Citations

Abstract Background Disease characteristics, treatment patterns, and outcomes of follicular lymphoma (FL) patients (pts) aged >80 years (yrs) are infrequently reported. Further, the original Follicular Lymphoma International Prognostic Index (FLIPI) has not been formally studied in pts aged >80 yrs. Also, whether FLIPI is associated with overall survival (OS) in pts aged >80 yrs is unknown. Patients/Methods We used the National LymphoCare Study—a Genentech-sponsored, prospective, multicenter registry of FL pts across the United States without study-specific treatment—to comprehensively analyze FL pts aged >80 yrs. Using Pearson chi-squared tests, associations of age groups with disease characteristics and overall response rate (ORR) were examined. Median progression-free survival (PFS) and OS by treatment regimen were estimated using the Kaplan-Meier method. Cox proportional hazards regression that were adjusted for baseline disease factors were used to assess treatment differences in PFS, lymphoma-related mortality (LRM, which includes both disease and treatment-related deaths), and OS, as well as the significance of age by treatment interactions. FLIPI and a prognostic model that was constructed based on the findings were used to predict outcomes. Results Of 2649 evaluable pts, 209 (8%) were aged >80 yrs. Compared with pts aged ≤60, pts aged >80 yrs were more likely to be Caucasian, to have worse performance status, to have lower hemoglobin (Hgb) value (<12 g/dL), to have less advanced stage, and were less likely to be treated at academic institutions. When treated, pts aged >80 yrs had lower ORR compared with younger pts and were less likely to receive rituximab + chemotherapy (P <.001) or anthracyclines (P <.001). Use of maintenance rituximab was not significantly different between pt groups when rituximab induction was given (61% for pts aged ≤60, 38% for pts aged >80, P=.11), but it was more frequent in pts aged >80 yrs when rituximab + chemotherapy induction was administered (44% for pts aged ≤60, 59% for pts aged >80, P=.04). After adjusting for maintenance use, sex, and baseline factors, age significantly differentiated PFS impact of observation, rituximab monotherapy, and rituximab + chemotherapy (P=.01). No treatment regimen provided superior PFS or OS in pts aged >80 yrs. With a median follow-up of 6.5 yrs for all pts (4.3 yrs for pts aged >80 yrs), 5-year OS was 59% and 92%for patients aged >80 and ≤60 yrs, respectively. OS in pts aged >80 yrs varied based on FLIPI score (log-rank test, P=.01; Figure 1). Interestingly, the percentage of deaths that were disease-related was 40% in pts aged >80 yrs, which was comparable to the percentage in pts aged ≤60 yrs of 48%. Cox modeling showed that lower Hgb, B symptoms, and male sex predicted worse OS (P<.01) but not PFS in pts aged >80 yrs. Recognizing that males have inferior OS compared with females in the general population, we constructed a prognostic model composed only of B symptoms and Hgb level <12 (low risk=no factors; high risk=1 or more factors; P<.0001; Figure 2). FLIPI and the proposed prognostic model significantly differentiated both OS and LRM (Table 1). Conclusions In the largest, prospectively published study of FL pts aged >80 yrs, OS, PFS, ORR, and treatment selection varied compared with younger pts. Surprisingly, the proportion of deaths attributed to lymphoma in these older FL pts was 40%. FLIPI was associated with outcome in pts aged >80 yrs and so was a proposed prognostic model comprising lower Hgb and B symptoms. Independent validation of this model is required, and additional prospective studies that are designed for the oldest old are warranted. Disclosures: Nabhan: Genentech Inc.: Advisory Board Other, Honoraria. Byrtek:Genentech, a member of the Roche group: Employment, Equity Ownership; Roche: Equity Ownership, stock options, stock options Other. Dawson:Genentech: Employment; Roche: Equity Ownership. Link:Genentech: Consultancy; Millenium: Consultancy; Pharmacyclics: Consultancy; Spectrum: Consultancy; Genentech: Research Funding; Millenium: Research Funding; Pharacyclics: Research Funding. Zelenetz:GSK: Consultancy; Celgene: Consultancy; Cephalon: Consultancy; Gilead: Consultancy; Seattle Genetics: Consultancy; Sanofi-Aventis: Consultancy; Genentech: Research Funding; GSK: Research Funding; Roche: Research Funding; Cancer Genetics: Scientific Advisor Other. Cerhan:Genentech: Scientific Advisory Board of the National LymphoCare Study Other. Flowers:Abbott, Celgene, Millennium/Takeda, Sanofi, Spectrum, Janssen: Research Funding; Celgene, Genentech Bio-oncology: Consultancy.

