Patients' perspectives and safety of COVID-19 vaccination among cancer patients: A prospective single-center study

e24043

Background: Concerns about safety and treatment interference are known barriers to COVID-19 vaccination in cancer patients. Data on safety and tolerability in this population remain scarce. One of the objectives of this study is to describe COVID-19 vaccination safety in cancer patients. Methods: Patients diagnosed with a malignancy requiring systemic treatment in the last 12 months and undergoing COVID-19 vaccination were prospectively enrolled in this single-center study. Validated questionnaires to assess vaccine-related adverse events (VRAEs) were collected; chart review identified baseline characteristics and treatments received. Descriptive statistics and logistic regressions were performed. Results: 253 questionnaires were collected from 171 patients, enrolled between May and September 2021. 130 patients were survey-eligible after the 1st dose (D1) and 185 after 2nd dose (D2). 91 questionnaires were collected after D1 (Questionnaire 1: Q1) and 162 after D2 (Questionnaire 2: Q2). Surveys couldn’t be collected due to interval > 1 month between D1 / enrollment, patients’ unavailability, withdrawal of study or death. Median age was 55 (24-87) and 62.8% were female. 58.5% had solid tumors, treated with chemotherapy (49%) or checkpoint inhibitors only (9.5%); 19.4% malignancies were treated with targeted therapies and 22.1% had hematological malignancies. Most frequent solid tumors were breast (31.3%), lung (15.9%) and gastro-intestinal (GI) (14.3%). Patients received 45.6% Pfizer/BioNTech, 52.8% Moderna and 1.6% Oxford/AstraZeneca. A combination of 2 different vaccines was administered to 11.9%. Interval between D1 and D2 was ≤30 days in 53.1%, 31-90 days in 42.6%, and 91-180 days in 4.3%. Among all patients, 84.1% developed VRAEs after a median of 2 days post-vaccine for a median of 4 days. 74.5% had local symptoms (Sx) (pain, sensitivity and/or redness at injection site and/or arm) and 65.8% had systemic Sx. Most frequent systemic Sx were fatigue, chills or myalgia (39.4%), GI (6.3%) and fever (2.9%). Most patients (90.7%) described their Sx as having no / minimal impact (Gr 1), 7.8% reported seeking medical consultation (Gr 2), and 1.5% lead to hospitalization (Gr 3) (1 cardiovascular event, 1 infection; causality with concurrent systemic treatment not excluded and 1 due to malignancy). Gr 2, but not Gr 3, VRAEs were more common after D2 (11.4% vs 2.5%, p = 0.03). 41.7% considered their Sx as a new health problem. On multivariate analysis, younger age and female sex were significantly associated with the development of any Sx (OR 1.08, p = 0.01; OR 2.92, p = 0.02, respectively) and local Sx (OR 1.04, p = 0.04; OR 2.19, p = 0.04), but not systemic Sx or new health problem. Conclusions: Patients experienced mostly minor and transient symptoms post-vaccination; few perceived these as a new health problem. COVID-19 vaccination is overall safe and well-tolerated among cancer patients.

P14.122 Integrin α5 is a poor prognostic factor in patients with glioblastoma treated by the Stupp protocol

BACKGROUND

Integrin α5β1 was suggested to be involved in glioblastoma (GBM) aggressiveness through preclinical studies and genomic analysis of several cohorts of patients. However, protein expression data are still missing to confirm this hypothesis. Our aim was to investigate the prognostic value of integrin α5 protein expression level in GBM.

MATERIAL AND METHODS

We retrospectively determined the protein expression level of integrin α5 using immunochemistry in tumors from patients treated in 6 French centers. Paraffin sections of GBM were labeled by immunofluorescence and analyzed by confocal microscopy. The corresponding clinical and survival data have been identified and analyzed. The primary end-point was overall survival (OS).

RESULTS

Out of 297 patients newly diagnosed with GBM between 2006 and 2013, 152 met the inclusion criteria (scheduled for initial treatment with the Stupp protocol, age > 18 years) and 95 tumor samples were suitable for immunohistochemical analysis. The median age is 58 years, (64 men, 34 women). Most of patients received macroscopic (43%) or partial (36%) surgery. In univariate analysis using the Log Rank test, high integrin α5 expression level was associated with poor prognosis (PFS: hazard ratio (HR) = 1,696, p=0,0355; OS: HR=1,598, p = 0,0508). Corresponding median OS were 15,6 versus 19,2 months. Similarly, OS was significantly reduced with age (> 60 years), lower resection degree, higher RPA (recursive partitioning analysis) score and non-methylated MGMT (O-6-methylguanine-DNA methyltransferase) promoter. In the subgroup of patients who received the full initial protocol (temozolomide treatment together with radiotherapy and later as adjuvant treatment; n=58) mean OS was strongly reduced when integrin α5 expression level was high (15,6 versus 22,8 months, p=0,0162) suggesting an impact of integrin signaling on temozolomide response in GBM.

