Future of Personalized Therapy Targeting Aberrant Signaling Pathways in Multiple Myeloma

Multiple myeloma (MM) is a genetically complex disease. Identification of mutations and aberrant signaling pathways that contribute to the progression of MM and drug resistance has potential to lead to specific targets and personalized treatment. Aberrant signal pathways include RAS pathway activation due to RAS or BRAF mutations (targeted by vemurafenib alone or combined with cobimetinib), BCL-2 overexpression in t(11:14) (targeted by venetoclax), JAK2 pathway activation (targeted by ruxolitinib), NF-κB pathway activation (treated with DANFIN combined with bortezomib), MDM2 overexpression, and PI3K/mTOR pathway activation (targeted by BEZ235). Cyclin D1 (CCND1) and MYC are also emerging as key potential targets. In addition, histone deacetylase inhibitors are already in use for the treatment of MM in combination therapy, and targeted inhibition of FGFR3 (AZD4547) is effective in myeloma cells with t(4;14) translocation. Bromodomain and extra terminal (BET) protein antagonists decrease the expression of MYC and have displayed promising antimyeloma activity. A better understanding of the alterations in signaling pathways that promote MM progression will further inform the development of precision therapy for patients.

Plinabulin, an inhibitor of tubulin polymerization, targets KRAS signaling through disruption of endosomal recycling

Constitutive activation of Kirsten rat sarcoma viral oncogene homolog (KRAS) is the most common oncogenic event in certain types of human cancer and is associated with poor patient survival. Small molecule signaling inhibitors have improved the clinical outcomes of patients with various cancer types but attempts to target KRAS have been unsuccessful. Plinabulin represents a novel class of agents that inhibit tubulin polymerization with a favorable safety profile in clinical trials. In the present study, the potency of plinabulin to inhibit tubulin polymerization and growth of KRAS-driven cancer cells was characterized. In vivo efficacy of plinabulin was tested in two different mouse models; one being the RCAS/t-va gene transfer system and the other being a xenograft model. In vitro cell culture tubulin polymerization assays were used to complement the mouse models. There was improved survival in a KRAS-driven mouse gene transfer glioma model, but lack of benefit in a similar model, without constitutively active KRAS, which supports the notion of a KRAS-specific effect. This survival benefit was mediated, at least in part, by the ability of plinabulin to inhibit tubulin polymerization and disrupt endosomal recycling. It was proposed a mechanism of compromised endosomal recycling of displaced KRAS through targeting microtubules that yields inhibition of protein kinase B, but not extracellular signal regulated kinase (ERK) signaling, therefore lending rationale to combination treatments of tubulin- and ERK-targeting agents in KRAS-driven cancer.

Abstract 1686: A Phase 1 dose escalation study to establish the maximum tolerated dose (MTD), pharmacokinetic (PK) and pharmacodynamic (PD) parameters of hydroxychloroquine (HCQ) in combination with vorinostat (V) in patients with advanced solid tumors - final results

Background: Autophagy is a cellular process that generates energy to assure cell survival in response to insults such as hypoxia, nutrient deprivation or cytotoxic mediators. Autophagy contributes to cancer cell survival as well as drug resistance. Several anticancer agents, including Vorinostat (V) are reported to induce autophagy as a cytoprotective mechanism. In preclinical models, the addition of Hydroxycholoquine (HCQ) to V inhibited autophagy and significantly increased the anticancer effects of V. The objectives of this trial were to determine the MTD of HCQ in combination with V both administered daily (QD) in patients (pts) with advanced solid tumors, to evaluate PK and PD parameters, and test anti-tumor activity. Biomarkers were evaluated in tumors and peripheral blood mononuclear cells (PBMC) to investigate synergistic antitumor activity of V in combination with HCQ.

Methods: We used a 3+3 dose escalation design of V at 300-400 mg QD plus HCQ QD at 400-1000 mg in 21 day cycles. Patients with advanced solid tumors and no available treatment with ECOG PS 0-2 and adequate organ function were eligible.

