PRT543, a protein arginine methyltransferase 5 inhibitor, in patients with advanced adenoid cystic carcinoma: An open-label, phase I dose-expansion study

OBJECTIVES

Currently, no systemic treatments are approved for patients with recurrent and/or metastatic (R/M) adenoid cystic carcinoma (ACC). PRT543, a protein arginine methyltransferase 5 inhibitor that downregulates NOTCH1 and MYB signalling in tumours, is a potential candidate for R/M ACC treatment. We report the safety, tolerability and preliminary efficacy of PRT543 in a dose-expansion cohort of patients with R/M ACC.

MATERIALS AND METHODS

This phase I multicentre, open-label, sequential-cohort, dose-escalation and dose-expansion study (NCT03886831) enrolled patients with advanced solid tumours and select haematologic malignancies. Dose-escalation study design and results were reported previously. In the dose expansion, patients with R/M ACC received recommended phase II doses of 35 or 45 mg PRT543 orally on days 1-5 of each week. Primary objectives were to establish the safety and tolerability of PRT543. Secondary objectives included efficacy.

RESULTS

Between February 2019 and May 2022, 56 patients with ACC were enrolled across 23 US sites and received either 35 mg (n = 28) or 45 mg (n = 28) of PRT543. Overall, 23% of patients experienced a grade 3 treatment-related adverse event, most commonly anaemia (16%) and thrombocytopaenia (9%). No grade 4/5 treatment-emergent adverse events were reported. Median progression-free survival was 5.9 months (95% CI: 3.8-8.3). The clinical benefit rate was 57% (95% CI: 43-70). Overall response rate (per Response Evaluation Criteria in Solid Tumours v1.1) was 2%, with 70% of patients having stable disease.

CONCLUSION

In this analysis, PRT543 was tolerable, and the observed efficacy was limited in patients with R/M ACC.

Allogeneic hematopoietic cell transplantation for blastic plasmacytoid dendritic cell neoplasm: a CIBMTR analysis

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy with a poor prognosis and considered incurable with conventional chemotherapy. Small observational studies reported allogeneic hematopoietic cell transplantation (allo-HCT) offers durable remissions in patients with BPDCN. We report an analysis of patients with BPDCN who received an allo-HCT, using data reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). We identified 164 patients with BPDCN from 78 centers who underwent allo-HCT between 2007 and 2018. The 5-year overall survival (OS), disease-free survival (DFS), relapse, and nonrelapse mortality (NRM) rates were 51.2% (95% confidence interval [CI], 42.5-59.8), 44.4% (95% CI, 36.2-52.8), 32.2% (95% CI, 24.7-40.3), and 23.3% (95% CI, 16.9-30.4), respectively. Disease relapse was the most common cause of death. On multivariate analyses, age of ≥60 years was predictive for inferior OS (hazard ratio [HR], 2.16; 95% CI, 1.35-3.46; P = .001), and higher NRM (HR, 2.19; 95% CI, 1.13-4.22; P = .02). Remission status at time of allo-HCT (CR2/primary induction failure/relapse vs CR1) was predictive of inferior OS (HR, 1.87; 95% CI, 1.14-3.06; P = .01) and DFS (HR, 1.75; 95% CI, 1.11-2.76; P = .02). Use of myeloablative conditioning with total body irradiation (MAC-TBI) was predictive of improved DFS and reduced relapse risk. Allo-HCT is effective in providing durable remissions and long-term survival in BPDCN. Younger age and allo-HCT in CR1 predicted for improved survival, whereas MAC-TBI predicted for less relapse and improved DFS. Novel strategies incorporating allo-HCT are needed to further improve outcomes.

A Phase I Trial of Sirolimus with "7&3" Induction Chemotherapy in Patients with Newly Diagnosed Acute Myeloid Leukemia

Chemotherapy remains a primary treatment for younger AML patients, though many relapse. Data from our group have shown that highly phosphorylated S6 in blasts may predict response to sirolimus given with chemotherapy. We report the results of a phase I study of this combination in newly diagnosed AML and the pharmacodynamic analysis of pS6 before and after treatment. Subjects received sirolimus (12 mg on day 1, 4 mg daily, days 2-10), then idarubicin and cytarabine (days 4-10). Response was assessed at hematologic recovery or by day 42 using a modified IWG criteria. Fifty-five patients received sirolimus. Toxicity was similar to published 7 + 3 data, and 53% had high-, 27% intermediate-, and 20% favorable-risk disease. Forty-four percent of the high-risk patients entered into CR/CRp. Seventy-nine percent of the intermediate-risk subjects had a CR/CRp. All favorable-risk patients had a CR by day 42; 9/11 remained alive and in remission with a median follow-up of 660 days. Additionally, 41/55 patients had adequate samples for pharmacodynamic analysis. All patients demonstrated activation of S6 prior to therapy, in contrast to 67% seen in previous studies of relapsed AML. mTORC1 inhibition was observed in 66% of patients without enrichment among patients who achieved remission. We conclude that sirolimus and 7 + 3 is a well-tolerated and safe regimen. mTORC1 appears to be activated in almost all patients at diagnosis of AML. Inhibition of mTORC1 did not differ based on response, suggesting that AML cells may have redundant signaling pathways that regulate chemosensitivity in the presence of mTORC1 inhibition.

A phase I study of the combination of palbociclib and dexamethasone for the treatment of relapsed or refractory B-cell acute lymphoblastic leukemia

PURPOSE

Despite advances in the treatment of B-cell acute lymphoblastic leukemia (B-ALL), outcomes for relapsed/refractory (R/R) disease remain poor. Preclinical studies suggest that the combination of the CDK4/6 inhibitor palbociclib and dexamethasone may be effective in targeting leukemic cell growth. We conducted a phase I study of escalating doses of palbociclib in combination with dexamethasone in adults with R/R B-ALL.

METHODS

Cycle 1 consisted of single agent palbociclib given for 7 days and continued for 28 additional days in combination with dexamethasone 20 mg daily. Palbociclib dosing began at 100 mg daily. Patients with a response were eligible for maintenance consisting of 1 week of palbociclib plus dexamethasone (20 mg daily × 2 days, 16 mg daily × 2 days, 12 mg daily × 2 days, 6 mg daily × 1 day), followed by 3 weeks of palbociclib alone. Safety, efficacy, and the expression of phospho-RB and c-MYB/BCL-2 were measured.

