11111 Background: In cancers with longer natural histories, progression free survival (PFS) alone may not adequately capture the impact of treatment side effects (SE) and may, therefore, be complemented by robust measures of patient-reported tolerability (PRT) to quantify overall SE burden. Here, we pioneer the use of a novel, scalable, quantitative PRT metric as a key secondary endpoint to support the regulatory review and inform clinical decision-making of selpercatinib use in LIBRETTO-531 (NCT04211337), an RCT that demonstrated the PFS benefit (HR=0.28) of selpercatinib over vandetanib/cabozantinib (control) in RET-mutant MTC. Methods: We first assessed PRT using the single Functional Assessment of Cancer Therapy (FACT) item GP5, asking patients to rate “bothered by treatment side effects” from 0 to 4. Patients who reported “3=quite a bit” or “4=very much” on GP5 were classified as “high SE bother,” a validated meaningful cutoff for treatment SE burden. In a second pre-specified step, PRT was defined as the proportion of time on treatment (PTOT) with “high SE bother” and was compared between selpercatinib vs. control arms in the tolerability evaluable population. PRT was tested at a 1-sided significance level of 0.025, conditional on achieving statistical significance for PFS and treatment failure-free survival by BICR. To complement PRT, other patient-reported outcomes including health-related quality of life (HRQoL, using EORTC QLQ-C30) and symptomatic adverse events (AEs; using PRO-CTCAE) were evaluated. We calculated the PTOT that patients reported clinically meaningful impairment of HRQoL (using pre-specified cutoff scores) and highly symptomatic AEs (scores of 3 or 4). Results: Patients on selpercatinib (n=161) had a significantly better PRT (lower PTOT with high SE bother) than control (n=81) (8% vs. 24%, p<.0001). Sensitivity analyses using different cutoffs for high SE bother showed consistent results (p<.0001). On QLQ-C30, patients on selpercatinib reported significantly less PTOT with HRQoL impairment across physical (36% vs. 52%), role (2% vs. 11%), cognitive (4% vs. 8%), emotional (6% vs. 11%), and social (2% vs. 8%) functions (all p<0.01) vs. control. On PRO-CTCAE, patients on selpercatinib reported significantly less PTOT with diarrhea (5% vs. 38%), fatigue (6% vs. 21%), taste change (3% vs. 15%), decreased appetite (2% vs. 15%), hand/foot syndrome (2% vs. 9%) (all p<.001) vs. control. Conclusions: Through the incorporation of a novel, single question and quantifiable metric that measured time on treatment under high SE bother into the LIBRETTO-531 study, we demonstrated superior PRT and improved PFS for selpercatinib in patients with RET-mutant MTC versus vandetanib/cabozantinib. This simplified PRT metric deserves further adoption as a quantitative endpoint to complement PFS in future RCTs.

