Rita Assi

Immune therapies in acute myeloid leukemia: A focus on monoclonal antibodies and immune checkpoint inhibitors

Purpose of review This review discusses the rationale, efficacy, and toxicity of a variety of immune approaches being evaluated in the therapy of acute myeloid leukemia (AML) including naked and conjugated monoclonal antibodies, bispecific T-cell engager antibodies, and immune checkpoint blockade via antibodies targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed-death 1 (PD-1). Recent findings The stellar success of immune therapies that harness the power of T cells in solid tumors and an improved understanding of the immune system in patients with hematologic malignancies have resulted in major efforts to develop immune therapies for the treatment of patients with AML. Monoclonal antibodies in AML therapy include naked antibodies against AML surface antigens such as CD33 (e.g. lintuzumab) or CD38 (e.g. daratumumab), antibodies conjugated to toxins in various anti-CD33 (gemtuzumab ozogamicin, SGN33A, IMGN779) and anti-CD123 (SL-401, SGN-CD123A) formulations, and antibodies conjugated to radioactive particles such as 131I or 225Ac-labeled anti-CD33 or anti-CD45 antibodies. Additional antigenic targets of interest in AML include CLL1, CD38, CD25, TIM3, FLT3, and others. Approaches to harness the bodys own T cells against AML include antibodies that recruit and induce cytotoxicity of tumor cells by T cells (bispecific T-cell engager [BiTE] such as CD33 x CD3 (e.g. AMG 330) or CD123 x CD3 (e.g. flotetuzumab, JNJ-63709178) or antibodies that block immune checkpoint receptors CTLA4 (e.g. ipilimumab) or PD1/PD-L1 (e.g. nivolumab, pembrolizumab, avelumab) on T cells, unleashing the patients’ T cells against leukemic cells. Summary The ongoing trials and well designed correlative interrogation of the immune system in patients treated on such trials will further enhance our understanding and clinical application of immune therapies as single-agent and combination approaches for the treatment of AML.

Safety and Efficacy of Blinatumomab in Combination with a Tyrosine Kinase Inhibitor for the Treatment of Relapsed Philadelphia Chromosome-Positive Leukemia

Micro‐Abstract The prognosis of patients with relapsed refractory Philadelphia chromosome–positive acute leukemia is considered poor. The combination of blinatumomab and a TKI resulted in high overall response rates among 13 patients. These results are promising and this strategy may minimize the use of chemotherapy in this setting. Objective: The treatment of Philadelphia chromosome‐positive (Ph+) acute lymphoblastic leukemia has been revolutionized with the introduction of tyrosine kinase inhibitors (TKIs) and the combination of these agents with chemotherapy. Blinatumomab is a bispecific anti‐CD3/CD19 monoclonal antibody with clinical activity as single‐agent in the relapsed setting and independent of BCR‐ABL1 mutational status, including T315I. The combination of blinatumomab with a TKI may further improve outcomes for this high‐risk population, including higher eradication of minimal residual disease and minimize the use of chemotherapy. Patients and Methods: We retrospectively studied 12 adults with relapsed/refractory Ph+ acute lymphoblastic leukemia (n = 9) and chronic myeloid leukemia in blast crisis (n = 3), treated with the combination blinatumomab and a TKI (ponatinib, n = 8; dasatinib, n = 3; bosutinib, n = 1). All patients have previously failed at least 1 line of chemotherapy, including allogeneic stem cell transplantation, and 1 class of TKIs. Patients were treated for either overt hematologic relapse (n = 6) or persistent minimal residual disease following other regimens (n = 6). Results: The complete hematologic, cytogenetic, and molecular response rates were 50% (3/6), 71% (5/7), and 75% (9/12), respectively. Two cases of grade 2 cytokine release syndrome were observed, all of which resolved with steroids and tocilizumab. No cardiovascular adverse events were encountered. With a median follow‐up of 8 months, the median survival was not reached; the 6‐month and 1‐year overall survival rates were 73%. Conclusions: The combination of blinatumomab with TKI is safe and effective in patients with relapsed/refractory Ph+ disease. Prospective studies are warranted.

