Caitlin Costello

Ipilimumab for Patients with Relapse after Allogeneic Transplantation

BACKGROUND Loss of donor-mediated immune antitumor activity after allogeneic hematopoietic stem-cell transplantation (HSCT) permits relapse of hematologic cancers. We hypothesized that immune checkpoint blockade established by targeting cytotoxic T-lymphocyte-associated protein 4 with ipilimumab could restore antitumor reactivity through a graft-versus-tumor effect. METHODS We conducted a phase 1/1b multicenter, investigator-initiated study to determine the safety and efficacy of ipilimumab in patients with relapsed hematologic cancer after allogeneic HSCT. Patients received induction therapy with ipilimumab at a dose of 3 or 10 mg per kilogram of body weight every 3 weeks for a total of 4 doses, with additional doses every 12 weeks for up to 60 weeks in patients who had a clinical benefit. RESULTS A total of 28 patients were enrolled. Immune-related adverse events, including one death, were observed in 6 patients (21%), and graft-versus-host disease (GVHD) that precluded further administration of ipilimumab was observed in 4 patients (14%). No responses that met formal response criteria occurred in patients who received a dose of 3 mg per kilogram. Among 22 patients who received a dose of 10 mg per kilogram, 5 (23%) had a complete response, 2 (9%) had a partial response, and 6 (27%) had decreased tumor burden. Complete responses occurred in 4 patients with extramedullary acute myeloid leukemia and 1 patient with the myelodysplastic syndrome developing into acute myeloid leukemia. Four patients had a durable response for more than 1 year. Responses were associated with in situ infiltration of cytotoxic CD8+ T cells, decreased activation of regulatory T cells, and expansion of subpopulations of effector T cells in the blood. CONCLUSIONS Our early-phase data showed that administration of ipilimumab was feasible in patients with recurrent hematologic cancers after allogeneic HSCT, although immune-mediated toxic effects and GVHD occurred. Durable responses were observed in association with several histologic subtypes of these cancers, including extramedullary acute myeloid leukemia. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT01822509.).

Multiple Myeloma, version 3.2018: Featured updates to the NCCN guidelines

The NCCN Guidelines for Multiple Myeloma provide recommendations for diagnosis, evaluation, treatment, including supportive-care, and follow-up for patients with myeloma. These NCCN Guidelines Insights highlight the important updates/changes specific to the myeloma therapy options in the 2018 version of the NCCN Guidelines.

An update on the role of daratumumab in the treatment of multiple myeloma.

Monoclonal antibodies (mAbs) have emerged as a promising new drug class for the treatment of multiple myeloma (MM). Daratumumab (DARA), a CD38 mAb, has demonstrated safety, tolerability and activity in a range of clinical trials, both as monotherapy and in combination strategies for MM. The favorable efficacy results in heavily pretreated patients with advanced MM have provided the rationale for the investigation of DARA in a number of ongoing and future phase II and III trials. The general tolerability of mAbs has allowed for widespread investigation and use of DARA among a variety of MM patients, however their use requires special consideration. Infusion-related reactions (IRRs), interference with blood compatibility assays and response assessments are all unique factors related to the use of DARA. This review provides an update of the results from the DARA clinical trials conducted to date, its future plans for investigation, and practical management considerations for the use of DARA in daily practice.

Next-Generation Sequencing Reveals Potentially Actionable Alterations in the Majority of Patients With Lymphoid Malignancies

Next generation sequencing (NGS) identifies alterations that may be potentially targetable by Food and Drug Administration (FDA) approved drugs and/or by available experimental agents that may not have otherwise been contemplated. Many targeted drugs have been developed for diverse solid cancers; a smaller number of genomically targeted drugs have been approved for lymphoid malignancies. We analyzed NGS results from 60 patients with various lymphoid malignancies and found a total of 224 alterations (median per patient = 3). Forty-nine patients (82%) had potentially actionable alterations using FDA-approved drugs and/or experimental therapies; only 11 patients (18%) had no theoretically actionable alterations. Only three patients (5%) had an alteration for which an approved drug in the disease is available (on-label); 45 patients (75%) had an alteration for which an approved drug is available in another disease (off-label). The median number of alterations per patient potentially actionable by an FDA-approved drug was 1. Interestingly, 19 of 60 patients (32%) had intermediate to high tumor mutational burden, which may predict response to certain immunotherapy agents. In conclusion, NGS identifies alterations that may be pharmacologically tractable in most patients with lymphoid malignancies, albeit with drugs that have usually been developed in the context of solid tumors. These observations merit expanded exploration in the clinical trials setting.

