AT-101 downregulates BCL2 and MCL1 and potentiates the cytotoxic effects of lenalidomide and dexamethasone in preclinical models of multiple myeloma and Waldenström macroglobulinaemia.

Multiple myeloma, the second most common haematological malignancy in the U.S., is currently incurable. Disruption of the intrinsic apoptotic pathway by BCL2 and MCL1 upregulation is observed in >80% of myeloma cases and is associated with an aggressive clinical course. Remarkably, there is no approved drug with the ability to target BCL2 or MCL1. Thus, we investigated the anti-tumour effects of a pan-BCL2 inhibitor, AT-101, which has high binding specificity for BCL2 and MCL1 in preclinical models of plasma cell cancers (Multiple myeloma and Waldenström macroglobulinaemia). Gene expression and immunoblot analysis of six plasma cell cancer models showed upregulation of BCL2 family members. AT-101 was able to downregulate BCL2 and MCL1 in all plasma cell cancer models and induced apoptotic cell death in a caspase-dependent manner by altering mitochondrial membrane permeability. This cytotoxic effect and BCL2 downregulation were further potentiated when AT-101 was combined with lenalidomide/dexamethasone (LDA). NanoString nCounter mRNA quantification and Ingenuity Pathways Analysis revealed differential changes in the CCNA2, FRZB, FYN, IRF1, PTPN11 genes in LDA-treated cells. In summary, we describe for the first time the cellular and molecular events associated with the use of AT-101 in combination with lenalidomide/dexamethasone in preclinical models of plasma cell malignancy.

The investigational agent MLN2238 induces apoptosis and is cytotoxic to CLL cells in vitro, as a single agent and in combination with other drugs.

Chronic lymphocytic leukaemia (CLL) is the most common haematological malignancy in the U.S. The course of the disease has been shown to be negatively impacted by increased levels of BCL2. Strategies to downregulate BCL2 and shift the balance towards cellular demise are actively being explored. Therefore, we examined whether the investigational agent MLN2238 could inhibit the proteasomal machinery and induce CLL cell death while also downregulating BCL2. MLN2238-induced cell death was studied in peripheral blood mononuclear cells from 28 CLL patients. MLN2238 produced a dose-dependent reduction in BCL2 and CLL cell viability with maximum cell death observed at a 50 nmol/l concentration by 48 h. Annexin-V staining, PARP1 and caspase-3 cleavage along with an increase in mitochondrial membrane permeability were noted after cells were treated with MLN2238; however, apoptosis was only partially blocked by the pan-caspase inhibitor z-VAD.fmk. Furthermore, we observed enhanced anti-CLL effects in tumour cells treated with either a combination of MLN2238 and the BH3 mimetic AT-101 or MLN2238 and fludarabine. Together, our data suggest the potential for proteasome inhibitor based therapy in CLL and the rationale design of drug combination strategies based on CLL biology.

Downregulation of BCL2 by AT-101 enhances the antileukaemic effect of lenalidomide both by an immune dependant and independent manner.

Over-expression of anti-apoptotic BCL2 has been reported in chronic lymphocytic leukaemia (CLL), but targeting BCL2 alone did not yield appreciable clinical results. However, it was demonstrated that BCL2 inhibitors enhanced the clinical efficacy of chemo and immunotherapeutics. Lenalidomide, an immunomodulator, is clinically effective in CLL and can enhance the anti-CLL effects of CD20 targeting monoclonal antibody, rituximab. Here, we investigated the mechanism of immune-directed killing of lenalidomide in CLL and evaluated if concurrent targeting of CD20 and BCL2 can enhance this effect. In vitro treatment with lenalidomide enhanced the antibody-mediated cellular cytotoxicity (ADCC) directed by rituximab in autologous leukaemic cells. Furthermore, peripheral blood mononuclear cells obtained from patients after treatment with lenalidomide and rituximab showed increased ADCC in vitro versus control (pre-treatment sample). This effect was further enhanced with pre-treatment of tumour cells with AT-101 (a BH3 mimetic that functions as BCL2 antagonist). Our data suggest that AT-101 in combination with lenalidomide can potentially be an effective therapeutic regimen for CLL.

Acyclovir prophylaxis against varicella zoster virus reactivation in multiple myeloma patients treated with bortezomib-based therapies: a retrospective analysis of 100 patients.