CONCLUSION

Our study validates for the first time that the high protein level expression of α5 integrin is associated with poor prognosis in GBM. It also confirms its potential as a therapeutic target and its likely role in resistance to temozolomide as previously shown in preclinical study.

The MYRACLE protocol study: a multicentric observational prospective cohort study of patients with multiple myeloma

Background

Despite recent advances in the treatment of multiple myeloma, the disease constantly relapses and is still considered as incurable. The current knowledge about the biological mechanisms underlying resistance to the different class of drugs in multiple myeloma remains poor. The primary objective of the MYRACLE (Myeloma Resistance And Clonal Evolution) cohort, a multicenter prospective cohort of patients with multiple myeloma, is to address this limitation. We here describe the study background, design and methods used for this cohort.

Methods/design

All patients (> 18 year old) diagnosed with de novo or relapsed multiple myeloma and treated in two hematology department from west of France are included in the MYRACLE cohort. Patients provide a signed informed to be included in the study. All subjects are followed until refusal to participate in the study or death. The MYRACLE cohort prospectively collects data on socio-economic status, medical status, imaging, prognosis factors, MM therapies and associated events (resistance, safety issues). Patients also complete standardized quality of life questionnaires. In addition, bone marrow samples will be collected at time of diagnosis and relapses to perform biomarkers analysis and functional assays exploring mechanisms underlying drug resistance.

Discussion

The “real-life” MYRACLE cohort offers the opportunity to prospectively collect epidemiological, medical, QoL and biological data from MM patients during the course of the disease (at time of diagnosis and subsequent relapses). At mid-tem, this integrative cohort will be unique at producing a large variety of data that can be used to conceive the most effective personalized therapy for MM patients. Additionally, the MYRACLE cohort will allow integrating the medical care of MM patients in a health and pharmacoeconomic perspective.

Update on elotuzumab for the treatment of relapsed/refractory multiple myeloma: patients' selection and perspective

Monoclonal antibodies (mAbs) targeting antigens expressed by plasma cells demonstrated major clinical activity in multiple myeloma patients and therefore became a new major class of drug for these patients. Elotuzumab is a humanized mAb targeting the cell surface signaling lymphocytic activation molecule family member 7, a glycoprotein highly expressed on plasma cells, that is the second mAb approved for the treatment of myeloma patients. The mechanism of action of elotuzumab includes natural killer cell (NK) mediated antibody-dependent cellular cytotoxicity and direct activation of NK-cells. Elotuzumab has been approved in combination with lenalidomide and dexamethasone (Elo-Rd) and pomalidomide and dexamethasone (Elo-Pd) for the treatment of relapsed myeloma patients. The present review will focus on elotuzumab, providing a summary of the mechanism of action, efficacy and safety and taking into consideration patients’ selection.

Pomalidomide, cyclophosphamide, and dexamethasone for relapsed/refractory multiple myeloma patients in a real-life setting: a single-center retrospective study

Pomalidomide dexamethasone is a standard of care for relapsed multiple myeloma (MM) patients who received at least two prior lines of therapy, including both lenalidomide and proteasome inhibitors (PI). We report here a real-life single-center series of 49 consecutive patients with relapsed and refractory MM treated with the triplet pomalidomide cyclophosphamide dexamethasone (PCD) combination. The median of prior lines of therapy was 3 and all patients were previously exposed to proteasome inhibitors and lenalidomide. The overall response rate was 76%, including 27% very good partial response or better. With a median follow-up of 16 months, the median progression-free survival (PFS) was 7.3 months and the median overall survival was not reached. Regarding safety, most frequent toxicity was hematologic, including 37% grade 3-4 cytopenias. Nine patients (18%) discontinued therapy due to adverse event. Our study confirms that PCD combination is feasible and results in favorable response rate and PFS in comparison with pomalidomide dexamethasone alone.

