Modified Delphi Panel Consensus Recommendations for Management of Severe Aplastic Anemia

Severe aplastic anemia (SAA) is a rare hematologic condition for which there is no clear management algorithm. A panel of 11 adult and pediatric experts on aplastic anemia was assembled and, using the RAND/UCLA modified Delphi panel method, evaluated >600 varying patient care scenarios to develop clinical recommendations for the initial and subsequent management of patients of all ages with SAA. Here we present the panel's recommendations to rule out inherited bone marrow failure (IBMF) syndromes, on supportive care prior to and during first-line therapy, and on first-line (initial management) and second-line (subsequent management) therapy of acquired SAA, focusing on when transplant versus medical therapy is most appropriate. These recommendations represent the consensus of 11 experts informed by published literature and experience. They are intended only as general guidance for experienced clinicians who treat patients with SAA and are in no way intended to supersede individual physician and patient decision-making. Current and future research should validate this consensus using clinical data. Once validated, we hope these expert panel recommendations will improve outcomes for patients with SAA.

Impact of academic medical center access on outcomes in multiple myeloma

Treatment at academic cancer centers (ACs) is associated with improved survival across hematologic malignancies, though the benefit in multiple myeloma (MM) has not been examined. This study aims to evaluate survival outcomes at Commission on Cancer accredited ACs compared to non-academic centers (NACs) for patients receiving MM-directed therapy. The National Cancer Database (NCDB) was used to identify demographics and overall survival (OS) of MM patients diagnosed from 2004 to 2017 and to compare outcomes by facility type. Survival analysis was repeated in a propensity score matched cohort, with NACs matched 1:1 to ACs by age, race, comorbidity score, insurance, year of diagnosis, distance traveled, and income. Of 163 375 MM patients, 44.5% were treated at ACs. Patients at ACs were more likely to receive MM-directed therapy compared to NACs (81% vs. 73%, p < .001). For patients receiving treatment, median OS at ACs was 71.3 months versus 41.2 months at NACs (p < .001). When adjusted for baseline demographics, patients treated at ACs had reduced mortality; hazard ratio (HR) 0.79 (95% CI 0.78-0.81, p < .001). The propensity score matched cohort maintained this survival benefit with a median OS of 59.9 months at ACs versus 37.0 months at NACs (p < .001), HR of 0.66 (95% CI 0.64-0.67, p < .001). ACs treated younger patients with fewer comorbidities and were more likely to treat racial minorities and patients with Medicaid or private insurance, and the uninsured. In this analysis, MM patients treated at ACs have significantly improved survival. While potentially related to access to specialized care, socioeconomic factors that drive facility selection may also contribute.

Abstract LB108: Addition of navitoclax to ruxolitinib mediates responses suggestive of disease modification in patients with myelofibrosis previously treated with ruxolitinib monotherapy

