Aggressive Chemotherapy Research Articles

A Multi-cohort Study of the Prognostic Significance of Microsatellite Instability or Mismatch Repair Status after Recurrence of Resectable Gastric Cancer.

PurposeHigh microsatellite instability (MSI) is related to good prognosis in gastric cancer. We aimed to identify the prognostic factors of patients with recurrent gastric cancer and investigate the role of MSI as a prognostic and predictive biomarker of survival after tumor recurrence.Materials and MethodsThis retrospective cohort study enrolled patients treated for stage II/III gastric cancer who developed tumor recurrence and in whom the MSI status or mismatch repair (MMR) status of the tumor was known. MSI status and the expression of MMR proteins were evaluated using polymerase chain reaction and immunohistochemical analysis, respectively.ResultsOf the 790 patients included, 64 (8.1%) had high MSI status or MMR deficiency. The tumor-node-metastasis stage, type of recurrence, Lauren classification, chemotherapy after recurrence, and interval to recurrence were independently associated with survival after tumor recurrence. The MSI/MMR status and receiving adjuvant chemotherapy were not associated with survival after recurrence. In a subgroup analysis of patients with high MSI or MMR-deficient gastric cancer, those who did not receive adjuvant chemotherapy had better treatment response to chemotherapy after recurrence than those who received adjuvant chemotherapy.ConclusionPatients with high MSI/MMR-deficient gastric cancer should be spared from adjuvant chemotherapy after surgery, but aggressive chemotherapy after recurrence should be considered. Higher tumor-node-metastasis stage, Lauren classification, interval to recurrence, and type of recurrence are associated with survival after tumor recurrence and should thus be considered when establishing a treatment plan and designing clinical trials targeting recurrent gastric cancer.

In vivo antitumoral effect of 4-nerolidylcatechol (4-NC) in NRAS-mutant human melanoma

NRAS-mutations arise in 15–20% of all melanomas and are associated with aggressive disease and poor prognosis. Besides, the treatment for NRAS-mutant melanoma are not very efficient and is currently limited to immune checkpoints inhibitors or aggressive chemotherapy. 4-nerolidylcathecol (4-NC), a natural product extracted from Pothomorphe umbellata, induces apoptosis in melanoma cells by ROS production, DNA damage and increased p53 expression, in addition to inhibiting invasion in reconstructed skin. Moreover, 4-NC showed cytotoxicity in BRAF/MEKi-resistant and naive melanoma cells by Endoplasmic Reticulum (ER) stress induction in vitro. We evaluated the in vivo efficacy and the systemic toxicity of 4-NC in a NRAS-mutant melanoma model. 4-NC was able to significantly suppress tumor growth 4-fold compared to controls. Cleaved PARP and p53 expression were increased indicating cell death. As a proof of concept, MMP-2 and MMP-14 gene expression were decreased, demonstrating a possible role of 4-NC in melanoma invasion inhibition. Toxicological analysis indicated minor changes in the liver and bone marrow, but this toxicity was very mild when compared to other proteasome inhibitors and ER stress inductors already described. Our data indicate that 4-NC can counteract melanoma growth in vivo with minor adverse effects, suggesting further investigation as a potential NRAS-mutant melanoma treatment.

MYC rearrangement but not extra MYC copies is an independent prognostic factor in patients with mantle cell lymphoma.

Mantle cell lymphoma (MCL) with MYC rearrangement (MYC-R) is rare and little is known about the importance of MYC extra copies (EC) in the absence of MYC-R in MCL patients. This study includes 88 MCL patients with MYC tested by fluorescence in situ hybridization and/or conventional cytogenetics, including 27 with MYC-R, 21 with MYC-EC, and 40 with normal MYC-NL. MCL patients with MYC-R more often had blastoid/pleomorphic morphology; a higher frequency of CD10, MYC, and simultaneous MYC and BCL2 expression; a higher level of MYC; and a higher Ki67 proliferation rate (P<0.05) than those without MYC-R. Although patients with MYC-R more frequently received intensive chemotherapy (P=0.001), their overall survival (OS) was significantly shorter than those without MYC-R. Compared with patients with MYC/BCL2 double-hit lymphoma (DHL), patients with MYC-R MCL had a similar OS but more commonly had bone marrow involvement, Ann Arbor stage IV disease, and a different immunophenotype. MCL patients with MYC-EC showed an OS intermediate between those with MYC-R and MYC-NL, either all or only blastoid/pleomorphic MCL patients included. Multivariate analysis showed that MYC-R, but not MYC-EC, had an independent and negative impact on OS. In conclusion, MYC-R but not MYC-EC showed a higher MYC expression and is an adverse prognostic factor for MCL patients. Although the OS of MCL patients with MYC-R is similar to that of MYC/BCL2DHL patients, these groups have different clinicopathologic features supporting the retention of MCL with MYC-R in the category of MCL, as recommended in the revised World Health Organization classification.