199 Background: Selpercatinib is a highly selective and potent CNS active RET inhibitor approved for treatment of advanced RET fusion-positive ( RET+) NSCLC. Treatment or prevention of CNS disease is critical in RET+ NSCLC patients (pts), who have nearly a 50% lifetime prevalence of brain metastases (mets) (Drilon et al. JTO 2018). LIBRETTO-431 is the first study to compare intracranial (IC) efficacy of a targeted therapy to chemo/IO in pts with oncogene driven NSCLC. Methods: LIBRETTO-431 (NCT04194944) is a randomized, open-label, phase 3 trial comparing 1L selpercatinib vs chemotherapy (cisplatin/carboplatin + pemetrexed) +/- pembrolizumab. As previously reported, the study met its primary endpoint of PFS by blinded independent central review (BICR) at the pre-planned interim analysis. IC analyses included CNS and non-CNS PD, IC PFS and IC responses by BICR per RECIST 1.1 in all pts who had a baseline and one or more post-baseline CNS scans (CNS-evaluable) and were designated to receive pembrolizumab if randomized to the control arm (CNS-pembro population). Adverse events were evaluated in the CNS safety population. Results: A total of 192 of 261 pts enrolled were CNS-evaluable (selpercatinib: 120, control: 72). Baseline characteristics were generally balanced with the selpercatinib arm having a slightly lower proportion of pts with BICR-assessed baseline brain mets (21% vs 25%) and prior CNS radiotherapy (RT; 6% vs 10%) compared to the control arm. Selpercatinib delayed CNS PD as evidenced by a lower 12 mo cumulative incidence rate (CIR) for CNS PD, as well as delaying non-CNS PD compared to control in pts with and without brain mets (Table). In pts with measurable brain mets at baseline (n=29), median time to IC response per RECIST 1.1 was similar between selpercatinib and control (1.4 mo [range: 1.2-2.9] vs 1.6 mo [range: 1.2-2.9]); however, as previously reported the IC response rates were higher (82% vs 58%) and more durable (12 mo DOR rate 76% vs 63%) with selpercatinib vs control (Zhou et al. NEJM 2023). IC responses to selpercatinib were more common in pts without prior CNS RT (14/15, 93%) than with prior CNS RT (3/6, 50%). Conclusions: Selpercatinib delayed IC progression in advanced RET+ NSCLC pts with or without baseline brain mets and achieved higher IC response rates compared to chemotherapy + pembrolizumab. LIBRETTO-431 is the first study to demonstrate IC efficacy improvement of a targeted therapy vs chemo/IO in a biomarker selected NSCLC population. These data further support selpercatinib as the preferred 1L regimen in pts with advanced RET+ NSCLC. Clinical trial information: NCT04194944 . [Table: see text]

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported. Although the CNS activity of selpercatinib in patients with RET fusion-positive non–small cell lung cancer (NSCLC) has been previously described, the ability of potent RET inhibition to prevent new CNS metastases from developing has been challenging to measure without randomized data. Serial CNS scans were studied from LIBRETTO-431, a randomized phase III trial of selpercatinib versus platinum/pemetrexed ± pembrolizumab whose primary results have been previously disclosed. Intracranial outcomes were assessed by neuroradiologic blinded independent central review in patients with baseline and ≥1 postbaseline CNS scans. Of the 192 patients within the intention-to-treat pembrolizumab population with baseline CNS scans, 150 patients were without baseline CNS metastases. The cumulative incidence of CNS progression in these patients was reduced with selpercatinib versus chemotherapy + pembrolizumab (cause-specific hazard ratio [HR], 0.17 [95% CI, 0.04 to 0.69]). The HR for intracranial progression-free survival (PFS) was 0.46 (95% CI, 0.18 to 1.18). Among the 42 patients with baseline CNS metastases, similar trends were observed in the cumulative incidence of CNS progression (cause-specific HR, 0.61 [95% CI, 0.19 to 1.92]) and intracranial PFS (HR, 0.74 [95% CI, 0.28 to 1.97]). These data demonstrate that selpercatinib effectively treats existing CNS disease and prevents or delays the formation of new CNS metastases. These results reinforce the importance of identifying RET fusions in first-line patients with NSCLC and treating with selpercatinib.

BACKGROUND Selpercatinib, a highly selective potent and brain-penetrant RET inhibitor, was shown to have efficacy in patients with advanced RET fusion-positive non-small-cell lung cancer (NSCLC) in a nonrandomized phase 1-2 study. METHODS In a randomized phase 3 trial, we evaluated the efficacy and safety of first-line selpercatinib as compared with control treatment that consisted of platinum-based chemotherapy with or without pembrolizumab at the investigator's discretion. The primary end point was progression-free survival assessed by blinded independent central review in both the intention-to-treat-pembrolizumab population (i.e., patients whose physicians had planned to treat them with pembrolizumab in the event that they were assigned to the control group) and the overall intention-to-treat population. Crossover from the control group to the selpercatinib group was allowed if disease progression as assessed by blinded independent central review occurred during receipt of control treatment. RESULTS In total, 212 patients underwent randomization in the intention-to-treat-pembrolizumab population. At the time of the preplanned interim efficacy analysis, median progression-free survival was 24.8 months (95% confidence interval [CI], 16.9 to not estimable) with selpercatinib and 11.2 months (95% CI, 8.8 to 16.8) with control treatment (hazard ratio for progression or death, 0.46; 95% CI, 0.31 to 0.70; P<0.001). The percentage of patients with an objective response was 84% (95% CI, 76 to 90) with selpercatinib and 65% (95% CI, 54 to 75) with control treatment. The cause-specific hazard ratio for the time to progression affecting the central nervous system was 0.28 (95% CI, 0.12 to 0.68). Efficacy results in the overall intention-to-treat population (261 patients) were similar to those in the intention-to-treat-pembrolizumab population. The adverse events that occurred with selpercatinib and control treatment were consistent with those previously reported. CONCLUSIONS Treatment with selpercatinib led to significantly longer progression-free survival than platinum-based chemotherapy with or without pembrolizumab among patients with advanced RET fusion-positive NSCLC. (Funded by Eli Lilly and others; ClinicalTrials.gov number, NCT04194944.).