CONCLUSIONS

Seven patients were treated on study before it was closed early due to slow accrual. No dose limiting toxicities were identified. One patient had a complete response with incomplete hematologic recovery, suggesting possible efficacy of the treatment. Reduction in CD34+ cells, p-RB, c-MYB, and BCL-2 expression also suggested on-target therapy effects.

Disparities in receiving disease-directed therapy, allogeneic stem cell transplantation in non-Hispanic Black patients with TP53-mutated acute myeloid leukemia

BACKGROUND

Although the clinical outcomes of patients with TP53-mutated acute myeloid leukemia (AML) are dismal, subsets of patients eligible for curative-intent therapies may fare better. Because racial disparities are known to affect outcome in hematologic malignancies, the authors sought to explore disparities among patients with TP53-mutated AML.

METHODS

A multicenter, retrospective study was conducted in a cohort of 340 patients who had TP53-mutated AML (275 non-Hispanic White [NHW] and 65 non-Hispanic Black [NHB]) to analyze differences in treatment and outcome among NHW and NHB patients.

RESULTS

The median patient age was comparable between NHW and NHB patients (p = .76). A higher proportion of NHB patients had therapy-related AML (31% vs. 20%; p = .08) and had co-mutations (74% vs. 61%; p = .06). A higher proportion of NHW patients received intensive chemotherapy compared with NHB patients (47% vs. 31%; p = .02). Conversely, a higher proportion of NHB patients received low-intensity chemotherapy (9% vs. 5.5%; p = .02) or best supportive care (22% vs. 7%; p < .001). The complete response rate (including complete responses with or without complete count recovery) was 31% versus 24.5% (p = .39) in NHW and NHB patients, respectively. Only 5% of NHB patients received allogeneic stem cell transplantation compared with 15.5% of NHW patients (p = .02). The proportion of patients who were event-free (18.5% vs. 8.5%; p = .49) or who remained alive (24.9% vs. 8.3%; p = .13) at 18 months was numerically higher in NHW versus NHB patients, respectively, but was not statistically significant.

CONCLUSIONS

The current study highlights disparities between NHW and NHB patients with TP53-mutated AML. Efforts are warranted to eliminate treatment disparities in minority populations.

Survival of TP53-mutated acute myeloid leukemia patients receiving allogeneic stem cell transplantation after first induction or salvage therapy: results from the Consortium on Myeloid Malignancies and Neoplastic Diseases (COMMAND)

We conducted a multi-center study to analyze factors predicting survival among patients with TP53-mutated (m) AML receiving allogeneic hematopoietic stem cell transplant (allo-HSCT) in the recent era. Out of 370 TP53m AML patients, 68 (18%) patients were bridged to allo-HSCT. The median age of the patients was 63 years (range, 33-75), 82% of patients had complex cytogenetics and 66% of patients had multi-hit TP53m. Forty three percent received myeloablative conditioning and 57% received reduced intensity conditioning. The incidence of acute graft versus host disease (GVHD) was 37% and chronic GVHD was 44%. The median event-free survival (EFS) from the time of allo-HSCT was 12.4 months (95% CI: 6.24-18.55) and median overall survival (OS) was 24.5 months (95% CI: 21.80-27.25). In multivariate analysis utilizing variables that showed significance in univariate analysis, complete remission at day 100 post allo-HSCT retained significance for EFS (HR: 0.24, 95% CI: 0.10-0.57, p = 0.001) and OS (HR: 0.22, 95% CI: 0.10-0.50, p ≤ 0.001). Similarly, occurrence of chronic GVHD retained significance for EFS (HR: 0.21, 95% CI: 0.09-0.46, p ≤ 0.001) and OS (HR: 0.34, 95% CI: 0.15-0.75, p = 0.007). Our report suggests that allo-HSCT offers the best opportunity to improve long-term outcome among patients with TP53m AML.

A Prospective, Randomized Trial Examining the Use of G-CSF Versus No G-CSF in Patients Post-Autologous Transplantation

Contemporary, prospective data regarding the impact of granulocyte-colony stimulating factor (G-CSF) on outcomes after autologous hematopoietic stem cell transplantation (Auto-HSCT) in an era when stem cell grafts are more qualitatively robust are limited. Recent retrospective analyses have not supported a beneficial effect of post-transplantation G-CSF use on major outcomes after Auto-HSCT leading to strategies to delay or eliminate the use of G-CSF altogether in this context. To test the hypothesis that the infusion of consistently higher doses of stem cells (defined as ≥4 × 10⁶/kg) in Auto-HSCT will obviate the need for post-transplantation G-CSF. If so, the impact of withholding G-CSF will be noninferior to the use of G-CSF in terms of length of stay (LOS). The specific objectives were to conduct a prospective, randomized clinical trial primarily examining the impact of post-transplantation G-CSF on LOS, and secondarily on engraftment, infectious complications, antibiotic usage, and incidence of engraftment syndrome after Auto-HSCT in patients receiving versus not receiving G-CSF after Auto-HSCT. Patients with multiple myeloma or non-Hodgkin lymphoma (NHL) who underwent Pegfilgrastim plus Plerixafor-primed stem cell collection followed by Auto-HSCT were randomized to the G-CSF group (receive G-CSF starting at day 3 after Auto-HSCT) or the no G-CSF group (G-CSF withheld after Auto-HSCT). Seventy patients per arm were planned to demonstrate the primary endpoint of noninferiority in LOS between the G-CSF and the no G-CSF groups. Patient outcomes in the two groups were followed up and compared after Auto-HSCT, and an interim analysis for futility was planned when accrual reached 50%.The primary finding of this study was that despite only a 2-day longer median absolute neutrophil count (ANC) recovery in the no G-CSF arm (median 11 versus 13 days; P = .001), LOS was 4 days longer in patients not treated with G-CSF (median 11 days versus 15 days; P = .001). G-CSF use was associated with more robust incremental daily increases in ANC once recovered (P = .001), fewer days of febrile neutropenia (P = .001), and fewer days on antibiotics (P = .001), potentially contributing to this disproportionate finding. Inferiority in LOS in the no G-CSF group was demonstrated on the interim analysis, and the study was closed at the half-way point. There were no significant group differences in platelet recovery, documented infections, hospital readmissions, or overall survival at 1 year. Engraftment syndrome occurred in 54.3% of patients and was not related to G-CSF use. These results suggest that the increased LOS associated with the omission of G-CSF is largely due to concerns regarding the potential for infection in patients without a stable, recovered ANC in a hospital setting. Engraftment syndrome represented a significant source of febrile neutropenia further contributing to patient safety concerns and requires strategies to decrease its incidence. Infectious complications and death were not affected by the omission of G-CSF supporting a carefully monitored outpatient approach to Auto-HSCT in which white blood cell growth factor is eliminated or given as needed for documented infection. © 2023 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

miR-196b-TLR7/8 Signaling Axis Regulates Innate Immune Signaling and Myeloid Maturation in DNMT3A-Mutant AML

