Safety and efficacy of ofatumumab, a fully human monoclonal anti-CD20 antibody, in patients with relapsed or refractory B-cell chronic lymphocytic leukemia: a phase 1-2 study

Treatment of fludarabine-refractory chronic lymphocytic leukemia

The development of resistance to purine analogs defines a poor-risk subset of patients with chronic lymphocytic leukemia (CLL). Although in recent years chemoimmunotherapeutic combinations such as fludarabine, cyclophosphamide, and rituximab have induced response rates of 95% in previously untreated patients and increased the rates of failure-free survival, CLL remains incurable for many patients because of a lack of disease response or the development of refractoriness to fludarabine. Fludarabine-refractory disease is defined as CLL that does not respond to fludarabine or that recurs within 6 months of treatment with a fludarabine-containing regimen. The natural course of the disease is associated with poor survival. Salvage therapeutic strategies include alemtuzumab-containing regimens, targeted agents, and allogeneic stem cell transplantation. Single-agent alemtuzumab induces response in up to 40% of patients with fludarabine-refractory CLL, but responses are not durable, and the median survival is approximately 1 to 2 years. Alemtuzumab is also combined with fludarabine, cyclophosphamide, and/or rituximab, and other agents such as lenalidomide and flavopiridol, as well as targeted agents, and used in fludarabine-refractory CLL. Cumulative evidence suggests that allogeneic stem cell transplantation is an efficacious therapeutic strategy for patients who do not respond to fludarabine or who develop disease recurrence within 12 months after purine analog treatment. In conclusion, chemoimmunotherapy regimens that include alemtuzumab and/or rituximab and allogeneic stem cell transplantation improve the prognosis of this disease, but there is a continued need for novel, more effective therapies.

Ofatumumab

Ofatumumab is an anti-CD20 IgG1kappa human monoclonal antibody that is being considered by the US Food and Drug Administration and the European Medicines Agency for marketing approval as a treatment for chronic lymphocytic leukemia. The mAb is also being studied as a treatment for lymphoma, rheumatoid arthritis and multiple sclerosis. The candidate targets the same antigen as rituximab, but ofatumumab binds a novel, membrane-proximal epitope, and dissociates from its target at a slower rate compared to rituximab. Ofatumumab might be approved in the US by August 2009.

Binding of submaximal C1q promotes complement-dependent cytotoxicity (CDC) of B cells opsonized with anti-CD20 mAbs ofatumumab (OFA) or rituximab (RTX): considerably higher levels of CDC are induced by OFA than by RTX

The CD20 mAb ofatumumab (OFA) is more effective than rituximab (RTX) in promoting complement-dependent cytotoxicity (CDC) of B cells via the classical pathway (CP) of complement. CP activation is initiated by C1q binding to cell-bound IgG. Therefore, we examined the role of C1q in the dynamics of complement activation and CDC of B cell lines and primary cells from patients with chronic lymphocytic leukemia, reacted with OFA or RTX. C1q binding, complement activation, and colocalization of C1q with cell-bound mAbs were determined by flow cytometry and high-resolution digital imaging. C1q binds avidly to OFA-opsonized Raji and Daudi cells (K(D) = 12-16 nM) and colocalizes substantially with cell-bound OFA. Cells opsonized with OFA undergo high levels of complement activation and CDC in C1q-depleted serum supplemented with low concentrations of C1q. Under comparable conditions, RTX-opsonized cells bind less C1q; in addition, even when higher concentrations of C1q are used to achieve comparable C1q binding to RTX-opsonized cells, less complement activation and CDC are observed. Greater CDC induced by OFA may occur because C1q is bound in close proximity and with high avidity to OFA, resulting in effective CP activation. Moreover, OFA binds to the small, extracellular CD20 loop, placing the mAb considerably closer to the cell membrane than does RTX. This may facilitate effective capture and concentration of activated complement components closer to the cell membrane, potentially shielding them from inactivation by fluid phase agents and promoting efficient generation of the membrane attack complex.

Applications of monoclonal antibodies for the treatment of hematological malignancies

BACKGROUND

The introduction of mAbs has changed the clinical approach to patients with lymphoma and leukemia.

OBJECTIVE

To summarize the most significant applications of mAb-based regimens in the treatment of hematological malignancies and explore their possible role in the future management of these patients.

