The protein phosphatase inhibitor-1 (PPI-1) inhibits phosphatase type-1 (PP1) only when phosphorylated by protein kinase A and could play a pivotal role in the phosphorylation/dephosphorylation balance. Rat cardiac PPI-1 was cloned by reverse transcriptase-polymerase chain reaction, expressed in Eschericia coli, evaluated in phosphatase assays, and used to generate an antiserum. An adenovirus was constructed encoding PPI-1 and green fluorescent protein (GFP) under separate cytomegalovirus promotors (AdPPI-1/GFP). A GFP-only virus (AdGFP) served as control. Engineered heart tissue (EHT) from neonatal rat cardiomyocytes and adult rat cardiac myocytes (ARCMs) were used as model systems. PPI-1 expression was determined in human ventricular samples by Northern blots. Compared with AdGFP, AdPPI-1/GFP-infected neonatal rat cardiomyocytes displayed a 73% reduction in PP1 activity. EHTs infected with AdPPI-1/GFP exhibited a fivefold increase in isoprenaline sensitivity. AdPPI-1/GFP-infected ARCMs displayed enhanced cell shortening as well as enhanced phospholamban phosphorylation when stimulated with 1 nM isoprenaline. PPI-1 mRNA levels were reduced by 57+/-12% in failing hearts with dilated and ischemic cardiomyopathy (n=8 each) compared with nonfailing hearts (n=8). In summary, increased PPI-1 expression enhances myocyte sensitivity to isoprenaline, indicating that PPI-1 acts as an amplifier in beta-adrenergic signaling. Decreased PPI-1 in failing human hearts could participate in desensitization of the cAMP pathway.
The results suggest that the reduction in I-1 protein and phosphorylation in failing human hearts leads to increased phosphatase activity which in turn may result in reduced phosphorylation of cardiac proteins such as PLB.
324 Introduction and classification: This is the largest adult T-ALL cohort treated according to immunologic subtypes. All patients were immunophenotyped in one central lab (Berlin). T-ALL (cyCD3+, CD7+) were subclassified into early T-ALL (sCD3-, CD1a-), thymic T-ALL (sCD3-/+, CD1a+) and mature T-ALL (sCD3+, CD1a-). T-ALL constitutes in 3 consecutive GMALL-studies 24% of ALL patients. Patients and methods: A total of 744 T-ALL pts (15 to 55 yrs) were accrued in 102 hospitals in the GMALL studies 05/93, 06/99 and 07/2003. In GMALL 05/93 239 adult T-ALL patients, were treated according to a multi-agent chemoprotocol. Stem cell transplantation (SCT) was not recommended in CR1. In GMALL studies 06/99 and 07/03 505 T-ALL pts received intensified chemotherapy; particularly with introduction of PEG-asparaginase in induction as well as HDMTX/PEG-Asp consolidation cycles. Based on study 05/93 results, SCT from sibling (Sib) as well as matched unrelated (MUD) donor in CR1 was recommended for all patients with early T-ALL, mature T-ALL and for high-risk (HR) pts with thymic T-ALL (defined as late CR, complex karyotype or MRD positivity (MRD+)). Results: T-ALL subtype distribution in the total cohort of 744 adult T-ALL was early-T 23% (N=170), thymic-T 56% (N=420), mature-T 21% (N=154), without any differences between the studies. GMALL Study 05/93: The overall CR rate was 86% (early-T 72%, thymic-T 93%, mature-T 84%. The lower CR rate in early T-ALL was mainly due to early death (19%). The overall CCR rate was 47% (early-T 45%, thymic-T 54%, mature-T 30%). The overall survival rate at 10 yrs for all pts was 47% (early-T 47%, thymic-T 55%, mature-T 25%). GMALL Study 06/99 and 07/03: Of the 505 patients, 87% achieved CR (early-T 84%, thymic-T 92%, mature-T 77%). PR/Failure was higher in early-T (13%) and mature-T (17%) compared to thymic-T (5%). Early death was 4% and equally distributed. 267 pts (64%) received chemotherapy only and the majority were 229 pts (86%) with thymic T-ALL, not considered for SCT in CR1. The CCR rate was 61%. The few early (n = 15) and mature (n = 23) T-ALL pts, which could not have a transplant in CR1, are a negative selection (e.g. early relapse, comorbidity, no donor) and their CCR rate was 33% and 22% respectively. This was due to a high relapse rate in early T-ALL (60%) and mature-T (74%) compared to 33% in thymic-T. Overall survival rate at 8 yrs for thymic T-ALL with chemotherapy was 68%, for the 77 adolescent pts (15 to 25 yrs) even 76%. Stem cell transplantation: 153 T-ALL pts in studies 06/99 and 07/03 