A phase II trial of ruxolitinib in combination with azacytidine in myelodysplastic syndrome/myeloproliferative neoplasms

Ruxolitinib and azacytidine target distinct disease manifestations of myelodysplastic syndrome/myeloproliferative neoplasms (MDS/MPNs). Patients with MDS/MPNs initially received ruxolitinib BID (doses based on platelets count), continuously in 28‐day cycles for the first 3 cycles. Azacytidine 25 mg/m2 (Day 1‐5) intravenously or subcutaneously was recommended to be added to each cycle starting cycle 4 and could be increased to 75 mg/m2 (Days 1‐5) for disease control. Azacytidine could be started earlier than cycle 4 and/or at higher dose in patients with rapidly proliferative disease or with elevated blasts. Thirty‐five patients were treated (MDS/MPN‐U, n =14; CMML, n =17; aCML, n =4), with a median follow‐up of 15.2 months (range, 1.0–41.5). All patients were evaluable by the 2015 international consortium proposal of response criteria for MDS/MPNs (ICP MDS/MPN) and 20 (57%) responded. Nine patients (45%) responded after the addition of azacytidine. A greater than 50% reduction in palpable splenomegaly at 24 weeks was noted in 9/14 (64%) patients. Responders more frequently were JAK2‐mutated (P = .02) and had splenomegaly (P = .03) compared to nonresponders. New onset grade 3/4 anemia and thrombocytopenia occurred in 18 (51%) and 19 (54%) patients, respectively, but required therapy discontinuation in only 1 (3%) patient. Patients with MDS/MPN‐U had better median survival compared to CMML and aCML (26.5 vs 15.1 vs 8 months; P = .034). The combination of ruxolitinib and azacytidine was well‐tolerated with an ICP MDS/MPN‐response rate of 57% in patients with MDS/MPNs. The survival benefit was most prominent in patients with MDS/MPN‐U.

'JAK-ing' up the treatment of primary myelofibrosis: Building better combination strategies

Purpose of review The article discusses the promising agents that are approved or currently under investigation for the treatment of myelofibrosis and reviews the ongoing Janus kinase (JAK) inhibitors–based combinatorial strategies in this setting. Recent findings Myelofibrosis is a Philadelphia-negative myeloproliferative neoplasm with constitutive JAK/STAT activation. The JAK-inhibitor ruxolitinib is the only approved drug for this disease in the United States and Europe based on two randomized phase III studies that demonstrated clinically meaningful reduction in spleen size, improvement in symptoms, quality of life, and an overall survival advantage with prolonged follow-up. Emerging data have revealed the complex molecular architecture of myelofibrosis with clonal evolution playing a central role in disease progression or transformation. These molecular pathways may explain the heterogeneous benefits obtained by JAK-inhibitors in patients with myelofibrosis. In addition, the genetic and epigenetic mutations appear to work in concert with overactive JAK/STAT signaling and contribute to myelofibrosis pathogenesis and prognosis, suggesting a potential to exploit them as potential therapeutic targets. Summary Combining JAK-inhibitors with agents that target parallel prosurvival pathways or agents that enhance hematopoiesis may enhance efficacy and/or mitigate on-target myelosuppression, thereby extending the therapeutic benefits observed with JAK-inhibitors alone.

Final results of a phase 2, open-label study of indisulam, idarubicin, and cytarabine in patients with relapsed or refractory acute myeloid leukemia and high-risk myelodysplastic syndrome

Indisulam possesses anticancer properties through down‐regulation of various cell‐cycle checkpoint molecules, thereby blocking the phosphorylation of retinoblastoma protein and inducing p53 and p21. Indisulam exhibits synergy with nucleoside analogs and topoisomerase inhibitors.

Addition of eltrombopag to immunosuppressive therapy in patients with newly diagnosed aplastic anemia

The immune‐mediated destruction of hematopoietic stem cells is implicated in the pathophysiology of aplastic anemia (AA). Immunosuppressive therapy (IST) using antithymocyte globulin and cyclosporine is successful in this setting. Eltrombopag is active in patients with refractory AA, presumably by increasing the bone marrow progenitors.