Abstract Abstract 3708 Background: Rituximab maintenance (RM) following induction therapy has been demonstrated to increase PFS in randomized trials in both first-line and relapsed settings (ECOG 1496, EORTC 20981, and most recently, PRIMA), and RM has been frequently used in clinical practice in the U.S. and other countries. We examined the various RM approaches used by practicing physicians in the U.S., factors that predicted whether RM was used, and compared the “real-world” effectiveness of RM to the outcomes of observation (Obs) following front-line R-based induction in FL patients (pts). Methods: The National LymphoCare Study is a prospective, multi-center, longitudinal, observational study that collects data on treatment and outcomes for pts diagnosed with FL in the U.S. from 2004–2007. Pts who achieved complete response (CR), partial response (PR) or stable disease (SD) following initial treatment with R-based therapy and who did not initiate second line therapy during the 215-day period following the date of last dose of initial therapy were categorized as Obs. Pts meeting the same criteria who started maintenance R treatment in the 215-day period comprise the RM group. Multivariable logistic regression analyses were performed to identify characteristics related to receiving RM. We compared RM and Obs groups in progression-free survival (PFS), time to next treatment (TTNT), and overall survival (OS) using Cox proportional hazards models controlling for confounding factors of clinical interest (sex, FLIPI risk group, treatment setting [academic vs. community], and induction therapy). PFS was defined as the number of days from the 215 day period following induction that defined the Obs and RM groups up to and including the date of disease progression as assessed by the treating physician or death from any cause. Pts who had not yet experienced a PFS event at the time of analysis were censored at the date of the most recent response assessment. Results: Of the 2,732 pts enrolled in NLCS, 1,536 pts completed R-based induction therapy. Among these,1,236 pts achieved CR/PR/SD and met other criteria described above to be included in analysis. 557 pts started RM treatment in the 215-day post-induction work up period (128 following R and 429 following R-chemo), and 679 pts were observed (125 following R and 554 following R-chemo). The mean duration of RM was 528 days, and the mean number of RM doses received was 13. 23% received Rx4 every 6 months, 20% Rx1 every 2 or 3 months, and 57% received another schedule. 14% of pts discontinued RM early (n=79). The most common reasons for early discontinuations were disease progression (29%), toxicity (11%), or death (7%). Pts who received R induction were more likely to receive RM than those who received R-chemo as induction (51% vs. 44%). Pts treated in community practices were slightly more likely to receive RM compared with those who were treated in academic centers (46% vs. 40%). In multivariable models, the most significant predictors of receiving RM were grade (I/II), stage (III/IV), geographic region (other than West), community practice setting, and R induction treatment (all p<0.05). After adjusting for FLIPI risk group, induction treatment, and clinical factors, RM significantly improved PFS (HR= 0.72; p= 0.010) and TTNT (HR= 0.74; p= 0.03). At 4 years of follow-up, 11% of pts in the combined population have died and there was no significant difference in OS between RM and Obs groups. 22% (n=124) of RM pts had received 2nd line treatment at the time of analysis, of whom 36% received R alone and 31% received R-chemo. The response rate for 2nd treatment was similar between RM and Obs groups (60% CR/PR for both groups). Conclusions: RM following front-line R-based induction was common in this period. However, a large percentage of pts received a RM schedule that was not consistent with standard published schedules reflecting variation among community practices. Nevertheless, RM use in clinical practice produced significant differences in PFS and TTNT compared to Obs. Importantly, response to second-line treatment was similar between RM and Obs groups. Additional followup is needed to determine whether RM produces OS benefits in this context. Disclosures: Sinha: Celgene: Research Funding. Zhou:RTI-HS: Employment; Novartis: Research Funding. Friedberg:Genentech: Consultancy; astellas: ; Lilly: ; Abbott/Trubion: ; Seattle Genetics: Honoraria; Cephalon: Consultancy. Hirata:Genentech Inc/Roche: Employment; Roche: Equity Ownership. Flowers:Spectrum: Consultancy, Research Funding; Millennium/Takeda: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Genentech/Roche (unpaid): Consultancy; Novartis: Research Funding; Seattle Genetics: Consultancy.