Ewing’s sarcoma of proximal humerus: A rare case report

Ewing’s sarcoma is a highly malignant small round cell tumor from bone or soft tissue. The clinical manifestation is non-specific, with local pain being the most common symptom by far. It affects prevalently among children younger than ten years. The chromosomal translocation t(11;22)(q24:q12) is one of the causes of Ewing’s sarcoma. The gold standard diagnostic is incisional biopsy, additionally with cytogenic immunohistochemical. The current standard treatment for resectable Ewing’s sarcoma begins with neoadjuvant chemotherapy, followed by limb salvage procedure and postoperative adjuvant chemotherapy. After resection of Ewing’s sarcoma, the large bone defects should be reconstructed to restore the function of the affected limbs. The main options for reconstruction include autogenous bone grafts and endoprosthesis. Prognosis of Ewing’s sarcoma is highly dependent on clinically evident metastatic disease, which may be preventable with early detection and treatment with aggressive local disease control and systemic multidrug chemotherapy. This article presents a rare case of an 8-year-old elementary schoolboy, diagnosed with Ewing’s sarcoma of the proximal left humerus that was confirmed by plain radiograph and immunohistochemical biopsy. Patient’s family discontinued the chemotherapy schedule and ignored the surgical reconstruction procedure.

Outcome of Surgically Treated 79 Patients of Hepatic Hydatidosis: A Single Center Tertiary Care Hospital Experience in Bangladesh

Background: Proper patient selection for most appropriate treatment option for hepatic hydatid is crucial to ensure successful treatment outcome. Chemotherapy, newer approaches, like PAIR procedure, (puncture, aspiration, injection and reaspiration) laparoscopy are available. As the indications for these approaches are restricted, surgery remains the key treatment strategy with hope for complete cure. Radical surgical excision coupled with chemotherapy and long-term aggressive chemotherapy for partially resected ensures lowest morbidity and mortality.&#x0D; Methods: This cross sectional observational study of 15-year single-institution experience, intended to further validate different surgical procedures in management of hydatid disease of liver and its outcome. Patients were randomly selected irrespective of their age, sex and mode of presentation. Different preferred surgical treatment modalities, perioperative complications, recurrences, and length of hospital stay were retrospectively analyzed.&#x0D; Result: The study was carried out on 79 Bangladeshi patients diagnosed hepatic hydatidosis, treated surgically from January 2002 to December 2017 in BIRDEM General Hospital. Among them was no anastomotic leakage or mortality in the immediate postoperative period in our series.&#x0D; Conclusion: This study revealed, proper case selection and consideration of risks-benefits, indicationscontraindications for each case of Hydatid cyst of liver, for making a decision for type and timing of surgery is key to successful outcome. Surgery is the mainstay of treatment strategy. Radical surgery is key to effective and successful outcome, ensures better quality of life and prevents recurrence of the disease.&#x0D; Journal of Surgical Sciences (2018) Vol. 22 (2) : 118-124

Rab25-Mediated EGFR Recycling Causes Tumor Acquired Radioresistance.

SummaryTumor acquired radioresistance remains as the major limit in cancer radiotherapy (RT). Rab25, a receptor recycling protein, has been reported to be enhanced in tumors with aggressive phenotype and chemotherapy resistance. In this study, elevated Rab25 expression was identified in an array of radioresistant human cancer cell lines, in vivo radioresistant xenograft tumors. Clinical investigation confirmed that Rab25 expression was also associated with a worse prognosis in patients with lung adenocarcinoma (LUAD) and nasopharyngeal carcinoma (NPC). Enhanced activities of EGFR were observed in both NPC and LUAD radioresistant cells. Rab25 interacts with EGFR to enhance EGFR recycling to cell surface and to decrease degradation in cytoplasm. Inhibition of Rab25 showed synergized radiosensitivity with reduced aggressive phenotype. This study provides the clinical and experimental evidence that Rab25 is a potential therapeutic target to alleviate the hyperactive EGFR signaling and to prevent RT-acquired tumor resistance in patients with LUAD and NPC.

Recent advances in the treatment of pancreatic cancer.

Pancreatic ductal adenocarcinoma is one of the deadliest solid tumor malignancies and is projected to become a leading cause of cancer-related death in coming years. Improving quality of life and survival amongst these patients will require new ideas and novel therapies in a multidisciplinary approach. This review will cover the most recent advances in the comprehensive treatment of pancreatic cancer and place them within a historical context when necessary. Treatment of all disease stages will be discussed, but the focus is on systemic therapy as novel drugs and new treatment combinations enter the clinic. This will include more aggressive chemotherapy in earlier disease stages, approved uses for immunotherapy, and targetable mutations. In addition, negative trials of importance and controversial topics will be noted.

Abstract P6-11-16: Survey on attitude towards treatment recommendations for elderly patients with breast cancer