FLT3 inhibitors in acute myeloid leukemia: Choosing the best when the optimal does not exist

Despite significant advances in deciphering the molecular and cytogenetic pathways governing acute myeloid leukemia, improvements in treatment strategies and clinical outcomes have been limited. The discovery of FLT3 pathway and its potential role in leukemogenesis has generated excitement in the field and has provided a potential target for drug development. Despite setbacks encountered with first‐generation inhibitors, we are witnessing an outbreak of novel agents with potent activity and improved pharmacodynamics which continue to generate promising results. The disease, however, remains a challenge to both patients and physicians with rapid emergence of resistance and subsequent treatment failure. Multiple unanswered questions remain as to which are the optimal FLT3‐inhibitors and which strategies and combinations are likely to overcome resistance. This review revisits the development of FLT3‐inhibitors, the pathways incriminated in their failure and summarizes available molecularly‐designed strategies to design better clinical trials.

P53 protein overexpression in de novo acute myeloid leukemia patients with normal diploid karyotype correlates with FLT3 internal tandem duplication and worse relapse-free survival

Although ~50% of acute myeloid leukemia (AML) patients have a normal diploid karyotype by conventional cytogenetics at diagnosis, this patient subset has a variable disease course and outcome. Aberrant overexpression of the p53 protein is usually associated with TP53 alterations and a complex karyotype, but the prevalence and impact of p53 overexpression in AML with diploid cytogenetics is unknown. We examined 100 newly diagnosed AML patients to evaluate the impact of p53 expression status quantified in bone marrow core biopsy samples using immunohistochemistry and computer‐assisted image analysis. A total of 24 patients had p53 overexpression defined as 3+ staining intensity in ≥5% of cells; this finding correlated with lower platelet counts (P = .002), absence of CD34 expression in blasts (P = .009), higher bone marrow blast counts (P = .04), and a higher frequency of FLT3 internal tandem duplication (P = .007). Overexpression of p53 independently predicted for shorter leukemia‐free survival in patients who underwent allogeneic stem cell transplantation by univariate (P = .021) and multivariate analyses (P = .004). There was no correlation between MDM2 and p53 protein expression in this cohort. We conclude that p53 expression evaluated by immunohistochemistry in bone marrow biopsy specimens at the time of AML diagnosis may indicate distinct clinical characteristics in patients with normal diploid cytogenetics and is a potentially valuable tool that can enhance risk‐stratification.

A Phase I/II Study of Selinexor (SEL) with Sorafenib in Patients (pts) with Relapsed and/or Refractory (R/R) FLT3 Mutated Acute Myeloid Leukemia (AML)

AML-025 A Phase I/II Study of Selinexor (SEL) with Sorafenib in Patients (pts) with Relapsed and/or Refractory (R/R) FLT3 Mutated Acute Myeloid Leukemia (AML) Naval Daver, Rita Assi, Farhad Ravandi, Guillermo Garcia-Manero, Elias Jabbour, Courtney D. DiNardo, Tapan M. Kadia, Jing Ning, Graciela Nogueras-Gonzalez, Sherry Pierce, Dan Gombos, Steven Kornblau, Marina Konopleva, Mary Kelly, Gautam Borthakur, Weiguo Zhang, Jorge Cortes, Hagop Kantarjian, Michael Andreeff Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA; Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA; Department of Ophthalmology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA

Hemophagocytic lymphohistiocytosis in adults: An under recognized entity

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of severe immune activation with macrophage and T-cell infiltration resulting in, multi organ damage. HLH may be primary or secondary in etiology. A high index of suspicion is essential for early diagnosis and treatment. Diagnostic criteria need to be refined and newer treatment options to be explored in order to improve survival especially in adult HLH and malignancy-associated HLH (M-HLH). We report a case of malignancy associated HLH (M-HLH) in adult treated on one of the only FDA-approved protocols for adult HLH to highlight the diagnostic and therapeutic challenges of this disease entity.