Supplementary Figure 3. LSN2478185 reduces the loss of skeletal muscle mass under conditions of caloric restriction.

Supplementary Figure from Phase Ib/II Study of Enzalutamide with Samotolisib (LY3023414) or Placebo in Patients with Metastatic Castration-Resistant Prostate Cancer

Selpercatinib (LOXO-292) is a highly selective and potent inhibitor of RET signaling. In the LIBRETTO-001 Phase I/II trial, selpercatinib treatment resulted in a 64% objective response rate (ORR) (95% confidence interval [CI]: 54-73%) in the registration dataset (n=105) of patients with RET+ NSCLC who previously received platinum-based chemotherapy and an 85% ORR (95% CI: 70-94%) in treatment-naïve patients with RET+ NSCLC (n=39). Although the duration of response (DOR) and progression free-survival (PFS) were not yet mature in treatment-naïve patients, in patients who previously received chemotherapy, the median DOR was 18 months (95% CI: 12-not estimable [NE]), median PFS was 17.5 months (95% CI: 12-NE), and CNS ORR per RECIST 1.1 was 91% (95% CI: 59-100%) (n=10/11).

Selpercatinib, a novel, highly selective and potent, inhibitor of RET, demonstrated clinically meaningful antitumor activity with manageable toxicity in heavily pretreated and treatment-naive RET fusion-positive non-small-cell lung cancer patients in a Phase I/II clinical trial. LIBRETTO-431 (NCT04194944) is a randomized, global, multicenter, open-label, Phase III trial, evaluating selpercatinib versus carboplatin or cisplatin and pemetrexed chemotherapy with or without pembrolizumab in treatment-naive patients with locally advanced/metastatic RET fusion-positive nonsquamous non-small-cell lung cancer. The primary end point is progression-free survival by independent review. Key secondary end points include overall survival, response rate, duration of response and progression-free survival. Clinical trial registration: NCT04194944 (ClinicalTrials.gov).

3588 Background: Randomized trials involving agents targeting oncogene addicted tumors have greatly increased over the past decade. Whether clinical response rates can predict or correlate with efficacy measures such as progression-free survival (PFS) or overall survival (OS) has not been established in molecularly enriched patient populations. In this meta-analysis, we investigated whether improvements in objective response rate (ORR) in comparative trials using targeted agents could serve as a potential surrogate endpoint for improvements in PFS or OS in populations with oncogene addicted cancer. Methods: CT.gov and MEDLINE databases were queried (using commercial text mining software I2E) for randomized, phase 3 clinical trials based on the following prospectively defined criteria: (1) use of agents targeting EGFR activating mutations (erlotinib, gefitinib, afatinib, dacomitinib, osimertinib), ALK and ROS1 rearrangements (crizotinib, ceritinib, alectinib), BRAF V600E or V600K mutations (dabrafenib), and BCR-ABL fusion protein (imatinib, dasatinib, nilotinib, ponatinib); (2) must include molecularly enriched trial populations (biomarker subgroup data included if available); (3) control arms should not include targeted agents directed towards those molecularly enriched populations. ORR, OS, and PFS data were manually extracted from the relevant studies and correlative analyses (weighted Pearson correlation) were performed. Results: 61 trials were identified with 15 ultimately meeting the prespecified criteria. ORR effect size (both the ORR difference and log odds ratio) and the log PFS hazard ratio were strongly correlated (-0.78, p-value = 0.0007). No significant correlation was found between ORR and OS. Conclusions: In our analyses, a strong correlation between ORR and PFS was found in randomized clinical trials investigating agents targeting oncogene-driven cancers. Establishing a correlation between ORR and OS was limited, most probably due to confounding factors such as treatment cross-over following progression, number of subsequent therapies and long post-progression survival in this setting. These findings further warrant the use of ORR as a surrogate for PFS in biomarker-driven studies.