RESULTS

Rituximab (anti-CD20) was the first mAb developed for the treatment of B-cell lymphomas. Several randomized studies have demonstrated its efficacy in lymphomas and low toxicity profile; rituximab also has significant activity in chronic lymphocytic leukemia (CLL). Alemtuzumab (anti-CD52) has shown efficacy in previously untreated or refractory CLL patients, while gemtuzumab ozogamicin (anti-CD33) appears to have significant activity in acute myeloid leukemias and myelodysplastic syndromes.

CONCLUSIONS

In the next few years, investigations will be concentrated on the improvement of the older mAbs, and the development of new mAbs, targeting molecules important for malignant cell cycle and survival in an attempt to further improve patient survival.

Humanized anti-CD20 antibody, veltuzumab, in refractory/recurrent non-Hodgkin's lymphoma: phase I/II results

PURPOSE

This is a multicenter phase I/II dose-finding study in relapsed/refractory B-cell non-Hodgkin's lymphoma (NHL) evaluating veltuzumab, a humanized anti-CD20 antibody with structure-function differences from chimeric rituximab.

PATIENTS AND METHODS

Eighty-two patients (median age, 64 years; 79% stage III/IV, one to nine prior treatments) received four once-weekly doses of 80 to 750 mg/m(2) of veltuzumab and were assessed for safety, efficacy, pharmacodynamics, pharmacokinetics, and immunogenicity.

RESULTS

Veltuzumab was well tolerated, with no grade 3 to 4 drug-related adverse events despite short infusion times (typically 2 hours initially, 1 hour subsequently at doses < 375 mg/m(2)). In follicular lymphoma, 24 (44%) of 55 patients had objective responses (OR), with 15 (27%) complete responses (CRs) or CRs unconfirmed (CRus) by International Working Group criteria, and with some responses occurring despite two to five prior rituximab-containing regimens, less favorable prognosis (elevated lactate dehydrogenase, tumors > 5 cm, and Follicular Lymphoma International Prognostic Index > or = 2), and at all dose levels. The CRs/CRus were durable (median duration, 19.7 months), with five patients still ongoing (15.9 to 37.6 months duration). In marginal zone lymphoma, five (83%) of six patients had ORs, with two CRs/CRus (33%), and in diffuse large B-cell lymphoma, three (43%) of seven patients achieved partial responses. At all dose levels studied, B cells were depleted after the first infusion, veltuzumab serum half-lives were similar after the fourth infusion, and mean antibody serum levels exceeded values considered important for anti-CD20 therapy (ie, 25 microg/mL).

CONCLUSION

Veltuzumab appeared safe and active at all tested doses, encouraging further study, including dose levels less than those typically used with rituximab.

Structure of the Fab fragment of therapeutic antibody Ofatumumab provides insights into the recognition mechanism with CD20

CD20 is an important drug target for B-cell depletion therapy against certain B-cell lymphomas and autoimmune diseases. The success of anti-CD20 antibody drugs such as Rituximab, Ibritumomab, and Tositumomab has promoted the development of new generation of anti-CD20 antibodies for therapeutic applications. Ofatumumab is a fully human anti-CD20 antibody that is currently in phase III clinical trial for several types of malignancies and autoimmune diseases and is one of the most promising anti-CD20 drugs. Here we report the crystal structure of the Fab fragment of Ofatumumab at 2.2A resolution. The antigen combining site is composed of a large, deep pocket formed by six CDR loops. The pocket has a hydrophobic periphery and a positively charged bottom. Structure analysis and comparison with other antibodies suggest that the hydrophobic periphery might interact with the epitope on CD20 that is enriched with hydrophobic residues and very close to cell membrane, and the positively charged bottom might interact with Glu(150) of CD20 which is the only negatively charged residue within the epitope. These results provide some insights into the recognition of Ofatumumab with CD20 and explain how the antibody can recognize an epitope so close to the cell membrane.