BACKGROUND: Previous studies have indicated that, in patients with multiple myeloma (MM), bortezomib is associated with an increased incidence of herpes zoster, resulting from reactivation of latent varicella zoster virus (VZV). OBJECTIVE: Our objective was to determine whether increased risk of VZV reactivation could be abrogated by using prophylactic acyclovir. METHODS: We retrospectively evaluated 100 consecutive MM patients treated with bortezomib-based therapies at the Roswell Park Cancer Institute for development of herpes zoster. Frontline and relapsed/refractory patients were included, and patients received bortezomib alone or in combination with agents such as doxorubicin, melphalan, or dexamethasone. All patients received >4 weeks of acyclovir prophylaxis (400 mg twice daily), which was initiated prior to starting treatment with bortezomib and discontinued 4 weeks following bortezomib. RESULTS: Median patient age was 62 years, 57% were male, and most (56%) had Durie-Salmon stage IIIA MM. None of the 100 MM patients receiving acyclovir prophylaxis developed herpes zoster during treatment with bortezomib, irrespective of patients receiving a wide variety of concomitant antimyeloma therapies and regardless of response to bortezomib-based therapy. One additional patient, found to be noncompliant with acyclovir therapy, experienced VZV reactivation, having received 3 cycles of bortezomib (3 weeks each cycle) in combination with cyclophosphamide and dexamethasone. LIMITATIONS: Limitations of the study include its small size and retrospective nature. CONCLUSIONS: The increased risk of VZV reactivation observed in previous studies of bortezomib-based therapy was completely abrogated in this series of patients who received prophylaxis with acyclovir.

A steroid-independent regimen of bortezomib, liposomal doxorubicin and thalidomide demonstrate high response rates in newly diagnosed multiple myeloma patients.

Novel agents have provided a new foundation for multiple myeloma therapies. When combined with other anti-myeloma agents, these compounds significantly enhance clinical efficacy. High-dose steroids are frequently used in anti-myeloma combination regimens; however, the doses employed are often poorly tolerated, especially in patients with concurrent comorbid conditions. We hypothesized that a steroid-independent combination regimen could be developed without significant compromise of efficacy. The availability of such a regimen will be important for patients whose concurrent ailments make them poor candidates for steroid containing anti-myeloma regimens. A phase II single institute, non-randomized clinical trial was conducted to investigate a novel steroid-free three-drug combination of bortezomib (V), pegylated liposomal doxorubicin (D), and thalidomide (T), the VDT regimen. Forty-three newly diagnosed multiple myeloma patients requiring treatment were enrolled on this study. The overall response rate and complete response (CR) + near complete response (nCR) rate was 78% and 35%, respectively. Median time to progression was 29·5 months. Fatigue, rash, neuropathy, constipation and infections were the most common side effects. We concluded that VDT is a tolerable and an effective regimen capable of inducing high response rates and can be employed in patients considered to be poor candidates for steroid-based treatment regimens.

Plasma cell leukaemia and other aggressive plasma cell malignancies.

Extramedullary plasma cell cancers, such as plasma cell leukaemia (PCL) and multiple extramedullary plasmacytomas (MEP) are very aggressive malignancies. These can be primary (de-novo) or secondary due to progressive prior multiple myeloma (MM). Recent reports suggest an increase in incidence of these disorders. Compared to MM, organ invasion is common in PCL, while soft tissue tumors involving the head, neck or paraspinal area are common sites for MEP. Markers of poor prognosis are frequently observed in these extramedullary forms of plasma cell cancers, and survival is significantly inferior compared to patients with MM. Conventional chemotherapeutic and radiotherapy approaches have been employed with variable results. Even high dose chemotherapy with autologous stem cell rescue has not been able to demonstrate consistent improvement in survival outcome. Although not specifically evaluated, novel anti-plasma cell agents, such as the proteasome inhibitor bortezomib, and immunomodulatory drugs, such as lenalidomide, appear to be active against these aggressive cancers. Clinical and translational research directed at improved understanding of disease biology and development of novel therapeutics is urgently needed.

Bortezomib in combination with pegylated liposomal doxorubicin for the treatment of multiple myeloma.