PURPOSE

DNMT3A mutations confer a poor prognosis in acute myeloid leukemia (AML), but the molecular mechanisms downstream of DNMT3A mutations in disease pathogenesis are not completely understood, limiting targeted therapeutic options. The role of miRNA in DNMT3A-mutant AML pathogenesis is understudied.

EXPERIMENTAL DESIGN

DNA methylation and miRNA expression was evaluated in human AML patient samples and in Dnmt3a/Flt3-mutant AML mice. The treatment efficacy and molecular mechanisms of TLR7/8-directed therapies on DNMT3A-mutant AML were evaluated in vitro on human AML patient samples and in Dnmt3a/Flt3-mutant AML mice.

RESULTS

miR-196b is hypomethylated and overexpressed in DNMT3A-mutant AML and is associated with poor patient outcome. miR-196b overexpression in DNMT3A-mutant AML is important to maintain an immature state and leukemic cell survival through repression of TLR signaling. The TLR7/8 agonist resiquimod induces dendritic cell-like differentiation with costimulatory molecule expression in DNMT3A-mutant AML cells and provides a survival benefit to Dnmt3a/Flt3-mutant AML mice. The small molecule bryostatin-1 augments resiquimod-mediated AML growth inhibition and differentiation.

CONCLUSIONS

DNMT3A loss-of-function mutations cause miRNA locus-specific hypomethylation and overexpression important for mutant DNMT3A-mediated pathogenesis and clinical outcomes. Specifically, the overexpression of miR-196b in DNMT3A-mutant AML creates a novel therapeutic vulnerability by controlling sensitivity to TLR7/8-directed therapies.

Predictive factors and outcomes for ibrutinib in relapsed/refractory marginal zone lymphoma: a multicenter cohort study

Ibrutinib is effective in the treatment of relapsed/refractory (R/R) marginal zone lymphoma (MZL) with an overall response rate (ORR) of 48%. However, factors associated with response (or lack thereof) to ibrutinib in R/R MZL in clinical practice are largely unknown. To answer this question, we performed a multicenter (25 US centers) cohort study and divided the study population into three groups: "ibrutinib responders"-patients who achieved complete or partial response (CR/PR) to ibrutinib; "stable disease (SD)"; and "primary progressors (PP)"-patients with progression of disease as their best response to ibrutinib. One hundred and nineteen patients met the eligibility criteria with 58%/17% ORR/CR, 29% with SD, and 13% with PP. The median PFS and OS were 29 and 71.4 months, respectively, with no difference in PFS or OS based on the ibrutinib line of therapy or type of therapy before ibrutinib. Patients with complex cytogenetics had an inferior PFS (HR = 3.08, 95% CI 1.23-7.67, p = 0.02), while those with both complex cytogenetics (HR = 3.00, 95% CI 1.03-8.68, p = 0.04) and PP (HR = 13.94, 95% CI 5.17-37.62, p < 0.001) had inferior OS. Only primary refractory disease to first-line therapy predicted a higher probability of PP to ibrutinib (RR = 3.77, 95% CI 1.15-12.33, p = 0.03). In this largest study to date evaluating outcomes of R/R MZL treated with ibrutinib, we show that patients with primary refractory disease and those with PP on ibrutinib are very high-risk subsets and need to be prioritized for experimental therapies.

Racial disparities in patients with TP53 mutated acute myeloid leukemia

e19007

Background: While clinical outcomes of patients (pts) with TP53 mutated (m) acute myeloid leukemia (AML) are dismal, subsets of pts with eligibility to curative intent therapies can do better. As racial disparities are known to impact outcome in hematological malignancies, we sought to explore disparities in TP53m AML. Methods: We conducted a multicenter study of 304 TP53m AML pts, divided into 2 groups, White (n= 240) and Black/Hispanic (n=64), to compare difference in disease characteristics and clinical outcome. We grouped Black and Hispanic together as the number of pts were small in each group and our aim was to evaluate outcome in under-represented races/ethnicities. Results: Baseline characteristics are summarized in Table. The median age of the pts was comparable between White and Black/Hispanic (p= 0.97). A significantly higher proportion of Black/Hispanic pts (23%) had diabetes mellitus when compared with White (14%) pts (p= 0.02). A higher proportion of Black/Hispanic pts had therapy-related AML (33% vs. 20%, p= 0.03), complex cytogenetics (98% vs. 87%, p= 0.003) and co-mutations (70% vs. 57%, p= 0.02). The proportion of pts who received hypomethylating agent + venetoclax (29% vs 20%, p= 0.20) or CPX-351 (22% vs 20%, p= 0.13) were comparable between White and Black/Hispanic, respectively. A higher proportion of Black/Hispanic pts received supportive care (17% vs. 4%, p= 0.002). White pts had higher rates of complete remission with or without count recovery (25% vs. 19%, p= 0.07). Only 6% of Black/Hispanic pts received allogeneic stem cell transplantation (alloHCT) compared to 16% for White pts (p= 0.01). The median event free survival was 2 months (mo) (95% CI;1.52-2.41) and 2.5 mo (95% CI:1.62-3.31) in White and Black/Hispanic pts, respectively (p= 0.71). The median overall OS was shorter for Black/Hispanic (6.37 mo [95% CI:2.88-9.85]) than for White (6.90 mo [95% CI:5.55-8.24] [p= 0.009]). Conclusions: Our study demonstrates poorer OS in Black/Hispanic pts with TP53m AML. Potential drivers of this disparity include lower alloHCT rates, higher rates of pts receiving supportive care, and higher-risk disease in Black/Hispanic pts.[Table: see text]