Abstract Background: With the rapid aging of the society, breast cancer in elderly people is also increasing. Although it is important to avoid unnecessary toxicity to maintain the quality of life of elderly patients, it is suggested that they are undertreated compared to younger counterparts which leads to poorer outcomes. The objective of this study was to assess the practice of the clinical care for elderly breast cancer patients aged 75 or over, and to explore the factors associated with physicians’ attitude regarding treatment recommendations towards elderly breast cancer patients in Japan. Methods: We conducted an online survey towards 1690 Breast Care Specialists belonging to the Japanese Breast Cancer Society. The respondents were asked to complete a questionnaire including (1) sociodemographic background, (2) hypothetical case scenarios in patients with Stage IIB breast cancer, (3) clinical experience of elderly breast cancer patients, (4) Good Death Inventory (GDI), a measure for evaluating good death from the bereaved family member's perspective and (5) belief regarding cancer treatment for elderly breast cancer patients. We used descriptive statistics to summarize respondents' sociodemographic data. Chi-square tests were used to evaluate differences in proportion. Differences in GDI scores were estimated using Mann-Whitney tests. Statistical analyses were performed using SPSS software. Results: 508 (30%) physicians responded to the survey. 353 (69.4%) were male. 464 (91.3%) were breast surgeons and 43 (8.4%) were others, including medical oncology, radiology and general surgery. 46 (9%), 115 (22.6%), 284 (55.9%) and 47 (9.3%) belonged to cancer centers, university hospitals, general hospitals and clinics, respectively. 136 (26.8%) of the physicians responded that they have a specialized department or a team which serve for elderly patients in their institutions, whereas 369 (72.6%) answered there was no such support. In questions based on hypothetical case scenarios, significantly more physicians responded that they would not recommend chemotherapy in a 78 year-old with luminal-type breast cancer, good performance status (PS) and no complications compared to a 55 year-old with the same clinical status (p&amp;lt;0.001). Physicians who would recommend chemotherapy significantly decreased in a clinical scenario of a 78 year-old with the same clinical stage and subtype but with a lower PS and some complications (p&amp;lt;0.001). More physicians recommended chemotherapy in a 78 year-old with HER2 type tumor compared to a patient with luminal type tumor when the PS and complication status were the same (p&amp;lt;0.001). The respondents’ GDI Scores were not related to the treatment recommendations in any clinical scenario. Physicians who treated larger number of outpatients per day and those who had lower proportion of elderly patients in the clinic tended not to recommend chemotherapy for elderly patients with poorer PS and serious complications. Those who believed that “it is a doctor’s responsibility not to pursue aggressive chemotherapy in elderly patients” tended not to recommend chemotherapy in a 78-year-old patient with luminal type breast cancer with good PS and without complication. Conclusions: The attitude towards treatment recommendation on adjuvant chemotherapy in elderly breast cancer patients were related to performance status, complications and subtype of the tumor. Physicians’ experience and belief may also affect their attitude. Citation Format: Kanako Nakayama, Chikako Shimizu, Keiko Iino, Shigeaki Watanuki, Masataka Sawaki. Survey on attitude towards treatment recommendations for elderly patients with breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-11-16.

Effects of proactive and rescue enteral tube feedings on weight change in children undergoing treatment for high-grade CNS tumors.

Children with high-grade CNS cancers frequently experience malnutrition during treatment. We assessed the effects of proactive enteral tube (ET) placement/enteral tube feedings (ETF) on weight in infants/children with high-grade CNS tumors treated with aggressive chemotherapy. We conducted a retrospective study of patients age 0 to 19 years treated for new high-grade CNS tumors between 2002 and 2017 at a tertiary pediatric hospital system. Patients underwent placement of proactive ET (≤ 31 days postdiagnosis; n = 45), rescue ET (> 31 days, due to weight loss; n = 9), or no ET (n = 18). Most received surgically placed ET (98%), with percutaneous endoscopic gastrojejunostomy or gastrojejunostomy tubes favored to allow jejunal feeding. The majority of patients with ET used ETF (91%). Using mixed-effects regression models, we examined differences in mean weights between ET/ETF groups across the first year of treatment. We also evaluated observed weight changes. All infants (n = 22, median age, 1.5 years) had proactive ET placed and 21 of 22 used proactive ETF. Infants showed an initial increase in mean percentage weight change that eventually leveled off, for an estimated increase of 10.4% over the year. For the pediatric cohort (n = 50, median, 8.1 years), those receiving proactive ETF experienced weight increases (+9.9%), those with rescue ETF experienced an initial decline and eventually rebounded for no net change (0.0%), and those with no ETF demonstrated an initial decline that persisted (-11.9%; P interaction < .001). Analysis of observed weights revealed nearly identical patterns. Proactive ETF was effective at maintaining weight and/or facilitating weight gain over the first year of treatment and was acceptable to patients/families.

Clinical, Cytological, Histopathological and Immunohistochemical Features of a T-Zone Lymphoma in a Mixed-Breed Dog

