Bortezomib-induced severe hepatitis in multiple myeloma: a case report

Bortezomib is a novel proteasome inhibitor with significant antimyeloma activity. Its toxicity is manageable, and the most frequent adverse effects mainly consist of gastrointestinal symptoms, peripheral neuropathy, neuropatic pain, and thrombocytopenia. Severe liver toxicity has not been previously recognized. A patient with relapsed multiple myeloma who developed bortezomib-induced severe recurrent hepatitis is described. The importance of recognizing this rare potential toxicity is highlighted in order to discontinue this agent if liver adverse reaction is suspected.     

Bortezomib-induced "BRCAness" sensitizes multiple myeloma cells to PARP inhibitors

Chromosomal instability is a defining feature of clonal myeloma plasma cells that results in the perpetual accumulation of genomic aberrations. In addition to its role in protein homeostasis, the ubiquitin-proteasome system is also involved in the regulation of DNA damage-repair proteins. In the present study, we show that proteasome inhibition induces a "BRCAness" state in myeloma cells (MM), with depletion of their nuclear pool of ubiquitin and abrogation of H2AX polyubiquitylation, an essential step for the recruitment of BRCA1 and RAD51 to the sites of DNA double-stranded breaks (DSBs) and the initiation of homologous recombination (HR)-mediated DNA repair. Inhibition of poly-ADP-ribose-polymerase 1 and 2 (PARP1/2) with ABT-888 induced transient DNA DSBs that were rapidly resolved and thus had no effect on viability of the MM cells. In contrast, cotreatment of MM cell lines and primary CD138(+) cells with bortezomib and ABT-888 resulted in the sustained accumulation of unrepaired DNA DSBs with persistence of unubiquitylated γH2AX foci, lack of recruitment of BRCA1 and RAD51, and ensuing MM-cell death. The heightened cytotoxicity of ABT-888 in combination with bortezomib compared with either drug alone was also confirmed in MM xenografts in SCID mice. Our studies indicate that bortezomib impairs HR in MM and results in a contextual synthetic lethality when combined with PARP inhibitors.     

Bortezomib-induced cardiogenic shock in a multiple myeloma patient with K light-chain cardiac amyloidosis

Annals of Hematology -     

Bortezomib-induced peripheral neuropathy in multiple myeloma: a comprehensive review of the literature

Bortezomib has demonstrated significant activity in clinical trials, mainly against recurrent or newly diagnosed multiple myeloma (MM). Peripheral neuropathy is a significant toxicity of bortezomib, requiring dose modification and potential changes in the treatment plan when it occurs. The mechanism underlying bortezomib-induced peripheral neuropathy (BIPN) is unknown. Metabolic changes resulting from the accumulation of bortezomib in the dorsal root ganglia cells, mitochondrial-mediated disregulation of Ca(++) homeostasis, and disregulation of neurotrophins may contribute to the pathogenesis of BIPN. It is increasingly recognized that BIPN may be a proteasome inhibitor class effect, producing primarily a small fiber and painful, axonal, sensory distal neuropathy. Incidence of BIPN is mainly related to various risk factors, including cumulative dose and evidence of preexisting neuropathy. Assessment of BIPN is based primarily on neurologic clinical examination and neurophysiologic methods. To date, apart from the use of dose reduction and schedule change algorithm, there is no effective treatment with neuroprotective agents for BIPN. Analgesics, tricyclic antidepressants, anticonvulsants, and vitamin supplements have been used as symptomatic treatment against bortezomib-associated neuropathic pain with some success. This review looks critically at the pathogenesis, incidence, risk factors, diagnosis, characteristics, and management of BIPN, and highlights areas for future research.     

A possible pathogenic mechanism for rhabdomyolysis associated with multiple myeloma

A case of a 44-year-old man in whom kappa light chain multiple myeloma and rhabdomyolysis (RDM) were diagnosed simultaneously is reported. Deposition of the kappa light chain in the cellular membrane of muscle fibers (observed with immunofluorescence techniques and ultrastructural examination) suggests a possible pathogenic mechanism for RDM.     

Bortezomib-induced tumor lysis syndrome with a remarkable elevation of LDH in a case of relapsed and therapy-resistant multiple myeloma

A 60-year-old female patient with a therapy-resistant Bence-Jones (BJ) lambda-type multiple myeloma was treated with bortezomib. She had been treated with tandem autologous stem cell transplantations and achieved complete remission before her disease relapsed. Sixteen hours after the first administration of bortezomib, an episode of fever, slight consciousness disturbance and vomiting occurred, which was accompanied by a remarkable elevation of LDH (3608 IU/l). Serum levels of creatinine, uric acid, and AST were also transiently elevated. Serum interleukin-6 level was also increased after the administration of bortezomib. The symptoms disappeared rapidly within 48 hours. Bortezomib at a 25%-reduced dose was administered again along with dexamethasone 26 days later, which caused a moderate increase in LDH levels, but no other symptoms. Further treatment caused no increase in LDH. The treatment was very effective and eradicated both urinary BJ protein and bone marrow myeloma cells after 8 sessions of bortezomib administration. These findings suggest that a bortezomib-induced rapid reduction in tumor burden led to tumor lysis syndrome, for which caution is needed when treating myeloma patients with this very effective agent.     

Hyperphosphatemia in multiple myeloma

Summary We report three cases of IgG kappa multiple myeloma with pseudohyperphosphatemia. The patients' serum calcium levels were normal, and the hyperphosphatemia was not related to impaired renal function. No hypoparathyroidism was found, and no exogenous phosphate preparation had been given. Since the hyperphosphatemia was of no obvious clinical or physiological significance, as evidenced by normal serum levels of 1,25 dihydroxy vitamin D₃, it was diagnosed as spurious and was connected to interference of the paraprotein with the chromogenic assay. In two of the patients major fluctuations in serum phosphate levels were seen, induced by the changes in globulin and paraprotein levels that occurred during therapy and relapse.     