FV-162 is a novel, orally bioavailable, irreversible proteasome inhibitor with improved pharmacokinetics displaying preclinical efficacy with continuous daily dosing

Approved proteasome inhibitors have advanced the treatment of multiple myeloma but are associated with serious toxicities, poor pharmacokinetics, and most with the inconvenience of intravenous administration. We therefore sought to identify novel orally bioavailable proteasome inhibitors with a continuous daily dosing schedule and improved therapeutic window using a unique drug discovery platform. We employed a fluorine-based medicinal chemistry technology to synthesize 14 novel analogs of epoxyketone-based proteasome inhibitors and screened them for their stability, ability to inhibit the chymotrypsin-like proteasome, and antimyeloma activity in vitro. The tolerability, pharmacokinetics, pharmacodynamic activity, and antimyeloma efficacy of our lead candidate were examined in NOD/SCID mice. We identified a tripeptide epoxyketone, FV-162, as a metabolically stable, potent proteasome inhibitor cytotoxic to human myeloma cell lines and primary myeloma cells. FV-162 had limited toxicity and was well tolerated on a continuous daily dosing schedule. Compared with the benchmark oral irreversible proteasome inhibitor, ONX-0192, FV-162 had a lower peak plasma concentration and longer half-life, resulting in a larger area under the curve (AUC). Oral FV-162 treatment induced rapid, irreversible inhibition of chymotrypsin-like proteasome activity in murine red blood cells and inhibited tumor growth in a myeloma xenograft model. Our data suggest that oral FV-162 with continuous daily dosing schedule displays a favorable safety, efficacy, and pharmacokinetic profile in vivo, identifying it as a promising lead for clinical evaluation in myeloma therapy.

CyBorD induction therapy in clinical practice

Cyclophosphamide, bortezomib and dexamethasone (CyBorD) is a highly active three-drug induction regimen for untreated transplant-eligible multiple myeloma patients. Although CyBorD has been evaluated only in the phase 2 setting in a limited number of patients, its high efficacy and ease of administration have led to its widespread use. Given that clinical trial efficacy can overestimate real-life effectiveness, we reviewed our institutional experience with 109 newly diagnosed patients who were treated with CyBorD in a non-clinical trial setting. After a median of four cycles, overall response rate (ORR) and very good partial response rate or better (⩾VGPR) were 95 and 66%, respectively, comparable to phase 2 studies of CyBorD and other three/four-drug induction regimens. All patients subsequently underwent successful stem cell collection and upgraded responses to ORR 98% and ⩾VGPR 79% post transplant. At a median follow-up of 19.8 months after diagnosis, the 2-year OS probability was 95.3% (95%CI: 89-98). The presence of concurrent plasmacytoma at diagnosis was the only prognostic factor predicting poorer survival (HR=5.56; 95%CI: 0.92-33.74; P=0.03). CyBorD was well-tolerated, with no severe peripheral neuropathy and minimal hematologic toxicity. Therefore, CyBorD is a convenient, well-tolerated, highly effective induction regimen in preparation for autologous SCT in real-life clinical practice.

Nondiffractive subwavelength wave beams in a medium with externally controlled anisotropy

We predict and experimentally demonstrate that in a medium with externally induced anisotropy, a wave source of a sufficiently small size can excite practically nondiffractive wave beams with stable subwavelength transverse aperture. The direction of beam propagation is controlled by rotating the induced anisotropy axis. Nondiffractive wave beam propagation, reflection, and scattering, as well as beam steering have been directly observed by optically probing dipolar spin waves in yttrium iron garnet films, where the uniaxial anisotropy was created by an in-plane bias magnetic field.

Final results of PX-171–003-A0, part 1 of an open-label, single-arm, phase II study of carfilzomib (CFZ) in patients (pts) with relapsed and refractory multiple myeloma (MM)

