCT with matched related donor between January, 2011 - May, 2018, receiving IV Bu (0.8mg/kg Q6H days x 4 days) / Cy (50mg/kg x 4 days) with anti-thymocyte globulin based conditioning regimen were included in this study. Busulfan levels were monitored after the 1st dose of busulfan and further doses adjusted to achieve a target range of 900-1300um*min. The Bu plasma levels achieved on day 1 and on day 3 were compared with HSCT outcome endpoints including chimerism status on D28, overall and event-free survival (OS, EFS), and graft rejection. There were 52 children, median age of 3 years (range:1-6); 44 class I/II and 8 class III low risk. Different proprietary Bu products were used: 26 received Bucelon™ (Celon Labs, Hyderabad, India), 23 patients received Buslera™ (Biem Pharma, Ankara, Turkey), and 3 received Bufatas™ (Intas Pharma, Ahmedabad, India). The 3rd dose of Bu was increased in 35, decreased in 2 and unchanged in 15 patients. The median 1st dose Bu AUC was 625 um*min (range: 115- 2466) while the 9th dose AUC was 1105 um*min (range: 543-2656). Target Bu AUC was achieved in 40 patients (77%) as assessed by Bu AUC on Day 3 while the AUC in the remaining 12 patients (23%) was lower than 900 um*min (range: 543-872). Twenty-three of the 50 evaluable patients showed mixed chimerism (MC) or rejection on day 28 (46%; MC level 1 - 14; MC level 2 - 3; MC level 3 - 2 and 〉90 recipient chimerism - 4, as per our previous data- Fouzia et al, BMT, 2017). 11/23 (47%) had graft rejection; The OS and EFS were 96% and 79% respectively. Two patients died - 1 class III, of diffuse alveolar hemorrhage/ idiopathic pulmonary syndrome and the other of complications related to primary graft failure. Correlation of PK with all demographic variables by univariate analysis did not reveal any significant associations. However, while 11 out of 39 patients (28%) with 9th dose Bu AUC in the lower three quartiles rejected the graft (Q1: 1292 (1299-2656) um*min) rejected the graft (p=0.034). While none of the 13 patients in Q4 died, 7 had hepatotoxicity (grade 2 and above) and mucositis (grade 2 and above). The incidence of hepatotoxicity in the first three quartiles were as follows: Q1: 11 had grade 2-3 hepatotoxicity and 2 had grade 2-3 mucositis; in Q2: 5 had grade 2-3 hepatotoxicity while 7 had grade 2-3 mucositis; Q3: 3 had grade 4 hepatotoxicity while 4 had grade 2-3 mucositis (p=ns with respect to toxicity in Q4 vs. the other 3 quartiles). There was no significant association between the busulfan formulation used and the incidence of graft rejection. We then compared the HSCT outcome parameters in these patients with age and Pesaro class matched retrospective cohort of thalassemia patients (n=79) who had received a similar conditioning regimen but with oral Bu without PK guided dose adjustment. There was a significantly better OS (Fig A) in the TBu cohort compared to the oral Bu (p=0.03) but this did not translate to better EFS (Fig B) due to increased incidence of graft rejection (Figure C). In conclusion, our data suggests that targeting higher Bu AUCs within the therapeutic window could reduce the risk of graft rejection and improve OS without increasing toxicity. Strategies for rapid dose adjustments after the first dose PK are needed to better achieve these target values to reduce rejections and improve outcome. Figure. Figure. Disclosures No relevant conflicts of interest to declare.