Alu-dependent RNA editing of GLI1 promotes malignant regeneration in multiple myeloma

Despite novel therapies, relapse of multiple myeloma (MM) is virtually inevitable. Amplification of chromosome 1q, which harbors the inflammation-responsive RNA editase adenosine deaminase acting on RNA (ADAR)1 gene, occurs in 30–50% of MM patients and portends a poor prognosis. Since adenosine-to-inosine RNA editing has recently emerged as a driver of cancer progression, genomic amplification combined with inflammatory cytokine activation of ADAR1 could stimulate MM progression and therapeutic resistance. Here, we report that high ADAR1 RNA expression correlates with reduced patient survival rates in the MMRF CoMMpass data set. Expression of wild-type, but not mutant, ADAR1 enhances Alu-dependent editing and transcriptional activity of GLI1, a Hedgehog (Hh) pathway transcriptional activator and self-renewal agonist, and promotes immunomodulatory drug resistance in vitro. Finally, ADAR1 knockdown reduces regeneration of high-risk MM in serially transplantable patient-derived xenografts. These data demonstrate that ADAR1 promotes malignant regeneration of MM and if selectively inhibited may obviate progression and relapse.The treatment of multiple myeloma is challenging due to high relapse rates. Here the authors show that expression of ADAR1 correlates with poor patient outcomes, and that ADAR1-mediated editing of GLI1 is a mechanism relevant in the context of multiple myeloma progression and drug resistance.

Abstract 3351: Aberrant RNA editing of GLI1 promotes malignant regeneration in multiple myeloma

Introduction: Despite novel therapies, most of multiple myeloma (MM) patients relapse as a result of clonal evolution in inflammatory microenvironments. Adenosine-to-inosine (A-to-I) RNA editing, driven by inflammatory cytokine-responsive adenosine deaminase acting on RNA1 (ADAR1), promotes cancer progression by enhancing survival and self-renewal of malignant progenitor cells. Amplifications of chromosome 1q21, containing IL-6R and ADAR1 loci, occur frequently in high-risk MM patients, who frequently develop secondary plasma cell leukemia (PCL) and have shorter survival. While increased IL-6 signaling has been linked to relapse and A-to-I editing contributes to therapeutic resistance in a broad array of malignancies, the role of ADAR1 in MM pathogenesis has not been elucidated. This study aimed to investigate whether pro-inflammatory cues in MM activate ADAR1 editing thereby promoting malignant regeneration. Procedures: Publicly available primary patient datasets were analyzed and validated in a separate cohort of biobanked primary samples and human myeloma cell lines. Lentiviral vector-mediated activation or knockdown of ADAR1, or treatment with extrinsic pro-inflammatory stimuli, was utilized to probe the functional impact of RNA editing activity in MM models. Site-specific qPCR was used to quantify RNA editing in specific cancer stem cell-associated loci. Functional effects of ADAR1 activity were assessed in in vitro survival and self-renewal assays, and in novel in vivo PCL xenografts. Results: Patients harboring 1q21 amplification showed significant and stage-dependent increases in ADAR1 expression. In a set of separate primary PCL samples, aberrant RNA editing in the coding region of the Hedgehog (Hh) pathway transcription factor GLI1 was observed in high ADAR1-expressing samples. Notably, increased GLI1 editing, previously reported to have increased capacity to activate its transcriptional targets, was detected in serially transplantable, patient-derived xenograft models. Furthermore, abolition of ADAR1 editase activity impaired GLI1 editing. Lastly, in vitro pro-inflammatory IL-6 stimulation, or continuous exposure to the immunomodulatory drug lenalidomide led to increased ADAR1 mRNA and protein levels, with a concomitant induction of RNA editing activity. Conclusions: In MM, 1q21 amplification has been linked to progression. We provide new evidence linking expression and activity of ADAR1, located on 1q21, and disease stage. Because ADAR1 induces transcript recoding, A-to-I editing could contribute to the marked transcriptomic diversity typical of advanced MM. While the Hh pathway has been linked to cancer stem cell generation in human MM, here we identified a primate-specific mechanism of Hh pathway activation in MM through RNA editing-dependent stabilization of GLI1. Together, both genetic and microenvironmental factors modulate epitranscriptomic deregulation of cancer stem cell pathways in MM. Citation Format: Elisa Lazzari, Nathaniel Delos Santos, Christina Wu, Heather Leu, Gabriel Pineda, Shawn Ali, Caitlin Costello, Mark Minden, Raffaella Chiaramonte, Leslie Crews, Catriona Jamieson. Aberrant RNA editing of GLI1 promotes malignant regeneration in multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3351. doi:10.1158/1538-7445.AM2017-3351