Although ruxolitinib (RUX) is effective in alleviating splenomegaly and constitutional symptoms for patients with myelofibrosis (MF), it does not appear to modify underlying disease biology. RUX discontinuation rate within 5 years is approximately 40%, and patients have poor prognosis after discontinuing RUX [1]. The definition of disease modification in MF is evolving. Reversal of bone marrow fibrosis (BMF) and reduction in driver gene variant allele frequency (VAF) have been suggested as evidence of disease modification; however, clinical benefits derived from achieving these responses have not been fully elucidated. Ultimately, benefits in patient survival are requisite to claim true clinically meaningful disease modification. There is also an unmet need of effective therapies for patients with MF with high molecular risk (HMR) mutations (ASXL1, EZH2, IDH1/2, SRSF2, and U2AF1 Q157). REFINE (NCT03222609) is a phase 2 trial evaluating navitoclax (NAV), a BCL-XL/BCL-2 inhibitor, combined with RUX, in patients with MF who progressed on or had a suboptimal response to RUX monotherapy. Here, we report the exploratory analyses assessing BMF, VAF, and HMR with respect to outcomes. As BMF improvements were often observed in patients who achieved ≥35% reduction in spleen volume (SVR35), we explored if the survival benefit observed was due to this potentially disease modification-related response. All statistics were descriptive. As of May 6, 2021, 34 patients were enrolled in Cohort 1a and received ≥1 dose of NAV plus RUX. Of these, 32 were evaluable for BMF and 12 (38%) had ≥1 grade improvement during anytime on study, 4 of whom improved by 2 grades. For driver gene VAF reductions, 26 patients (JAK2, n=19; CALR, n=7) were evaluable and 6 (23%) achieved ≥20% reduction at Week 24. Five patients achieved both BMF and VAF responses. Median overall survival (OS) for patients who had ≥1 grade improvement in BMF was not reached compared with 28.5 months for those without improvement (P &lt;0.01). Similarly, the median OS was also not reached for patients who achieved ≥20% VAF reduction versus 28.5 months for those who did not (P=0.05). Furthermore, no deaths were observed in patients with improvements in BMF or VAF. Within the patient group who had an SVR35 response at any time, median OS was not reached in those who had improved BMF (n=9), compared with an OS of 28.5 months for patients without BMF improvement (n=6; P &lt;0.01). Of 34 patients, 33 were evaluable for molecular risk; 19 (58%) had HMR and 14 (42%) were without (non-HMR); at the time of analysis, median OS was not reached in either subgroup; there was no statistical significance in survival between HMR and non-HMR groups. Taken together, the results of these analyses demonstrate the ability of NAV, combined with RUX, to induce BMF improvement and VAF reduction. These responses are suggestive of disease modification as they were associated with improved OS for patients. In addition, the NAV plus RUX regimen potentially improved the outcome for patients with MF regardless of HMR status.

Reference 1. Palandri F, Breccia M, Bonifacio M, et al. Life after ruxolitinib: Reasons for discontinuation, impact of disease phase, and outcomes in 218 patients with myelofibrosis. Cancer 2020; 126(6): 1243-52

Citation Format: Naveen Pemmaraju, Jacqueline Garcia, Jalaja Potluri, Yan Sun, Jason Harb, Srinivas K. Tantravahi, Srdan Verstovsek, Claire Harrison. Addition of navitoclax to ruxolitinib mediates responses suggestive of disease modification in patients with myelofibrosis previously treated with ruxolitinib monotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB108.

Addition of Navitoclax to Ongoing Ruxolitinib Therapy for Patients With Myelofibrosis With Progression or Suboptimal Response: Phase II Safety and Efficacy

PURPOSE

Targeting the BCL-XL pathway has demonstrated the ability to overcome Janus kinase inhibitor resistance in preclinical models. This phase II trial investigated the efficacy and safety of adding BCL-XL/BCL-2 inhibitor navitoclax to ruxolitinib therapy in patients with myelofibrosis with progression or suboptimal response to ruxolitinib monotherapy (ClinicalTrials.gov identifier: NCT03222609).

METHODS

Thirty-four adult patients with intermediate-/high-risk myelofibrosis who had progression or suboptimal response on stable ruxolitinib dose (≥ 10 mg twice daily) were administered navitoclax at 50 mg once daily starting dose, followed by escalation to a maximum of 300 mg once daily in once in weekly increments (if platelets were ≥ 75 × 109/L). The primary end point was ≥ 35% spleen volume reduction (SVR35) from baseline at week 24. Secondary end points included ≥ 50% reduction in total symptom score (TSS50) from baseline at week 24, hemoglobin improvement, change in bone marrow fibrosis (BMF) grade, and safety.

RESULTS

High molecular risk mutations were identified in 58% of patients, and 52% harbored ≥ 3 mutations. SVR35 was achieved by 26.5% of patients at week 24, and by 41%, at any time on study, with an estimated median duration of SVR35 of 13.8 months. TSS50 was achieved by 30% (6 of 20) of patients at week 24, and BMF improved by 1-2 grades in 33% (11 of 33) of evaluable patients. Anemia response was achieved by 64% (7 of 11), including one patient with baseline transfusion dependence. Median overall survival was not reached with a median follow-up of 21.6 months. The most common adverse event was reversible thrombocytopenia without clinically significant bleeding (88%).