8504

Background: CFZ is a novel proteasome inhibitor of the epoxyketone class that exhibits a high level of proteasome selectivityand demonstrates antitumor activity in bortezomib (BTZ)-resistant MM pts in phase I studies. Methods: PX-171–003-A0 was an open-label, multicenter study that enrolled MM pts who relapsed from >2 prior therapies, failed BTZ and at least 1 immunomodulatory agent [thalidomide (THAL) or lenalidomide (LEN)], and were refractory to last treatment [progressing on or within 60 d of last therapy or <25% response to last therapy]. Pts received CFZ 20 mg/m2 IV d 1, 2, 8, 9, 15 and 16 every 28 d for up to 12 cycles (C). Clinical benefit response (CBR) was defined as MR or better. Results: 46 pts were enrolled, including 78% with progression on or within 60 d of last therapy and 22% with no response to last therapy. 39 pts completed at least 1 C of CFZ, had measurable M-protein, and were evaluable for response. Median prior therapies was 5 (range 2–15). 100% of pts received prior BTZ, 91% prior THAL, 89% prior LEN, and 83% prior stem cell transplant (SCT) and all had failed combinations including anthracyclines (80%) and/or alkylating agents (94%). Pts received a median of 3 C (range 1–12); 13 pts completed ≥6 C. CBR was 26% (10/39 eval pts), including 5 pts achieving PR and 5 pts achieving MR. 5 BTZ-refractory pts achieved MR or PR. Median TTP was 6.2 mo, the median DOR for the MR + PR was 7.4 mo. 8/10 pts achieved response during C1. 16 additional pts achieved SD for at least 6 wks. The most common adverse events were fatigue, anemia, thrombocytopenia, nausea, upper respiratory infection, increased creatinine and diarrhea. Peripheral neuropathy occured in < 10% of pts with 1 Gr 3 in a pt with pre-existing Gr 2. Conclusions: Single-agent CFZ achieved a TTP of > 6 mo in relapsed and refractory MM pts who failed available therapies. 26% of patients had at least an MR and median duration of >7 mo with this steroid- and anthracycline-sparing regimen. CFZ toxicities were manageable and importantly, exacerbation of pre-existing PN was rare. The study has been expanded to enroll an additional 250 pts in this unmet medical need population at an escalated dose, and treatment has been extended beyond a year.

[Table: see text]

A phase I MMRC clinical trial testing the combination of bortezomib and tipifarnib in relapsed/refractory multiple myeloma

8597

Background: Preclinical work from our group has demonstrated that the combination of a farnesyl transferase inhibitor and bortezomib results in enhanced plasma cell apoptosis, and more recently, we have suggested that the mechanism for this synergy is due to inhibition of HDAC6, and inhibition of the proteasome and aggresome pathway. Methods: Patients with relapsed or refractory myeloma were treated with bortezomib at 1.0 or 1.3 mg/m2 on a standard schedule in conjunction with escalating doses of tipifarnib (100–400mg/BID) given on days 2–15 every 21 days. Dose escalation was accomplished using an adaptive phase I design (Escalation With Overdose Control). Results: 22 patients have been enrolled, of which 18 are evaluable, into respective tipifarnib dose levels 100 mg (n=6), 200mg (n=5) and 300mg (n=5) and 400mg (n=2). Median age for the enrolled patients is 59 and median time from myeloma diagnosis was 4.7 years. The average number of prior therapies was 4.5. Among these patients with advanced myeloma and refractory disease, stabilization of disease or better was seen among 8/10 patients with 2 of the 8 achieving an MR. Among the patients achieving clinical benefit, 1 patient had a stable M-protein, but experienced an 80% reduction in circulating plasma cells while on therapy, and another has had a 75% reduction in the free light chain assay. The most common drug related side effect was was Gr2 diarrhea (23.5%). Hematologic toxicities were difficult to ascertain as patients had advanced myeloma and many were entered onto study with platelet counts between 25 and 50. Additional grade 3 toxicities included renal insufficiency (related to PD), pneumonia and altered mental status which were all considered not related to study drug but to progression of disease. There were no Grade 3-5 drug related toxicities. One patient experienced grade 2 peripheral neuropathy who did not have pre existing PN at baseline. Conclusions: The combination of bortezomib and tipifarnib is supported by preclinical rationale and has produced stable disease or better among 10 of 18 patients with refractory myeloma. Optimal dose of tipifarnib and bortezomib have yet to be defined, and additional patients are being enrolled with 1.3mg/m2 of bortezomib, and escalating doses of tipifarnib.