Background: Non-Hodgkin lymphoma are a group of lymphoid neoplasms originated from the proliferation of precursors or mature, T, B and/ or NK lymphocytes. T-Zone lymphoma (TZL) is characterized as an indolent lymphoma due to its slow progression and poor chemotherapy´s response. Dogs affected by this neoplasm may live for many years without clinical signs and are often underdiagnosed. The aim of the present article is report a TZL case in a nine-year old male mixed breed dog, submitted to clinical follow-up and chemotherapy. Case: A nine-year old male mixed-breed dog was presented due to the observation of an increased left mandibular lymph node. The previous cytological examination was suggestive of reactive hyperplasia and histopathological examination, by incisional biopsy, compatible with lymphocytic low-grade lymphoma. Physical examination revealed enlarged and firm left mandibular lymph node and adequate physical condition.A cytological examination was performed in the mandibular and both popliteal lymph nodes and revealed many small lymphocytes with hyperchromatic chromatin, rarely evident nucleolus and whose cytoplasm often projected in the form of a “hind-mirror” or “comet tail”, compatible with lymphocytic lymphoma (low grade) and suggestive of TZL, in the both lymph nodes. The histopathological and immunohistochemical examination, of the mandibular lymph node, were chosen to confirm the diagnosis. At histopathology it was observed 40% of the sample contained a monotonous cell population, composed by small lymphocytes, with some presenting “hand-mirror” morphology. Two mitotic figures were evidenced per field of high magnification (40x), inferring a low-grade disease. Immunohistochemical analysis revealed neoplastic proliferation with immunolabeling of CD3 lymphocytes and positivity for Ki-67, but negative for CD20, CD79a, CD45, MUM-1 and PAX-5. Although there is no consensus about requirements and treatment´s efficacy, it has been chosen to treat the dog with chlorambucil, because of the elevated Ki-67 value (48%). The patient obtained a free-progression interval higher than 820 days, from the earlier investigations of lymphadenopathy, with excellent quality of life and no side effects related to the use of chlorambucil. Discussion: Although TZL is a common subtype of lymphoproliferative disease in dog, it is still underdiagnosed. The TZL diagnosis can be suggested by cytology, from the disclosures in neoplastic cells of a cytoplasmic projections, recognized as a “hand-mirror” or “comet tail”, corroborated with the present case, however the histopathology is confirmatory. Immunohistochemistry in which the neoplasm cells showed a positive immunolabeling for CD3 and negative for CD79a, CD20, CD45, MUM1 and PAX5, as evidenced in this report, confirming the T-cell origin. According to the literature, lymphomas composed by small clear cells and cytoplasm projecting by cytology, immunolabeling CD3 and CD25 positive and CD45 negative are, together, findings that confirmed TZL. The biological behaviour of indolent lymphoma is still largely unknown, however the prognosis of dogs, with indolent lymphoma of T or B cells, seems to be favourable. Studies showed different days of median overall survival, such as 760 days and 4.4 years. In the present case, the dog showed 820 days, confirming the good prognosis and an indolent behavoiur. Aggressive chemotherapy protocols are not necessary for such cases and the treatment with chlorambucil, without the association of prednisolone, has been well tolerated by the patient, which showed no side effects until the moment.

Maintenance Therapy in the Treatment of Recurrent Epithelial Ovarian Cancer.

A diagnosis of recurrent epithelial ovarian cancer carries with it a very poor prognosis despite aggressive chemotherapy with or without secondary surgical cytoreduction. Recently, maintenance treatment after second-line chemotherapy has gained momentum given promising results of antiangiogenics and PARP inhibitors used in this setting. When used appropriately, these agents may provide a meaningful survival benefit with minimal effects on quality of life. This paper reveals the current literature evaluating the use of maintenance therapy in the recurrent setting for the epithelial ovarian, fallopian tube, or primary peritoneal cancers.

Germline mutations of SMARCA4 in small cell carcinoma of the ovary, hypercalcemic type and in SMARCA4-deficient undifferentiated uterine sarcoma: Clinical features of a single family and comparison of large cohorts

ObjectiveSmall cell carcinoma of the ovary, hypercalcemic type (SCCOHT) and SMARCA4-deficient undifferentiated uterine sarcoma (SMARCA4-DUS) are rare and aggressive tumors, primarily affecting pre- and perimenopausal women. Inactivating SMARCA4 mutations are thought to be the driving molecular events in the majority of these tumors. Here, we report the clinical course of a family with germline SMARCA4 mutation and compare large cohorts of these rare tumor types. MethodsWe extracted clinico-pathological medical record data for the family with germline SMARCA4 mutation. Clinico-genomic data from SCCOHT and SMARCA4-DUS cohorts were retrospectively extracted from the archives of a large CLIA-certified reference molecular laboratory. ResultsWe identified a single family with an inherited germline SMARCA4 mutation, in which two different family members developed either SCCOHT or SMARCA4-DUS, both of whom died within one year of diagnosis, despite aggressive surgical, chemotherapy and immunotherapy treatment. Retrospective comparative analysis of large SCCOHT (n = 48) and SMARCA4-DUS (n = 17) cohorts revealed that SCCOHT patients were younger (median age: 28.5 vs. 49.0) and more likely to have germline SMARCA4 alterations (37.5% vs. 11.8%) than SMARCA4-DUS patients. ConclusionsGrowing understanding of the role SMARCA4 plays in the pathogenesis of these rare cancers may inform recommended genetic testing and counseling in families with these tumor types.

Importance of endothelial markers in detection of lymphovascular invasion in carcinoma breast and its correlation with axillary lymph node metastasis

Background: Lymphovascular invasion (LVI) is one of the important prognostic factors in carcinoma breast and its accurate diagnosis is important, particularly in node-negative cases for making the decision regarding aggressive adjuvant chemotherapy. Sometimes, it becomes very difficult to diagnose LVI on routine hematoxylin and eosin (H and E) stained tissue sections. Staining with endothelial immunomarkers makes the identification easy. Aim of the Study: This study aims to compare LVI detection on H and E and immunohistochemistry (IHC) stained sections and its correlation with axillary lymph node metastasis. Materials and Methods: A total of 45 cases of invasive breast carcinoma were studied. LVI was evaluated in routine H and E and IHC stained sections. The results were compared. The LVI status on IHC was correlated with axillary lymph node status. Results: The accuracy of H and E stained sections in detection of LVI was 75.6% with a false-positive and false-negative rate of 20% and 4.4%, respectively. There was no significant association between LVI on IHC and axillary lymph node status. Conclusions: The detection of LVI on routine H and E sections can be erroneous. IHC should be done in cases with confusing focus on routine H and E stained sections, particularly in node-negative cases.