5009 Background: Preclinical and phase 1 results suggest PI3K/mTOR pathway inhibition may enhance androgen receptor inhibition. We report the results of a double-blind, placebo-controlled, randomized Phase 1b/2 study of ENZ±LY (a dual PI3K/mTOR inhibitor) in pts with mCRPC who progressed on abiraterone. Methods: Phase 1b pts received single-agent LY 200 mg twice daily (BID) for 1 wk prior to starting LY+ENZ. Phase 2 pts were randomized 1:1 to 160 mg daily ENZ with PL or 200 mg BID LY on a 28-d cycle. The primary objective was progression-free survival (PFS: serological, radiographic [rPFS], or death) by PCWG2 criteria. Secondary objectives were rPFS, safety, decline in PSA, and PK. Exploratory biomarker analyses included outcomes by presence of androgen receptor variant 7 (AR-V7). 92 primary PFS events were needed for the study to have at least 80% power at one-sided alpha=0.20. Results: LY+ENZ was tolerable during Phase 1b with 1 dose limiting toxicity observed in 13 enrolled pts. Mean LY exposures remained in an efficacious range despite a 30% average decrease when combined with ENZ. In Phase 2, 129 pts were randomized to LY+ENZ (N=65) and PL+ENZ (N=64) (Table). Median PCWG2-PFS was 3.7 mos (LY+ENZ) vs 2.9 mos (PL+ENZ) (HR 0.66, 95% CI 0.43, 0.99; p-value 0.0208). Conclusions: Combination LY+ENZ had a clinically manageable safety profile. The primary end-point of PCWG2-PFS was met and is supported by a clinically meaningful delay in rPFS in AR-V7 negative pts. The biomarker data provide important insights to inform future development strategies. Clinical trial information: NCT02407054. [Table: see text]

Abstract Background Cachexia is a formidable clinical challenge in pancreatic cancer. We assessed LY2495655 (antimyostatin antibody) plus standard‐of‐care chemotherapy in pancreatic cancer using cachexia status as a stratifier. Methods In this randomized, phase 2 trial, patients with stage II–IV pancreatic cancer were randomized to 300 mg LY2495655, 100 mg LY2495655, or placebo, plus physician‐choice chemotherapy from a prespecified list of standard‐of‐care regimens for first and later lines of care. Investigational treatment was continued during second‐line treatment. The primary endpoint was overall survival. Results Overall, 125 patients were randomized. In August 2014, 300 mg LY2495655 was terminated due to imbalance in death rates between the treatment arms; in January 2015, 100 mg LY2495655 treatment was terminated due to futility. LY2495655 did not improve overall survival: the hazard ratio was 1.70 (90% confidence interval, 1.1–2.7) for 300 mg vs. placebo and 1.3 (0.82–2.1) for 100 mg vs. placebo (recommended doses). Progression‐free survival results were consistent with the overall survival results. A numerically higher hazard ratio was observed in patients with weight loss (WL) of ≥5% (cachexia) than with <5% WL within 6 months before randomization. Subgroup analyses for patients stratified by WL in the 6 months preceding enrollment suggested that functional responses to LY2495655 (either dose) may have been superior in patients with <5% WL vs. patients with ≥5% WL. Among possibly drug‐related adverse events, fatigue, diarrhoea, and anorexia were more common in LY2495655‐treated than in placebo‐treated patients. Conclusions In the intention‐to‐treat analysis, LY2495655 did not confer clinical benefit in pancreatic cancer. Our data highlight the importance of assessing survival when investigating therapeutic management of cachexia and support the use of WL as a stratifier (independent of performance status).