CONCLUSION

The addition of navitoclax to ruxolitinib in patients with persistent or progressive myelofibrosis resulted in durable SVR35, improved TSS, hemoglobin response, and BMF. Further investigation is underway to qualify the potential for disease modification.

Histiocytic Neoplasms, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

Histiocytic neoplasms are rare hematologic disorders accounting for less than 1% of cancers of the soft tissue and lymph nodes. Clinical presentation and prognosis of these disorders can be highly variable, leading to challenges for diagnosis and optimal management of these patients. Treatment often consists of systemic therapy, and recent studies support use of targeted therapies for patients with these disorders. Observation ("watch and wait") may be sufficient for select patients with mild disease. These NCCN Guidelines for Histiocytic Neoplasms include recommendations for diagnosis and treatment of adults with the most common histiocytic disorders: Langerhans cell histiocytosis, Erdheim-Chester disease, and Rosai-Dorfman disease.

Dasatinib overcomes stroma-based resistance to the FLT3 inhibitor quizartinib using multiple mechanisms

FLT3-ITD mutations occur in 20–30% of AML patients and are associated with aggressive disease. Patients with relapsed FLT3-mutated disease respond well to 2^nd generation FLT3 TKIs but inevitably relapse within a short timeframe. In this setting, until overt relapse occurs, the bone marrow microenvironment facilitates leukemia cell survival despite continued on-target inhibition. We demonstrate that human bone marrow derived conditioned medium (CM) protects FLT3-ITD⁺ AML cells from the 2^nd generation FLT3 TKI quizartinib and activates STAT3 and STAT5 in leukemia cells. Extrinsic activation of STAT5 by CM is the primary mediator of leukemia cell resistance to FLT3 inhibition. Combination treatment with quizartinib and dasatinib abolishes STAT5 activation and significantly reduces the IC₅₀ of quizartinib in FLT3-ITD⁺ AML cells cultured in CM. We demonstrate that CM protects FLT3-ITD⁺ AML cells from the inhibitory effects of quizartinib on glycolysis and that this is partially reversed by treating cells with the combination of quizartinib and dasatinib. Using a doxycycline-inducible STAT5 knockdown in the FLT3-ITD⁺ MOLM-13 cell line, we show that dasatinib-mediated suppression of leukemia cell glycolytic activity is STAT5-independent and provide a preclinical rationale for combination treatment with quizartinib and dasatinib in FLT3-ITD⁺ AML.

Effect of treatment dose reductions in the setting of hand-foot syndrome on survival outcomes in patients with metastatic renal cell carcinoma treated with vascular endothelial growth factor receptor inhibitors

Purpose Hand-foot syndrome is a common dose limiting toxicity of vascular endothelial growth factor receptor tyrosine kinase inhibitors used for treatment of patients with metastatic renal cell carcinoma. The effect of treatment dose reductions, in the context of hand-foot syndrome, on survival outcomes is reported. Methods This was a retrospective case series of patients receiving vascular endothelial growth factor receptor tyrosine kinase inhibitors from 1 January 2004 to 31 October 2013. The main outcomes were progression-free and overall survival in these patients experiencing hand-foot syndrome and undergoing treatment dose reductions. Univariate and multivariate analyses were conducted utilizing Kaplan-Meier method and COX Proportional Hazard model with landmark analyses at 2 months. Results Of the 120 patients evaluated, treatment dose reductions for any reason were required in 68 (56.7%) patients. The most common reasons for treatment dose reductions were mucositis, hand-foot syndrome, and fatigue. The median progression-free survival and overall survival were significantly longer in patients with hand-foot syndrome with or without treatment dose reductions as compared to those without hand-foot syndrome. Conclusions An improvement in survival outcomes was observed in metastatic renal cell carcinoma patients with treatment-associated hand-foot syndrome despite treatment dose reductions. These data need validation in a larger cohort to confirm the hypothesis that treatment dose reductions in the setting of hand-foot syndrome do not negatively impatient survival.