Current status of cancer immunotherapy for relapsed/refractory acute lymphoblastic leukemia in children and adolescents in Japan

Several novel therapeutics that employ immunological mechanisms have been introduced in recent years for the treatment of hematological malignancies. To date, very few drugs have been introduced for acute lymphoblastic leukemia (ALL). Nonetheless, three novel agents have been approved recently in the US, Europe, Australia, and Japan: blinatumomab, which kills CD19-positive leukemia cells via cytotoxic activity of the patient's autologous T cells; inotuzumab ozogamicin, which delivers the anti-cancer antibiotic calicheamicin via CD22 internalization after antibody binding; and tisagenlecleucel, which uses patient's T cells via anti-CD19 chimeric antigen receptors. Aggressive multi-agent chemotherapy followed by allogeneic hematopoietic cell transplantation has been the only curative strategy for relapsed or refractory ALL. However, treatment strategies for such patients are about to change dramatically. In this article, I review the clinical development of the new therapeutics and discuss their roles in modern therapy for ALL in children and adolescents. An approach for treatment selection has not yet been established. Therefore, it is important to understand the advantages and disadvantages of each treatment for choosing a treatment strategy for each individual.

Relapse of multiple myeloma presenting as extramedullary plasmacytoma surrounding the aorta: A rare case report

Multiple myeloma (MM) is a hematological disease characterized by the malignant proliferation of plasma cells. MM can be concomitant with plasmacytoma, at diagnosis or during relapse. Extramedullary plasmacytoma (EMP) is rare and is encountered most frequently in the upper respiratory tract and nasopharynx. It is of much less frequent occurrence in the intraabdominal and thoracic regions. EMPs tend to have a poor prognosis with a characteristic of high relapse/refractory disease rates and a relatively short overall survival, despite the use of various novel medications. Here, we present a case of relapse of MM concomitant with a large EMP surrounding the aorta, which is an extremely rare pattern of involvement. Our case showed nearly complete remission with an aggressive chemotherapy regimen. MR imaging served as a guidepost in both the diagnosis and the post-treatment follow-up.

A high-throughput screening identifies histone deacetylase inhibitors as therapeutic agents against medulloblastoma

BackgroundMedulloblastoma is the most frequently occurring malignant brain tumor in children. Current treatment strategies for medulloblastoma include aggressive surgery, cranio-spinal irradiation and adjuvant chemotherapy. Because current treatments can cause severe long-term side effects and are not curative, successful treatment remains a challenge.MethodsIn this study, we employed a high-throughput cell viability assay to screen 12,800 compounds and to identify drug candidates with anti-proliferative properties for medulloblastoma cells. We also tested these compounds for attenuating medulloblastoma tumor development using mouse xenografts.ResultsWe identified two histone deacetylase inhibitors (dacinostat and quisinostat) with anti-proliferative properties for medulloblastoma cells. We showed that both compounds induce cytotoxicity, trigger cell apoptosis, and block cell cycle progression at the G2/M phase. In addition, dacinostat and quisinostat attenuated xenograft medulloblastoma growth in mice.ConclusionsOur findings suggest that histone deacetylase inhibitors are potent therapeutic agents against medulloblastoma.