Phase 1 results of a phase 1/2 trial of CYT-0851, a first-in-class inhibitor of RAD51-mediated homologous recombination, in patients with advanced solid and hematologic cancers

3084

Background: Homologous recombination (HR) is an essential, high-fidelity mechanism to repair DNA double strand breaks (DSBs) in cancer cells. CYT-0851 inhibits HR leading to an accumulation of unrepaired DSBs and tumor cell death. We are reporting the completed Phase 1 dose-escalation results and RP2D selection to support ongoing development of CYT-0851. Methods: Patients (pts) with advanced hematologic and solid tumors were treated with continuous 28-day cycles of increasing doses of CYT-0851 following a 3+3 design. The primary objective was determining the maximum tolerated dose. Secondary objectives included safety, pharmacokinetics, and anti-tumor activity. Results: As of a 15 Nov 2021 data cutoff (DCO), 73 pts with advanced cancers (NHL n = 18; Sarcoma n = 16; Pancreas n = 11; Breast n = 8; HNSCC n = 6; Ovarian n = 4; SCLC n = 4; Other n = 4; Myeloma n = 2) were treated in 12 cohorts (total daily doses: 30 mg to 1200 mg). One pt experienced a dose-limiting toxicity (DLT) of reversible metabolic acidosis at 1200 mg. Two of 3 pts at 800 mg experienced reversible DLT-like events in Cycle 2 of Gr3 dry skin and Gr3 myalgia and polyarthritis, respectively. Three of 10 pts treated at 600 mg experienced DLT-like events in Cycle 1: 1 pt experienced an SAE of Gr3 anorexia with Gr3 stomatitis, vomiting, and dehydration and 2 pts had Gr3 fatigue. No DLTs occurred at 400 mg daily which was selected as the RP2D. 42 pts (57.5%) experienced a CYT-0851-related adverse event (AE), including 12 (16.4%) with a Gr3/4 AE. There were no treatment-related deaths. AE leading to CYT-0851 withdrawal were reported in 2 pts (2.7%) treated with 600 and 800 mg. The most common CYT-0851-related AEs were primarily Gr1/2 and included fatigue (20.5%), hyperuricemia (11%), nausea (11%), alopecia (9.6%), constipation (8.2%) and headache (8.2%). CYT-0851 exposure was approximately dose-proportional across the evaluated doses with an effective half-life of ̃3 days. Exposure at 400 mg daily was consistent with efficacy in preclinical models. 46 pts were evaluable for response at the DCO. 12 pts with NHL were evaluable by Lugano and included 1 CR in FL and 1 PR in DLBCL treated for 393+ and 244 days respectively. 34 pts with solid tumors were evaluable by RECIST v1.1 with 1 PR in a pt with myxofibrosarcoma treated for 313 days and 16 pts with stable disease. Fifteen pts were treated for 100+ days and 5 for 180+ days. Conclusions: CYT-0851 has demonstrated promising and broad clinical activity in a Ph 1 population of pts with advanced cancers. The safety profile is favorable as characterized by events that were infrequent, primarily Gr1/2, and reversible. Six expansion cohorts (DLBCL, Follicular Lymphoma, Myeloma, Pancreatic, Ovarian and Sarcoma) are enrolling to characterize activity at the RP2D. Ph 1 evaluation of CYT-0851 in combination with 3 chemotherapy backbones is also ongoing. Clinical trial information: NCT03997968.

The prognostic impact of cigarette smoking on survival in acute myeloid leukemia with TP53 mutations and/or 17p deletions

Cigarette smoking has been associated with increased risk of developing acute myeloid leukemia (AML) in adults. There is limited data on the impact of smoking in AML patients with certain cytogenetic abnormalities. The aim of this study is to assess whether cigarette smoking affected the survival outcome of patients with newly diagnosed AML with TP53 alterations. We conducted a retrospective study of patients who were diagnosed with AML at the Thomas Jefferson Hospital with presence of TP53 mutations and/or 17p deletions. Patients' sex, age, race, smoking status (ever vs. never), cytogenetics, mutational profile, induction regimen, and induction response were analyzed. A total of 102 patients were included in the study with a median follow-up of 27.8 months. Among 100 patients who had documentation of smoking status, 59 patients (59%) were ever-smokers and 41 (41%) were never-smokers. Kaplan-Meier survival analysis showed that never-smokers did not differ in overall survival (OS) when compared to ever-smokers (P = 0.34). Univariate analysis revealed that age and cytogenetics had a statistically significant impact on survival. In multivariate analysis incorporating sex, age, race, smoking status, cytogenetics, and induction regimen as covariates, cytogenetics and induction regimen were independent prognostic factors for OS. In summary, no significant difference in OS was found between ever- and never-smokers in AML patients with TP53 alterations. Additional studies are needed to examine the prognostic impact of cigarette smoking in AML with specific cytogenetic abnormalities.

Targeting chemotherapy to de-condensed H3K27me3-marked chromatin of AML cells enhances leukemia suppression

Despite treatment with intensive chemotherapy, acute myeloid leukemia (AML) remains an aggressive malignancy with a dismal outcome in most patients. We found that AML cells exhibit an unusually rapid accumulation of the repressive histone mark H3K27me3 on nascent DNA. In cell lines, primary cells and xenograft mouse models, inhibition of the H3K27 histone methyltransferase EZH2 to de-condense the H3K27me3-marked chromatin of AML cells enhanced chromatin accessibility and chemotherapy-induced DNA damage, apoptosis, and leukemia suppression. These effects were further promoted when chromatin de-condensation of AML cells was induced upon S-phase entry after release from a transient G1 arrest mediated by CDK4/6 inhibition. In the p53-null KG-1 and THP-1 AML cell lines, EZH2 inhibitor and doxorubicin co-treatment induced transcriptional reprogramming that was, in part, dependent on de-repression of H3K27me3-marked gene promoters and led to increased expression of cell death-promoting and growth-inhibitory genes. In conclusion, decondensing H3K27me3-marked chromatin by EZH2 inhibition represents a promising approach to improve the efficacy of DNA-damaging cytotoxic agents in AML patients. This strategy might allow for a lowering of chemotherapy doses with a consequent reduction of treatment-related side effects in elderly AML patients or those with significant comorbidities.