Results: 32 patients were enrolled with 27 evaluable for toxicity studies. No dose limiting toxicity (DLT) was observed in cohorts 1 or 2. In cohort 3 (400 mg V/600 mg HCQ), 1/6 pts had DLT of Gr 3 anemia and fatigue. In cohort 4 (400 mg V/800 mg HCQ), 4/8 pts had DLT with Gr 3 fatigue (3 pts) and Gr 2 seizure on C1D8 (1 pt). De-escalation to 400 mg V/600 mg HCQ resulted in no further DLTs, defining the MTD. 10 pts were treated at the MTD. Treatment-related toxicities were Gr 1-2: nausea (11 pts), diarrhea (8), fatigue (6), anorexia (4), weight loss (4), anemia (4), and elevated creatinine (4). Gr 3 toxicities were fatigue (3), anemia, thrombocytopenia and neutropenia (1 each). One pt (renal cell cancer) had a confirmed PR (cohort 2, completed 43 cycles), and 2 pts with colorectal cancer had prolonged SD (>4 cycles). HCQ trough and V plasma concentrations (preliminary) showed no drug interactions compared to previously published data. PD analyses of biomarkers of HCQ and V in PBMCs at baseline compared to weeks 1 and 6 confirmed the results from pre-clinical studies showing accumulation of autophagic vesicles and induction of LC3-II, p21 and cathepsin D. The results of biopsies from 3 patients at MTD demonstrated greater induction of these PD markers in tumor compared to PBMC.

Conclusions: The MTD was established as HCQ 600 mg + V 400 mg. Dose-dependent fatigue represented DLT in several patients. Anti-tumor activity was seen in one patient with RCC and 2 patients with CRC had prolonged SD. Based on these data phase II studies are planned in patients with renal and colorectal cancer.

Citation Format: Monica M. Mita, Devalingam Mahalingam, John Sarantopoulos, Ravi Amaravadi, Alain Mita, Tyler Curiel, Steffan Nawrocki, Frank Giles, Jennifer Carew. A Phase 1 dose escalation study to establish the maximum tolerated dose (MTD), pharmacokinetic (PK) and pharmacodynamic (PD) parameters of hydroxychloroquine (HCQ) in combination with vorinostat (V) in patients with advanced solid tumors - final results. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1686. doi:10.1158/1538-7445.AM2013-1686

Reovirus-based therapy for cancer

Reovirus is an oncolytic virus that is not associated with significant disease in humans, but is selectively able to replicate in cancer cells through exploitation of abnormal Ras signaling. Pre-clinical studies have demonstrated that treatment with reovirus is associated with significant anticancer activity across a range of tumor types. Reolysin is a proprietary formulation of the human reovirus developed by Oncolytics Biotech. Clinical evaluation of reovirus therapy has shown that it is well tolerated when administered locally or systemically. Encouraging anticancer efficacy has been observed with single-agent treatment and in combination with chemotherapy and radiotherapy. Phase II studies are currently evaluating reovirus alone and in combination with standard therapy in an array of tumor types. While immune sensitization hinders the anticancer efficacy of reovirus, it is important in preventing systemic toxicity. Immunosuppressive strategies are being developed that reduce immune neutralization of the virus to allow for improved tumor penetration, but retain sufficient antibody levels to protect normal tissues. The lack of toxicity and promising efficacy of reovirus has raised hopes that it will become an established anticancer agent.

Palliative radiotherapy versus palliative chemoradiotherapy in treatment of NSCLC stage IIIA and IIIB: Phase II randomized trial

