Combination targeted therapy with sorafenib and bevacizumab results in enhanced toxicity and antitumor activity

PURPOSE

Sorafenib inhibits Raf kinase and vascular endothelial growth factor (VEGF) receptor. Bevacizumab is a monoclonal antibody targeted against VEGF. We hypothesized that the complementary inhibition of VEGF signaling would have synergistic therapeutic effects.

PATIENTS AND METHODS

Patients had advanced solid tumors, Eastern Cooperative Oncology Group performance status of 0 to 1, and good end-organ function. A phase I dose-escalation trial of sorafenib and bevacizumab was initiated at below-recommended single-agent doses because of possible overlapping toxicity: sorafenib 200 mg orally twice daily and bevacizumab intravenously at 5 mg/kg (dose level [DL] 1) or 10 mg/kg (DL2) every 2 weeks. Additional patients were enrolled at the maximum-tolerated dose (MTD).

RESULTS

Thirty-nine patients were treated. DL1 was the MTD and administered in cohort 2 (N = 27). Dose-limiting toxicity in DL2 was grade 3 proteinuria and thrombocytopenia. Adverse events included hypertension, hand-foot syndrome, diarrhea, transaminitis, and fatigue. Partial responses (PRs) were seen in six (43%) of 13 patients with ovarian cancer (response duration range, 4 to 22+ months) and one of three patients with renal cell cancer (response duration, 14 months). PR or disease stabilization >or= 4 months (median, 6 months; range, 4 to 22+ months) was seen in 22 (59%) of 37 assessable patients. The majority (74%) required sorafenib dose reduction to 200 mg/d at a median of four cycles (range, one to 12 cycles).

CONCLUSION

Combination therapy with sorafenib and bevacizumab has promising clinical activity, especially in patients with ovarian cancer. The rapidity and frequency of sorafenib dose reductions indicates that sorafenib at 200 mg twice daily with bevacizumab 5 mg/kg every 2 weeks may not be tolerable long term, and alternate sorafenib dosing schedules should be explored.

Lack of reliability of CA125 response criteria with anti-VEGF molecularly targeted therapy

BACKGROUND

CA125 is an accepted indicator of epithelial ovarian cancer (EOC) response and is used to monitor patients treated with cytotoxic chemotherapy. It is uncertain how CA125 is affected by molecularly targeted drugs. In this pilot study, the authors analyzed the utility of CA125 to predict disease behavior in patients who were receiving sorafenib, a Raf-kinase/VEGFR2 inhibitor, and bevacizumab, an anti-VEGF monoclonal antibody.

METHODS

Fifteen of 42 patients had recurrent EOC. Patients received sorafenib 200 mg orally twice daily or D1-5 of 7 and bevacizumab 5 mg/kg to 10 mg/kg intravenously every 2 weeks for 28-day cycles. Computed tomography (CT) scans were performed every 2 cycles for restaging, and CA125 was measured monthly. CA125 concentrations were retrospectively analyzed as a function of clinical behavior.

RESULTS

Fourteen of 15 patients had abnormal CA125 concentrations at study entry (median 1056 U/mL; range, 67 U/mL to 9813 U/mL). Seven (47%) patients had partial response by imaging criteria. Five of these 7 patients had partial response by CA125 criteria (71% sensitivity). Eight (53%) patients would have had partial responses if CA125 criteria were used; only 5 were confirmed by CT (63 % specificity). Imaging and CA125 criteria combined yielded a higher total response rate of 10 of 15 (67%). Three patients with objective partial response by imaging lasting >20, >22, and >24 cycles would have terminated treatment prematurely if CA125 had been used.

CONCLUSIONS

CA125 changes may not correspond to imaging response criteria for EOC patients who are receiving sorafenib and bevacizumab. Caution is recommended when using CA125 as a response criterion of molecularly targeted agents until prospective studies validate CA125 changes with objective imaging response results.

BAG-4/SODD and associated antiapoptotic proteins are linked to aggressiveness of epithelial ovarian cancer

PURPOSE

We hypothesized that elevated expression in ovarian cancer of the BAG family of prosurvival proteins and associated partners would be associated with clinical features of aggressiveness in ovarian cancer.

EXPERIMENTAL DESIGN

Expression patterns of BAG-1, BAG-3, BAG-4, and Bcl-xL were determined by immunohistochemical analysis of tissue samples obtained at diagnosis from 28 women with stage III or stage IV ovarian cancer treated with cisplatin, paclitaxel, and cyclophosphamide after initial cytoreduction. Association of these proteins, BAG-6, heat shock protein 70 (Hsp70), Hsp27, and Bcl-2, with clinical variables was tested in ovarian cancer tissue arrays from Gynecologic Oncology Group tissue bank.

RESULTS

A statistically significant relationship was found between elevated cytoplasmic expression of BAG-4 and improved overall (P = 0.0002) and progression-free survival (P = 0.003) in the prospectively collected samples. Bcl-2 staining was significantly more frequent on the tissue array in lower stage (P = 0.005) and grade (P = 0.0009) tumors, whereas Hsp70 was prominent in higher grade cases (P = 0.002). Furthermore, Bcl-xL was more closely associated with serous compared with endometrioid ovarian cancers (P = 0.004).