Many novel agents and new combinations (including bortezomib, thalidomide, and lenalidomide) have been developed in recent years for the treatment of multiple myeloma (MM), creating major shifts in therapeutic management. Achieving complete response (CR)/near CR (nCR) generally serves as a reliable clinical surrogate for overall treatment outcome, ie, prolonged survival. Indeed, some newer induction regimens are yielding similar median time to disease progression effects compared with transplantation. Thus, it can be a dilemma whether a patient with CR/nCR needs to be subjected to the potential morbidity associated with transplantation after induction therapy. Combining new agents with chemotherapy-based regimens appears to offer higher overall response and CR/nCR rates than similar combinations that do not include chemotherapy. We review the preclinical and clinical rationale for combining bortezomib with pegylated liposomal doxorubicin for the treatment of MM. The synergistic interaction in sensitizing each other toward myeloma cells in vitro and their complementary in vivo activities have justified clinical studies. We summarize data for completed and ongoing phase I/II trials of this combination. To date, results have been sufficiently encouraging to initiate an international, multicenter, randomized, phase III trial comparing bortezomib with or without pegylated liposomal doxorubicin in patients with relapsed/refractory MM. The results of this trial will confirm whether the rationale for combining bortezomib with pegylated liposomal doxorubicin is validated by improved clinical outcome, ie, improved time to progression, for patients with MM.

Prospective evaluation of low-dose warfarin for prevention of thalidomide associated venous thromboembolism.

Venous thromboemobolism (VTE) is an important complication of thalidomide therapy especially when it is combined with steroids or chemotherapy. Currently there is no consensus on the most appropriate prophylactic approach. We prospectively investigated the use of low-dose warfarin sodium in prevention of thalidomide-associated VTE in patients receiving thalidomide-based combination therapies. Patients with multiple myeloma or chronic lymphocytic leukemia who were treated on thalidomide based-combination therapies were treated on low-dose warfarin (1 or 2 mg) continuously through the duration of their therapy. Among the 68 patients enrolled, four developed an episode of VTE, an overall incidence of 5.9% (odds = 0.063). Median duration of thalidomide therapy was 4 months. Low-does warfarin decreases the incidence of VTE compared to historical control and is an effective mechanism of prevention of VTE in thalidomide-based chemotherapy regimens.

Supportive care in multiple myeloma.

Significant progress in the treatment of multiple myeloma has resulted in improvement of disease control with a trend toward overall and progression-free survival benefit. With the availability of several new therapeutic agents and combinations, a careful emphasis should be placed in the management of disease- and therapy-associated complications. Aggressive management of these complications can impact patients' quality of life as well as treatment outcome. This review highlights some of the critical supportive care measures integral to the optimal care of patients with multiple myeloma.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) restores allostimulatory function to accessory cells in patients with AIDS.

BACKGROUND: Impaired allostimulatory function of dendritic cells in patients with AIDS has been reported previously. Granulocyte-macrophage colony-stimulating factor (GM-CSF) can restore the T-cell stimulatory function in transforming growth factor-beta 1 (TGF-beta 1)-inhibited murine accessory cells. We now report the effect of intravenous recombinant human GM-CSF (rhGM-CSF) on accessory cells of HIV-infected patients. METHOD: The in vivo effect of GM-CSF on allostimulatory function of accessory cells was evaluated. Seventeen individuals with AIDS received a single infusion of rhGM-CSF (125 mg/m(2) over 120 minutes). Samples of peripheral blood lymphocytes (PBL) were taken at 1, 5, and 24 hours after infusion, and the allostimulatory capacity was measured. RESULTS: A single bolus infusion of rhGM-CSF resulted in significantly increased accessory cell function in 13/17 (88%) patients at one or more assayed time points after infusion. CONCLUSION: These results suggest that the administration of rhGM-CSF can potentially restore allostimulatory function to accessory cells in HIV-infected patients, and this presents a novel way of immune reconstitution. Clinical significance of this approach of immune reconstitution in AIDS patients warrants further investigations.

Long-term survival with allogeneic stem cell transplant and donor lymphocyte infusion following salvage therapy with anti-CD52 monoclonal antibody (Campath) in a patient with alpha/beta hepatosplenic T-cell non-Hodgkin's lymphoma.

Hepatosplenic T-cell non-Hodgkin's lymphoma (HSTCL) is a rare, aggressive form of NHL, with a median survival of approximately 8 months. We were able to successfully induce complete remission in a patient with alpha/beta HSTCL who was refractory to multiple prior chemotherapy regimens, using the humanized anti-CD52 monoclonal antibody alemtuzumab (Campath). Once disease was controlled, the patient was able to undergo allogeneic stem cell transplantation (SCT), which resulted in complete remission. Furthermore, upon relapse, we were able to re-induce complete clinical and molecular remission with donor lymphocyte infusions. At Day 655 (post-SCT), the patient remains in complete remission. These data suggest a potential role for alemtuzumab and allogeneic SCT in the treatment of T-cell NHL.