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Background: The optimal treatment for stage IIIA/IIIB NSCLC patients who do not qualify for radical treatment has not been identified. Different palliative radiotherapy regimens and chemotherapy are used but have not been compared. We decided to combine short chemotherapy and radiotherapy (CT-RT) in order to improve therapeutic index of radiotherapy (RT). Methods: Eligibility criteria: Locally advanced, inoperable patients (pts) in IIIA (N2 positive) -IIIB clinical stage with tumor larger than 8 cm in longest diameter or/and FEV1 smaller than 40%, PS: 0–2 (ECOG), non-eligible for radical CT-RT. Treatment: RT arm - 3-D radiotherapy, 30 Gy/3 Gy, 2 weeks. CT-RT arm - two cycles of CT (cisplatin: 80 mg/m2; d 1, 22; vinorelbine: 25 mg/m2 iv; d 1,8,22,29) followed by RT as in Arm 1 with concurrent third cycle of CT (cisplatin 80 mg/m2, d 43; vinorelbine 25 mg/m2 iv., d 43, 50). Study design: Phase II, two-center, randomized study, stratification IIIA vs. IIIB, PS 0–1 vs. 2, treating center (Warsaw vs. Olsztyn). Two-stage design, a and β errors = 0,1; p1 minus p0 = 0,20. Planned sample size - 46 pts/arm. Primary endpoint: response rate (RECIST). Secondary end-points: overall survival (OS), toxicity, progression free survival (PFS). Results: During 2 years 104 pts randomized, 98 eligible for toxicity and survival/progression analysis, 82 for response assessment. Demographics: median age - 65 (45–78), IIIA/IIIB: 27/71 pts. PS 0–1/2: 72/26. Well balanced between arms. Response rate: RT arm- 26%, CT-RT arm- 46%, median OS for RT arm - 195 days, CT-RT arm 2 - 385 days, log-rank test p=0,047, median PFS for RT arm - 140 days, CT-RT arm - 172 days, log-rank test p=0,16. Toxicity: deaths - 2 in RT arm, 2 in CT-RT arm; hematological G3–4 - 0 in RT arm, Arm CT- RT: anemia - 2, thrombocytopenia - 6, neutropenia - 11, esophagitis - 2. Other G3–4: RT arm -3, CT-RT arm -1. Conclusions: Palliative radiotherapy (30Gy) with chemotherapy postponed to progression is a suboptimal treatment for patients with locally advanced NSCLC. 2 cycles of cisplatin/vinorelbine plus RT concomitantly with 3 cycle increases clinical response rate and significantly prolongs survival at the cost of acceptable toxicity in palliative setting.

No significant financial relationships to disclose.

Toxicity of g-csf given for neutropenia during chest radiotherapy in limited-stage small cell lung cancer (SCLC)

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Background: There are concerns that use of white blood cell growth factors during radiotherapy, especially chest radiotherapy may lead to severe thrombocytopenia. Bunn P reported (J Clin Oncol 1995) that use of gm-csf during radical CT-RT of limited- stage SCLC is associated with life-threatening thrombocytopenia and did not reduce significantly neutropenia. On the other hand the prolongation of CT-RT total time in limited-stage SCLC has negative impact on survival. We have evaluated the safety of g-scf administration given for neutropenia (ANC<500/mm3) in limited-stage SCLC. Methods: 32 patients, 19 men, 13 women (median age 58,5 range 49–71, PS (WHO) = 0 or 1 - 30 patients, PS=2 - 2 patients. Chemotherapy during RT: cisplatin 60 mg/m2 d 1, etoposide 120 mg/m2 d 1–3, every 3 weeks. RT: 54 Gy/2 Gy/5 days a week together with 3rd and 4th CT cycle to gross tumor, ipsilateral hilar and bilateral lymph nodes planned in 3-D planning system, 6 MV photons. G-csf given for 3 to 10 days (median - 6 d) once (22 patients) or twice during RT-CT (10 patients) for G4 (CTC) neutropenia or febrile neutropenia, 30 mln u/d for 19 patients, 48 mln u/d for 13 patients. Toxicity was recorded (CTC v.2.0) Hematology tests done every 7 days during RT and every 7 days after RT till resolution of thrombocytopenia. No breaks in RT due to neutropenia, break if thrombocytopenia G3/G4. Results: G3-G4 thrombocytopenia was observed in 15 out of 32 patients during or after RT. In 2 patients platelet’s transfusions were given, in 1 patient haemoptysis was observed, no toxic deaths were noticed. Febrile neutropenia in 10 out of 32 patients. No breaks in RT in 20 out of 32 patients. 1 to 3 days’ breaks in 7 patients, 4 to 6 days breaks in 2 patients, longer breaks in 3 patients. Mean platelet count before RT - 221,000/mm3, after RT in 3 following weeks: 135,000/mm3, 149,000/mm3, 137,000/mm3. In 21 out of 32 patients clinical response (CR or PR) was observed after CT-RT. Thrombocytopenia was not associated (p>0,1) with age, PS or radiotherapy dose, associated with number of chemotherapy cycles (p=0.07). Conclusions: Use of g-csf during CT-RT in SCLC seems to be safe, regarding thrombocytpenia. G-csf given in lower doses for shorter times than in P. Bunn’s paper may be safer. Randomized study with g-csf in limited- stage SCLC is justified.

