Hearn Jay Cho

Patients with newly diagnosed multiple myeloma and chromosome 1 amplification have poor outcomes despite the use of novel triplet regimens

The prognostic impact of amplification of chromosome 1(C1A) in newly diagnosed multiple myeloma (nMM) patients treated with the most commonly used bortezomib‐based triplet regimens is unclear. In this study, we analyzed the outcome of novel triplet therapies in a series of unselected patients with C1A detected by FISH. We identified 28 unselected nMM patients with C1A who had a gain of 1q21 locus. Despite 50% of patients being diagnosed at ISS stage 1 or 2 and 93% having no other high‐risk molecular findings, the median overall survival of all patients was only 37 months, with 8 deaths (29%) occurring 8–37 months after diagnosis. Those who died had a median of four lines (range was 1–8) of therapy. Moreover, 71% of patients were non‐Caucasian. Extra‐osseous and CNS involvement occurred in 36 and 11% of patients respectively. Gain of the long arm of chromosome 1 detected by FISH remains a high‐risk prognostic marker even in the setting of novel triplet therapies.Am. J. Hematol. 89:616–620, 2014.

Dual Targeting of CDK4 and ARK5 Using a Novel Kinase Inhibitor ON123300 Exerts Potent Anticancer Activity against Multiple Myeloma

Multiple myeloma is a fatal plasma cell neoplasm accounting for over 10,000 deaths in the United States each year. Despite new therapies, multiple myeloma remains incurable, and patients ultimately develop drug resistance and succumb to the disease. The response to selective CDK4/6 inhibitors has been modest in multiple myeloma, potentially because of incomplete targeting of other critical myeloma oncogenic kinases. As a substantial number of multiple myeloma cell lines and primary samples were found to express AMPK-related protein kinase 5(ARK5), a member of the AMPK family associated with tumor growth and invasion, we examined whether dual inhibition of CDK4 and ARK5 kinases using ON123300 results in a better therapeutic outcome. Treatment of multiple myeloma cell lines and primary samples with ON123300 in vitro resulted in rapid induction of cell-cycle arrest followed by apoptosis. ON123300-mediated ARK5 inhibition or ARK5-specific siRNAs resulted in the inhibition of the mTOR/S6K pathway and upregulation of the AMPK kinase cascade. AMPK upregulation resulted in increased SIRT1 levels and destabilization of steady-state MYC protein. Furthermore, ON123300 was very effective in inhibiting tumor growth in mouse xenograft assays. In addition, multiple myeloma cells sensitive to ON123300 were found to have a unique genomic signature that can guide the clinical development of ON123300. Our study provides preclinical evidence that ON123300 is unique in simultaneously inhibiting key oncogenic pathways in multiple myeloma and supports further development of ARK5 inhibition as a therapeutic approach in multiple myeloma.

Risk stratification of smoldering multiple myeloma: predictive value of free light chains and group-based trajectory modeling

We investigated the predictive role for serum free light chain ratio (FLCr) ≥100, bone marrow plasma cell (BMPC) ≥60%, and evolving biomarkers through group-based trajectory modeling (GBTM) as high-risk defining events in 273 smoldering multiple myeloma (SMM) patients with a median follow-up of 74 months. FLCr ≥100 was confirmed as a marker for high-risk progression with a median time to progression (TTP) of 40 months with a 44% risk of progression of disease (PD) at 2 years; however, 44% of FLCr ≥100 also did not progress during follow-up. For patients with BMPC ≥60% by core biopsy, the median TTP was 31 months with a 2-year PD of 41%. GBTM established high-risk trajectories for evolving hemoglobin (eHb; characterized as a 1.57 g/dL decrease in hemoglobin), evolving m-protein (eMP; 64% increase in m-protein), and evolving differences in FLC (edFLC; 169% increase in dFLC) within 1 year of diagnosis associated with a decreased median TTP and an increased 2 year rate of PD. Of all the variables examined, we identify a model where immunoparesis, eHb, eMP, and edFLC were significant predictors for ultra-high-risk progression with a median TTP of only 13 months with 3 or more variables present. Our results not only confirm a more modest 2 year PD associated with FLCr ≥100 and BMPC ≥60 but also suggest that eHb, eMP, and edFLC may help identify an ultra-high-risk SMM group.