PRMT5 Inhibition Drives Therapeutic Vulnerability to BCL-2 Inhibition with Venetoclax and Provides Rationale for Combination Therapy in Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is an incurable B cell malignancy, defined by the t(11;14) translocation and comprises 3-6% of non-Hodgkin lymphomas diagnosed annually. MCL is associated with a poor prognosis due to emergence of resistance to immuno-chemotherapy and targeted agents. Due to the late median age of diagnosis, aggressive chemotherapy and stem cell transplantation are often not realistic options. The average overall survival of patients with MCL is 5 years and for the majority of patients who progress on targeted agents like ibrutinib, survival remains at a dismal 3-8 months. There is a major unmet need to identify new therapeutic approaches that are well tolerated by elderly patients to improve treatment outcomes and quality of life. Our group has identified the type II protein arginine methyltransferase enzyme, PRMT5, to be dysregulated in MCL and to promote growth and survival by supporting the cell cycle, PRC2 activity, and signaling via the BCR and PI3K/AKT pathways. We have developed first-in-class selective inhibitors of PRMT5 and, in collaboration with Prelude Therapeutics, we have demonstrated that novel SAM-competitive PRMT5 inhibitors provide potent anti-tumor activity in aggressive preclinical models of human MCL. Selective inhibition of PRMT5 in these models and MCL cell lines leads to disruption of constitutive PI3K/AKT signaling, dephosphorylation and nuclear translocation of FOXO1, and enhanced recruitment of this tumor suppressor protein to chromatin. We identified 136 newly emerged FOXO1-bound genomic loci following 48 hours of PRMT5 inhibition in the CCMCL1 MCL line by performing chromatin immunoprecipitation-seq analysis. These genes were markedly upregulated in CCMCL1 cells treated with the PRMT5 inhibitor PRT382 as determined by RNA-seq analysis. Among those genes, we identified and confirmed FOXO1 recruitment to the promoter of BAX, a pro-apoptotic member of the BCL2 family of proteins. Treatment of MCL cell lines (Granta-519, CCMCL1, Z-138, and SEFA) with the selective PRMT5 inhibitor PRT382 (10, 100nM) led to upregulation of BAX protein levels and induction of programmed cell death as measured by annexin V/PI staining and flow cytometry. We hypothesized that induction of BAX would trigger a therapeutic vulnerability to the BCL2 inhibitor venetoclax, and that combination PRMT5/BCL2 inhibitor therapy would drive synergistic cell death in MCL. Single agent and combination treatment with venetoclax and PRT382 was performed in eight MCL lines including a new cell line generated from our ibrutinib-refractory PDX model (SEFA) and IC50 and synergy scores were calculated. The Z-138 line was most sensitive to venetoclax (IC50&amp;lt;10nM) while CCMCL-1, SP53, JeKo-1, and Granta-519 demonstrated relative resistance (IC50&amp;gt;1uM). All lines reached an IC50 &amp;lt;1uM when co-treated with PRT382, with IC50 values ranging from 20 - 500nM. Combination treatments showed high levels of synergy (scores &amp;gt; 20) in 4 lines and moderate synergy (scores 10-20) in 2 lines. The two lines with the highest levels of synergy, Z-138 and SEFA, express high levels of BCL-2 and are Ibrutinib resistant. Overall there was a strong positive correlation between BCL2 expression and synergy score (r=0.707), and no correlation between PRMT5 expression and synergy score (r=0.084). In vivo evaluation in two preclinical MCL models (Granta-519 NSG mouse flank and an ibrutinib-resistant MCL PDX) showed therapeutic synergy with combination venetoclax/PRT382 treatment. In both models, mice were treated with sub-therapeutic doses of venetoclax and/or PRT543 (Granta) or PRT382 (IR-MCL PDX) and tumor burden assessed weekly via flank mass measurement (Granta) or flow cytometry (IR-MCL-PDX). Combination treatment with well-tolerated doses of venetoclax and PRMT5 inhibitors in both MCL in vivo models showed synergistic anti-tumor activity without evidence of toxicity. This preclinical data provides mechanistic rationale while demonstrating therapeutic synergy and lack of toxicity in this preclinical study and justifies further consideration of this combination strategy targeting PRMT5 and BCL2 in MCL in the clinical setting. PRT543, a selective PRMT5 inhibitor, has been advanced into clinical studies for the treatment of patients with solid tumors and hematologic malignancies, including MCL (NCT03886831). Disclosures Zhang: Prelude Therapeutics: Employment. Vaddi:Prelude Therapeutics: Employment. Scherle:Prelude Therapeutics: Employment. Baiocchi:Prelude: Consultancy.

Inhibition of BMP-Smad Pathway Reduces Leukemic Stemness in Pediatric AML

Despite aggressive chemotherapy, relapse occurs in almost half of children with acute myeloid leukemia (AML), with very dismal survival. Novel and mechanism-driven therapies are desperately needed to conquer chemotherapy resistance and leukemic stemness in pediatric AML. Within the bone marrow niche, stromal cells protect leukemia cells from chemotherapy, maintain leukemic stemness, and eventually lead to disease recurrence. We developed an in vitro AML cell-stromal cell co-culture model to mimic bone marrow microenvironment. Stroma-leukemia cell interaction leads to activation of various signaling molecules in AML cells that allow them to evade apoptosis. One such example is extracellular signal-regulated kinases 1/2 (ERK1/2), important pro-survival proteins. ERK1/2 are activated by the Ras/Raf/ mitogen-activated protein kinase kinase (MAPK/ERK kinase or MEK) pathway downstream of signals from the stroma. We recently showed that stromal co-culture activates ERK1/2 in pediatric AML samples, contributing to chemotherapy resistance (Long, et al, 2017, Oncotarget, 8:90037). To identify genes that are regulated in AML cells by ERK1/2 activation, 4 pediatric AML samples were cultured alone, or co-cultured with mOrange-expressing stroma for 24 hours, in the presence or absence of a selective MEK inhibitor, selumetinib (1 μM). Thereafter, cells were flow sorted to exclude mOrange+ stroma and CD45high/SSClow lymphocytes. Sorted AML cells underwent total RNA extraction for nCounter® PanCancer Pathways Panel (Nanostring Technologies) gene expression profiling study. We focused on the genes that were either up- or down-regulated by co-culture with stroma, and changed in the reverse direction by the addition of selumetinib. We chose a few genes among the list (BMP2, BNIP3, H2AFX, DUSP2, FZD3, BCL2L1, CHEK2) that are reported to be involved in oncogenesis, chemotherapy resistance, cell growth and survival. Using qRT-PCR, we confirmed bone morphogenic protein 2 (BMP2) to be upregulated in AML cells by stroma, and the effect of stroma was reversed by selumetinib. Further, we confirmed the same change of BMP2 at the protein level by FACS. Smad1, 5 and 8 are transcriptional factors immediately downstream from BMP receptors and play a central role in BMP signal transduction. Using FACS we discovered stroma-induced activation of Smad 1/8 in pediatric AML patient samples, which was partially alleviated by selumetinib and a selective BMP inhibitor, K02288 (10 μM). BMPs are growth factors that belong to the transforming growth factor beta (TGF-beta) superfamily and are thought to be involved in stem cell properties such as self-renewal. To determine if the BMP-Smad pathway plays a role in chemotherapy resistance, 4 pediatric AML patient samples were cultured on or off stromal cells, and treated with cytarabine (10 μM) with or without K02288 (10 μM) for 24h. Cells were analyzed for cytarabine-induced apoptosis with Annexin V staining by FACS, excluding stromal cells and lymphocytes. K02288 treatment did not alter cytarabine-induced apoptosis. We next tested the potential role of BMP-Smad pathway in leukemic self-renewal in pediatric AML samples. Pediatric AML patient samples were plated at 50,000/ml or 100,000/ml in Methocult medium (H-4535) to quantify stem and progenitor cells. Samples were treated with vehicle or K02288 (10 μM). Colonies and viable cells were counted and normalized to control 7-14 days after plating. Harvested cells were stained for CD34, CD14 and CD11b to evaluate differentiation by FACS. Remaining cells were replated at the same density for 2 more rounds. We found that K02288 reduced colony counts (e.g., 100±0% in vehicle control, v. 25±10% in K02288, n=5, p&lt;0.002, post 2nd plating) and decreased the number of viable cells at 2nd and 3rd plating (Figure 1). The BMP inhibitor also promoted differentiation of leukemic stem cell in pediatric AML samples, as evidenced by increased CD14 and CD11b expression. In contrast, for normal pediatric bone marrow samples, K02288 did not change colony counts or the number of viable cells, and it did not promote differentiation. Those data suggested BMP-Smad is likely to contribute to leukemic stemness in pediatric AML without disrupting normal hematopoietic stem cells. Therefore, BMP-Smad pathway may be a promising therapeutic target to reduce leukemia burden and improve survival for children with AML. Disclosures No relevant conflicts of interest to declare.