KAT6A and ENL form an epigenetic transcriptional control module to drive critical leukemogenic gene expression programs

Epigenetic programs are dysregulated in acute myeloid leukemia (AML) and help enforce an oncogenic state of differentiation arrest. To identify key epigenetic regulators of AML cell fate, we performed a differentiation-focused CRISPR screen in AML cells. This screen identified the histone acetyltransferase KAT6A as a novel regulator of myeloid differentiation that drives critical leukemogenic gene expression programs. We show that KAT6A is the initiator of a newly-described transcriptional control module in which KAT6A-catalyzed promoter H3K9ac is bound by the acetyllysine reader ENL, which in turn cooperates with a network of chromatin factors to induce transcriptional elongation. Inhibition of KAT6A has strong anti-AML phenotypes in vitro and in vivo, suggesting that KAT6A small molecule inhibitors could be of high therapeutic interest for mono or combinatorial differentiation-based treatment of AML.

Impact of depth of clinical response on outcomes of acute myeloid leukemia patients in first complete remission who undergo allogeneic hematopoietic cell transplantation

Acute myeloid leukemia (AML) patients often undergo allogeneic hematopoietic cell transplantation (alloHCT) in first complete remission (CR). We examined the effect of depth of clinical response, including incomplete count recovery (CRi) and/or measurable residual disease (MRD), in patients from the Center for International Blood and Marrow Transplantation Research (CIBMTR) registry. We identified 2492 adult patients (1799 CR and 693 CRi) who underwent alloHCT between January 1, 2007 and December 31, 2015. The primary outcome was overall survival (OS). Multivariable analysis was performed to adjust for patient-, disease-, and transplant-related factors. Baseline characteristics were similar. Patients in CRi compared to those in CR had an increased likelihood of death (HR: 1.27; 95% confidence interval: 1.13-1.43). Compared to CR, CRi was significantly associated with increased non-relapse mortality (NRM), shorter disease-free survival (DFS), and a trend toward increased relapse. Detectable MRD was associated with shorter OS, shorter DFS, higher NRM, and increased relapse compared to absence of MRD. The deleterious effects of CRi and MRD were independent. In this large CIBMTR cohort, survival outcomes differ among AML patients based on depth of CR and presence of MRD at the time of alloHCT. Further studies should focus on optimizing post-alloHCT outcomes for patients with responses less than CR.

Efficacy of Half-Day Workshops for Internal Medicine Interns in Educating Breaking-Bad-News Discussions

Background: Adequate end-of-life (EOL) care/breaking-bad-news (BBN) discussions with patients are becoming increasingly essential to adequate patient care.

Purpose: Whether a half-day workshop would lead to improved confidence in EOL/BBN care discussions for internal medicine interns.

Methods: Internal medicine interns (n = 43) were assigned to participate in a half-day workshop at Thomas Jefferson University Hospital. The workshop involved two standardized patient (SP) interactions involving delivering news of a terminal illness/initiating goals of care discussion with the intervention of SP feedback, a didactic and lecture on proper EOL/BBN discussion. Voluntary anonymous surveys before and after the workshop were utilized to assess impact.

Results: A majority of interns felt more comfortable with leading EOL care/BBN discussions after the workshop and had a positive experience.

Conclusions: A half-day curriculum is efficacious in educating EOL/BBN communication to internal medicine interns, but should be further assessed in a larger more standardized study involving an objective assessment.

Outcomes of Burkitt lymphoma with central nervous system involvement: evidence from a large multicenter cohort study

Central nervous system (CNS) involvement in Burkitt lymphoma poses a major therapeutic challenge, and the relative ability of contemporary regimens to treat CNS involvement remains uncertain. We describe the prognostic significance of CNS involvement and the incidence of CNS recurrence/progression after contemporary immunochemotherapy using real-world clinicopathological data from adults with Burkitt lymphoma diagnosed between 2009 and 2018 in 30 institutions in the USA. We examined associations between baseline CNS involvement, patients’ characteristics, complete response rates, and survival. We also examined risk factors for CNS recurrence. Of 641 patients (aged 18 to 88 years), 120 (19%) had CNS involvement. CNS involvement was independently associated with human immunodeficiency virus infection, poor performance status, involvement of ≥2 extranodal sites, and bone marrow involvement. Selection of the first-line treatment regimen was unaffected by CNS involvement (P=0.93). Patients with CNS disease had significantly lower rates of complete response (59% vs. 77% for patients with and without CNS involvement, respectively; P<0.001), worse 3-year progression-free survival (adjusted hazard ratio [aHR]=1.53, 95% confidence interval [95% CI]: 1.14-2.06; P=0.004) and overall survival (aHR=1.62, 95% CI: 1.18-2.22; P=0.003). The 3-year cumulative incidence of CNS recurrence was 6% (95% CI: 4-8%) and was significantly lower among patients receiving other regimens (CODOX-M/IVAC, 4%, or hyperCVAD/MA, 3%) compared with DA-EPOCH-R (13%; adjusted sub-distribution HR=4.38, 95% CI:, 2.16-8.87; P<0.001). Baseline CNS involvement in Burkitt lymphoma is relatively common and portends inferior prognosis independently of the first-line treatment regimen selected. In real-world practice, regimens including intravenous systemic agents with pronounced CNS penetrance were associated with a lower risk of CNS recurrence. This finding may be influenced by observed suboptimal adherence to the strict CNS staging and intrathecal therapy procedures incorporated in the DA-EPOCH-R regimen.