[Table: see text]

Retrospective review of DPACE therapy for aggressive, refractory multiple myeloma (MM)

18500

Background: Oral dexamethasone ± thalidomide with a 4-day infusion of cisplatin, doxorubicin, cyclophosphamide, and etoposide (DPACE) is an effective induction therapy prior to transplant in patients (pts) with MM. Limited experience also suggests DPACE may reduce disease burden as a salvage regimen for aggressive, refractory MM. Methods: We performed a retrospective review from 1999- 2005 of all MM pts who received DPACE ± thalidomide as a salvage regimen at our center. Results: A total of 39 pts received DPACE at a median 23 mos from diagnosis (range, 10–84). Median age was 53 years (34–70), 51% stage 3 at diagnosis. Plasma cell leukemia had developed in 12 pts and leptomeningeal disease in 4 pts at time of DPACE. Ten of 24 pts (42%) with cytogenetics had del 13q. Pts were heavily pretreated (median 3 prior regimens; prior autotransplant [ASCT] 38%; thalidomide 64%; and bortezomib 10%). Pts received 1–4 cycles as tolerated for refractory (83%) or relapsed (17%) disease. Thalidomide was used in 41% of cycles. Hematologic toxicity was common (grade 3–4 neutropenia 92% and thrombocytopenia 72%). Although G-CSF was used in 71% of cycles, febrile neutropenia was common (53%) and 26% required hospitalization. Overall RR was 36% (14 pts: PR 12, VGPR 2). An additional 8% achieved MR, 23% SD. PD occurred in 15% and 18% died on therapy (4 progressive MM; 2 neutropenic sepsis, 1 GI bleed). No prior ASCT (p=0.04) and <4 prior regimens (p=0.04) predicted for response to DPACE. Eleven pts proceeded to ASCT and one pt to a clinical trial with lenalidomide with a median OS from DPACE of 24.7 mos (95% CI, 11.2–63.6). Those who did not bridge to transplant or trial (n=27) had a short median PFS of 3.0 months (95% CI, 1.2–5.5) and OS of 6.7 mos (95% CI, 1.8–9.7). OS for all 39 pts was 8.7 mos (95% CI, 6.4–12.4). Conclusion: DPACE may be effective salvage therapy for heavily pretreated MM pts. Although the RR of 36% in this poor prognosis cohort is reasonable, the PFS is short and suggests that the best role for this regimen is in bridging to more definitive therapy such as transplantation.

[Table: see text]

Phase I evaluation of carfilzomib (PR-171) in hematological malignancies: Responses in multiple myeloma and Waldenstrom’s macroglobulinemia at well-tolerated doses

8003

Background: Carfilzomib is a novel, irreversible tetrapeptide proteasome inhibitor derived from the natural product epoxomicin. Carfilzomib was well tolerated in preclinical animal studies when administered on a two-week cycle, QDx5; proteasome inhibition one hour after dosing at the MTD was >80%. Two Phase I dose-escalation studies are ongoing, aimed at determining the safety, tolerability, and biological response to carfilzomib. Methods: Carfilzomib was administered according to two different dose-intensive schedules. In PX-171–001, carfilzomib was administered on a two week cycle, QDx5 with nine days rest; in PX-171–002, carfilzomib was administered on a four week cycle, QDx2 weekly for three weeks with 12 days rest. Eligible patients have multiple myeloma (MM), Non-Hodgkin's Lymphoma (NHL), Hodgkin's Disease (HD), or Waldenström's Macroglobulinemia (WM). Results: Thus far, a total of 54 subjects have been enrolled. Although the maximum tolerated dose (MTD) has not yet been identified on either study, responses seen on both protocols have established 11 and 15 mg/m2 as the minimal effective doses (MEDs) on PX-171–001 and 002, respectively. Of 3 patients with MM or WM treated on the 001 protocol, one MM patient has had a Partial Response (PR) and one WM patient had a Minimal Response (MR). Of 8 patients with MM treated on the 002 protocol, 3 patients have had PRs. 6 additional patients have had Stable Disease lasting longer than 6 months and symptomatic improvement has been seen in patients on both protocols. 11 subjects remain on study with stable disease or better. Proteasome inhibition in whole blood at the highest dose levels exceeded 80% one hour after the first dose. Carfilzomib has been well tolerated at doses at and above the MED thus far. There has been no incidence of painful peripheral neuropathy on either study. No dose-limiting toxicities (DLTs) have occurred on PX-171–001; one DLT (Gr 4 anemia and thrombocytopenia) was observed at 27 mg/m2 on PX-171–002. Conclusions: Thus far, intensive dosing with carfilzomib is well-tolerated at proteasome inhibition levels of more than 80%. Five responses have been observed, and several subjects have achieved long lasting SD and/or symptomatic improvement.

No significant financial relationships to disclose.

