Chanan‐Khan, Asher

BACKGROUNDNational Cancer Institute (NCI)/National Comprehensive Cancer Network (NCCN)–designated cancer centers (CCs) offer patients state‐of‐the‐art treatment, but their impact on multiple myeloma (MM) patient outcomes has not been evaluated.METHODSAdult MM patients diagnosed between 1973 and 2011 were identified from the Surveillance, Epidemiology, and End Results database and were stratified by the county of residence at the time of diagnosis and the year of CC designation. The influence of NCI/NCCN CC access, race, and the year of diagnosis on overall survival (OS) was evaluated with a Cox regression model.RESULTSA statistically significant OS improvement was noted in patients diagnosed after 1995 with access to 2 or more NCI CCs overall (P = .002 for 1996‐2002; P < .001 for 2003‐2011) and by race for whites (hazard ratio [HR] for 1996‐2002, 0.85; 95% confidence interval [CI], 0.78‐0.91; HR for 2003‐2011, 0.85; 95% CI, 0.79‐0.91) but not for nonwhites. For NCCN access, improvement was seen in 1996‐2002 (P = .003), in 2003‐2011 (P < .001), and by race for whites (HR, 0.917; 95% CI, 0.88‐0.95) and nonwhites (0.94; 95% CI, 0.89‐0.99), but within nonwhites, this was true only for African Americans (AAs; HR, 0.88; 95% CI, 0.81‐0.97) and not for Asians, Hispanics, or Native Americans.CONCLUSIONSImprovement in OS was seen in MM patients diagnosed after 1995 with access to 1 NCCN CC or 2 or more NCI CCs. NCI access benefited only whites, whereas NCCN access benefited only white and AA patients. No OS benefit was seen for any subgroup with access to only 1 NCI center. Eliminating racial disparities in health care access and utilization is needed to improve outcomes. Cancer 2016;122:618–625. © 2015 American Cancer Society.

Abstract Inhibitors of the proteasome-ubiquitin system have been found to be effective in the clinical management of multiple myeloma. We here describe the compound VLX1570, an optimized lead of the 19S deubiquitinase inhibitor b- AP15. VLX1570 was shown to inhibit the enzymatic activities of both USP14 and UCHL5 in vitro, and was shown to induce accumulation of high molecular weight polyubiquitinated proteins in multiple myeloma cells. The compound showed limited inhibitory activity of a panel of kinases. VLX1570 induces apoptosis and cell death of multiple myeloma cell lines at submicromolar concentrations. Importantly, a multiple myeloma cell line selected for bortezomib resistance was found to be sensitive to VLX1570. VLX1570 was found to be able to overcome apoptosis resistance by these cells. Induction of the phosphorylation of stress-activated kinases (JNK and p38) and inhibition of ERK phosphorylation was observed in multiple myeloma cells. We finally showed that VLX1570 confers antineoplastic activity in two different myeloma xenograft models and conclude that VLX1570 is a candidate agent for treatment of multiple myeloma. Citation Format: Xin Wang, Chitralehka Mohanty, Padraig D'Arcy, Maria Hägg Olofsson, Felicitas Bossler, Asher Chanan-Khan, Stig Linder. Development of the proteasome deubiquitinase inhibitor VLX1570 for treatment of multiple myeloma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4557A. doi:10.1158/1538-7445.AM2015-4557A

SummaryLong‐term outcomes and updated clinical efficacy and safety data were evaluated for newly‐diagnosed multiple myeloma patients treated on a phase II study of bortezomib and pegylated liposomal doxorubicin (PegLD). Out of 61 patients, the overall response rate was 57% and the near‐complete/complete response rate was 7%. Patients aged ≥65 years old had a higher incidence of treatment‐related ≥Grade 3 non‐haematological toxicity (80% vs. 51%, P = 0·020). Median overall survival was 5·6 years and negatively impacted by the presence of International Staging System stage III disease, underscoring the need for novel treatment strategies for this group of patients.

Key PointsIn a randomized phase 3 trial, overall response rates, PFS, and overall survival were similar between MPT-T and mPR-R. Toxicity with both regimens was common, but mPR-R was better tolerated, and patients on the mPR-R regimen reported better quality of life.

Although ibrutinib and idelalisib are profound treatment advances, they will dramatically increase individual out-of-pocket and societal costs of caring for patients with CLL.

BACKGROUND Although hypogammaglobulinemia is a well recognized complication in patients with chronic lymphocytic leukemia (CLL), its prevalence at the time of CLL diagnosis, and association with novel prognostic markers and clinical outcome is not well understood. METHODS All patients at the Mayo Clinic between January 1999 and July 2013 who had newly diagnosed CLL and had a baseline assessment of serum immunoglobulin G (IgG) were included. The relation between hypogammaglobulinemia at diagnosis and the novel prognostic parameters time to first treatment (TFT) and overall survival (OS) were evaluated. RESULTS Of 1485 patients who met the eligibility criteria, 382 (26%) had hypogammaglobulinemia (median IgG, 624 mg/dL), whereas the remaining 1103 patients (74%) had normal serum IgG levels (median IgG, 1040 mg/dL). Patients who had hypogammaglobulinemia at diagnosis were more likely to have advanced Rai stage (III‐IV; P = .001) and higher expression of CD49d ( P < .001) compared with patients who had normal IgG levels. Although the median TFT for patients who had hypogammaglobulinemia was shorter compared with that for patients who had normal IgG levels (3.8 years vs 7.4 years; P < .001), on multivariable analysis, there was no difference in OS between these 2 groups (12.8 years vs 11.3 years, respectively; P = .73). Of 1103 patients who had CLL with normal IgG levels at diagnosis and who did not receive CLL therapy, the risk of acquired hypogammaglobulinemia was 11% at 5 years and 23% at 10 years. CONCLUSIONS Hypogammaglobulinemia is present in 25% of patients with newly diagnosed CLL. Approximately 25% of patients who have CLL with normal IgG levels at diagnosis will subsequently develop hypogammaglobulinemia on long‐term follow‐up. The presence of hypogammaglobulinemia does not appear to impact overall survival. Cancer 2015;121:2883–2891. © 2015 American Cancer Society .

The ubiquitin–proteasome system (UPS) is increasingly recognized as a therapeutic target for the development of anticancer therapies. The success of the 20S proteasome core particle (20S CP) inhibitor bortezomib in the clinical management of multiple myeloma has raised the possibility of identifying other UPS components for therapeutic intervention. We previously identified the small molecule b‐AP15 as an inhibitor of 19S proteasome deubiquitinase (DUB) activity. Building upon our previous data, we performed a structure–activity relationship (SAR) study on b‐AP15 and identified VLX1570 as an analog with promising properties, including enhanced potency and improved solubility in aqueous solution. In silico modeling was consistent with interaction of VLX1570 with key cysteine residues located at the active sites of the proteasome DUBs USP14 and UCHL5. VLX1570 was found to inhibit proteasome deubiquitinase activity in vitro in a manner consistent with competitive inhibition. Furthermore, using active‐site‐directed probes, VLX1570 also inhibited proteasome DUB activity in exposed cells. Importantly, VLX1570 did not show inhibitory activity on a panel of recombinant non‐proteasome DUBs, on recombinant kinases, or on caspase‐3 activity, suggesting that VLX1570 is not an overtly reactive general enzyme inhibitor. Taken together, our data shows the chemical and biological properties of VLX1570 as an optimized proteasome DUB inhibitor.