Everolimus Versus Temsirolimus in Metastatic Renal Cell Carcinoma After Progression With Previous Systemic Therapies

BACKGROUND

Everolimus is an approved agent for use after disease progression with vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFR-TKIs) in patients with metastatic renal cell carcinoma. With recently published trials showing efficacy of nivolumab and cabozantinib in the second-line therapy setting, the use of everolimus will likely move to the third- or fourth-line therapy setting. Temsirolimus has occasionally been used instead of everolimus for many reasons, including financial considerations, assurance of patient compliance given its intravenous administration, its toxicity profile, patient performance status, and patient or physician preference. However, efficacy of everolimus and temsirolimus in this setting have not been compared in a randomized trial. The results from retrospective studies have been inconsistent.

MATERIALS AND METHODS

We identified patients treated with a first-line VEGFR-TKI for metastatic renal cell carcinoma and then treated with either everolimus or temsirolimus on progression from the databases of 2 large academic cancer centers. Progression-free survival (PFS) and overall survival (OS) were assessed from the initiation of second-line treatment using the Kaplan-Meier method.

RESULTS

A total of 90 patients received either everolimus (n = 59; 66%) or temsirolimus (n = 31; 34%) after progression during first-line VEGFR-TKI therapy. The patient and disease characteristics were similar in both groups. The median PFS was not different, but OS was superior with everolimus compared with temsirolimus (24.2 months vs. 12.1 months; hazard ratio, 0.58; P = .047).

CONCLUSION

Our results bolster existing guidelines supporting everolimus over temsirolimus as salvage therapy after previous systemic therapies.

Age-related mutations and chronic myelomonocytic leukemia

Chronic myelomonocytic leukemia (CMML) is a hematologic malignancy nearly confined to the elderly. Previous studies to determine incidence and prognostic significance of somatic mutations in CMML have relied on candidate gene sequencing, although an unbiased mutational search has not been conducted. As many of the genes commonly mutated in CMML were recently associated with age-related clonal hematopoiesis (ARCH) and aged hematopoiesis is characterized by a myelomonocytic differentiation bias, we hypothesized that CMML and aged hematopoiesis may be closely related. We initially established the somatic mutation landscape of CMML by whole exome sequencing followed by gene-targeted validation. Genes mutated in ⩾10% of patients were SRSF2, TET2, ASXL1, RUNX1, SETBP1, KRAS, EZH2, CBL and NRAS, as well as the novel CMML genes FAT4, ARIH1, DNAH2 and CSMD1. Most CMML patients (71%) had mutations in ⩾2 ARCH genes and 52% had ⩾7 mutations overall. Higher mutation burden was associated with shorter survival. Age-adjusted population incidence and reported ARCH mutation rates are consistent with a model in which clinical CMML ensues when a sufficient number of stochastically acquired age-related mutations has accumulated, suggesting that CMML represents the leukemic conversion of the myelomonocytic-lineage-biased aged hematopoietic system.

shRNA library screening identifies nucleocytoplasmic transport as a mediator of BCR-ABL1 kinase-independent resistance