PURPOSE To compare disease-free survival (DFS) after maintenance therapy with the selective protein kinase C β (PKCβ) inhibitor, enzastaurin, versus placebo in patients with diffuse large B-cell lymphoma (DLBCL) in complete remission and with a high risk of relapse after first-line therapy. PATIENTS AND METHODS This multicenter, phase III, randomized, double-blind, placebo-controlled trial enrolled patients who were at high risk of recurrence after rituximab-cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). Patients (N = 758) with stage II bulky or stage III to IV DLBCL, three or more International Prognostic Index risk factors at diagnosis, and a complete response or unconfirmed complete response after 6 to 8 cycles of R-CHOP were assigned 2:1 to receive oral enzastaurin 500 mg daily or placebo for 3 years or until disease progression or unacceptable toxicity. Primary end point was DFS 3 years after the last patient entered treatment. Correlative analyses of biomarkers, including cell of origin by immunohistochemistry and PKCβ expression, with efficacy outcomes were exploratory objectives. RESULTS After a median follow-up of 48 months, DFS hazard ratio for enzastaurin versus placebo was 0.92 (95% CI, 0.689 to 1.216; two-sided log-rank P = .541; 4-year DFS, 70% v 71%, respectively). Independent of treatment, no significant associations were observed between PKCβ protein expression or cell of origin and DFS or overall survival. CONCLUSION Enzastaurin did not significantly improve DFS in patients with high-risk DLBCL after achieving complete response to R-CHOP. Achievement of a complete response may have abrogated the prognostic significance of cell of origin by immunohistochemistry.

Abstract Skeletal muscle wasting occurs in a great majority of cancer patients with advanced disease and is associated with a poor prognosis and decreased survival. Myostatin functions as a negative regulator of skeletal muscle mass and has recently become a therapeutic target for reducing the loss of skeletal muscle and strength associated with clinical myopathies. We generated neutralizing antibodies to myostatin to test their potential use as therapeutic agents to attenuate the skeletal muscle wasting due to cancer. We show that our neutralizing antimyostatin antibodies significantly increase body weight, skeletal muscle mass, and strength in non–tumor-bearing mice with a concomitant increase in mean myofiber area. The administration of these neutralizing antibodies in two preclinical models of cancer-induced muscle wasting (C26 colon adenocarcinoma and PC3 prostate carcinoma) resulted in a significant attenuation of the loss of muscle mass and strength with no effect on tumor growth. We also show that the skeletal muscle mass– and strength-preserving effect of the antibodies is not affected by the coadministration of gemcitabine, a common chemotherapeutic agent, in both non–tumor-bearing mice and mice bearing C26 tumors. In addition, we show that myostatin neutralization with these antibodies results in the preservation of skeletal muscle mass following reduced caloric intake, a common comorbidity associated with advanced cancer. Our findings support the use of neutralizing antimyostatin antibodies as potential therapeutics for cancer-induced muscle wasting. Mol Cancer Ther; 14(7); 1661–70. ©2015 AACR.

