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Introduction Genomic minimal residual disease (MRD) detected in complete remission using droplet digital PCR (ddPCR) is associated with inferior survival in AML patients when measured after induction chemotherapy and before and after allogeneic HSCT. However, the utility of high sensitivity genomic MRD detection in the context of allogeneic HSCT for patients with myelodysplastic syndrome (MDS) is unclear. Here we present data evaluating the association of genomic MRD with survival in HSCT recipients with MDS. Methods Peripheral blood mononuclear cells (PBMC) from 72 MDS patients sampled prior to HSCT were enriched for CD34+ cells and CD3+ cells using MACS columns. Genomic DNA extracted from CD34+ fractions underwent targeted next generation sequencing of 49 genes recurrently mutated in MDS. Variants were confirmed in the CD34+ fraction and germline polymorphisms excluded in the CD3+ fraction using Sanger resequencing. To date, mutations identified in 43 cases have been quantified with ddPCR in unfractionated PBMC genomic DNA prior to conditioning and at day 30 post-transplant with a sensitivity as low as 0.002%. Results A median of 2 mutations per case (range 1-4) was identified with NGS and subsequently measured with ddPCR. Prior to HSCT, 70% of cases had mutations with a variant allele frequency (VAF) ≥10% and had inferior OS compared to those with <10% VAF (HR 2.7 [1.2-5.7], p=0.04). At Day 30 after HSCT, 65% of patients still had detectable mutations in circulating PBMC (≥0.002% VAF) (MRDpos) and had inferior DFS (median 347d vs not reached; HR 3.6 [1.6-8.1], p<0.01) and OS (median 560d vs not reached; HR 4.0 [1.7-9.2], p<0.01) compared to patients with undetectable mutations (MRDneg). TP53 mutations remained detectable in all cases (8 of 8) along with most DNMT3A (4 of 7), RUNX1 (3 of 4), ASXL1 (3 of 5) and spliceosome gene mutations (5 of 8). The 1-year relapse rate was 35% in the MRDpos group and 5% in the MRDneg group (p=0.02). Non-relapse mortality in the MRDpos and MRDneg groups was 44% and 31%, respectively (p=0.99). In bivariate analyses, DFS and OS remained significantly inferior in MRDpos patients versus MRDneg patients when controlled for age, cytogenetics, IPSS-R at diagnosis or pre-HSCT, or presence of adverse gene mutations. In addition, MRDpos patients with mutations detected at <0.1% VAF (58% of MRDpos cases; median 0.009%, range 0.002-0.082% VAF) had equally inferior DFS and OS as MRDpos patients with mutations detected at ≥0.1% (42% of MRDpos cases; median 0.48%, range 0.12-16.1% VAF). Conclusion Ultrasensitive genomic MRD detection in PBMC of MDS patients 30 days after HSCT is feasible and is associated with increased relapse risk and inferior DFS and OS. The gene mutations of most MRDpos patients were detected at <0.1% VAF, suggesting ultrasensitive genomic MRD detection in peripheral blood identifies patients with very low level MRD at high risk for relapse and death post-HSCT. [ABSTRACT FROM AUTHOR]

INTRODUCTION The composite endpoint of GVHD-free, relapse-free survival (GRFS), defined as survival free from grade 3–4 acute GVHD (aGVHD), chronic GVHD (cGVHD) requiring systemic immunosuppressive therapy (IST), or relapse has emerged as an outcome to capture clinically meaningful events. In the present study, we validated GRFS as a useful surrogate endpoint by examining the relative importance of individual events and the GRFS composite itself on overall survival (OS) at 5-years after allogeneic HCT. METHODS We conducted an IRB-approved retrospective cohort study on 565 consecutive patients (age ≥18 years) undergoing first-time allogeneic HCT for hematologic malignancy (January 2007–March 2013). Data abstraction of GRFS events was performed through chart review of the EHR. To determine the impact of each event of the GRFS composite endpoint, we accounted for competing risks using Fine and Gray