No significant financial relationships to disclose.

Celecoxib inhibits angiogenesis by inducing endothelial cell apoptosis in human pancreatic tumor xenografts

Previous studies suggest that antagonists of cyclooxygenases 1 and 2 (COX-1, -2) inhibit angiogenesis in tumor xenografts, but the molecular mechanisms involved remain unclear. Here we characterized the effects of non-selective (indomethacin) and selective (NS398, celecoxib) cyclooxygenase inhibitors on parameters of angiogenesis in human pancreatic adenocarcinoma cells. COX-1 expression was constitutive in 9/9 pancreatic cancer cell lines, whereas COX-2 and cytosolic phospholipase A2 (cPLA2) expression were observed in 4/9 cell lines (BxPC3, Capan2, Cfpac1, and L3.6 pl). Production of the COX product, prostaglandin E2, correlated with expression of cPLA2 and COX-2 and was blocked by non-steroidal anti-inflammatory drugs (NSAIDs, indomethacin or NS398). In contrast to the findings of others, neither indomethacin nor NS398 affected tumor cell secretion of angiogenic factors (VEGF, bFGF, IL-8) at concentrations that produced maximal inhibition of PGE2 production, and higher concentrations increased angiogenic factor production. We also studied the effects of celecoxib in orthotopic L3.6 pl xenografts. Immunofluorescence analyses revealed high-level expression of COX-2 in endothelial cells in L3.6 pl xenografts that increased following therapy with celecoxib, whereas the tumor cells expressed uniformly low levels of COX-2. Celecoxib did not decrease tumor-associated VEGF levels in orthotopic human L3.6 pl xenografts, but the drug did decrease tumor microvessel density (MVD) and increase apoptosis in tumor-associated endothelial cells in a dose-dependent fashion. Together, our results demonstrate that the anti-angiogeneic effects of NSAIDs in human pancreatic cancer cells are exerted via direct effects on endothelial cells.

In vitro assessment of nucleoside analogs in multiple myeloma

PURPOSE

To identify nucleoside analogs that may be effective for multiple myeloma (MM), we tested fludarabine, clofarabine, arabinosylguanine, cytarabine, troxacitabine, and gemcitabine in MM cell lines.

METHODS

We employed biologic and biochemical assays in MM cell lines to evaluate the clinical potential of these nucleoside analogs.

RESULTS

Among these purine and pyrimidine nucleoside analogs, fludarabine, clofarabine and gemcitabine were the most potent. MM cell lines, resistant to commonly used chemotherapeutic agents for this disease, were more sensitive to gemcitabine with an IC50 in the nanomolar range. The greater cytotoxicity of gemcitabine in MM cells was consistent with greater accumulation of gemcitabine triphosphate, the major cytotoxic metabolite of this drug. MM.1S cells accumulated >100 microM gemcitabine triphosphate but accumulated <20 microM of the other analogs as the respective triphosphates. In addition incubation with gemcitabine resulted in inhibition of DNA synthesis. Incubation with 25, 50 or 100 nM gemcitabine resulted in a dose- and time-dependent increase in the cell population with a subG1 DNA content indicative of apoptosis.

CONCLUSIONS

These results suggest that gemcitabine is a potent nucleoside analog in MM cell lines including cell types resistant to other chemotherapeutic agents. The greater activity of gemcitabine compared to other analogs seems to be due to favorable metabolism of this agent.