The safety profile of concurrent therapy for multiple myeloma in the modern era

Purpose The management of multiple myeloma has evolved in the modern era, partially owing to the increasing number of biologic therapeutics. Nonetheless, radiation remains an important treatment in the management of painful lytic lesions from multiple myeloma. The goal of this study is to evaluate the side effect profile of radiation therapy (RT) while patients are concurrently treated with biologic agents. Methods and Materials We conducted a retrospective study based on data collected from patients receiving RT at our institute from 2007 to 2017. A total of 130 patients (279 treatment sites) were included in this study with a median follow-up time of 14 months. Patients were required to be receiving a biological agent at least within 1 month before starting and up to 1 month after RT. Generalized estimating equations with a log link function and binomial distribution were used to estimate the prevalence ratio (PR) and corresponding 95% confidence interval (CI) and compare the side effects between patients with RT alone and RT + biologic agent. Results The median age of all patients in our cohort was 64 years, with 53 men (58.9%) and 37 women (41.1%). The mean Karnofsky performance status score of all cohorts was 80. No significant difference in incidence of acute (PR: 1.33; 95% CI, 0.80-2.22; P = .2660) or subacute (PR: 0.90; 95% CI, 0.49-1.67; P = .7464) toxicities was found between patients with or without biologic agents who were treated concurrently with RT. No significant difference was found in reduction in laboratory values between patients with or without biologic agents treated concurrently with RT for white blood cells (P = .6916), platelets (P = .7779), or hematocrit (P = .0858). Conclusions Our study did not detect any significant toxicity rates from palliative radiation while patients were concurrently treated with biologic agents.

Abstract A41: Targeting the ARK5/MYC axis to develop second generation CDK4/6 inhibitors

Inhibition of cyclin dependent kinases CDK4/6 is an emerging therapeutic approach in myeloma and other cancers. A direct link between MYC and the cell cycle machinery exists through its ability to directly transactivate the CCND1 and CCNE genes. Deregulated MYC expression is linked to increased cyclin A, cyclin E expression and activation of CDK4 via its direct target gene CDC25. We describe a novel mechanism of MYC silencing that is therapeutically targeted by small molecule inhibitors. ARK5 (AMPK-related protein kinase 5), a novel member of the human AMPK family, represses MYC and MYC-driven gene expression, leading to rapid induction of apoptosis and cell cycle arrest. RNAi loss of function studies confirm that ARK5 decreases MYC expression via post-translational de-acetylation by NAD-dependent deacetylase sirtuin 1 (SIRT1). In ARK5 over-expressing primary myeloma cells and cell lines, treatment with dual ARK5 and CDK4/6 inhibitor ON123300 resulted in down-regulation of pS6K, Rb and MYC, resulting in cell cycle arrest followed by apoptosis in vitro. Treatment of MM tumor-bearing mice with ON123300 significantly decreased the growth of tumors as opposed to control treated mice and was well tolerated, with no significant weight loss. The CDK4/6 selective inhibitor PD0332991 in contrast does not inhibit the ARK5 or mTOR/pS6K pathways. We hypothesized that the modest activity for the current class of CDK4/6 inhibitors could be the result of a narrow kinase inhibition profile and incomplete targeting of critical onco-kinases, resulting in cytostatic rather than cytotoxic effects. This is the first report showing that dual CDK4/6 and ARK5 inhibitor ON123300 has significant effects on mTOR and MYC. In summary, our results demonstrate a novel mechanistic connection between ARK5 and SIRT1 in the regulation of MYC in MM cells. Our data showing potent cytotoxicity of ARK5 inhibition along with inhibition of MYC and mTOR signaling provides the foundation for further development of ARK5 inhibitors and second generation CDK inhibitors such as ON123300 for MM and potentially other MYC over expressing cancers. Citation Format: Samir Parekh, Deepal Perumal, Pei Yu Kuo, Violetta Leshchenko, Zewei Jiang, Ajai Chari, Hearn Jay Cho, Sundar Jagannath, E. Premkumar Reddy. Targeting the ARK5/MYC axis to develop second generation CDK4/6 inhibitors. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A41.