Belinostat Induces High Overall Response Rate (ORR) in Patients with Relapsed or Refractory Angioimmunoblastic T-Cell Lymphoma (AITL)

Background: Angioimmunoblastic T-cell lymphoma (AITL) is a relatively common subtype of peripheral T-cell lymphoma (PTCL) that typically presents with lymphadenopathy, extranodal disease, including rash, and is associated with frequent infections due to immune dysregulation. Patients with AITL generally have a poor prognosis, even with aggressive chemotherapy as responses to standard chemotherapy are often suboptimal. Recent advances in cancer biology suggest that AITL is derived from T-follicular helper cells and is often characterized by gross epigenetic dysregulation. Histone deacetylase (HDAC) inhibitors have demonstrated significant activity in T-cell neoplasms. The BELIEF trial established an overall response rate of 25% in patients with relapsed/refractory PTCL who were treated with belinostat, with a duration of response of about 1 year, leading to accelerated approval. Herein, we present a subset analysis of the data for patients with AITL. Methods: Patients with histologically confirmed PTCL (N = 129) who experienced failure with or refractory to ≥ 1 prior systemic therapy received belinostat 1,000 mg/m(2) as daily 30-minute infusions on days 1 to 5 every 21 days. Central assessment of response used International Working Group criteria. Primary endpoint was overall response rate (ORR). Secondary endpoints included duration of response (DoR) and progression-free and overall survival (PFS). Results: Of 129 patients, 22 patients had AITL; most had advanced disease (91% stage III/IV; 36% with bone marrow involvement). The median number of prior therapies was 2 (range, 1-5), and 3 (14%) patients were refractory to their last line of therapy. The ORR for patients with AITL was 46% (10/22; 95%CI: 24 - 68%), with a complete response (CR) in 4 of 22 patients (18%). Of the ten responders, the median time to response of 11.3 weeks (range, 4.7 - 24.4 weeks) in the AITL subgroup. After a median follow up of 21.5 months, the median PFS was 4.2 months (95%CI: 1.5 -13.9) and the median DOR was 13.6 months (95%CI: 1.4 - 29.4) as shown in Figure 1. For all patients with AITL treated with belinostat, the median OS was 9.2 months (95%CI: 6.8 - 21.5). The most common grade 3 to 4 adverse events were asthenia (n=2), fatigue (n=2), anemia (n=2), thrombocytopenia (n=2), neutropenia (n=2), and septic shock (n=2). Conclusions: Single-agent belinostat induced rapid and durable responses in patients with relapsed/refractory AITL. At the end of the study, there were 37% patients with ongoing responses at 2 years. Patients with clinical benefit from belinostat continued treatment until progression of disease. These results support the use of belinostat in relapsed/refractory AITL as a single agent and provide rationale for combination therapies in clinical trials. Disclosures Sawas: Seattle Genetics, Gilead, Daiichi Sanko: Consultancy; Affimed: Research Funding. Shustov:Spectrum Pharmaceuticals: Consultancy, Research Funding. Hsu:Spectrum Pharmaceuticals: Employment. Bhat:Spectrum Pharmaceuticals: Employment. Acosta:Acrotech Biopharma: Employment. Horwitz:Astex: Consultancy; Kyowa Hakko Kirin: Consultancy; Infinity/Verastem: Consultancy, Research Funding; Innate Pharma: Consultancy; Kyowa Hakko Kirin: Consultancy; Trillium: Research Funding; Affimed: Consultancy; ADCT Therapeutics: Research Funding; Kura: Consultancy; ADCT Therapeutics: Research Funding; Aileron: Research Funding; Seattle Genetics: Consultancy, Research Funding; Corvus Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Trillium: Research Funding; Aileron: Research Funding; Trillium: Research Funding; Miragen: Consultancy; Millennium/Takeda: Consultancy, Research Funding; Infinity/Verastem: Consultancy, Research Funding; Kura: Consultancy; Forty-Seven: Research Funding; Millennium/Takeda: Consultancy, Research Funding; ADCT Therapeutics: Research Funding; Mundipharma: Consultancy; Kura: Consultancy; Miragen: Consultancy; Corvus Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Mundipharma: Consultancy; Astex: Consultancy; Seattle Genetics: Consultancy, Research Funding; Astex: Consultancy; Portola: Consultancy; Celgene: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Infinity/Verastem: Consultancy, Research Funding; Aileron: Research Funding; Trillium: Research Funding; Forty-Seven: Research Funding; Infinity/Verastem: Consultancy, Research Funding; Innate Pharma: Consultancy; Miragen: Consultancy; Millennium/Takeda: Consultancy, Research Funding; Mundipharma: Consultancy; Portola: Consultancy; Mundipharma: Consultancy; Portola: Consultancy; Aileron: Research Funding; Forty-Seven: Research Funding; Kura: Consultancy; Kyowa Hakko Kirin: Consultancy; Seattle Genetics: Consultancy, Research Funding; Portola: Consultancy; ADCT Therapeutics: Research Funding; Corvus Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astex: Consultancy; Innate Pharma: Consultancy; Kyowa Hakko Kirin: Consultancy; Miragen: Consultancy; Affimed: Consultancy; Affimed: Consultancy; Corvus Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Innate Pharma: Consultancy; Seattle Genetics: Consultancy, Research Funding; Forty-Seven: Research Funding; Affimed: Consultancy; Millennium/Takeda: Consultancy, Research Funding. O'Connor:Mundipharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; ADCT Therapeutics, Affimed, Agensys, Merck, Seattle Genetics, Spectrum, Trillium, and Verastem Oncology.: Research Funding; TG Therapeutics: Other: Travel Support, Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Combination Therapy Targeting CKS1-Dependent Protein Degradation Reduces AML Burden Whilst Protecting Normal Haematopoietic Stem Cellsfrom Cytarabine Toxicity