Genetically modified tumour vaccines: an obstacle race to break host tolerance to cancer

The development of genetically modified tumour vaccines (GMTV) has been prompted by a better understanding of antitumour immune responses and genetic engineering technologies, as well as the identification of numerous tumour antigens (TA) in several malignancies which occasionally induce spontaneous tumour regressions. Cellular vaccines are based on autologous or allogeneic tumour cells genetically engineered to secrete different cytokines, co-stimulatory molecules, or allogeneic HLA molecules in order to provide a strong stimulatory signal together with the presented TA. Another promising approach that is targeted towards breaking immune tolerance to TA, exploits dendritic cells (DC) loaded or genetically modified with TA (and sometimes cytokines). Effective nonviral and viral gene delivery systems have been constructed including a third generation of adenoviral, lentiviral and hybrid vectors. Studies in mice demonstrated that therapeutic, curative immune responses might be elicited by GMTV. Promising results from animal studies are rarely seen in human trials. Several reasons, such as numerous escape mechanisms of slowly evolving spontaneous tumours and immune incompetence of advanced patients, are major concerns. Improved monitoring of immune responses to GMTV is essential to distinguish between responders and non-responders in order to tailor immune therapy strategy to the individual patient.

The 14th European Immunology Meeting--EFIS 2000. 23-27 September 2000, Poznañ, Poland

The 14th European Immunology Meeting--EFIS 2000, held in Poznan, Poland on 23-27 September 2000, was the last major meeting of European immunologists in the second millennium. This conference was intended to summarise past achievements and to present future prospects in immunology. The philosophy of the scientific program was to fuse fundamental and clinical immunology and give a chance for basic scientists and clinicians to discuss mutual topics in a general view. There were eight state-of-art lectures, 12 'meet an expert' sessions, 20 plenary sessions and 46 workshops. More than 900 works were presented. Significant interest was focused on several aspects of cancer immunology and immunotherapy. EFIS 2000 was accompanied by six pre-congress satellite symposia held in various Polish cities. The topics were, 'Heat shock proteins: immune, stress response and apoptosis' (Gdansk), 'Infectious immunity and vaccines' (Kazimierz Dolny), 'Mononuclear phagocytes in basic and clinical immunology' (Cracow), 'Immunology of reproduction' (Poznan), 'Primary immunodeficiencies' (Warsaw) and 'Glycoimmunology' (Wroclaw).

Genetically modified tumour vaccines (GMTV) in melanoma clinical trials

Since melanoma is a model immunogenic malignancy incurable in the disseminated phase of its natural course different immunotherapeutic approaches are tested in clinical trials. A number of tumour vaccines genetically modified (GMTV), with various immunostimulatory factors, are tested in phase I/II clinical trials. These factors include cytokines, tumour antigens (TA), costimulatory molecules or HLA antigens. We have designed a novel, mixed auto/allogeneic cellular melanoma vaccine modified with the IL-6 and the sIL-6R genes. Preclinical studies in a mouse model demonstrated that the IL-6/sIL-6R based vaccine is able to elicit efficient anti-tumour responses, mediated by CD8+ and NK cells, which resulted in inhibition of the tumour growth, metastases formation and prolonged survival of the animals treated. Irradiation of vaccine cells does not only lead to their sterilisation but also causes increased secretion of exogenous IL-6 and sIL-6R. Since January 1996 we have vaccinated more than one hundred metastatic melanoma patients. Promising clinical results (22% CR+PR, 32% SD) and the evidence of immune responses in the vaccinated patients have prompted us to design a phase III clinical trial which is to be open in 2000.