Bendamustine in multiple myeloma

The advent of high‐dose melphalan with autologous stem‐cell transplantation (ASCT), the availability of novel agents such as thalidomide, lenalidomide (immunomodulatory drugs or IMiDs) and bortezomib (proteasome inhibitor) and improvements in supportive care have allowed to increase overall survival in multiple myeloma (MM) patients; nevertheless, MM remains an incurable pathology. For this reason, newer agents are required for continued disease control. Bendamustine is an old drug rediscovered in the last decade. In fact, its unique mechanism of action with structural similarities to both alkylating agents and antimetabolities, but which is not cross‐resistant to alkylating agents, has reawakened interest in the use of this drug in the treatment of MM. Studies have proven the safety and efficacy of bendamustine administered alone or in combination with new drugs in both upfront and relapse/refractory settings of MM patients, including those with renal impairment. Moreover, bendamustine has been successfully used as conditioning for autologous stem‐cell transplantation. Finally, the use of bendamustine does not compromise peripheral blood stem‐cell collection. This drug is generally well tolerated, with the majority of adverse events being due to myelosuppression. Non‐haematological adverse events are infrequent and usually mild.     

Chylomicronaemia in multiple myeloma

A patient with multiple myeloma presented with an accumulation of chylomicron-like particles. This rare finding resembled that of the type V hyperlipoproteinaemia phenotype. The lipid and lipoprotein concentration and composition were compared with values obtained from other patients with multiple myeloma, patients with the type V hyperlipoproteinaemia phenotype (accumulation of chylomicrons and very low density lipoproteins), and normal subjects. An immunoglobulin-lipid complex was demonstrated in our patient. This complex was found not to be associated with the chylomicrons and was detected only in the lipoprotein-deficient plasma. Lipid and lipoprotein concentration and composition differed from the other groups. Very low density lipoprotein concentration was reduced, and there was thus a marked difference from the type V phenotype. The chylomicrons derived from this patient were also richer in apolipoprotein C compared to chylomicrons derived from the patients with type V hypolipoproteinaemia. It appears that the abnormal composition of the triglyceride-rich lipoproteins observed in this patient renders her refractory to the normal pathways of metabolism.     

Hyperammonemia in multiple myeloma

Two patients with multiple myeloma who appeared to be producing ammonia are reported. Both patients showed hyperammonemia and amino acid disturbances, such as a low Fischer ratio. One patient had Bence Jones protein (lambda) type myeloma and became comatose, but the hyperammonemia and disturbance of consciousness were improved by chemotherapy for the myeloma. The other patient had IgA kappa type myeloma and somnolence and died of malignant pleurisy despite intensive chemotherapy. Autopsy showed widespread multiple myeloma and an almost normal liver. Ammonia levels in the supernatant of cultured myeloma cells from the patient's pleural effusion increased almost linearly from the time of cell seeding. These observations showed that ammonia was produced at a high level by these human myeloma cells. We also found that one of the common myeloma cell lines, RPMI 8226, could produce ammonia as well.     

Bortezomib in multiple myeloma

Multiple myeloma (MM) remains an incurable disease, and novel agents are therefore needed to improve outcome. Bortezomib is the first proteasome inhibitor to be approved by the US Food and Drug Administration and the European Agency for the Evaluation of Medicinal Products for the treatment of refractory/relapsed MM. Bortezomib has demonstrated significant anti-myeloma activity as a single agent in refractory/relapsed MM. When used in combination with other agents, responses have suggested the possibility of chemosensitization and synergy. All these facts have been the rationale for the use of bortezomib-based regimens as upfront treatment in young and elderly newly diagnosed MM patients. Furthermore, bortezomib does not appear to have an adverse effect on subsequent stem-cell collection. Bortezomib is well tolerated; most side-effects are only mild to moderate and manageable. Practical management of these side-effects is given so that they can be recognized and minimized by dose modification or concomitant therapy.     

Lenalidomide in multiple myeloma

For many years the treatment of multiple myeloma was limited to such regimens as melphalan-prednisone, high-dose dexamethasone, and vincristine-doxorubicin-dexamethasone (VAD). These combinations provided response rates of 45-55%, with complete remission rates of up to 10%. With the advent of thalidomide- and bortezomib-based combinations, response rates to induction therapy have risen to 85-95% in previously untreated patients and are associated with complete remission rates up to 25%. However, these agents are associated with such side-effects as somnolence, constipation and neuropathy. Lenalidomide, a thalidomide analog, was developed with the hope of improving both the efficacy and toxicity profile of thalidomide, and has subsequently shown significant clinical activity in patients with multiple myeloma. We describe the role of lenalidomide in patients with symptomatic multiple myeloma that is newly diagnosed, relapsed and/or refractory to other therapies, or concurrent with primary amyloidosis.     

Chemokines in multiple myeloma

OBJECTIVE: In this article we focus on the role that chemokines and chemokine receptors play in the pathogenesis of multiple myeloma and the associated bone destructive process, and consider their utility as novel therapeutic targets for treating this devastating disease. METHODS: Current research on the role that chemokine and chemokine receptors play in the pathogenesis of myeloma is reviewed. RESULTS: The chemokines, MIP-1alpha, MCP-1, IL-8, and SDF-1, and their receptors play important roles in homing of MM cells, tumor growth, and bone destruction in myeloma. They are attractive therapeutic targets for treating myeloma patients. CONCLUSION: Addition of chemokine antagonists to current treatment regimens for myeloma should result in better therapeutic responses because of the loss of both the protective effect of the marrow microenvironment on the MM cells and the induction of osteoclast activity.