Association of combined phase I/II study of a novel bicyclic peptide and MMAE conjugate BT8009 in patients with advanced malignancies with Nectin-4 expression

TPS2668

Background: BT8009 is a Bicycle Toxin Conjugate (BTC), a novel class of chemically synthesized molecules, comprising a bicyclic peptide targeting Nectin-4 tumor antigen, linked to cytotoxin (monomethyl auristatin E [MMAE]) via a valine-citrulline (val-cit) cleavable linker. Nectins (Nectin-1, -2, -3, and -4) and nectin-like molecules (Necl) are Ca2+ independent immunoglobulin-like cell adhesion molecules. Recent studies have shown the importance of Nectin-4 in several human cancers, including lung, ovarian, breast and bladder cancer; however, the precise roles and clinical relevance of Nectin-4 in tumors remain largely unknown. The Nectin-4 targeted enfortumab vedotin, linked to MMAE via a val-cit linker, is highly active in late-stage bladder cancer and demonstrates notable additional clinical activity as a single agent and in combination with pembrolizumab1. Skin toxicities, bone marrow suppression, peripheral neuropathy and diabetes have been associated with enfortumab, with some of these toxicities already noted with MMAE-bearing antibody therapies. We anticipate a similar toxicity profile for BT8009 in clinical studies. BT8009 exhibited a favorable preclinical profile and was effective in a range of cell-derived xenograph tumor models. Methods: Study BT8009-100 (NCT04561362) will evaluate safety and tolerability of weekly and every other week BT8009 administration, alone and in combination with q4w nivolumab. Determination of both a realistic phase 2 dose and a sequence will also be key to further exploration of safety and efficacy signals, along with an early examination of the role of baseline immunohistochemistry-ascertained levels of tumor Nectin-4. Patients will be recruited with advanced solid tumors associated with Nectin-4 expression after exhausting SOC options (i.e., bladder, breast, pancreatic, head and neck, gastric, esophageal and ovarian). Patients must have available tumor tissue, acceptable hematologic and other critical organ function and be willing to participate. Appropriate ethical and regulatory approvals and advice will be in place and adhered to. Exclusion criteria include uncontrolled brain metastases, uncontrolled hypertension, concomitant CYP3A4 inhibitors and significant history of autoimmune disease for the nivolumab cohorts. PK serial collections will be taken on D1 through D15. Radiologic tumor assessments for response per RECIST will be taken every two months. 1. Enfortumab Vedotin. FDA_data. 761137Orig1s000MultiDiscliplineR.pdf (fda.gov). Clinical trial information: NCT04561362.

First-in-human phase I/II study of CYT-0851, a first-in-class inhibitor of RAD51-mediated homologous recombination in patients with advanced solid and hematologic cancers

3006

Background: Homologous recombination (HR) is an essential, high-fidelity mechanism to repair DNA double strand breaks (DSBs). Inhibition of HR in cancer cells leads to accumulation of unrepaired DSBs and tumor cell death. This is the first reporting of the first-in-human study of CYT-0851, an oral, first-in-class, small molecule inhibitor of RAD51-mediated DNA repair. Methods: Patients (pts) with advanced hematologic and solid tumors were treated with continuous 28-day cycles of increasing doses of CYT-0851 with an accelerated titration and 3+3 trial design. Primary objectives included safety, maximum tolerated dose (MTD), recommended Phase 2 dose (RP2D) (Phase 1), and antitumor activity (Phase 2). Secondary and exploratory objectives included pharmacokinetics (PK), pharmacodynamics (PD) and predictive biomarkers of response. Results: As of an 8 Dec 2020 data cutoff (DCO), 23 pts with advanced cancers (Sarcoma n = 8, Breast n = 4, Non-Hodgkin’s Lymphoma n = 5; Pancreas n = 3; Ovarian n = 2; mucoepidermoid carcinoma n = 1) were enrolled in 6 cohorts (15 mg, 20 mg, 30 mg, and 45 mg BID; 90 mg and 130 mg QD). No pts experienced a dose-limiting toxicity and escalation continues per protocol to identify the MTD. 6 pts (26.1%) experienced a CYT-0851-related adverse event with only Gr 1/2 nausea (n = 3, 13%) and constipation (n = 2, 8.7%) occurring in > 1 pt. There has been no reported CYT-0851-related myelosuppression, serious adverse events, study discontinuation, or death. Preliminary PK analyses showed dose proportional systemic exposure with a half-life of ̃3 days supporting transition from BID to QD dosing. PD effects were observed with increases in ɣH2AX in on-treatment circulating tumor cells compared to baseline at exposures associated with preclinical anti-tumor activity. Ten pts were response evaluable prior to the DCO. Two partial responses by Lugano and RECIST v1.1 criterion were achieved in pts with DLBCL (-74%) and myxofibrosarcoma (-30%) at 45 mg BID with treatment ongoing at 126+ and 250+ days. An additional two pts, with pancreatic cancer (-19%) and follicular lymphoma (-42%) had stable disease with tumor shrinkage at 45 mg BID for 111 and 99+ days. Conclusions: CYT-0851, a first-in-class inhibitor of RAD51-mediated HR, is well tolerated, with linear PK, target-directed PD effects and promising antitumor activity across different tumor types. CYT-0851 is the first DNA-damage repair (DDR) therapeutic with demonstrated clinical activity in both hematologic malignancies and solid tumors. Dose escalation continues to establish the RP2D, with planned expansion in 7 disease-specific cohorts in hematologic and solid cancers. Clinical trial information: NCT03997968.

Burkitt Lymphoma International Prognostic Index

PURPOSE

Burkitt lymphoma (BL) has unique biology and clinical course but lacks a standardized prognostic model. We developed and validated a novel prognostic index specific for BL to aid risk stratification, interpretation of clinical trials, and targeted development of novel treatment approaches.

METHODS

We derived the BL International Prognostic Index (BL-IPI) from a real-world data set of adult patients with BL treated with immunochemotherapy in the United States between 2009 and 2018, identifying candidate variables that showed the strongest prognostic association with progression-free survival (PFS). The index was validated in an external data set of patients treated in Europe, Canada, and Australia between 2004 and 2019.

RESULTS

In the derivation cohort of 633 patients with BL, age ≥ 40 years, performance status ≥ 2, serum lactate dehydrogenase > 3× upper limit of normal, and CNS involvement were selected as equally weighted factors with an independent prognostic value. The resulting BL-IPI identified groups with low (zero risk factors, 18% of patients), intermediate (one factor, 36% of patients), and high risk (≥ 2 factors, 46% of patients) with 3-year PFS estimates of 92%, 72%, and 53%, respectively, and 3-year overall survival estimates of 96%, 76%, and 59%, respectively. The index discriminated outcomes regardless of HIV status, stage, or first-line chemotherapy regimen. Patient characteristics, relative size of the BL-IPI groupings, and outcome discrimination were consistent in the validation cohort of 457 patients, with 3-year PFS estimates of 96%, 82%, and 63% for low-, intermediate-, and high-risk BL-IPI, respectively.