Altered gene expression in cells from patients with lysosomal storage disorders suggests impairment of the ubiquitin pathway

By comparing mRNA profiles in cultured fibroblasts from patients affected with lysosomal storage diseases, we identified differentially expressed genes common to these conditions. These studies, confirmed by biochemical experiments, demonstrated that lysosomal storage is associated with downregulation of ubiquitin C-terminal hydrolase, UCH-L1 in the cells of eight different lysosomal disorders, as well as in the brain of a mouse model of Sandhoff disease. Induction of lysosomal storage by the cysteine protease inhibitor E-64 also reduced UCH-L1 mRNA, protein level and activity. All cells exhibiting lysosomal storage contained ubiquitinated protein aggregates and showed reduced levels of free ubiquitin and decreased proteasome activity. The caspase-mediated apoptosis in E-64-treated fibroblasts was reversed by transfection with a UCH-L1 plasmid, and increased after downregulation of UCH-L1 by siRNA, suggesting that UCH-L1 deficiency and impairment of the ubiquitin-dependent protein degradation pathway can contribute to the increased cell death observed in many lysosomal storage disorders.

Genetic risk identifies multiple myeloma patients who do not benefit from autologous stem cell transplantation

Genetic aberrations have emerged as major prognostic factors for patients with multiple myeloma (MM). We evaluated 126 MM patients for t(4;14) or t(11;14), 13q or p53 deletions and correlated the number of genetic aberrations with patient's clinical outcome following undergoing autologous stem cell transplantation. We demonstrate the significance of genetic-based risk classification that clearly segregate patients into low (no genetic abnormalities or only t(11;14)), intermediate (any one of the genetic abnormalities other than t(11;14)) and high-risk groups (any two or more of the genetic abnormalities other than t(11;14)). High-risk patients do not benefit from stem cell transplant and should be offered alternative therapies.

Intracellular distribution of lysosomal sialidase is controlled by the internalization signal in its cytoplasmic tail

Sialidase (neuraminidase), encoded by the neu-1 gene in the major histocompatibility complex locus catalyzes the intralysosomal degradation of sialylated glycoconjugates. Inherited deficiency of sialidase results in sialidosis or galactosialidosis, both severe metabolic disorders associated with lysosomal storage of oligosaccharides and glycopeptides. Sialidase also plays an important role in cellular signaling and is specifically required for the production of cytokine interleukin-4 by activated T lymphocytes. In these cells, neu-1-encoded sialidase activity is increased on the cell surface, suggesting that a specific mechanism regulates sorting of this enzyme to the plasma membrane. We investigated that mechanism by first showing that sialidase contains the internalization signal found in lysosomal membrane proteins targeted to endosomes via clathrin-coated pits. The signal consists of a C-terminal tetrapeptide (412)YGTL(415), with Tyr(412) and Leu(415) essential for endocytosis of the enzyme. We further demonstrated that redistribution of sialidase from lysosomes to the cell surface of activated lymphocytes is accompanied by increased reactivity of the enzyme with anti-phosphotyrosine antibodies. We speculate that phosphorylation of Tyr(412) results in inhibition of sialidase internalization in activated lymphocytes.

Adenovector engineered interleukin-2 expressing autologous plasma cell vaccination after high-dose chemotherapy for multiple myeloma - a phase 1 study

Eight multiple myeloma patients participated in a phase I trial evaluating the feasibility and safety of subcutaneous vaccination with adenovirus engineered, autologous plasma cells after high-dose therapy. Plasma cells were concentrated from bone marrow harvests by negative selection and high gradient magnetic separation. The mean plasma cell yield was 2.61 x 10(8). Transgene expression measured 48 h after plasma cell infection with an IL-2 expressing adenovirus averaged 2.95 ng/ml/10(6) cells. Vaccine production was successful for 88% of patients. Two months after high-dose therapy, six patients received from one to five injections of 3.5-9.0 x 10(7) cells/vaccine. Vaccines were well tolerated with only minor systemic symptoms reported. Injection with tumor cells induced a local inflammatory response consisting predominantly of CD8+ and/or TIA-1+ T-lymphocytes. Myeloma specific anti-tumor responses, assessed by interferon-gamma (IFN-gamma) release and cytotoxic T cell killing of autologous tumor cells, were not enhanced after vaccination in one evaluable patient. Clinical response, manifested as a decrease in serum paraprotein, was not observed in the one patient who had measurable disease at the time of vaccination. These results demonstrate that the generation of adenovector modified plasma cell vaccines is technically feasible and can be safely administered post-transplant. Further studies of immunlogic and clinical efficacy are required.