Insecticide resistance status, esterase activity, and electromorphs from mosquito populations of Culex quinquefasciatus Say (Diptera: Culicidae), in Houston (Harris County), Texas

Culex quinquefasciatus Say is a vector of St. Louis encephalitis (SLE) in Texas. This disease is endemic and prevalent in the Houston area. Disease prevention through mosquito control is mainly targeted against adults by application of a resmethrin-piperonyl butoxide formulation (Scourge). Immature mosquitoes were collected from eight areas in Harris County during 1998. The susceptibility status of these populations to Scourge, malathion, and resmethrin, the latter alone or with an esterase inhibitor as a synergist, was determined using a bottle assay with females. The population structure was investigated by electrophoretic analysis of esterases and their activity. Individual females were also analyzed for esterase activity by plate assay and for isoenzyme pattern by native PAGE. Bioassays indicated high levels of resistance to malathion in all areas. In addition, the effectiveness of Scourge in mosquitoes from area 51 deteriorated throughout the season. A localized, distinctive esterase pattern and activity level was observed in mosquitoes from different areas. Overall, the frequency of esterases Est alpha 2 (A2)/Est beta 2 (B2) was higher than that of Est beta 1 (B1). Altogether, these results indicate the onset of a fragile situation for mosquito control that should be further analyzed to effectively maintain the SLE prevention program for Harris County.

Expression of interleukin-6, interleukin-6 receptor, and glycoprotein 130 correlates with good prognoses for patients with breast carcinoma

BACKGROUND

Interleukin-6 (IL-6) is secreted by normal epithelial breast cells but not by oncogene-transformed cells. Interleukin-6 is able to inhibit growth of breast carcinoma cells in culture. Interleukin-6 exerts its activity via two receptor subunits, IL-6R and glycoprotein 130 (gp130). The expression of these receptor subunits in breast tumors has been studied, but there are no previous reports of their prognostic significance, to the authors' knowledge.

METHODS

mRNA of IL-6, IL-6R, and gp130 was studied in 75 tumor samples obtained from breast carcinoma patients. Patients were followed for a maximum of 71 months (median follow-up, 61 months; 60 patients were followed for a minimum of 5 years or died during the observation period). Prognostic factors were analyzed in univariate and multivariate analysis.

RESULTS

mRNA specific to IL-6, IL-6R, and gp130 was detected in 57%, 53%, and 71% of breast carcinoma tissues, respectively. Expression was strongly correlated with earlier stages of the disease. In univariate analysis, expression of IL-6 and its receptor subunits proved to be a positive prognostic factor for overall survival (OS) and disease free survival (DFS). IL-6R and gp130 expression were good independent prognostic factors for OS. The 5-year OS of all patients was 66%. The 5-year OS in IL-6, IL-6R, and gp130 positive groups was 95%, 94%, and 90%, respectively, whereas in negative groups it was 26%, 31%, and 9%, respectively.

CONCLUSIONS

Expression of IL-6, IL-6R, and gp130 in breast carcinoma tissue is associated with earlier stages of the disease. In advanced stages, expression of IL-6 and its receptor subunits predicts better prognosis.

Genetically modified tumour vaccines--where we are today

Tumour vaccines are based on weakly immunogenic specific tumour antigens admixed with adjutants in order to elicit, restore or augment antitumour immune responses against residual or metastatic tumour cells. Cellular cytotoxicity is considered to play a major role in eliminating tumour cells. Activation of cellular toxicity requires at least three synergistic signals: presentation of specific tumour antigen, constimulatory signal (B7 molecules) and propagation signal (cytokines). Recently several HLA-restricted specific tumour antigens recognized by cytotoxic T-cells have been characterized. Antibody defined antigens, heat shock proteins and viral antigens are also discussed. First generation vaccines made of whole cancer cells or tumour-cell lysates together with non-specific adjutants produced about 20% of clinical responses and are currently tested in prospective clinical trials. Novel second generation of tumour vaccines employ genetically modified tumour cells, antigen presenting cells (dendritic cells) or recombinant tumour antigens. Tumour cells are modified with genes encoding molecules providing signals for cytotoxic T-cells required for recognition and killing of cancer cells such as B7 constimulatory molecules, HLA proteins and genes of different cytokines. Dendritic cells are modified with genes of specific tumour antigens in order to activate both helper and cytotoxic T-cells. Novel vaccines produce specific immune responses and objective clinical responses with minimal toxicity in phase I/II trials. Advances in gene transfer technology, tumour immunology and better methods of monitoring specific antitumour immune responses allow the hope that tumour vaccines will be introduced into the clinic, at least in some malignancies resistant to systemic therapy so far such as melanoma and renal cell carcinoma.