Richter syndrome: molecular insights and clinical perspectives

Richter syndrome (RS) represents the clinico-pathologic transformation of chronic lymphocytic leukaemia (CLL) to an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL). The clinical definition of RS is heterogeneous, and encompasses at least two biologically different conditions: (i) CLL transformation to a clonally related DLBCL, that accounts for the majority of cases; (ii) development of a DLBCL unrelated to the CLL clone. In clonally related RS, the pathogenetic link between the CLL and the DLBCL phases is substantiated by the acquisition of novel molecular lesions at the time of clinico-pathologic transformation. RS is not a rare event in the natural history of CLL, since the cumulative incidence of RS at 10 years exceeds 10%. Prompt recognition of RS is known to be clinically useful, and may be favoured by close monitoring of CLL patients harbouring clinical and/or biological risk factors of RS development. Conventional risk factors that are independent predictors of RS development at the time of CLL diagnosis include: (i) expression of CD38; (ii) absence of del13q14 and (iii) lymph node size > or =3 cm. Other risk factors of RS development include CD38 genotype and usage of specific immunoglobulin variable genes. The molecular pathogenesis of RS has been elucidated to a certain extent. Acquisition of TP53 mutations and/or 17p13 deletion is a frequent molecular event in RS, as it is in other types of transformation from indolent to aggressive B-cell malignancies. Additional molecular alterations are being revealed by genome wide studies. Once that transformation has occurred, RS prognosis may be predicted by the RS score, based on performance status, LDH, platelet count, tumour size and number of prior therapies. Depending on patient's age and RS score, the therapeutic options for RS may range from conventional immunochemotherapy to allogeneic bone marrow transplantation.

Diffuse large B-cell lymphoma: reduced CD20 expression is associated with an inferior survival

CD19 and CD20 are B cell-specific antigens whose expression is heterogeneous when analyzed by flow cytometry (FCM). We determined the association between CD20 expression and clinical outcome in patients with diffuse large B-cell lymphoma (DLBCL). The mean fluorescence intensity of CD20 and CD19 was determined by FCM, and the cytoplasmic expression of CD20 was determined by immunohistochemistry (IHC) on 272 diagnostic DLBCL samples. Exon 5 of the MS4A1 gene coding for the extracellular component of the CD20 antigen was sequenced in 15 samples. A total of 43 of 272 (16%) samples had reduced CD20 expression by FCM; of these, 35 (13%) had bright CD19 expression. The latter had a markedly inferior survival when treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or rituximab-CHOP (R-CHOP; median survival of 1.2 and 3.0 years vs not reached for the others, P < .001 and P = .001), independent of the International Prognostic Index. A total of 41 of 43 samples with reduced CD20 expression by FCM had strong staining for CD20 by IHC. There were no mutations in exon 5 of the MS4A1 gene to explain the discrepancy between FCM and IHC. CD20 and CD19 expression by FCM should be determined on all biopsies of patients with DLBCL because reduced CD20 expression cannot be reliably detected by IHC.

Immunomodulation in the treatment of haematological malignancies

Despite the continuous advances in immunology and cancer biology, haematological malignancies are often incurable. Conventional chemotherapy and radiation are efficacious for some lymphoma and leukaemia, however relapse and progressive disease often occurs. The evidence that the immune system can play an essential role in controlling cancer progression provide a basis for the development of active therapies, such as immunization, aimed to evoke or amplify a tumour-specific immune response. However, the inability of the patient's own immune system to mount effective responses against tumour antigens is a major limit of vaccination approaches. The adoptive transfer of effectors of the adaptive immune system is an attractive strategy to circumvent the limitations of autologous immune responses. Donor lymphocyte infusion and the transfer of monoclonal antibodies (MoAbs) have been the first forms of adoptive therapy approved for clinical use and are still fundamental components of immunotherapy of haematological malignancies. Due to the continuous characterization of tumour-specific antigen, the development of tumour-tailored therapies that exploit the specificity of antibodies and T cell receptors (TCRs) is progressing rapidly. This review highlights the current advances in the field of adoptive immunotherapy of haematological malignancies, starting by elucidating the ongoing progress in passive transfer of MoAbs. We will also discuss recent advances in the adoptive transfer with tumour-specific high avidity T cells, which can be generated ex vivo by the transfer of gene constructs encoding single chain antibodies or TCRs, thus redirecting T cell specificity to selected tumour antigens. The ability to produce gene-modified T cells of desired specificity and defined functional activity may improve in the future T cell based immunotherapy of cancer.