Abstract 4437: Down-modulation of ADAR1-mediated GLI1 editing alters extracellular and immune response genes in multiple myeloma

Introduction: Representing 10% of hematologic malignancies, multiple myeloma (MM) is typified by clonal plasma cell proliferation in the bone marrow (BM) and may progress to therapy-resistant plasma cell leukemia (PCL). Despite many novel therapies, relapse rates remain high as a result of malignant regeneration (self-renewal) of MM cells in inflammatory microenvironments. In addition to recurrent DNA mutations and epigenetic deregulation, inflammatory cytokine-responsive adenosine deaminase associated with RNA (ADAR1)-mediated adenosine to inosine (A-to-I) RNA editing has emerged as a key driver of cancer relapse and progression. In MM, copy number amplification of chromosome 1q21, which contains both ADAR1 and interleukin-6 receptor (IL-6R) gene loci, portends a poor prognosis. Thus, we hypothesized that ADAR1 copy number amplification combined with inflammatory cytokine activation of ADAR1 stimulates malignant regeneration of MM and therapeutic resistance. Methods and Results: Analysis of MMRF CoMMpass RNA sequencing (RNA-seq) data revealed that high ADAR1 expression (n=162 patients) correlated with significantly reduced progression-free and overall survival compared with a low ADAR1 subset (n=159 patients). In contrast to lentiviral ADAR1 shRNA knockdown and overexpression of an editase defective ADAR1 mutant (ADAR1 E912A ), lentiviral wild-type ADAR1 overexpression enhanced editing of GLI1, a Hedgehog (Hh) pathway transcriptional activator and self-renewal agonist. Editing of GLI1 transcripts enhanced GLI transcriptional activity in luciferase reporter assays, and promoted lenalidomide resistance in vitro. Finally, lentiviral shRNA ADAR1 knockdown reduced regeneration of high-risk MM in humanized serial transplantation mouse models, indicative of reduced malignant self-renewal capacity. Whole-transcriptome RNA-sequencing of primary samples after lentiviral shRNA knockdown of ADAR1 revealed specific modulation of extracellular and immune response genes, while overexpression of wild-type versus edited GLI1 elicited distinct gene expression changes in human myeloma cells analyzed using NanoString nCounter assays. These data demonstrate that ADAR1 promotes malignant self-renewal of MM and, if selectively inhibited, may prevent progression and relapse through modulation of extracellular and immune response genes. Conclusions: Deregulated RNA editing, driven by aberrant ADAR1 activation, represents a unique source of transcriptomic and proteomic diversity, resulting in self-renewal of MM cells in inflammatory microenvironments. In summary, both genetic (1q21 amplification) and microenvironmental factors (inflammatory cytokines, IMiDs) combine to drive GLI1-dependent malignant regeneration in MM. Thus, ADAR1 represents both a vital prognostic biomarker and therapeutic target in MM. Citation Format: Leslie A. Crews, Elisa Lazzari, Phoebe K. Mondala, Nathaniel Delos Santos, Amber Miller, Gabriel Pineda, Qingfei Jiang, Anusha-Preethi Ganesan, Christina Wu, Caitlin Costello, Mark Minden, Raffaella Chiaramonte, A. Keith Stewart, Catriona H. M. Jamieson. Down-modulation of ADAR1-mediated GLI1 editing alters extracellular and immune response genes in multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4437.