Human chromosome translocations at 11q23, disrupting the MLL1 gene, result in poor prognostic mixed lineage leukaemias. Current chemotherapy treatment protocols produce an unsatisfactory outcome. Indeed, the average five-year event free survival rate is 44% in paediatric cases, and adult cases have been estimated as low as 15% for two-year survival rates, indicating there is an unmet critical need for more effective therapies. In recent years, there has been great interest in targeting the epigenetic factors involved in MLL-rearranged (MLL-r) leukaemic transformation and maintenance; however, epigenetic plasticity, the potential role of the remaining MLL1 allele and the elusive leukaemic stem cells present in acute myeloid leukaemia (AML), provide many routes to chemoresistance. There is currently great interest in targeting the cell cycle and key intracellular signalling pathways (e.g. Wnt signalling), independent of specific aberrant lesions in AML (e.g. MLL-fusion proteins, DNMT3a mutants), to combat highly quiescent leukaemic stem cells, which are the most difficult to eradicate. In addition, protection of the resident normal haematopoietic stem cells (HSCs), during aggressive induction chemotherapy protocols, provides another route to reduce the competitive advantage of AML cells in vivo. We previously identified two new genes, involved in the regulation of MLL1, Wnt signalling and the cell cycle: the CDK subunits CKS1 and CKS2 (Grey et al. 2017). Here, we investigated the roles of CKS1 and CKS2 during normal and malignant haematopoiesis in vivo, revealing differences in key signalling pathways involved in haematopoiesis and leukaemogenesis, implicating the CKS1/CKS2 axis as a valid therapeutic target. We demonstrate that primary AML patient samples, engrafted in immune deficient mice, are sensitive to inhibition of CKS1-dependent protein degradation, with reduced tumour burden after treatment and significant improvement in survival times. In addition, patient samples showed CKS1-sensitivity irrespective of inherent resistance to Cytarabine. Current chemotherapy protocols, using Cytarabine and Doxorubicin, can be significantly deleterious to resident normal HSCs in vivo. Transient inhibition of CKS1-dependent protein degradation, in vivo, provides a protective function to human CD34+ HSPCs when treated with Cytarabine/Doxorubicin (5+3 dosing protocol), resulting in reduced apoptosis and increased stem cell potential post-therapy. Importantly, combination treatment of CKS1 inhibition with Cytarabine/Doxorubicin significantly reduces AML tumour burden and improves overall survival, by selectively killing AML cells and preserving normal resident HSCs. Altogether, these results open a promising alternative approach for modulating protein phosphorylation and degradation to selectively target leukaemic cells, with the great advantage to protect normal resident HSCs from cytotoxic effects of induction chemotherapy. Disclosures No relevant conflicts of interest to declare.