Expanded use of rituximab in the management of non-Hodgkin lymphoma

Rituximab is a chimeric monoclonal antibody targeting the B cell antigen CD20. Since its first approval for clinical use in 1997, rituximab has become an inherent part of the treatment of CD20-positive lymphoma. In previously untreated non-Hodgkin lymphoma (NHL) conventional chemotherapy supplemented by rituximab (R-chemotherapy) was shown to be more effective than chemotherapy alone. This holds true for indolent as well as aggressive NHL. Rituximab was also shown to be beneficial when used as maintenance therapy or part of salvage and re-induction regimens in relapsed NHL. Administration of rituximab is generally well tolerated. The most common side effects including fever, urticaria and bronchospasm are mostly mild, treatable and restricted to the infusion period. Thus, rituximab can usually be administered in an outpatient setting. Due to its favorable effect/side effect ratio, clinical trials are currently evaluating a possible role for rituximab in several other diseases such as Hodgkin lymphoma (HL) and non-malignant autoimmune disorders. This review aims at giving an overview of the pharmacological properties of rituximab and summarizing key publications and recent literature on its use in NHL.

Chronic lymphocytic leukemia: new concepts and emerging therapies

OPINION STATEMENT

Remarkable progress in elucidating the biology of chronic lymphocytic leukemia (CLL) has been made over the last two decades. Improved understanding of CLL has lead to new prognostic tools and therapeutic options, and holds promise for eventually finding a cure for this disease. Challenges lie in incorporating the various treatment modalities, including chemotherapy, monoclonal antibodies, immunotherapeutic strategies and novel small molecules, into a comprehensive treatment strategy guided by the biological complexity of CLL.

Novel human antibody therapeutics: the age of the Umabs

Monoclonal antibodies represent a major and increasingly important category of biotechnology products for the treatment of human diseases. The state-of-the-art of antibody technology has evolved to the point where therapeutic monoclonal antibodies, that are practically indistinguishable from antibodies induced in humans, are routinely generated. We depict how our science-based approach can be used to further improve the efficacy of antibody therapeutics, illustrated by the development of three monoclonal antibodies for various cancer indications: zanolimumab (directed against CD4), ofatumumab (directed against CD20) and zalutumumab (directed against epidermal growth factor receptor).

New biologic agents and immunologic strategies

The treatment of non-Hodgkin lymphoma has traditionally consisted of cytotoxic chemotherapy, which can frequently induce remissions but less reliably delivers long-term disease-free survival. The last two decades have heralded an era of increasing exploration of therapies derived from improved biologic understanding of tumors and tumor-host interactions, including the development of therapeutic tactics that take advantage of immune mechanisms to target and kill tumors. Foremost among these has been the development of monoclonal antibodies. Currently, an array of novel therapeutics in development may improve outcomes further, including novel monoclonals and other agents that take advantage of or optimize immune system function in the treatment of lymphoma or that provide other mechanisms of antitumor activity.

The effect of in vivo T cell depletion with alemtuzumab on reduced-intensity allogeneic hematopoietic cell transplantation for chronic lymphocytic leukemia

Reduced-intensity conditioning (RIC) allogeneic hematopoietic cell transplantation is increasingly considered for patients with chronic lymphocytic leukemia (CLL). To investigate the impact of in vivo T cell depletion with alemtuzumab on the incidence of graft-versus-host disease (GVHD), nonrelapse mortality (NRM), progression-free survival (PFS), and overall survival (OS), we retrospectively analyzed the outcomes of 62 consecutive CLL patients conditioned with fludarabine and melphalan at 4 institutions. For GVHD prophylaxis, 41 patients (cohort 1) received alemtuzumab and cyclosporin; and 21 patients (cohort 2) received cyclosporin plus methotrexate or mycophenolate. Donors were 50 siblings and 12 unrelated volunteers. Twenty-two (36%) patients received donor lymphocyte infusions (DLI), 20 (49%) from cohort 1 and 2 (10%) from cohort 2 (P=.002). Grade III-IV acute GVHD (aGVHD) was observed in 20% and 38% of patients from cohorts 1 and 2, respectively (P=.14). Extensive chronic GVHD (cGVHD) was observed in 10% and 48% of patients from cohorts 1 and 2, respectively (P=.03). There was a trend toward a higher viral infection rate in cohort 1 compared to cohort 2 (68% versus 43%, P=.062), but the incidence of cytomegalovirus (CMV) reactivation was not significantly different. The 3-year OS, PFS, NRM, and relapse rates were 65%, 39%, 28%, and 32%, respectively, for cohort 1; and 57%, 47%, 34%, and 20%, respectively, for cohort 2 (P=.629, P=.361, P=.735, and P=0.112, respectively). In conclusion, both methods of GVHD prophylaxis were equivalent in terms of survival. The administration of alemtuzumab led to reduced cGVHD, possibly improving quality of life.