Abstract Abstract 3708 Background: There are few prospective studies on disease characteristics, patterns of care, response, and outcomes in elderly FL patients (pts) in the US. The NLCS is a Genentech-sponsored prospective multicenter registry study that collects this information without study-specific treatment. We utilized the NLCS database to better understand the impact of age on FL outcome. Patients and Methods: All evaluable pts with FL histology in the NLCS were included except pts with FL plus other lymphoma histology or pts who progressed before first treatment or before being assigned to watchful waiting (WW). Using Pearson Chi-Square tests, associations of age groups (≤60, 61–70, >70) with disease characteristics and overall response (ORR) were examined. Median PFS and OS by treatment regimen were estimated using Kaplan-Meier methods for each age group. Cox proportional hazards regression adjusted for baseline factors (grade, number of nodal sites, LDH, Hgb, stage, performance status (PS), bone marrow (BM) involvement, race, and treatment center type) were used to assess treatment differences in PFS and OS and the significance of age by treatment interactions. Results: Of 2,647 pts, 47% (n=1,254) were ≤60 yrs, 25% (n=666) were 61–70 yrs, and 27% (n=727) were >70 yrs (min age of 22; max of 97). Compared with pts ≤60 yrs, pts 61–70 and >70 were more likely to be white (93% >70, 92% 61–70, and 88% ≤60, P=.02 and .02 respectively), have stage I/II disease (37% >70, 36% 61–70, and 29% ≤60, P=.0008 and .0003), have <5 nodal sites (73% >70, 69% 61–70, and 61% ≤60, P=.001 and <.0001), and have poor-risk FLIPI (53% >70, 51% 61–70, and 15% ≤60, P<.0001 and <.0001). Compared with pts ≤60, elderly pts (>70) were more likely to have FL grade 3 (24% vs 18%, P=.01). While there were no differences in geographic distribution by age, elderly pts were more likely to receive therapy at community practices (86%) versus academic institutions than pts ≤60 (77%, P<.0001) or 61–70 (81%, P=.004). Treatments varied significantly by age (P<.0001). More elderly pts were observed compared to pts ≤60 (23% vs19%). When treated, elderly pts (22%) were more likely to receive rituximab (R) monotherapy compared with patients aged 61–70 (12%) or ≤60 (10%). When chemotherapy alone or plus R was given, elderly pts were less likely to receive anthracyclines (45% vs 65% (61–70) and 68% (≤60)). Among all variables, only grade 3 histology predicted anthracycline use in all age groups. Lack of BM involvement predicted anthracycline use for younger pts (≤60 and 61–70). Of those ≤60, white pts were more likely to receive anthracyclines, and of those 61–70, those with ≥5 nodal sites were more likely to receive anthracyclines. ORRs were similar across age groups receiving similar regimens with R plus chemo providing the highest ORR. Adjusting for baseline factors, treatment (WW, R, R-Chemo, or other) benefit varied for each age group in terms of PFS (P=.02), with treatment outcomes being most differentiated among younger pts (Table). PFS appeared shorter in elderly pts regardless of the treatment received. No significant interaction between age and efficacy of anthracycline in terms of PFS or OS was observed (P-values >.65), but the overall effect of anthracycline for all pts was beneficial for PFS (HR=0.80, P=.02) and OS (HR=0.67, P=.003). Median OS was 8 years for elderly and not reached for others. After adjusting for baseline factors, no significant differences in treatment impact by age on OS were seen. Elevated LDH, reduced Hgb, stage III/IV, PS ≥1, and BM involvement were all significantly associated with shortened OS. These factors were also significantly associated with treatment choice, as worse-prognosis elderly pts were more likely to receive either R or R+chemo than WW or other treatment. Conclusions: FL pts >70 yrs more commonly received R alone and less commonly received anthracyclines when treated with chemotherapy. The impact of anthracyclines on PFS did not vary by age, but differences in PFS for other treatment regimens showed a stronger association among younger pts Disclosures: Nabhan: Genentech: Research Funding, Speakers Bureau. Byrtek:Genentech, Inc., a member of the Riche Group: Employment, Equity Ownership. Dawson:Genentech, Inc., a member of the Riche Group: Employment, Equity Ownership. Link:Genentech, Inc., a member of the Riche Group: Consultancy; Celgene: Consultancy; Spectrum: Consultancy. Friedberg:Genentech: Consultancy. Cerhan:Genentech: National LymphoCare Scientific Advisory Board Other. Flowers:Celgene: Consultancy; Prescription Solutions: Consultancy; Seattle Genetics: Consultancy; Millennium: Consultancy, Research Funding; Genentech: Consultancy; GIlead: Research Funding; Spectrum: Research Funding; Janssen: Research Funding; Lymphoma Research Foundation: Membership on an entity's Board of Directors or advisory committees.