Effect of Celsior and University of Wisconsin solutions on myocardial metabolism and function after warm ischemia

BACKGROUND

Optimal preservation of donor hearts remains a significant concern during transplantation. Organ shortage led to an increase in the use of damaged hearts.

METHODS

To study the effect of preservation solutions on recovery of myocardial metabolism and function after warm ischemia, 10 dogs underwent 30 minutes of warm global ischemia under cardiopulmonary bypass. The animals were then administered 1 liter of Celsior (5 dogs), an extracellular crystalloid solution or 1 liter of University of Wisconsin solution (5 dogs), cooled at 4 degrees C, followed by 60 minutes of cold preservation and 30 minutes of warm blood reperfusion. Interstitial myocardial pH and pO2 changes were measured. The left ventricle dP/dt was measured before and after the ischemic episode, as where creatine kinase, troponine T and lactate serum levels.

RESULTS

Tissue pH averaged 6.9+/-0.1, 6.2+/-0.1, 6.7+/-0.1 and 6.8+/-0.1 before and after warm ischemia, following the 60 minutes of cold preservation and the reperfusion period in animals treated with the Celsior solution, compared to 6.8+/-0.1, 6.4+/-0.1, 7+/-0.1 and 6.8+/-0.2 respectively in dogs treated with the University of Wisconsin solution (p<0.05). Oxygen tension in the myocardium averaged 36+/-8 mmHg before warm ischemia and 59+/-31 mmHg after in animals that received Celsior compared to 30+/-10 mmHg and 49+/-7 mmHg in dogs treated with University of Wisconsin (p>0.05). Global myocardial function decreased significantly following reperfusion compared to baseline in both groups of animals. The serum levels of creatine kinase, troponine T and lactate increased significantly during the experiment although there was no significant difference between the 2 groups.

CONCLUSION

Both preservation solutions (Celsior and University of Wisconsin) resulted in suboptimal recovery of myocardial function and metabolism when administered after a period of warm ischemia. Strategies to improve recovery of damaged donor hearts remain to be appropriately defined.

Mechanism of vanadate-induced activation of tyrosine phosphorylation and of the respiratory burst in HL60 cells. Role of reduced oxygen metabolites

Vanadate induces phosphotyrosine accumulation and activates O2 consumption in permeabilized differentiated HL60 cells. NADPH, the substrate of the respiratory burst oxidase, was found to be necessary not only for the increased O2 consumption, but also for tyrosine phosphorylation. The effect of NADPH was not due to reduction of vanadate to vanadyl. Instead, NADPH was required for the synthesis of superoxide, which triggered the formation of peroxovanadyl [V(4+)-OO] and vanadyl hydroperoxide [V(4+)-OOH]. One or both of these species, rather than vanadate itself, appears to be responsible for phosphotyrosine accumulation and activation of the respiratory burst. Accordingly, the stimulatory effects of vanadate and NADPH were abrogated by superoxide dismutase. Moreover, phosphorylation was activated in the absence of NADPH by treatment with V(4+)-OO and/or V(4+)-OOH, generated by treatment of orthovanadate with KO2 or H2O2 respectively. The main source of the superoxide involved in the formation of V(4+)-OO and V(4+)-OOH is the NADPH oxidase. This was shown by the inhibitory effects of diphenylene iodonium and by the failure of undifferentiated cells, which lack oxidase activity, to undergo tyrosine phosphorylation when treated with vanadate and NADPH. By contrast, exogenously generated V(4+)-OO induced marked phosphorylation in the undifferentiated cells, demonstrating the presence of the appropriate tyrosine kinases and phosphatases. A good correlation was found to exist between induction of tyrosine phosphorylation and activation of the respiratory burst, suggesting a causal relationship. Therefore an amplification cycle appears to exist in cells treated with vanadate, whereby trace amounts of superoxide initiate the formation of V(4+)-OO and/or V(4+)-OOH. These peroxides promote phosphotyrosine formation, most likely by inhibition of tyrosine phosphatases. Accumulation of critical tyrosine-phosphorylated proteins then initiates a respiratory burst, with abundant production of superoxide. The newly formed superoxide catalyses the formation of additional V(4+)-OO and/or V(4+)-OOH, thereby magnifying the response. Since vanadium derivatives are ubiquitous in animal tissues, V(4+)-OO and/or V(4+)-OOH could be formed in vivo by reduced O2 metabolites, becoming potential endogenous tyrosine phosphatase inhibitors. Because of their potency, peroxides of vanadate may be useful as probes for the study of protein phosphotyrosine turnover.