Neem leaf extract induces cell death by apoptosis and autophagy in B-chronic lymphocytic leukemia cells.

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia and is currently incurable. To expand the therapeutic armamentarium, we investigated neem leaf extract (NLE) after a patient with CLL demonstrated disease regression upon taking oral NLE. NLE-mediated apoptosis was examined in peripheral blood mononuclear cells (PBMCs) from 41 patients with CLL. NLE induced a dose-dependent reduction in CLL cell viability with significant apoptosis observed at 0.06% (w/v) by 24 h. Annexin-V staining and poly(ADP-ribose) polymerase 1 (PARP-1) and caspase 3 cleavage were observed after NLE treatment. However, a pan-caspase inhibitor only partially blocked NLE-mediated cell death. NLE also caused loss of mitochondrial outer membrane permeability and nuclear translocation of apoptosis-inducing factor. Furthermore, NLE treatment resulted in LC3-I cleavage. Biochemical analyses revealed that NLE also inhibits Bcl-2 and p53 proteins. In summary, NLE exhibits anti-leukemic properties in patient primary CLL cells and demonstrates clinical efficacy, warranting further investigation as a potential therapy for CLL.

Development and characterization of a novel human Waldenström macroglobulinemia cell line: RPCI-WM1, Roswell Park Cancer Institute - Waldenström Macroglobulinemia 1.

Understanding the biology of Waldenström macroglobulinemia is hindered by a lack of preclinical models. We report a novel cell line, RPCI-WM1, from a patient treated for WM. The cell line secretes human immunoglobulin M (h-IgM) with κ-light chain restriction identical to the primary tumor. The cell line has a modal chromosomal number of 46 and harbors chromosomal changes such as deletion of 6q21, monoallelic deletion of 9p21 (CDKN2A), 13q14 (RB1) and 18q21 (BCL-2), with a consistent amplification of 14q32 (immunoglobulin heavy chain; IgH) identical to its founding tumor sample. The clonal relationship is confirmed by identical CDR3 length and single nucleotide polymorphisms as well as a matching IgH sequence of the cell line and founding tumor. Both also harbor a heterozygous, non-synonymous mutation at amino acid 265 in the MYD88 gene (L265P). The cell line expresses most of the cell surface markers present on the parent cells. Overall, RPCI-WM1 represents a valuable model to study Waldenström macroglobulinemia.

Monoallelic and biallelic deletions of 13q14.3 in chronic lymphocytic leukemia: FISH vs miRNA RT-qPCR detection.

Deletion of 13q14.3 (del(13q)) is the most common cytogenetic abnormality in chronic lymphocytic leukemia (CLL) and implies a favorable prognosis. We explored the feasibility of detecting del(13q) by real-time quantitative polymerase chain reaction (PCR) for miR-15a and miR-16-1, whose loci are located in the deleted region. We analyzed 23 cases of B-CLL with monoallelic (10 cases) or biallelic del(13q) (5 cases) and used trisomy 12-positive CLL samples (n = 8) as control samples. As expected, miR-15a was expressed at significantly lower levels in monoallelic del(13qx1) samples compared with trisomy 12 control samples (P = .001). Biallelic del(13q) (del(13qx2)) samples showed further reduction of miR-15a levels compared with monoallelic del(13q) (del(13qx1)) (P = .009). In contrast, miR-16-1 expression levels were generally much lower and variable, with the highest levels detected in del(13qx1). Analyzed retrospectively, miR-15a levels differ among the del(13q) groups. However, only del(13qx2) miR-15a levels are reduced enough to determine the allelic status of an individual sample prospectively by real-time quantitative PCR.

Targeted treatment for chronic lymphocytic leukemia.

The treatment of chronic lymphocytic leukemia (CLL) has evolved over the last few decades. Recognition has increased of several key components of CLL biology currently manipulated for therapeutics. A milestone in the treatment of CLL was reached with the incorporation of immunotherapy with conventional chemotherapy. The fludarabine/cyclophosphamide/rituximab combination has demonstrated survival advantage for the first time in the treatment of CLL. Several other biological compounds are being explored with the hope of improving responses, impacting survival, and ultimately curing CLL. Important agents being tested are targeted on CLL surface molecules and their ligands, signal transduction protein and oncogenes. This review provides a brief summary of the recent advances made in preclinical and clinical investigation of selected promising therapeutic agents, which lead the target-directed therapeutic approach.