ABSTRACT The adult zebrafish is an emerging vertebrate model for studying human cardiomyopathies; however, whether the simple zebrafish heart can model different subtypes of cardiomyopathies, such as dilated cardiomyopathy (DCM), remains elusive. Here, we generated and characterized an inherited DCM model in adult zebrafish and used this model to search for therapeutic strategies. We employed transcription activator-like effector nuclease (TALEN) genome editing technology to generate frame-shift mutants for the zebrafish ortholog of human BCL2-associated athanogene 3 (BAG3), an established DCM-causative gene. As in mammals, the zebrafish bag3 homozygous mutant (bag3e2/e2) exhibited aberrant proteostasis, as indicated by impaired autophagy flux and elevated ubiquitinated protein aggregation. Through comprehensive phenotyping analysis of the mutant, we identified phenotypic traits that resembled DCM phenotypes in mammals, including cardiac chamber enlargement, reduced ejection fraction characterized by increased end-systolic volume/body weight (ESV/BW), and reduced contractile myofibril activation kinetics. Nonbiased transcriptome analysis identified the hyperactivation of the mechanistic target of rapamycin (mTOR) signaling in bag3e2/e2 mutant hearts. Further genetic studies showed that mtorxu015/+, an mTOR haploinsufficiency mutant, repaired abnormal proteostasis, improved cardiac function and rescued the survival of the bag3e2/e2 mutant. This study established the bag3e2/e2 mutant as a DCM model in adult zebrafish and suggested mtor as a candidate therapeutic target gene for BAG3 cardiomyopathy.

Zebrafish are increasingly utilized to model cardiomyopathies and regeneration. Current methods evaluating cardiac function have known limitations, fail to reliably detect focal mechanics, and are not readily feasible in zebrafish. We developed a semiautomated, open-source method — displacement analysis of myocardial mechanical deformation (DIAMOND) — for quantitative assessment of 4D segmental cardiac function. We imaged transgenic embryonic zebrafish in vivo using a light-sheet fluorescence microscopy system with 4D cardiac motion synchronization. Our method permits the derivation of a transformation matrix to quantify the time-dependent 3D displacement of segmental myocardial mass centroids. Through treatment with doxorubicin, and by chemically and genetically manipulating the myocardial injury–activated Notch signaling pathway, we used DIAMOND to demonstrate that basal ventricular segments adjacent to the atrioventricular canal display the highest 3D displacement and are also the most susceptible to doxorubicin-induced injury. Thus, DIAMOND provides biomechanical insights into in vivo segmental cardiac function scalable to high-throughput research applications.

Rationale: We recently reported the association of S75Y, a point mutation in the Rag GTPase protein C ( RRAGC ) gene, with pediatric DCM. Because RRAGC directly binds and regulates mTOR and the S75Y mutation results in abnormally activated mTOR, these in vitro data prompts that the mTOR pathway could be harnessed for therapeutic benefits. Methods: We aimed to integrate in vitro neonatal rat ventricle cardiomyocytes (NRVCM) and in vivo zebrafish system to elucidate underling mechanism of RRAGC -S75Y-based cardiomyopathy, and to seek targeted therapeutic strategies. Results: Overexpression of RRAGC with S75Y mutation, but not RRAGC WT, significantly increased cell size of NRVCM, suggesting the establishment of a cellular model of RRAGC - S75Y-based cardiomyopathy. At the molecular level, overexpression of RRAGC S75Y mutant increased activity of mammalian target of rapamycin (mTOR) and decreased activity of transcription factor EB (tfeb), a direct downstream target of mTOR. Intriguingly, treatment with rapamycin, a mTOR inhibitor, did not affect cellular hypertrophy, whereas adenovirus-mediated overexpression of TFEB was able to rescue cellular hypertrophy induced by RRAGC S75Y mutation. Consistently, treatment with trehalose, an mTOR-independent tfeb activator, rescued cellular hypertrophy induced by RRAGC -S75Y. To confirm the in vitro results, we generated a knock-in (KI) zebrafish line harboring the S75Y corresponding point mutation in rragc via the TALEN (Transcription Activator-Like Effector Nucleases) technology. The cardiac function of rragc KI fish was determined by high frequency echocardiography, and the KI fish showed a significant decrease in fractional shortening compared with control littermates. Conclusion: Both cellular and in vivo models of RRAGC -S75Y-based cardiomyopathy have been generated. Studies in the cellular model suggested that tfeb, but not mTOR, is a therapeutic target for this particular type of cardiomyopathy. We will report our progress in validating this conclusion in our in vivo model, and will discuss potential mechanisms.