The mechanisms underlying tyrosine kinase inhibitor (TKI) resistance in chronic myeloid leukemia (CML) patients lacking explanatory BCR-ABL1 kinase domain mutations are incompletely understood. To identify mechanisms of TKI resistance that are independent of BCR-ABL1 kinase activity, we introduced a lentiviral short hairpin RNA (shRNA) library targeting ∼5000 cell signaling genes into K562(R), a CML cell line with BCR-ABL1 kinase-independent TKI resistance expressing exclusively native BCR-ABL1. A customized algorithm identified genes whose shRNA-mediated knockdown markedly impaired growth of K562(R) cells compared with TKI-sensitive controls. Among the top candidates were 2 components of the nucleocytoplasmic transport complex, RAN and XPO1 (CRM1). shRNA-mediated RAN inhibition or treatment of cells with the XPO1 inhibitor, KPT-330 (Selinexor), increased the imatinib sensitivity of CML cell lines with kinase-independent TKI resistance. Inhibition of either RAN or XPO1 impaired colony formation of CD34(+) cells from newly diagnosed and TKI-resistant CML patients in the presence of imatinib, without effects on CD34(+) cells from normal cord blood or from a patient harboring the BCR-ABL1(T315I) mutant. These data implicate RAN in BCR-ABL1 kinase-independent imatinib resistance and show that shRNA library screens are useful to identify alternative pathways critical to drug resistance in CML.

BCR-ABL1 compound mutations combining key kinase domain positions confer clinical resistance to ponatinib in Ph chromosome-positive leukemia

Ponatinib is the only currently approved tyrosine kinase inhibitor (TKI) that suppresses all BCR-ABL1 single mutants in Philadelphia chromosome-positive (Ph(+)) leukemia, including the recalcitrant BCR-ABL1(T315I) mutant. However, emergence of compound mutations in a BCR-ABL1 allele may confer ponatinib resistance. We found that clinically reported BCR-ABL1 compound mutants center on 12 key positions and confer varying resistance to imatinib, nilotinib, dasatinib, ponatinib, rebastinib, and bosutinib. T315I-inclusive compound mutants confer high-level resistance to TKIs, including ponatinib. In vitro resistance profiling was predictive of treatment outcomes in Ph(+) leukemia patients. Structural explanations for compound mutation-based resistance were obtained through molecular dynamics simulations. Our findings demonstrate that BCR-ABL1 compound mutants confer different levels of TKI resistance, necessitating rational treatment selection to optimize clinical outcome.

Combined STAT3 and BCR-ABL1 inhibition induces synthetic lethality in therapy-resistant chronic myeloid leukemia

Mutations in the BCR-ABL1 kinase domain are an established mechanism of tyrosine kinase inhibitor (TKI) resistance in Philadelphia chromosome-positive leukemia, but fail to explain many cases of clinical TKI failure. In contrast, it is largely unknown why some patients fail TKI therapy despite continued suppression of BCR-ABL1 kinase activity, a situation termed BCRABL1 kinase-independent TKI resistance. Here, we identified activation of signal transducer and activator of transcription 3 (STAT3) by extrinsic or intrinsic mechanisms as an essential feature of BCR-ABL1 kinase-independent TKI resistance. By combining synthetic chemistry, in vitro reporter assays, and molecular dynamics-guided rational inhibitor design and high-throughput screening, we discovered BP-5-087, a potent and selective STAT3 SH2 domain inhibitor that reduces STAT3 phosphorylation and nuclear transactivation. Computational simulations, fluorescence polarization assays, and hydrogen-deuterium exchange assays establish direct engagement of STAT3 by BP-5-087 and provide a high-resolution view of the STAT3 SH2 domain/BP-5-087 interface. In primary cells from CML patients with BCR-ABL1 kinase-independent TKI resistance, BP-5-087 (1.0 μM) restored TKI sensitivity to therapy-resistant CML progenitor cells, including leukemic stem cells (LSCs). Our findings implicate STAT3 as a critical signaling node in BCR-ABL1 kinase-independent TKI resistance, and suggest that BP-5-087 has clinical utility for treating malignancies characterized by STAT3 activation.

First-line Mammalian target of rapamycin inhibition in metastatic renal cell carcinoma: an analysis of practice patterns from the International Metastatic Renal Cell Carcinoma Database Consortium

INTRODUCTION/BACKGROUND

Approval of the mTOR inhibitors for the treatment of mRCC was based on efficacy in poor-risk patients in the first-line setting for temsirolimus and in vascular endothelial growth factor inhibitor-refractory patients for everolimus. We strove to characterize temsirolimus and everolimus use and effectiveness in the first-line setting.