Treatment of B-cell chronic lymphocytic leukemia with nonchemotherapeutic agents: experience with single-agent and combination therapy

Recent advances in purine analog-based combination chemotherapy and chemoimmunotherapy have significantly improved response rates and progression-free survival in patients with B-cell chronic lymphocytic leukemia (CLL). However, there are clinical scenarios in which purine analog-based treatment may not be appropriate, either because of the risk of toxicity in patients with comorbidity or because purine analog-based therapies are unlikely to achieve satisfactory responses. Novel, nonchemotherapeutic treatment regimens are becoming increasingly important in these patients, as well as in patients in whom combination chemotherapy-based treatment has failed or resulted in relapse. Nonchemotherapeutic agents include monoclonal antibodies, glucocorticoids, immunomodulatory drugs, drugs with specific intracellular molecular targets, vaccines and cellular immunotherapies. These agents use diverse mechanisms of action that may complement each other, therefore providing a scientific rationale to investigate combinations of these agents in the treatment of CLL. In this review, we will discuss current knowledge of available nonchemotherapeutic agents, available clinical experience with their use alone and in combination and how these approaches may affect outcomes in patients with CLL.

Properties and structure-function relationships of veltuzumab (hA20), a humanized anti-CD20 monoclonal antibody

Veltuzumab is a humanized anti-CD20 monoclonal antibody with complementarity-determining regions (CDRs) identical to rituximab, except for one residue at the 101st position (Kabat numbering) in CDR3 of the variable heavy chain (V(H)), having aspartic acid (Asp) instead of asparagine (Asn), with framework regions of epratuzumab, a humanized anti-CD22 antibody. When compared with rituximab, veltuzumab has significantly reduced off-rates in 3 human lymphoma cell lines tested, as well as increased complement-dependent cytotoxicity in 1 of 3 cell lines, but no other in vitro differences. Mutation studies confirmed that the differentiation of the off-rate between veltuzumab and rituximab is related to the single amino acid change in CDR3-V(H). Studies of intraperitoneal and subcutaneous doses in mouse models of human lymphoma and in normal cynomolgus monkeys disclosed that low doses of veltuzumab control tumor growth or deplete circulating or sessile B cells. Low- and high-dose veltuzumab were significantly more effective in vivo than rituximab in 3 lymphoma models. These findings are consistent with activity in patients with non-Hodgkin lymphoma given low intravenous or subcutaneous doses of veltuzumab. Thus, changing Asn(101) to Asp(101) in CDR3-V(H) of rituximab is responsible for veltuzumab's lower off-rate and apparent improved potency in preclinical models that could translate into advantages in patients.

Fully human antibodies from transgenic mouse and phage display platforms

Over the past two decades, technologies have emerged for generating monoclonal antibodies (MAbs) derived from human immunoglobulin gene sequences. These fully human MAbs provide an alternative to re-engineered, or de-immunized, rodent MAbs as a source of low immunogenicity therapeutic antibodies. There are now two marketed fully human therapeutic MAbs, adalimumab and panitumumab, and several dozen more in various stages of human clinical testing. Most of the drugs, including adalimumab and panitumumab, were generated using either phage display or transgenic mouse platforms. The reported clinical experience with fully human MAbs demonstrates that these two platforms are, and should continue to be, a significant source of active and well tolerated experimental therapeutics. While this body of reported clinical data does not yet provide a clear distinction between the platforms, the available descriptions of the drug discovery processes used to identify the clinical candidates highlight one difference. It appears that lead optimization is more commonly applied to phage display derived leads than transgenic mouse derived leads.