Description: Allogeneic hematopoietic stem cell transplantation (Allo-SCT) with fludarabine based reduced intensity or toxicity reduced conditioning regimen with Busulfan or Melphalan (Flu/Bu; Flu/Mel) has improved HSCT outcome in patients with AML. Limited reports on the PK of Flu in patients with malignant hematological diseases undergoing Allo-SCT suggest that Flu AUC is associated with transplant related mortality (TRM) (Long-Boyle et al, 2011). We prospectively analyzed the PK and pharmacogenetics (PG) of Flu and Bu on Allo-SCT outcome in patients with AML receiving Flu/Bu or Flu/Mel based regimen. Forty-eight adult AML patients receiving Flu/Bu(targeted) (Flu 40mg/m2 /day intravenously from day-5 to -2 and intravenous Bu 130mg/m2 /day from day-5 to-2; n=27) or Flu/Mel (Flu 30mg/m2 /day intravenously from day -6 to -2 and Mel 140mg/m2 intravenously on day -1; n=21) regimen prior to Allo-SCT between January 2012 and 2015 were enrolled in this study. Peripheral blood was collected for PK analysis at serial time points and plasma was separated and analyzed the same day (for Bu TDM). Bu dose was adjusted based on the first dose PK to achieve target cumulative total AUC (22000mmoles*min). Flu plasma levels was analyzed using LC-MS/MS and the concentration was expressed as mmol/ml. Genetic polymorphisms that influence Flu and Bu PK (NT5E 5'-UTR variant rs2295890 and GSTA1*B polymorphism) were screened using pre- HSCT genomic DNA. The influence of Flu/Bu PK and PG on clinical outcome endpoints such as overall survival (OS) and event-free survival (EFS) was evaluated using cox regression analysis. The demographics of the patients is listed in the Table. There was a significant inter-individual variation in the flu clearance (1.2mL/h/m2(0.5-4.3); 8.6 fold) and AUC (46mmol*h/ml (24-101); 4.2 fold). Fludarabine AUC trended higher in Flu/Bu group when compared to Flu/Mel group (median AUC 52 vs. 43 mmol*h/ml respectively; p=0.08). Neither of the polymorphisms significantly explained the variation in Bu or Flu PK in this cohort and none of the PK parameters was associated with EFS/OS. However, patients carrying variant genotype of the NT5E 5'UTR polymorphism (rs2295890) showed significantly better OS (p=0.016) and EFS (p=0.007) (Figure) compared to those carrying wild type genotype. We have previously reported that this variant is associated with decreased Flu Clearance in patients with aplastic anemia and thalassemia receiving Flu based conditioning regimen (Mohanan et al, December 06, 2014; 124 (21): 3884; Mohanan et al, December 03, 2015; 126 (23): 3120). Although not significant, the Flu clearance was lower in the NT5E variants in this cohort as well. It can be extrapolated that patients carrying the variant genotype of the NT5E polymorphism, have decreased relapse incidence (Wild type-8; Variants-1) and hence better EFS and OS post HSCT, due to decreased clearance and increased systemic exposure to Flu. This finding need to be validated in a larger number and in patients with other disease conditions undergoing HSCT with Flu based regimen, in order to achieve the goal of personalizing conditioning regimen. Table Table. Disclosures No relevant conflicts of interest to declare.

Description: Recent evidences suggests that the efficacy of Lenalidomide (LEN) depends upon its ability to degrade IKZF1 and IKZF3 proteins via cereblon dependent ubiquitin proteasome pathway [Science. 2014 Jan 17; 343(6168): 301-305]. Based on this model it would theoretically be antagonistic to combine LEN with proteasome inhibitors (PI). However, it is well recognized that there is significant synergism when LEN is combined with PI and this combination is routinely and effectively used in the clinic. The mechanism of synergy and the fate of IKZF1 and IKZF3 when these two agents are combined is poorly understood. We undertook a series of experiments to study the fate of IKZF1 when this combination of drugs was used in multiple myeloma cells. Combining LEN (1uM) along with bortezomib (BTZ; 1nM) a PI showed a significant kill on U266 cells (myeloma cell line) on day 5 post treatment (n=3; P=0.02) when compared to either of the agents alone. In an MTT assay, the synergism was well documented with a combination index of 0.5 (Fig 1a). Next we assessed the function of proteasome (chymotrypsin activity) when LEN was combined with PI. We observed that LEN alone does not interfere with proteasome activity. It was noted that BTZ alone at