Activation of permeabilized HL60 cells by vanadate. Evidence for divergent signalling pathways

The possible role of tyrosine phosphorylation in the activation of granulocytic HL60 cells was examined using vanadate, a phosphotyrosine phosphatase inhibitor. Treatment of permeabilized cells with micromolar concentrations of vanadate resulted in a substantial accumulation of tyrosine-phosphorylated proteins, detected by immunoblotting. At comparable concentrations, vanadate was also found to elicit an NADPH-dependent burst of oxygen utilization. Actin assembly, studied using 7-nitrobenz-2-oxa-1,3-diazole (NBD)-phallacidin, was similarly stimulated by vanadate, though considerably higher concentrations were required to observe this effect. In contrast with these responses, the secretion of lysozyme was not stimulated by vanadate, nor did vanadate affect calcium-induced secretion. Therefore, accumulation of tyrosine-phosphorylated proteins is associated with stimulation of some, but not all, of the responses characteristic of granulocytic cell activation. This indicates that the effects of vanadate are selective and suggests divergence of the signalling pathways leading to the individual effectors.

Actin assembly in electropermeabilized neutrophils: role of intracellular calcium

Assembly of microfilaments involves the conversion of actin from the monomeric (G) to the filamentous (F) form. The exact sequence of events responsible for this conversion is yet to be defined and, in particular, the role of calcium remains unclear. Intact and electropermeabilized human neutrophils were used to assess more directly the role of cytosolic calcium [( Ca2+]i) in actin assembly. Staining with 7-nitrobenz-2-oxa-1,3-diazole-phallacidin and right angle light scattering were used to monitor the formation of F-actin. Though addition of Ca2+ ionophores can be known to induce actin assembly, the following observations suggest that an increased [Ca2+]i is not directly responsible for receptor-induced actin polymerization: (a) intact cells in Ca2(+)-free medium, depleted of internal Ca2+ by addition of ionophore, responded to the formyl peptide fMLP with actin assembly despite the absence of changes in [Ca2+]i, assessed with Indo-1; (b) fMLP induced a significant increase in F-actin content in permeabilized cells equilibrated with medium containing 0.1 microM free Ca2+, buffered with up to 10 mM EGTA; (c) increasing [Ca2+]i beyond the resting level by direct addition of CaCl2 to permeabilized cells resulted in actin disassembly. Conversely, lowering [Ca2+]i resulted in spontaneous actin assembly. To reconcile these findings with the actin-polymerizing effects of Ca2+ ionophores, we investigated whether A23187 and ionomycin induced actin assembly by a mechanism independent of, or secondary to the increase in [Ca2+]i. We found that the ionophore-induced actin assembly was completely inhibited by the leukotriene B4 (LTB4) antagonist LY-223982, implying that the ionophore effect was secondary to LTB4 formation, possibly by stimulation of phospholipase A2. We conclude that actin assembly is not mediated by an increase in [Ca2+]i, but rather that elevated [Ca2+]i facilitates actin disassembly, an effect possibly mediated by Ca2(+)-sensitive actin filament-severing proteins such as gelsolin. Sequential actin assembly and disassembly may be necessary for functions such as chemotaxis.

Construction of a fused LuxAB gene by site-directed mutagenesis

Bacterial luciferases are heteropolymetric enzymes consisting of two non-identical subunits (alpha and beta). The two polypeptides are produced by transcription in the same direction of two genes, luxA and luxB, located immediately adjacent to each other and separated by only 29 base pairs in the Vibrio harveyi genome. Using site-directed mutagenesis, stop codons after luxA were eliminated and the luxB gene was placed in-frame with luxA, resulting in a fused luxAB gene. Transcription of two luxAB mutant genes from the bacteriophage T7 promoter and translation in Escherichia coli resulted in the synthesis of fused polypeptides containing the alpha and the beta subunits of luciferase linked by either a single amino acid residue or a decapeptide. E. coli synthesizing the latter fusion protein with the decapeptide linker expressed a level of luminescence comparable to E. coli containing the wild type genes while E. coli synthesizing the polypeptide with a single amino acid as a linker expressed about 2000-fold lower light. These results provide the basis for generating a bacterial luciferase system that can be expressed under the control of a single promoter in both eukaryotic and prokaryotic systems.