PATIENTS AND METHODS

We performed a retrospective database analysis of mRCC patients who received mTOR inhibitors as first-line targeted therapy. The Kaplan-Meier product-limit method was used to estimate the distribution of progression-free survival (PFS) and overall survival (OS).

RESULTS

We identified 127 mRCC patients who had received a first-line mTOR inhibitor. Temsirolimus was administered in 93 patients (73%) and everolimus in 34 patients (27%). The main reasons for choice of temsirolimus were poor-risk disease (38%), non-clear cell histology (27%), and clinical trial availability (15%), whereas clinical trial (82%) and non-clear cell histology (6%) drove everolimus selection. Of the temsirolimus and everolimus patients, 58% and 32% were poor-risk according to the International mRCC Database Consortium criteria, respectively. The median PFS and OS were 3.4 and 12.5 months and 4.8 and 15.9 months with temsirolimus and everolimus, respectively. Although limited by small numbers, this study characterizes a real-world, international experience with the use of mTOR inhibition in treatment-naive mRCC patients.

CONCLUSION

Poor-risk RCC, non-clear cell histology, and clinical trials were the predominant reasons for mTOR inhibitor selection in the front-line setting. Because of the different patient populations in which they were administered, direct comparisons of the front-line efficacy of temsirolimus and everolimus cannot be made.

Impact of bone and liver metastases on patients with renal cell carcinoma treated with targeted therapy

BACKGROUND

The skeleton and liver are frequently involved sites of metastasis in patients with metastatic renal cell carcinoma (RCC).

OBJECTIVE

To analyze outcomes based on the presence of bone metastases (BMs) and/or liver metastases (LMs) in patients with RCC treated with targeted therapy.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a review from the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) of 2027 patients with metastatic RCC.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We analyzed the impact of the site of metastasis on overall survival (OS) and time-to-treatment failure. Statistical analyses were performed using multivariable Cox regression.

RESULTS AND LIMITATIONS

The presence of BMs was 34% overall, and when stratified by IMDC risk groups was 27%, 33%, and 43% in the favorable-, intermediate-, and poor-risk groups, respectively (p<0.001). The presence of LMs was 19% overall and higher in the poor-risk patients (23%) compared with the favorable- or intermediate-risk groups (17%) (p=0.003). When patients were classified into four groups based on the presence of BMs and/or LMs, the hazard ratio, adjusted for IMDC risk factors, was 1.4 (95% confidence interval [CI], 1.22-1.62) for BMs, 1.42 (95% CI, 1.17-1.73) for LMs, and 1.82 (95% CI, 1.47-2.26) for both BMs and LMs compared with other metastatic sites (p<0.0001). The prediction model performance for OS was significantly improved when BMs and LMs were added to the IMDC prognostic model (likelihood ratio test p<0.0001). Data in this analysis were collected retrospectively.

CONCLUSIONS

The presence of BMs and LMs in patients treated with targeted agents has a negative impact on survival. Patients with BMs and/or LMs may benefit from earlier inclusion on clinical trials of novel agents or combination-based therapies.

An inherited disorder with splenomegaly, cytopenias, and vision loss

We describe a novel inherited disorder consisting of idiopathic massive splenomegaly, cytopenias, anhidrosis, chronic optic nerve edema, and vision loss. This disorder involves three affected patients in a single non-consanguineous Caucasian family, a mother and two daughters, who are half-sisters. All three patients have had splenectomies; histopathology revealed congestion of the red pulp, but otherwise no abnormalities. Electron microscopic studies of splenic tissue showed no evidence for a storage disorder or other ultrastructural abnormality. Two of the three patients had bone marrow examinations that were non-diagnostic. All three patients developed progressive vision loss such that the two oldest patients are now blind, possibly due to a cone-rod dystrophy. Characteristics of vision loss in this family include early chronic optic nerve edema, and progressive vision loss, particularly central and color vision. Despite numerous medical and ophthalmic evaluations, no diagnosis has been discovered.