Tumor flare reaction associated with lenalidomide treatment in patients with chronic lymphocytic leukemia predicts clinical response.

BACKGROUND: In patients with chronic lymphocytic leukemia (CLL), treatment with lenalidomide induces a unique, previously uncharacterized, immune response called tumor flare reaction (TFR). The clinical significance of this reaction remains unknown. METHODS: Forty-five patients with CLL who were treated with lenalidomide in a phase 2 clinical trial were evaluated for the clinical features, intensity, and duration of TFR. Correlation was made with tumor response and the immune cellular microenvironment. Steroids for the prophylaxis of TFR was not given to patients in Group A (n = 29) whereas patients in Group B (n = 16) received low-dose prednisone as well as a slow dose escalation of lenalidomide for the prevention of TFR. RESULTS: Thirty (67%) patients experienced a TFR, with a grade 2 or 3 reaction (according to National Cancer Institute Common Toxicity Criteria [version 3.0]) observed in 33% of patients (47% in Group A and 9% in Group B; P = .05). The median time to onset of the TFR was 6 days, and was longer in the patients receiving prophylaxis (4 days vs 9 days, respectively; P = .01). A complete response was observed in 7 of 30 (23%) patients with TFR and 1 of 15 (7%) patients without TFR. The median progression-free survival was 19.9 months and 19.4 months, respectively, for patients with versus those without TFR (P = .92). CONCLUSIONS: TFR is a unique immune-mediated phenomenon noted with lenalidomide treatment only in patients with CLL that correlates with clinical response. It can be effectively managed with anti-inflammatory agents.

Management of patients with chronic lymphocytic leukemia treated with lenalidomide.

Lenalidomide is an immunomodulatory drug that has shown preliminary activity in the treatment of chronic lymphocytic leukemia (CLL). Much is known about the safety profile of lenalidomide from experience in other hematologic malignancies, such as myelodysplastic syndromes and multiple myeloma. In addition to the known adverse effects associated with lenalidomide (e.g., myelosuppression, rash, fatigue), some unique effects (e.g., tumor flare reactions, tumor lysis syndrome) have arisen during clinical studies of CLL. Typical signs of tumor flare reactions include early onset of painful enlargement of the lymph nodes or spleen, with or without low-grade fever, rash, and bone pain. Management may require nonsteroidal anti-inflammatory drugs or a short course of corticosteroids. Dose delays or reductions usually are not required for tumor flare reactions. Signs of tumor lysis syndrome may include shortness of breath, peripheral edema, generalized weakness, sweating, fever, and tachycardia. Untreated tumor lysis syndrome can result in renal impairment and congestive heart failure. Careful monitoring and appropriate management of treatment-related side effects can help ensure that patients with CLL achieve maximum therapeutic benefit from lenalidomide therapy.

Single agent lenalidomide in newly diagnosed multiple myeloma: a retrospective analysis.

Recently, lenalidomide and low dose dexamethasone were found to result in superior overall survival compared to lenalidomide and high dose dexamethasone. The immune suppressive effects of dexamethasone can antagonize lenalidomide immunomodulatory activity and may explain this observation. We conducted a retrospective analysis to evaluate the single agent activity of lenalidomide in newly diagnosed myeloma. Records of patients with newly diagnosed symptomatic multiple myeloma treated with single agent lenalidomide at H. Lee Moffitt Cancer Center and Roswell Park Cancer Institute were reviewed. Data were collected on disease characteristics, demographics, and treatment outcomes. Responses were assessed as per the International Myeloma Working Group criteria. From March 2007 to July 2009, 17 patients with newly diagnosed multiple myeloma were treated with single agent lenalidomide at both institutions. The median age was 70 years (range 46-84 years). Lenalidomide was generally well tolerated and no grade 4 hematologic toxicities were noted. The overall response rate (> or =partial remission) to lenalidomide alone was 47% at a median follow-up of 7 months (range 1-26). This experience suggests that lenalidomide alone can induce an anti-myeloma effect in previously untreated patients who are considered poor candidates for concurrent dexamethasone.