CONCLUSION

Unexpectedly, cytoplasmic expression of BAG-4 and Bcl-2 marked less aggressive ovarian cancer, whereas nuclear Hsp70 suggested more aggressive behavior. Bcl-xL may play a more prominent function in the pathology of serous histology ovarian cancers compared with the endometrioid subtype. The findings presented here support involvement of these proteins in the propagation of ovarian cancer and provide a basis for the development of molecular therapeutics modulating these survival pathways.

Frequent engagement of the classical and alternative NF-kappaB pathways by diverse genetic abnormalities in multiple myeloma

Mechanisms of constitutive NF-kappaB signaling in multiple myeloma are unknown. An inhibitor of IkappaB kinase beta (IKKbeta) targeting the classical NF-kappaB pathway was lethal to many myeloma cell lines. Several cell lines had elevated expression of NIK due to genomic alterations or protein stabilization, while others had inactivating mutations of TRAF3; both kinds of abnormality triggered the classical and alternative NF-kappaB pathways. A majority of primary myeloma patient samples and cell lines had elevated NF-kappaB target gene expression, often associated with genetic or epigenetic alteration of NIK, TRAF3, CYLD, BIRC2/BIRC3, CD40, NFKB1, or NFKB2. These data demonstrate that addiction to the NF-kappaB pathway is frequent in myeloma and suggest that IKKbeta inhibitors hold promise for the treatment of this disease.

Proteomics in clinical trials and practice: present uses and future promise

The study of clinical proteomics is a promising new field that has the potential to have many applications, including the identification of biomarkers and monitoring of disease, especially in the field of oncology. Expression proteomics evaluates the cellular production of proteins encoded by a particular gene and exploits the differential expression and post-translational modifications of proteins between healthy and diseased states. These biomarkers may be applied towards early diagnosis, prognosis, and prediction of response to therapy. Functional proteomics seeks to decipher protein-protein interactions and biochemical pathways involved in disease biology and targeted by newer molecular therapeutics. Advanced spectrometry technologies and new protein array formats have improved these analyses and are now being applied prospectively in clinical trials. Further advancement of proteomics technology could usher in an era of personalized molecular medicine, where diseases are diagnosed at earlier stages and where therapies are more effective because they are tailored to the protein expression of a patient's malignancy.

Hodgkin disease: pharmacologic intervention of the CD40-NF kappa B pathway by a protease inhibitor

The malignant Reed-Sternberg cell of Hodgkin disease is an aberrant B cell that persists in an immunolgically mediated inflammatory infiltrate. Despite its nonproductive immunoglobulin genes, the Reed-Sternberg cell avoids the usual apoptotic fate of defective immune cells through an unknown mechanism. A likely candidate is the surface receptor, CD40, consistently expressed by Reed-Sternberg cells, and the first link in the pathway to NF-kappa B activation, the central regulator of cytokine production and apoptosis. CD40 signaling in B lymphocytes coordinates the immune response, including immunoglobulin isotype switch and Fas-mediated apoptosis. CD40-induced NF-kappa B activation is mediated by adapter proteins, the TNF receptor (TNFR)-associated factors (TRAFs), especially TRAFs 2, 3, and 5. Using a Hodgkin cell line, this study demonstrates that CD40 activation of NF-kappa B is mediated by proteolysis of TRAF3. Results further demonstrate that the pathway can be blocked by treatment with pharmacologic doses of a specific protease inhibitor, pepstatin-A, even in the presence of a mutated NF-kappa B inhibitor, I-kappa B alpha. The stability of TRAF3 regulates CD40/NF-kappa B-mediated control of the immune response, which is central to the biologic activity of the Reed-Sternberg cell. Prevention of TRAF3 proteolysis may be an entry point for design of novel pharmaceuticals to treat Hodgkin disease and immune system disorders. (Blood. 2000;96:2841-2848)

ECT in a patient with a deep brain-stimulating electrode in place

A 68-year-old woman had a deep brain-stimulating electrode placed for worsening of a long-standing essential tremor. There is currently no data available on the use of electroconvulsive therapy (ECT) in the presence of the deep brain stimulator (DBS). We report here the successful use of ECT in this patient with no adverse effects to the patient or to the DBS. No special provisions were made with the ECT administration except to ensure that the stimulator was turned off prior to administration of the ECT series, and remained off through the eight treatments administered to this patient. Following the course of treatment, her mood was markedly improved, and she displayed only minor postictal confusion.

Reed-Sternberg cell genome expression supports a B-cell lineage

The malignant Reed-Sternberg cell of Hodgkin's disease, first described a century ago, has resisted in-depth analysis due to its extreme rarity in lymphomatous tissue. To directly study its genome-wide gene expression, approximately 11,000,000 bases (27,518 cDNA sequences) of expressed gene sequence was determined from living single Reed-Sternberg cells, Hodgkin's tissue, and cell lines. This approach increased the number of genes known to be expressed in Hodgkin's disease by 20-fold to 2,666 named genes. The data here indicate that Reed-Sternberg cells from both nodular sclerosing and lymphocyte predominant Hodgkin's disease were derived from an unusual B-cell lineage based on a comparison of their gene expression to approximately 40,000,000 bases (10(5) sequences) of expressed gene sequence from germinal center B cells (GCB) and dendritic cells. The data set of expressed genes, reported here and on the World Wide Web, forms a basis to understand the genes responsible for Hodgkin's disease and develop novel diagnostic markers and therapies. This study of the rare Reed-Sternberg cell, concealed in its heterogenous cellular context, also provides a formidable test case to advance the limit of analysis of differential gene expression to the single disease cell.