CONCLUSION

The BL-IPI provides robust discrimination of survival in adult BL, suitable for use as prognostication and stratification in trials. The high-risk group has suboptimal outcomes with standard therapy and should be considered for innovative treatment approaches.

Burkitt lymphoma in the modern era: real-world outcomes and prognostication across 30 US cancer centers

We examined adults with untreated Burkitt lymphoma (BL) from 2009 to 2018 across 30 US cancer centers. Factors associated with progression-free survival (PFS) and overall survival (OS) were evaluated in univariate and multivariate Cox models. Among 641 BL patients, baseline features included the following: median age, 47 years; HIV+, 22%; Eastern Cooperative Oncology Group (ECOG) performance status (PS) 2 to 4, 23%; >1 extranodal site, 43%; advanced stage, 78%; and central nervous system (CNS) involvement, 19%. Treatment-related mortality was 10%, with most common causes being sepsis, gastrointestinal bleed/perforation, and respiratory failure. With 45-month median follow-up, 3-year PFS and OS rates were 64% and 70%, respectively, without differences by HIV status. Survival was better for patients who received rituximab vs not (3-year PFS, 67% vs 38%; OS, 72% vs 44%; P < .001) and without difference based on setting of administration (ie, inpatient vs outpatient). Outcomes were also improved at an academic vs community cancer center (3-year PFS, 67% vs 46%, P = .006; OS, 72% vs 53%, P = .01). In multivariate models, age ≥ 40 years (PFS, hazard ratio [HR] = 1.70, P = .001; OS, HR = 2.09, P < .001), ECOG PS 2 to 4 (PFS, HR = 1.60, P < .001; OS, HR = 1.74, P = .003), lactate dehydrogenase > 3× normal (PFS, HR = 1.83, P < .001; OS, HR = 1.63, P = .009), and CNS involvement (PFS, HR = 1.52, P = .017; OS, HR = 1.67, P = .014) predicted inferior survival. Furthermore, survival varied based on number of factors present (0, 1, 2 to 4 factors) yielding 3-year PFS rates of 91%, 73%, and 50%, respectively; and 3-year OS rates of 95%, 77%, and 56%, respectively. Collectively, outcomes for adult BL in this real-world analysis appeared more modest compared with results of clinical trials and smaller series. In addition, clinical prognostic factors at diagnosis identified patients with divergent survival rates.

Caring for AML Patients During the COVID-19 Crisis: An American and Italian Experience

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the subsequent pandemic have impacted every aspect of oncology care worldwide. Healthcare systems have been forced to rapidly change practices in order to maximize the safety of patients and healthcare providers and preserve scare resources. Patients with acute myeloid leukemia are at increased risk of complications from SARS-CoV-2 not only due to immune compromise related to the malignancy but also due to the acuity of the disease and intensity of treatment. These issues have created unique challenges during this difficult time. In this article, we present the approaches taken by two groups of hematologist/oncologists, one in the United States and one in Italy, who have been caring for acute myeloid leukemia (AML) patients in the face of the pandemic.

Treating Hematologic Malignancies During a Pandemic: Utilizing Telehealth and Digital Technology to Optimize Care

In late January 2020, Severe Acute Respiratory Syndrome Coronavirus-2 (SARS CoV-2) was reported as an outbreak in Wuhan, China. Within 2 months it became a global pandemic. Patients with cancer are at highest risk for both contracting and suffering complications of its resultant disease, Coronavirus 19 (COVID-19). Healthcare systems across the world had to adapt quickly to mitigate this risk, while continuing to provide potentially lifesaving treatment to patients. Bringing care to the home through the use of telehealth, home based chemotherapy, and remote patient monitoring technologies can help minimize risk to the patient and healthcare workers without sacrificing quality of care delivered. These care models provide the right treatment, to the right patient, at the right time, in the right place. Whether these patient-centered models of care will continue to be embraced by key stakeholders after the pandemic remains uncertain.

Outcomes of Burkitt lymphoma (BL) managed in academic (Acad) or community (Comm) centers: real-world evidence (RWE) from 30 US sites

8043

Background: Prior analyses have suggested better overall survival (OS) of cancer patients (pts) treated in Acad rather than Comm hospitals, but these disparities may reflect different patient characteristics. We examined outcomes of pts with BL in a large RWE cohort from 30 US healthcare systems (Evens, ASH 2019) with a mix of Acad and affiliated Comm sites. Methods: We collected clinical data on adults with BL diagnosed in 2009-2018, individually assigned to Acad or Comm principal setting of care. We compared duration of chemotherapy (CTx, incl. standard CODOX-M/IVAC, hCVAD/MA, DA-EPOCH), rates of complete response (CR), progression-free survival (PFS), and OS adjusting for age, sex, HIV, performance status (PS), stage, LDH > 3x upper limit of normal (ULN), involvement of bone marrow or cerebrospinal fluid (CSF), reporting adjusted risk (RR) or hazard ratio (HR) with 95% CI. Results: Among 641 BL pts, 77 (12%) were managed in Comm setting. Comm pts had lower median age (45 vs 48 in Acad, P= .049), less frequent HIV (13% vs 23%, P= .039), less marrow (21% vs 36%, P= .009) or detected CSF involvement (8% vs 15%, P= .11), and less LDH > 3xULN (21% vs 41%, P= .013), with no significant differences in sex, PS, stage, hemoglobin, or receipt of CTx (97% vs 99%). Acad sites more often applied standard intensive CTx regimens (93% vs 85%, P= .03) and rituximab (92% vs 79%, P= .001), without significant difference in median time to CTx ( P= .69) or treatment-related mortality (TRM, P= .16). Pts managed in Comm (vs Acad) sites were less likely to achieve CR (61% vs 75%, P= .03; RR = 0.79 [0.65-0.95]) and had worse 3-year PFS (46% vs 67%, log-rank P= .003; HR = 2.17 [1.51-3.14]) and OS (53% vs 72%, P= .006; HR = 2.20 [1.48-3.25]). There was no significant interaction with age, sex, HIV, PS, or CSF involvement. Excess mortality concentrated in the 1st year of follow-up. CR, PFS, and OS appeared similar between Acad and Comm settings for pts receiving hCVAD or DA-EPOCH, but outcomes were significantly worse in Comm setting for pts receiving CODOX-M/IVAC. Median number of cycles did not differ between Comm or Acad sites, but median duration of CODOX-M/IVAC delivery was significantly longer in Comm setting (113 vs 101 days, P= .023). Conclusions: In this large RWE analysis, superior outcomes of adults with BL in Acad setting were not explained by baseline patient characteristics or TRM. Differences in the use of standard CTx regimens, rituximab, duration of Ctx, and CR rates suggest need for further research on potential barriers to delivery of intensive CTx for BL in a broader Comm setting.

