Taimur Sher

Small Cell Lung Cancer

Small cell lung cancer accounts for approximately 15% of bronchogenic carcinomas. It is the cancer most commonly associated with various paraneoplastic syndromes, including the syndrome of inappropriate antidiuretic hormone secretion, paraneoplastic cerebellar degeneration, and Lambert-Eaton myasthenic syndrome. Because of the high propensity of small cell lung cancer to metastasize early, surgery has a limited role as primary therapy. Although the disease is highly sensitive to chemotherapy and radiation, cure is difficult to achieve. The combination of platinum and etoposide is the accepted standard chemotherapeutic regimen. It is also the accepted standard therapy in combination with thoracic radiotherapy (TRT) for limited-stage disease. Adding TRT increases absolute survival by approximately 5% over chemotherapy alone. Thoracic radiotherapy administered concurrently with chemotherapy is more efficacious than sequential therapy. Furthermore, the survival benefit is greater if TRT is given early rather than late in the course of chemotherapy. Regardless of disease stage, no relevant survival benefit results from increased chemotherapy dose intensity or dose density, altered mode of administration (eg, alternating or sequential administration) of various chemotherapeutic agents, or maintenance chemotherapy. Prophylactic cranial radiation prevents central nervous system recurrence and can improve survival. In Japan and some other Asian countries, the combination of irinotecan and cisplatin is the standard chemotherapeutic regimen. Clinical trials using thalidomide, gefitinib, imatinib, temsirolimus, and farnesyltransferase inhibitors have not shown clinical benefit. Other novel agents such as bevacizumab have shown promising early results and are being evaluated in larger trials.

Efficacy of lenalidomide in patients with chronic lymphocytic leukemia with high-risk cytogenetics.

Patients with chronic lymphocytic lymphoma (CLL) with high-risk cytogenetics [del(11q)(q22.3) or del(17p)(p13.1)] have limited therapeutic options and their prognosis remains poor. This analysis was conducted to determine the clinical activity of lenalidomide in patients with high-risk disease. Relapsed/refractory patients with CLL enrolled in a phase II clinical trial who had del(11q)(q22.3) or del(17p)(p13.1) were included in this analysis. Patients received single agent lenalidomide for 21 days of the 4 week treatment cycle. The overall response rate among patients with high-risk cytogenetics was 38%, with 19% of patients achieving a complete response. Median progression-free survival was 12.1 months, which is higher than demonstrated with other agents in comparable patient populations. In addition, the estimated 2-year survival probability was 58%, demonstrating that the responses achieved with lenalidomide are durable, even in patients with CLL with high-risk disease with poor risk cytogenetics.

Biological effects and clinical significance of lenalidomide-induced tumour flare reaction in patients with chronic lymphocytic leukaemia: in vivo evidence of immune activation and antitumour response.

Lenalidomide has demonstrated impressive antileukaemic effects in patients with chronic lymphocytic leukaemia (CLL). The mechanism(s) by which it mediates these effects remain unclear. Clinically, CLL patients treated with lenalidomide demonstrate an acute inflammatory reaction, the tumour flare reaction that is suggestive of an immune activation phenomenon. Samples from CLL patients treated with lenalidomide were used to evaluate its effect on the tumour cell and components of its microenvironment (immune cellular and cytokine). Lenalidomide was unable to directly induce apoptosis in CLL cells in vitro, however it modulated costimulatory (CD80, CD83, CD86) surface molecules on CLL cells in vitro and in vivo. Concurrently, we demonstrated that NK cell proliferation was induced by lenalidomide treatment in patients and correlated with clinical response. Cytokine analysis showed increase in levels of TNF‐α post‐lenalidomide treatment, consistent with acute inflammatory reaction. Furthermore, the basal cytokine profile (high IL‐8, MIG, IP‐10 and IL‐4 levels and low IL‐5, MIP1a, MIP1b, IL12/p70) was predictive of clinical response to lenalidomide. Collectively, our correlative studies provide further evidence that the antileukaemic effect of lenalidomide in CLL is mediated not only through modulation of the leukaemic clone but also through elements of the tumour microenvironment.

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 and thalidomide is an effective steroid independent salvage regimen for patients with relapsed or refractory multiple myeloma: results of a phase II clinical trial

Novel agents have demonstrated enhanced efficacy when combined with other antimyeloma agents especially dexamethasone. The steroid doses employed in myeloma regimens are often poorly tolerated. Therefore, in a phase II clinical trial we investigated the efficacy of a steroid-free combination including bortezomib, pegylated liposomal doxorubicin and thalidomide (VDT regimen). Twenty-three patients with relapsed or refractory myeloma or other plasma cell cancers were treated with the VDT regimen. Patient had a median of five prior therapies and 65.2% were refractory to their last regimen. The overall response rates were 55.5% and 22%, respectively. The median progression free survival was 10.9 months (95% CI: 7.3–15.8) and the median overall survival was 15.7 months (95% CI: 9.1–not reached). Fatigue and sensory neuropathy were the most common side effects noted. We observe that VDT is an effective steroid-free regimen with ability to induce durable remission even in patients with refractory myeloma.

Pharmacokinetic evaluation of oblimersen sodium for the treatment of chronic lymphocytic leukemia

Introduction: Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in the western hemisphere. Developing new therapies remains a priority as present treatment options do not offer a cure. BCL-2 overexpression in CLL is associated with aggressive disease features and resists chemotherapy. Oblimersen sodium (G3139) is a phosphorothioate oligonucleotide antisense drug targeting the BCL-2 mRNA and is the first antisense to reach advanced clinical testing in oncology. Preclinical evaluation has demonstrated good antineoplastic effect in B-cell cancers; several clinical trials have confirmed its safety and efficacy both alone and in combination with other therapeutics. Areas covered: This review focuses on the chemistry, pharmacodynamics, pharmacokinetics and clinical evaluation of oblimersen in CLL. PubMed and MEDLINE searches assisted in data collection. Expert opinion: Bcl-2 is an important target in CLL. Antisense therapy is a novel approach to target oncoproteins; this can be beneficial in the clinical setting. Oblimersen sodium demonstrates the clinical safety of the antisense therapeutic approach and, with chemotherapy, shows survival advantage in a subset of CLL patients. However, future approval of oblimersen sodium in CLL remains uncertain. Nevertheless, BCL-2 remains a critical target in drug development and is an area of high-priority research.

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.

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

Abstract 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.

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.

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 (≥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.