Abstract Background: Protein kinase Cβ (PKCβ) is critical for B-cell signaling and survival and overexpression of PKCβ in DLBCL is associated with inferior survival. ENZA, an oral serine/threonine kinase inhibitor, targets PKCβ. Here we report immunohistochemical (IHC) and fluorescence in-situ hybridization (FISH) correlative analyses. Methods: PRELUDE (NCT00332202) was a phase III, double-blind maintenance study of 758 pts with DLBCL who were randomized 2:1 to ENZA 500 mg daily (1125-mg loading dose) (n = 504) or PBO (n = 254), respectively, following CR to induction therapy with R-CHOP. The primary endpoint was disease-free survival (DFS). Overall survival (OS) and assessment of biomarkers specific to ENZA and DLBCL were secondary endpoints. Pre-treatment formalin-fixed, paraffin-embedded samples were assessed via IHC staining in a blinded manner (Eric Hsi) for cell of origin (COO) using Hans’ algorithm. In addition, IHC was performed for c-MYC, BCL2, BCL6, FOXP1, and MUM1 (10% increments/% tumor cells stained), markers relevant to ENZA, including PKCβ2. FISH was performed to identify translocations involving c-MYC, BCL2, and BCL6. Cox regression was used to determine statistical associations between efficacy outcomes and dichotomized markers, adjusting for treatment and additional baseline covariates. All tests of association were conducted at a 2-sided α = 0.05. Results: There was no difference in 4-year DFS (70% vs 71%) or OS (81% vs 82%) between ENZA and PBO arms, respectively. A total of 243 (32%) pts had ≥1 evaluable sample available for IHC and FISH. There was no difference in outcome for pts based on COO (GCB vs non-GCB). Independent of treatment, significant associations were observed for BCL2 (pre-specified cutpoint 20%) and MUM1 (cutpoint 30%) with OS, and FOXP1 (cutpoint 80%) by IHC with DFS (HR [95% CI]: 2.19 [1.01-4.73]), p = 0.031; 1.97 [1.04-3.71], p = 0.032; 1.74 [1.04-2.90], p = 0.032, respectively). Associations were not significant for other IHC markers, including c-MYC and BCL6. Low PKCβ2 (<50% expression) had numerically better (but not significant) DFS/OS vs high PKCβ2. Dual translocation lymphoma by FISH was identified in two pts (1.2%) each for c-MYC/BCL2 and c-MYC/BCL6, and one pt (0.6%) had a triple hit involving c-MYC/BCL2/BCL6. Conclusions: No difference in outcomes between treatment arms was observed for the trial. Independent of treatment, COO was not prognostic of outcomes. Pts with low PKCβ2 expression had numerically better DFS/OS compared with high PKCβ2 expression. Significant treatment-independent associations were observed for BCL2 and MUM1 with OS and for FOXP1 with DFS (low IHC expression corresponded to better outcomes). The small number of double hit and triple hit lymphomas seen in the study may reflect the enrollment of CR patients with more favorable biology. Citation Format: Eric D. Hsi, Kerry J. Savage, Sonali M. Smith, Fritz Offner, Scott P. Myrand, Thomas M. Habermann, Donald E. Thornton, Boris K. Lin, Tuan S. Nguyen, Oday Hamid, Michael Crump. Correlative results from PRELUDE, a phase III study of enzastaurin (ENZA) vs placebo (PBO) in patients (pts) with high-risk diffuse large B-cell lymphoma (DLBCL) following a response to R-CHOP therapy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5303. doi:10.1158/1538-7445.AM2015-5303

Summary This open‐label, phase II study investigated whether enzastaurin, a protein kinase C‐beta ( PKC β) inhibitor, had activity in patients with grade 1 or 2 follicular lymphoma ( FL ). Adults with grade 1 or 2 FL who had no more than one prior treatment received oral enzastaurin continuously for up to 3 years. Of the 66 patients who received enzastaurin, 53 were evaluable for response. Overall response rate ( ORR , primary efficacy endpoint) was 26·4% (3·8% complete response). Median (95% confidence interval) progression‐free survival, time to response, and duration of response were 18·1 (11·5–28·3), 4·9 (2·8–8·1), and 22·3 (8·8‐not applicable) months, respectively. In patients with tumour tissue available for biomarker analysis, ORR s in low versus high PKC β2 expression groups were 41·7% and 8·3%, respectively ( P = 0·041). The most common, mainly low‐grade drug‐related adverse events were fatigue (25·8%), diarrhoea (25·8%), nausea (18·2%), and chromaturia (18·2%). Four (6·1%) patients had Grade 3 toxicity and one (1·5%) patient had Grade 4 toxicity. Enzastaurin demonstrated limited clinical activity in grade 1 or 2 FL . Patients with low PKC β2 expression in tumours had higher ORR than those with high PKC β2 expression. Enzastaurin was well tolerated with mostly grade 1 or 2 toxicities. Further studies may be warranted in select patient populations.