The Role of Inhibition of Apoptosis in Acute Leukemias and Myelodysplastic Syndrome

Avoidance of apoptosis is a key mechanism that malignancies, including acute leukemias and MDS, utilize in order to proliferate and resist chemotherapy. Recently, venetoclax, an inhibitor of the anti-apoptotic protein BCL-2, has been approved for the treatment of upfront AML in an unfit, elderly population. This paper reviews the pre-clinical and clinical data for apoptosis inhibitors currently in development for the treatment of AML, ALL, and MDS.

Primary central nervous system plasmablastic lymphoma in an HIV-positive patient

Plasmablastic lymphoma (PBL) is a rare subtype of diffuse large B-cell lymphoma, highly associated with HIV and Epstein-Barr virus (EBV) infections. It commonly presents in extranodal sites, often an oral mass, but reports of primary central nervous system PBL (PCNSPBL) are exceedingly rare. Here, we report on a 33-year-old man with newly diagnosed HIV infection who presented with acute-onset unilateral visual disturbance and was found to have biopsy-proven PCNSPBL. The neoplastic cells displayed a plasmacytoid appearance, with the expression of CD38 and CD138, and were positive for EBV by in situ hybridisation for EBV-encoded RNA. Systemic workup revealed the presence of Kaposi sarcoma, but no evidence of lymphoma. He is currently being treated with high-dose methotrexate, as well as antiretroviral therapy for his HIV infection, and has achieved a complete response.

A Two-Step Haploidentical Versus a Two-Step Matched Related Allogeneic Myeloablative Peripheral Blood Stem Cell Transplantation

Haploidentical stem cell transplantation (SCT) offers a transplantation option to patients who lack an HLA-matched donor. We developed a 2-step approach to myeloablative allogeneic hematopoietic stem cell transplantation for patients with haploidentical or matched related (MR) donors. In this approach, the lymphoid and myeloid portions of the graft are administered in 2 separate steps to allow fixed T cell dosing. Cyclophosphamide is used for T cell tolerization. Given a uniform conditioning regimen, graft T cell dose, and graft-versus-host disease (GVHD) prophylaxis strategy, we compared immune reconstitution and clinical outcomes in patients undergoing 2-step haploidentical versus 2-step MR SCT. We retrospectively compared data on patients undergoing a 2-step haploidentical (n = 50) or MR (n = 27) peripheral blood SCT for high-risk hematological malignancies and aplastic anemia. Both groups received myeloablative total body irradiation conditioning. Immune reconstitution data included flow cytometric assessment of T cell subsets at day 28 and 90 after SCT. Both groups showed comparable early immune recovery in all assessed T cell subsets except for the median CD3/CD8 cell count, which was higher in the MR group at day 28 compared with that in the haploidentical group. The 3-year probability of overall survival was 70% in the haploidentical group and 71% in the MR group (P = .81), while the 3-year progression-free survival was 68% in the haploidentical group and 70% in the MR group (P = .97). The 3-year cumulative incidence of nonrelapse mortality was 10% in the haploidentical group and 4% in the MR group (P = .34). The 3-year cumulative incidence of relapse was 21% in the haploidentical group and 27% in the MR group (P = .93). The 100-day cumulative incidence of overall grades II to IV acute GVHD was higher in the haploidentical group compared with that in the MR group (40% versus 8%, P < .001), whereas the grades III and IV acute GVHD was not statistically different between both groups (haploidentical, 6%; MR, 4%; P = .49). The cumulative incidence of cytomegalovirus reactivation was also higher in the haploidentical group compared to the MR group (haploidentical, 68%; MR, 19%; P < .001). There were no deaths from GVHD in either group. Using an identical conditioning regimen, graft T cell dose, and GVHD prophylaxis strategy, comparable early immune recovery and clinical outcomes were observed in the 2-step haploidentical and MR SCT recipients.

Controversies in antiepidermal growth factor receptor therapy in metastatic colorectal cancer

The randomized first-line trials, including the CRYSTAL trial, the OPUS trial, and the PRIME trial, have demonstrated the significant efficacy of cetuximab or panitumumab in patients with v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) wild-type tumors. The addition of an antiepidermal growth factor receptor (anti-EGFR)-directed monoclonal antibody to chemotherapy for these patients significantly improved progression-free survival, response rates, and R0 resection rates to a greater extent than overall survival compared with patients who received chemotherapy alone. However, 2 recent randomized phase 3 trials, the MRC COIN trial and the Nordic VII trial, reported an unexpected lack of benefit from the addition of cetuximab to chemotherapy in the first-line setting. In addition, recent retrospective analyses performed on a pooled data set from major clinical trials added more complexity, reporting an unexpected association of KRAS G13D mutation with a better clinical outcome compared with patients who had other KRAS mutations in the first-line and salvage settings, whereas the other independent analysis failed to demonstrate a benefit from panitumumab in patients with the same KRAS G13D mutation. The anti-EGFR monoclonal antibody-associated skin toxicity and the controversial strategies of management also are discussed. In this review, the authors analyze the previous randomized clinical trials and more critically re-evaluate recent trials and subgroup analyses to derive 3 factors that need to be taken into consideration regarding the addition of EGFR-directed monoclonal antibodies to chemotherapy: the preclinical data on mechanisms of action between chemotherapy and anti-EGFR antibodies along with mechanisms of resistance to anti-EGFR antibodies, the role of cross-over events in overall survival data, and the significant dose reductions of chemotherapeutic agents when combined with anti-EGFR agents.