methods, and correlated each event with OS using Kaplan-Meier methods. Using statistical simulations, the relative consequences of successfully modulating individual or composite endpoints on OS were examined to further elucidate the role of GRFS in clinical trials research. RESULTS The median age of the cohort was 54 years (18–73 years), comprised predominantly of males (58%) and Caucasians (94%). The most common indication for transplant was AML (41%), followed by lymphoma (21%) and MDS/MPD (14%). Patients received HLA-matched related (47%), and matched unrelated (53%) donors, and mostly peripheral blood stem cells (90%) and myeloablative conditioning (68%). Relapse conferred the greatest risk for death (HR 7.89; 95% CI:5.83–10.69). Grade 3–4 aGVHD was associated with HR 6.16 (95%CI:4.42–8.56), while cGVHD requiring IST was associated with lower HR 1.69 (95%CI:1.16–2.46). Indeed, the GRFS composite correlated with less HR 4.81 (95% CI:3.61–6.41) compared with either relapse or grade 3–4 aGVHD events. To determine the impact of hypothetical improvements on individual events or combined events (composite) on OS, we next performed Monte Carlo simulations. Compared with individual events, modulating composite endpoints predicted the greatest change in 5-year OS (Figure 1). The greatest gain in OS was seen by proportionally reducing both grade 3–4 aGVHD and relapse (modified GRFS). Reducing chronic GVHD requiring IST proportionally with grade 3–4 aGVHD and relapse events (conventional GRFS) did not change 5-year OS. CONCLUSION These findings highlight the importance of influencing OS by targeting the major early adverse post-HCT events (i.e., grade 3–4 acute GVHD and relapse). Moreover, the simulations herein suggest that GRFS as currently defined may be less optimal for predicting OS than using early grade 3–4 aGVHD and relapse as composite endpoints. Importantly, further refinement of these endpoints will depend on the a priori defined study population as well as intervention. [ABSTRACT FROM AUTHOR]

BACKGROUND A recent U.S. Food and Drug Administration (FDA) safety communication (Aug 2018) warned prescribers of the risk of relapse in patients receiving azithromycin as prophylaxis for bronchiolitis obliterans syndrome (BOS) following hematopoietic cell transplant (HCT). However, the FDA warning was based upon a single multicenter trial, in which patients were randomized to receive azithromycin for 2 years, starting at the time of conditioning. We now examine relapse rates in a cohort of patients treated with azithromycin for management of moderate-severe CGVHD. PATIENT POPULATION A retrospective review of our HCT database (2010-2017) identified 239 patients (median age 55 years, range 4-72) with moderate-severe CGVHD following an allogeneic HCT for a primary hematologic malignancy. NIH consensus criteria (2015) were used for CGVHD grading. Patients were divided into 2 cohorts, a) those receiving an extended course of azithromycin (≥ 14 days) for CGVHD management (cohort 1, n=86) and b) those who did not (cohort 2, n=153). Patients in cohort 2 either did not receive any azithromycin (n=122) or had received an abbreviated (<14 day) course (n=31) of azithromycin post-HCT. For cohort 1, the median time to initiation of azithromycin therapy was 15 months post-HCT (range 3-68), with a 26 month median duration of azithromycin therapy (range 1-77). All patients in cohort 1 met NIH consensus criteria for BOS. Patients in cohort 2 did not exhibit BOS, but still met NIH criteria for moderate-severe CGVHD. Hematologic conditions included acute leukemia (n=139), MDS/MPD (n=44), malignant lymphomas (n=26), chronic leukemia (n=24), and multiple myeloma (n=6). Ninety-one patients exhibited moderate and 148 patients exhibited severe CGVHD. The two cohorts were balanced for CGVHD severity, with severe CGVHD noted in 69% and 63% of patients in cohorts 1 and 2 respectively. RESULTS Decreased