Immunotherapeutic mechanisms of anti-CD20 monoclonal antibodies

The anti-CD20, B-cell-specific mAb rituximab (RTX) has been approved for treatment of non-Hodgkin's B cell lymphoma and rheumatoid arthritis. Under conditions of high B cell burden, exhaustion of the body's effector mechanisms, for example, NK-cell-mediated killing, may lead to substantial decreases in the immunotherapeutic efficacy of this mAb. Moreover, RTX treatment of patients with chronic lymphocytic leukemia and high levels of circulating B cells can lead to removal of CD20 from the cells, thus allowing them to persist and resist clearance. RTX therapy for several autoimmune diseases has proven to be effective, but in numerous instances there has been little correlation between reductions in disease activity and changes in titers of pathogenic autoantibodies. This paradox may be explained by a separate mechanism: Binding of RTX to B cells generates immune complexes that act as decoys to attract monoycte/macrophages and thus reduce their inflammatory activity in certain autoantibody-mediated diseases. Several second-generation anti-CD20 mAbs with enhanced cytotoxic action have been developed and are being tested in the clinic for treatment of cancer and autoimmune diseases. The application of these mAbs, potentially in combination with immune effector modifying drugs, may successfully address the shortcomings of current anti-CD20 immunotherapy.

First clinical use of ofatumumab, a novel fully human anti-CD20 monoclonal antibody in relapsed or refractory follicular lymphoma: results of a phase 1/2 trial

Ofatumumab is a unique monoclonal antibody that targets a distinct small loop epitope on the CD20 molecule. Preclinical data show that ofatumumab is active against B-cell lymphoma/chronic lymphocytic leukemia cells with low CD20-antigen density and high expression of complement inhibitory molecules. In a phase 1/2 trial evaluating safety and efficacy of ofatumumab in relapsed or refractory follicular non-Hodgkin lymphoma (FL) grade 1 or 2, 4 dose groups of 10 patients received 4 weekly infusions of 300, 500, 700, or 1000 mg. Patients had a median of 2 prior FL therapies and 13% had elevated lactate dehydrogenase. No safety concerns or maximum tolerated dose was identified. A total of 274 adverse events were reported; 190 were judged related to ofatumumab, most occurring on the first infusion day with Common Terminology Criteria grade 1 or 2. Eight related events were grade 3. Treatment caused immediate and profound B-cell depletion, and 65% of patients reverted to negative BCL2 status. Clinical response rates ranged from 20% to 63%. Median time to progression for all patients/responders was 8.8/32.6 months, and median duration of response was 29.9 months at a median/maximum follow-up of 9.2/38.6 months. Ofatumumab is currently being evaluated in patients with rituximab-refractory FL. This trial was registered at www.clinicaltrials.gov as #NCT00092274.

Emerging drugs for rarer chronic lymphoid leukemias

BACKGROUND

Rarer indolent lymphoid leukemias include well defined mature B-cell and T-cell neoplasm with widely varying natural history and specific morphological, immunophenotypic and molecular characteristics. Among these are prolymphocytic leukemia (PLL), hairy cell leukemia (HCL) and its variants, large granular lymphocyte leukemia (LGLL) and adult T-cell leukemia/lymphoma (ATLL).

OBJECTIVE

To present current therapies and emerging drugs potentially useful in the treatment of rarer chronic lymphoid leukemias.

METHODS

After searching MEDLINE, PubMed and the Current Contents database, and conference proceedings from the previous 3 years of the American Society of Hematology (ASH), the European Society of Hematology (EHA) and the American Society of Clinical Oncology (ASCO) were searched manually; articles written in English and additional relevant publications were then selected.

RESULTS/CONCLUSION

New drugs including monoclonal antibodies (mAbs), new purine analogs, small molecules targeting specific molecular targets and other agents are included. Future research should focus on the novel therapeutic strategies based on the molecular pathogenic mechanisms and the development of new targeted therapies for each distinct chronic lymphoid leukemia.

New agents in the treatment of CLL

Chemoimmunotherapy has resulted in high complete remission rates and long remission duration in patients with chronic lymphocytic leukemia (CLL) but relapses occur and curative strategies still need to be developed. A wealth of new agents with a wide variety of mechanisms of action against CLL are currently in clinical trials. Twelve of these agents, which are in various stages of development varying from Phase I to Phase III trials, will be discussed. These include alkylating agents, monoclonal antibodies, immune modulators, cyclin-dependent kinase (CDK) inhibitors, BCL-2 family member inhibitors, protein kinase C (PKC) inhibitors, SRC inhibitors, HSP-90 inhibitors and small modular immune pharmaceutics (SMIP).