Purpose of reviewThis review summarizes recent progress in the development of myostatin inhibitors for the treatment of muscle wasting disorders. It also focuses on findings in myostatin biology that may have implications for the development of antimyostatin therapies.Recent findingsThere has been progress in evaluating antimyostatin therapies in animal models of muscle wasting disorders. Some programs have progressed into clinical development with initial results showing positive impact on muscle volume.In normal mice myostatin deficiency results in enlarged muscles with increased total force but decreased specific force (total force/total mass). An increase in myofibrillar protein synthesis without concomitant satellite cell proliferation and fusion leads to muscle hypertrophy with unchanged myonuclear number. A specific force reduction is not observed when atrophied muscle, the predominant therapeutic target of myostatin inhibitor therapy, is made myostatindeficient.Myostatin has been shown to be expressed by a number of tumor cell lines in mice and man.SummaryMyostatin inhibition remains a promising therapeutic strategy for a range of muscle wasting disorders.

Abstract Background Despite improvements in outcome following the addition of rituximab (R) to CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) (R-CHOP), patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL) and International Prognostic Index (IPI) scores of 3-5 at diagnosis have a poor outcome. Enzastaurin is a potent inhibitor of PKCβ, a component of the B-cell receptor signaling complex, with preclinical activity and clinical activity in a phase II trial in patients with relapsed DLBCL, providing the rationale for this study in the primary therapy setting. Methods PRELUDE was a multi-national, randomized, double-blinded, placebo-controlled study. Patients were required to have a histologic diagnosis of DLBCL, pre-treatment IPI score ≥3, and a complete response (CR) or CRu by International Working Group Criteria, or a negative FDG-PET scan after 6–8 cycles of R-CHOP. Patients were randomly assigned in a 2:1 ratio to receive either enzastaurin 500 mg daily or an identical placebo as maintenance therapy, for a planned treatment duration of 3 years. The primary endpoint was DFS, defined as lack of disease progression or death. Assuming a 2-year DFS rate in the control group of 70%, the primary analysis had 80% power to detect a HR of 0.67, eg, a 2-year DFS rate of 79% in the enzastaurin group. Secondary endpoints included overall survival (OS) and event-free survival (EFS). Data were analyzed 3 years after the last enrolled patient initiated treatment. Results From May 2006–April 2010, 758 patients were enrolled (enzastaurin, n=504; placebo, n=254). Median age at enrollment was 64 years (range 21-89); at diagnosis, 65% of patients had stage IV disease, 48% had B symptoms, and 25% had a mass >10 cm; baseline disease and patient characteristics were well balanced between treatment arms. Fifty-seven percent had a negative PET scan following completion of R-CHOP. Median follow-up time for all patients was 48 months (range 0.03–80). At the time of analysis, 209 events had occurred. The DFS HR for enzastaurin vs. placebo was 0.92 (95% CI: 0.69, 1.22; 2-sided log-rank p=0.54). DFS at 24 and 48 months were 79% and 70% for the enzastaurin arm, and 75% and 71% for placebo, respectively. OS at 24 and 48 months was 87% and 81% for enzastaurin, and 89% and 82% for placebo; HR for enzastaurin vs. placebo was 1.04 (95% CI: 0.74, 1.47; 2-sided log-rank p=0.81). Percent of ITT population patients on therapy at 12, 24, and 36 months was 70.6%, 60.6%, and 20.1% for enzastaurin; 72.3%, 60.6%, and 22.1% for placebo. Biomarker subgroup analysis was performed and will be available at time of presentation. Treatment emergent AEs (all grades) that were possibly study drug-related and significantly different between enzastaurin and placebo included chromaturia (18.5% vs. 0.4%), QTc prolongation (10.8% vs. 3.6%), and diarrhea (10.3% vs. 2.8%). There were no significant differences in number of patients with at least 1 grade 3 or higher AE between treatment arms. No significant differences were observed in the frequency of deaths while on therapy. Conclusion Enzastaurin did not improve DFS, EFS, or OS in patients with high-risk DLBCL and CR following R-CHOP treatment. Disclosures: Crump: Roche: Honoraria; Jansen-Ortho: Honoraria; Celgene: Honoraria; Lundbeck: Honoraria; Novartis: Research Funding; Seattle Genetics: Honoraria. Off Label Use: rituximab for maintenance therapy post autolgous transplant for lymphoma. Leppä:Eli Lilly: Research Funding. Ogura:Eli Lilly: Research Funding. Rifkin:Millenium, Celgene, ONYX: Membership on an entity’s Board of Directors or advisory committees. Mackensen:Eli Lilly: Consultancy. Offner:Eli Lilly: Membership on an entity’s Board of Directors or advisory committees. Smith:Genentech, Celgene, Spectrum, Seattle Genetics, Gilead, Amgen/Micronet: Consultancy. Tobinai:Eli Lilly: Research Funding. Hahka-Kemppinen:Eli Lilly: Employment. Thornton:Eli Lilly: Employment. Shi:Eli Lilly: Employment. Lin:Eli Lilly: Employment. Kahl:Genentech: Consultancy. Savage:Eli Lilly: Consultancy.