rates of relapse and improved survival were noted for patients treated with azithromycin for CGVHD. At 2 years, the cumulative incidence of relapse was 2% (95% CI:1-9%) for patients in cohort 1 vs 16% (95% CI: 11-23%) in cohort 2, p=0.001. Overall survival (2-year OS) in cohort 1 was 93% (95%CI: 88-99%) vs 78% (95% CI:72-85%) for cohort 2, p=0.003. Overall, 7 of 86 (8.1%) CGVHD patients treated with an extended course of azithromycin (cohort 1) have relapsed, the median time to relapse 876 days (range 379-1303) post-HCT. In comparison, 28 of 153 (18.3%) in cohort 2 have relapsed, a median 371 days (range 98-1252) post-HCT. CONCLUSION The use of azithromycin for the management of moderate to severe CGVHD was not associated with an increased risk of relapse in patients undergoing HCT for a hematologic malignancy. Azithromycin therapy for patients with CGVHD should not be contra-indicated in this patient population. [ABSTRACT FROM AUTHOR]

Introduction Relapse remains a significant challenge towards improving survival after allogeneic hematopoietic transplantation (HCT) for Acute Myeloid Leukemia (AML) not in remission or possessing poor cytogenetic/molecular features. Insights from murine pre-clinical studies demonstrate a central role for CD8+ dendritic cells in cross-presentation of leukemia associated antigens (LAA) in mediating GVL without aggravating acute Graft-versus-Host Disease (aGVHD)(Toubai, Blood 2013). We posited that enhancing LAA cross-presentation with exogenous Type I Interferon (pegIFNα) would promote GVL response and reduce rates of relapse after HCT. Methods We initiated a prospective, phase I/II, clinical trial of pegIFNα administration after myeloablative conditioning for prevention of relapse in pts with detectable AML at time of HCT (resistant to induction) or with cytogenetic/molecular features conferring high relapse risk and poor survival. Pts received up to four doses of 90mcg or 180mcg pegIFNα SubQ on d -1 and d 14, 28, 42 after PBSC or BMT. aGVHD prophy was tacrolimus + MTX or MMF. The primary endpoint was to determine the incidence of relapse in pts receiving the phase II dosage of pegIFNα. We hypothesized that 30 pts assigned to the same dose would provide 80% power to detect a difference between a promising day 180 relapse rate of 40% versus a rate of 60%. Results A total of 30 pts received study treatment at a median age of 60 years (17-72). Conditioning was myeloablative FluBu (n=9), CloBu (n=20) or FluCyTBI (n=1). At time of HCT, AML was detected in 28 pts and 2 pts enrolled for poor cytogenetic/molecular risk, complex/monosomal karyotype (n=1) and FLT3-ITD+ (n=1). There was no DLT at 90mcg (n=3) and one DLT (graft failure) after escalation to 180mcg (n=27). pegIFNα was well tolerated with ≥3 doses administered to 87% of pts. ≥Grade 3 SAEs during treatment include acute kidney injury(n=1), engraftment failure(n=1), bone pain/weakness(n=1), hypotension(n=1) and hypoxemia (n=1). 29 pts (97%) experienced primary engraftment and bone marrow exam at d 30 revealed CR in 100% of pts. Thirteen pts (43%) experienced infection. Grade II-IV aGVHD and grade III-IV aGVHD occurred in 35% (20 – 56%) and 11% (4 – 30%) by day 180. The incidence of TRM was 11% (3-30%) at day 180 and 19% (8-41%) at 1-yr. The day 180 (and 1-yr) incidence of relapse was 39% (24 – 60%) in the overall cohort and 36% (20 – 58%) in 27 pts treated at the phase II dose. At a median follow up of 19 months, the 1-yr OS was 42% (27 – 65%). Conclusion These data provide initial evidence of clinical translation for pegIFNα when administered prophylactically in an AML cohort at high risk for relapse. Type I Interferon did not significantly alter toxicity or aGVHD risk and produced relatively low rates of relapse suggesting a robust GVL response. The role of type 1 IFN in reducing clinical relapse and its underlying biological mechanisms warrants additional study. [ABSTRACT FROM AUTHOR]