received a SCT in first remission. SCT realisation rate in early T-ALL was 84%, in mature-T 68%. Overall CCR rate was 58% (early-T 47%, HR thymic-T 79%, mature-T 61%). Relapse rate after SCT was in early-T 33% and in mature-T 22%. The overall TRM rate was 18% despite more than half MUD SCT, without any TRM difference between the immunological subtypes. Overall survival rate after SCT in CR1 at 8 yrs was 53%, early-T 44%, thymic-T 67%, mature-T 59%. SCT modalit: 49% received alloSib, 55% alloMUD and 20% auto-SCT. Overall CCR rate after alloSib for the total cohort was 65% (early-T 60%, thymic-T 73% and mature-T 69%); for alloMUD total 55% (early-T 45%, thymic-T 77%, mature-T 61%) and for the small cohort of 20 pts with auto-SCT CCR was 35%. Conclusion: The strategy in three consecutive GMALL studies to stratify and treat adult T-ALL pts according to the immunologic T-subtypes was successful. Overall survival at 5 yrs could be improved to 56% from 44%. There was a particular improvement for mature T-ALL (49% vs. 30%) and early-T (40% vs. 33%). This was mainly due to a high realisation rate of SCT in early T-ALL and mature T-ALL and the substantial better results of SCT. Results of alloMUD SCT were comparable to alloSib SCT. The small cohort of HR thymic T-ALL pts also had a benefit from SCT. The excellent outcome of SR thymic T-ALL (∼ 50% of all T-ALL) with the OS of 68% and 76% in adolescents due to intensified chemo, partic. PEG-Asp, does not suggest SCT in CR1. Several molecular markers, such as ERG, BAALC, WT1, had in a retrospective analysis some prognostic relevance in this pt cohort. The new GMALL study generation will however focus in thymic T-ALL on early evaluation of MRD to decide for SCT (MRD+) or not (MRD-) whereas early/mature T-ALL remain allocated to high risk groups with SCT in CR1. Supported by Deutsche Krebshilfe 702657Ho2 and BMBF 01GI9971/8 Disclosures: No relevant conflicts of interest to declare.
8037 Background: Nowadays, therapy for relapsed or refractory multiple myeloma (rrMM) usually consists of multi-targeted combination regimens for achieving complete remission. In this context, resistance resembles a therapeutic challenge that may be overcome by novel biomodulatory therapies communicatively reprogramming dysregulated cellular and intercellular homeostasis in neoplasia. Methods: The present, prospective phase II, one-arm, one-stage multi-center, open label trial, following phase I, focused on reprogramming myeloma and adjacent stroma cells in order to control rrMM beyond > 2nd-line treatment and following lenalidomide resistance in prior line. Adults with rrMM were eligible for receiving continuously, oral, daily dexamethasone 1mg, pioglitazone 45mg, low-dose treosulfan as metronomic chemotherapy ( 250mg bid) and lenalidomide 15mg, respectively, until disease progression. Results: Thirty-nine patients (mean time since diagnosis, 5.7 years; 66.7% with age > 60 years) had received a median of 5.5 (range 2 to 10) prior treatments. 89.5% of the patients were refractory to last therapy (all IMiD resistant), and 48.7% had received autologous stem-cell transplants. The overall response rate (CR, VGPR) was 17.9%. Eighteen patients (46.2%) had partial response or better; ten patients (25.6%) had stable disease. The disease control rate (DCR) was 71.8%. Time-to-progression was not significantly different between IMiD refractory patients and those relapsing following prior IMiD therapy or between high-risk versus non-high-risk cytogenetics. The median progression-free survival (PFS) and overall survival was 5.6 months (95% confidence interval [CI], 3.8 to 8.5) and 17.6 months (95% [CI], 14.9 to 39.2), respectively. The major AE (NCI-CTCAE grade) with grade ≥ 3 and relation to study drugs was hematologic toxicity (N = 31, 67.4%). Due to scheduled dose reductions, this was associated with only 7 (15.2%) grade ≥ 3 infections. Conclusions: The favorable safety profile, encouraging efficacy and equivalent median PFS between biomodulatory and modern targeted therapy in a historic comparison reveal a proof of concept of combined biomodulatory therapy in patients with heavily pretreated and IMiD-resistant rrMM, which should be further evaluated. Clinical trial information: NCT001010243.
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