Abstract 1324: Dual targeting of CDK4 and ARK5 using a novel kinase inhibitor ON123300 is effective in vitro and in vivo in Multiple Myeloma

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Multiple Myeloma (MM) is an incurable malignancy of plasma cells afflicting over 21,000 patients and accounting for over 10,000 deaths in the US each year. It is characterized by recurrent chromosomal translocations resulting in the dysregulation of cyclinD1, cyclinD3, c-Maf, MafB and MMSET. Despite cell cycle dysregulation being prominent in myeloma pathogenesis, clinical efficacy of CDK4/CDK6 inhibitors has been modest. We therefore developed ON123300, an orally available and potent small inhibitor of CDK4/CDK6 and ARK5. ARK5 is a member of the AMP-activated protein kinase (AMPK) catalytic subunit family and is associated with increased tumor cell invasiveness in MM [Suzuki et al., Mol. Cell. Bio 2004] and transcriptionally regulated by oncogenes such as MMSET, c-Maf and MafB. In this study, we evaluated the in vitro and in vivo efficacy of ON123300 in MM cell lines. A panel of nine MM cell lines was treated with varying doses of ON123300 and cell viability assessed using the CellTitre Blue assay after 48 hours. ON123300 decreased cell viability by approximately 30 to 70% (IC50:50-200nM) in 9/9 MM cell lines examined. Based on IC50 of 50 nM, we could stratify the cell lines into two groups: 6 cell lines (MM.1R, MM.1S, KMS11, U266, RPMI-8226 and ARP1) had IC50 of 50-150 nm and three cell lines (EJM, JJN3 and NCI-H929) were very sensitive (IC50 <50nM). ARK5 protein expression was confirmed by western blot in MM.1R, MM.1S, RPMI-8226, ARP1, EJM and JJN3 and was significantly higher in the more sensitive cell lines EJM and JJN3. Transcriptomic differences between more sensitive cell lines EJM, JJN3, NCI-H929 as compared to the six less sensitive cell lines were culled from RNA-seq and analyzed in different databases Genego, IPA and DAVID. Cell cycle was the top KEGG pathway identified in this analysis and included CDK6, a key target of ON123300. Simultaneously a xenograft mouse model was used to evaluate the therapeutic potential of ON123300 in vivo. ARK5 positive MM.1S myeloma cells (with pcDNA-mCh-luc constitutively expressing luciferase) were injected subcutaneously into SCID mice. Following tumor growth the mice were grouped as- control/untreated (n=5) and ON123300 treated (n = 5). ON123300 (100mg/kg) was administered by IP injection on alternative days and tumor growth monitored using highly sensitive IVIS imaging system. Mice in the treated group responded with 100 fold decrease in bioluminescence intensity (Control- 3.7xE10p/sec/cm2/sr, Treated-3.5xE08p/sec/cm2/sr) in their tumors as compared to untreated control mice. Our results suggest that ON123300 to be a potent inhibitor of tumor growth in vitro and in vivo and could be an effective agent for myeloma treatment especially for patients with aggressive disease driven by cytogenetic changes involving the MAF/ MMSET transcription factors. We expect our studies to expand therapeutic options for patients with this challenging disease. Citation Format: Deepak Perumal, Venu Thirukonda, Zewei Jiang, Violetta V. Leshchenko, Pei-yu Kuo, Samira Shahnaz, Jennifer Rubel, Weijia Zhang, Hearn Jay Cho, M.V. Ramana Reddy, E. Premkumar Reddy, Samir Parekh. Dual targeting of CDK4 and ARK5 using a novel kinase inhibitor ON123300 is effective in vitro and in vivo in Multiple Myeloma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1324. doi:10.1158/1538-7445.AM2014-1324