the concentration used (5 nM) was able to effectively inhibit the activity of proteasome (Fig 1b). It was also observed that combining these two agents does not interfere with BTZ action in inhibiting proteasome complex (Fig 1b). As a result of efficient proteasome inhibition, we observed an accumulation of ubiquitinated proteins in the BTZ and LEN + BTZ treated cells when compared to control and LEN alone treated cells (Fig 1c). Next, we looked for the fate of IKZF1 in U266 cells treated with LEN, BTZ and in combination of both the drugs. As reported, we observed a degradation of IKZF1 in U266 cells upon treatment with LEN. While we did not see any degradation of IKZF1 in BTZ alone treated cells. It was noted that in combination treated cells (LEN+BTZ) there was a degradation of IKZF1 (Fig 1c). In spite of significant proteasome complex inhibition, degradation of IKZF1 was observed which suggested a proteasome independent mechanism. It is well known that proteasome inhibition results in upregulation of the autophagy pathway which in turn can degrade the accumulated ubiquitinated proteins. We noted that upon treatment with BTZ or LEN+BTZ an induction of autophagy was observed, as evidenced by an increase in generation of LC3II bands on an immunoblot (Fig 1c). To support our hypothesis that IKZF1 is degraded by autophagy in the absence of proteasome complex, we pre-treated the U266 cells with an autophagy inhibitor (3-methyladenine) followed by treatment with LEN and BTZ and noted an accumulation of IKZF1 proteins (Fig 1d). We also observed a downregulation of IKZF1 target genes IRF4 and c-MYC by 12 and 24 hours in the combination treated cells (data not shown). Taken together this data demonstrates that there is (i) significant in-vitro synergism between the two agents (ii) the combination additively induces autophagy pathway (iii) IKZF1 protein can be degraded via this autophagy pathway in the presence of effective proteasome inhibition. While additional mechanisms of synergy between these two agents cannot be excluded, further enhancing autophagy pathway in these cells by drugs like sirolimus (autophagy inducer in myeloma cells) could potentially improve the synergy between these two drugs. Disclosures No relevant conflicts of interest to declare.

Description: Introduction: The use of fecal surveillance cultures in predicting bacteremia in patients undergoing intensive chemotherapy and stem cell transplant is an unsettled issue (Neshar et al. Transpl. Infect Dis. 2015). With the increasing incidence of multi-drug resistant (MDR) organisms and high mortality rates with these infections, we sought to describe the spectrum of MDR identified in fecal surveillance, and re-visit the use of fecal surveillance in predicting infection with MDR organisms post-allogeneic stem cell transplant (allo-SCT). Methods: We analyzed data from all patients who underwent allogeneic stem cell transplant during a 2 year period (2014-2015). Patients with MDR strains of bacteria (defined in this study as defined as Vancomycin resistant enterococcus (VRE), Extended spectrum Beta-Lactamases (ESBL) and Carbapenem resistant enterobacteriacea (CRE)) in fecal surveillance were compared with patients who did not have MDR in fecal surveillance cultures. Baseline characteristics and post allo-SCT outcomes including MDR blood culture positivity, severe sepsis and 100-day transplant related mortality (TRM) were compared. Multivariate analysis using logistic regression model was used to determine independent predictors of outcome. Results: A total of 313 allogeneic stem cell transplants were performed in 299 patients, of which data on pre-transplant fecal surveillance cultures were available in 232 transplants. The incidence of MDR isolates in fecal surveillance cultures was 56% (134/232, with E.Coli 118, Klebsiella 33 and Enterococcus 13). Of these, 129 were ESBL alone (78.6%), 17 were CRE alone (10.3%), 10 were ESBL + CRE (6%), 6 (3.6%) were VRE alone. More than one drug resistant organism was isolated in fecal surveillance in 31 patients. The incidence of any MDR positivity in post-transplant blood cultures in all patients was 13.8% (32/232), with 9.4% CRE, 2.6% ESBL, and 1.7% VRE. Thirty-one patients had severe sepsis without any MDR organism isolated on blood culture, but of these 3 had CRE in sputum, 2 had Colistin resistant Acetinobacter (sputum), 2 had candidemia, 3 had NF-GNB and one had Enterococcus. Baseline characteristics