Ibrutinib alone or with dexamethasone for relapsed or relapsed and refractory multiple myeloma: Phase 2 trial results

Novel therapies with unique new targets are needed for patients who are relapsed/refractory to current treatments for multiple myeloma. Ibrutinib is a first‐in‐class, once‐daily, oral covalent inhibitor of Bruton tyrosine kinase, which is overexpressed in the myeloma stem cell population. This study examined various doses of ibrutinib ± low‐dose dexamethasone in patients who received ≥2 prior lines of therapy, including an immunomodulatory agent. Daily ibrutinib ± weekly dexamethasone 40 mg was assessed in 4 cohorts using a Simon 2‐stage design. The primary objective was clinical benefit rate (CBR; ≥minimal response); secondary objectives included safety. Patients (n = 92) received a median of 4 prior regimens. Ibrutinib + dexamethasone produced the highest CBR (28%) in Cohort 4 (840 mg + dexamethasone; n = 43), with median duration of 9·2 months (range, 3·0–14·7). Progression‐free survival was 4·6 months (range, 0·4–17·3). Grade 3–4 haematological adverse events included anaemia (16%), thrombocytopenia (11%), and neutropenia (2%); grade 3–4 non‐haematological adverse events included pneumonia (7%), syncope (3%) and urinary tract infection (3%). Ibrutinib + dexamethasone produced notable responses in this heavily pre‐treated population. The encouraging efficacy, coupled with the favourable safety and tolerability profile of ibrutinib, supports its further evaluation as part of combination treatment.

Abstract 2414: ADAR1-dependent RNA editing is a mechanism of therapeutic resistance in human plasma cell malignancies

Introduction Multiple myeloma (MM) is a plasma cell malignancy that accounts for more than 10% of all blood cancers and may progress to plasma cell leukemia (PCL). Despite treatment, virtually all patients become unresponsive to treatment. RNA editing is a post-transcriptional pre-mRNA processing activity that represents an unexplored potential source of clonal molecular heterogeneity contributing to therapeutic resistance. In particular, adenosine deaminase acting on RNA (ADAR) 1, which exists in two isoforms, one constitutive and one inflammation-responsive, has been associated with disease progression and cancer stem cell (CSC) maintenance. The aim of this study was to investigate whether enhanced ADAR1 expression and activity contributed to therapeutic resistance of MM and PCL. Procedures 1) ADAR Quantification: Whole gene and isoform-specific qRT-PCR was used to detect ADAR1 expression in PCL and MM primary samples and in human MM cell lines (HMCL). 2) RNA Editing Detection: We developed a RNA editing site-specific qPCR (RESS-qPCR) assay to detect RNA editing in cancer stem-cell associated transcripts. 3) Therapeutic Resistance Assay. A MM cell line was exposed to lenalidomide continuously in vitro to establish a model of therapeutic resistance. 4) Development of a humanized PCL mouse model: We established novel in vivo PCL primagrafts by intrahepatic transplantation of primary total mononuclear cells into neonatal RAG2-/-gc-/- mice. Results Approximately, 30% of MM patients in the MM Genomic Initiative dataset harbor copy number amplifications of the ADAR locus on chromosome 1q21, which portends a poor prognosis. We observed significantly increased ADAR1 expression in primary PCL samples and aberrant RNA editing of the stem cell transcription factor GLI1 and the DNA cytidine deaminase APOBEC3D. Notably, high-ADAR1-expressing PCL cells successfully engrafted in RAG2-/-gc-/- mice. As the inflammation-responsive isoform of ADAR1 was upregulated in primary samples, we sought to explore the effects of the anti-MM agent and immunomodulatory drug lenalidomide on ADAR1 expression and activity. Continuous in vitro exposure to lenalidomide led to increased ADAR1 mRNA and protein level and a potent induction of RNA editing activity. Increased RNA editing was detected in several cancer and stem cell-associated transcripts, including GLI1, APOBEC3D, AZIN1 and MDM2. Notably, this aberrant RNA editing activity was associated with increased self-renewal capacity in vitro and a cancer stem cell phenotype. Conclusions ADAR1 overexpression and deregulated RNA editing represents a unique source of RNA and proteomic diversity, and may confer a survival and self-renewal advantage to MM cells. This research identifies ADAR1 as a new diagnostic and therapeutic target in MM, and establishes a robust humanized PCL primagraft model for future pre-clinical testing of ADAR1 modulatory agents. Citation Format: Elisa Lazzari, Leslie A. Crews, Christina Wu, Heather Leu, Shawn Ali, Raffaella Chiaramonte, Mark Minden, Caitlin Costello, Catriona H.M. Jamieson. ADAR1-dependent RNA editing is a mechanism of therapeutic resistance in human plasma cell malignancies. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2414.