Atrial fibrillation (AF) is the most common cardiac arrhythmia and is a major cause of thromboembolic stroke in the United States. The risk of stroke is a 5-fold increase in patients with AF. The Sorbin and SH3 domain-containing protein 2 (Sorbs2) is a scaffolding protein known to interact with actin and several other cytoskeletal proteins in the intercalated discs and Z band of cardiomyocytes. However, the role of Sorbs2 gene in cardiovascular diseases is largely unknown. Using the loss-of-function of Sorbs2 ( Sorbs2 e8/e8 ) mice, we found that Sorbs2 e8/e8 mice had an abnormal lifespan and die at 4 to 7 months of age. Echocardiogram examine revealed that there was a significant decrease in right ventricle (RV) and left ventricular (LV) ejection fraction (EF), increase in RV end-diastolic volume (EDV) and end-systolic volume (ESV), and progressive chamber enlargement in left atria (LA) and RV, particularly in LA with severe fibrosis and intramural thrombus formation, in Sorbs2 e8/e8 mice after 3 months of age. Surface electrocardiograph also showed a significant conduction delay and spontaneous arrhythmias including those of bifid P wave configuration, right bundle branch block (RBBB), spontaneous AF and non-sustained ventricular tachycardia (VT) in Sorbs2 e8/e8 mice. Intracellular recordings in the freshly isolated LA demonstrated that Sorbs2 e8/e8 myocardium had a delayed action potential activation in response to electrical impulse excitation, reduced amplitude and upstroke velocity (dV/dt) at phase 0, slowed repolarization at phase 1 and phase 2, prolonged atrial effective refractory period (aERP), action potential durations at 50% (APD 50 ) and 90% (APD 90 ) repolarization, and decreased resting potentials. Moreover, the mRNA and protein expressions of voltage-gated Na + channels, L-type Ca 2+ channels, transient outward K + channels and inward rectifier K + channels were significantly downregulated in the LA of Sorbs2 e8/e8 mice, compared wo those of wild type mice. Our results indicate that Sorbs2 gene plays an important role in atrial myocardium architecture and electrophysiology. Sorbs2 dysfunction leads to atrial cardiomyopathy, spontaneous AF and cardiac embolism in mice. Hence, Sorbs2 is a new genetic association with cardioembolic stroke.

ABSTRACT Zebrafish are increasingly used as a vertebrate model to study human cardiovascular disorders. Although heart structure and function are readily visualized in zebrafish embryos because of their optical transparency, the lack of effective tools for evaluating the hearts of older, nontransparent fish has been a major limiting factor. The recent development of high-frequency echocardiography has been an important advance for in vivo cardiac assessment, but it necessitates anesthesia and has limited ability to study acute interventions. We report the development of an alternative experimental ex vivo technique for quantifying heart size and function that resembles the Langendorff heart preparations that have been widely used in mammalian models. Dissected adult zebrafish hearts were perfused with a calcium-containing buffer, and a beat frequency was maintained with electrical stimulation. The impact of pacing frequency, flow rate and perfusate calcium concentration on ventricular performance (including end-diastolic and end-systolic volumes, ejection fraction, radial strain, and maximal velocities of shortening and relaxation) were evaluated and optimal conditions defined. We determined the effects of age on heart function in wild-type male and female zebrafish, and successfully detected hypercontractile and hypocontractile responses after adrenergic stimulation or doxorubicin treatment, respectively. Good correlations were found between indices of cardiac contractility obtained with high-frequency echocardiography and with the ex vivo technique in a subset of fish studied with both methods. The ex vivo beating heart preparation is a valuable addition to the cardiac function tool kit that will expand the use of adult zebrafish for cardiovascular research.