between patients who were positive and negative for MDR in fecal surveillance were similar in relation in relation to age (p=0.058), diagnosis (0.133), type of transplant - matched family/MUD/Haplo (p=0.610), stem cell source (0.370), grade 3-4 GVHD (0.834). There was a significantly higher subsequent blood MDR positivity (any MDR) (p=0.012), 100-day mortality (p=0.012) and poor outcome (severe sepsis or 100 day mortality) (p=0.006) in patients who had MDR detected in fecal surveillance cultures. However, of the 25 patients who had MDR isolated in both fecal surveillance culture as well as subsequent blood cultures, only 9 patients had the same organism and susceptibility pattern in both. Factors influencing 100-day mortality included patient's age (p=0.001), MDR positivity in blood (p=0.0001), MDR in fecal surveillance (p=0.01), use of an alternate (Haplo/MUD/family) donor (p=0.0001), GVHD grade 3-4 (p=0.000) and severe sepsis (p=0.000). On multivariate analysis, only patient's age (p=0.015), alternate donor (0.009), severe sepsis (p=0.000) and grade 3-4 GVHD (p=0.001) retained significance in predicting 100-day mortality. Conclusion: Multidrug resistant organisms are frequently seen on fecal surveillance in the pre-transplant setting. MDR in fecal surveillance is associated with a higher incidence of MDR positive blood cultures but not with the same organism, and on univariate analysis is associated with higher incidence of 100 day mortality. Newer strategies to reduce bacteremia and mortality in this group of high risk patients need to be considered. Disclosures No relevant conflicts of interest to declare.

Description: Introduction: Haploidentical transplants are increasingly being used in patients who need a transplant but do not have a matched sibling or unrelated donor. The easy availability of a family donor makes it very attractive but it is associated with its own specific complications. We present the outcomes of haplo-identical transplants from a single centre in India Patients and methods: We reviewed the outcomes of all patients who underwent Haplo-identical transplant at the Christian Medical College, Vellore, India between 2010 to 2017 using post transplant Cyclophosphamide (PTCY) as graft versus host disease (GVHD) prophylaxis. Data was collected from individual medical records and databases available in the department. The disease status of all patients was classified into early, intermediate and advanced disease based on a modification of the CIBMTR criteria for malignant disease. Early disease included patients transplanted in CR1 for malignant disease, patients with aplastic anemia (AA) with 20 transfusions and primary immunodeficiency syndromes (PID) who have had previous infection. Patients who were transplanted 〉CR2 or refractory disease, second transplants or presence of active infection were classified as Advanced disease. Results: Between 2010 and 2017, 149 patients underwent 158 haplo-identical transplants. This included 101 males and 48 females with a median age of 18.1 years (range: 0.9 - 58). Seventy patients (46.9%) were children (〈 15 years of age). Patients underwent transplants for both malignant (n = 85) and non-malignant (n = 73) indications. Disease status was classified as Early in 20, Intermediate in 84 and Advanced in 54. Conditioning included both myeloablative (n = 90) and non-myeloablative conditioning (n = 68) and graft source was predominantly peripheral blood stem cells (PBSC in 93%). Engraftment was seen in 90.9% while graft failure occurred in 8% and death prior to engraftment occurred in 2%. Acute GVHD was seen in 32% of evaluable patients. Infections were a major problem with bacteraemia seen in 41% (majority were gram negative) and viral infections in 68% (CMV and BK virus). The 1 year OS for the entire cohort is 44.1 + 4.1% while the 2 year OS is 39.2 + 2.1%. The 1 and 2 yr OS for early disease was 71.8 + 1.1 and 63.8 + 1.2% respectively compared to 50 + 5.8% and 48 + 5.9% for intermediate disease and 23.4 + 5.9% and 18.2 + 5.6% for advanced disease. Conclusions: Haplo-identical transplants are feasible and associated with moderate outcomes in a developing country like India. Infectious complications are the major challenge with haploSCT and early transplantation remains the key to improving outcomes. Figure 1 - 2 year overall survival of patients with the early, intermediate and advanced disease Disclosures No relevant conflicts of interest to declare.