The lack of a standard therapy for relapsed non-Hodgkin lymphoma warrants investigation of new therapeutic agents. This screening study evaluated the antitumor activity of enzastaurin in 57 patients with 3 types of relapsed non-Hodgkin lymphoma (including 7 tumor subtypes). Three of the tumor subtypes, cutaneous T cell, follicular, and small lymphocytic lymphoma, showed a long-term response to enzastaurin, which was well tolerated.Purpose: To assess the antitumor activity of enzastaurin in patients with non-Hodgkin lymphomas: T-cell lymphoma (n = 23): cutaneous and peripheral T-cell lymphoma; indolent B-cell lymphomas (n = 19): small lymphocytic, follicular grade 1 or 2, marginal zone lymphomas; and aggressive B-cell lymphomas (n = 15): follicular lymphomas grade 3, aggressive lymphoma with a clinical history. The primary objective was to determine overall tumor response. Secondary objectives included duration of response and safety. Materials and Methods: In this multicenter, open-label, non-comparative, screening study conducted between December 2007 and February 2009, patients (>= 18 years) who relapsed after >= 1 prior systemic treatment or who were intolerant to standard systemic therapy received 250 mg oral enzastaurin (125 mg tablets twice a day; a 1125-mg loading dose on day 1), in 28-day cycles for up to 2 years unless unacceptable toxicity or progressive disease occurred. Results: Responses were seen in follicular lymphomas grade 3 (1/5, 20.0%), cutaneous T-cell lymphoma (2/11, 18.2%), small lymphocytic lymphomas (1/7, 14.3%), and aggressive lymphoma with a clinical history (1/10, 10.0%) in this heavily pretreated patient population (median prior therapies range from 4 to 10). Most drug-related toxicities were grade 1/2, the most common being diarrhea, peripheral edema, and pruritus. Conclusions: Enzastaurin was well tolerated but demonstrated modest responses across subgroups in this heavily pretreated patient population. (C) 2013 Elsevier Inc. All rights reserved.

Abstract 777 Background: Protein kinase C β (PKCβ) is critical for B-cell signaling and survival. Over-expression of PKCβ is implicated in the pathogenesis of follicular lymphoma (FL). Enzastaurin (ENZ), an oral serine/threonine kinase inhibitor, targets the PKCβ and PI3K/AKT pathways to inhibit tumor cell proliferation, induce apoptosis, and suppress tumor-induced angiogenesis. Reported here are the final clinical and correlative study results from a phase II study. Methods: This was an open-label, single-arm, study of patients (pts) with hiastologically confirmed grade 1/2 and stage III/IV measurable FL. Pts were either chemonaive or relapsed after 1 chemotherapy regimen or single-agent rituximab. Pts received 500 mg oral ENZ once daily (1125-mg loading dose on D1) ≤ 3 years or until progression, withdrawal, or toxicity. The primary endpoint was response rate (RR). Secondary objectives included progression-free survival (PFS), duration of response (DoR), and safety. Pre-treatment samples were used for correlative research. Staining was performed for BCL2, BCL6, CD10, Ki67, FOXP1, FOXP3, CD20, MUM1, CD68, and PD1 expression. ENZ-specific biomarkers investigated by immunohistochemistry (IHC; standard H scores range 0–300) included PKCβ2, PTEN, pS6, pGSK3β, and pCREB. Logistic/Cox regression determined the statistical correlation between clinical outcomes (RR or PFS) and IHC for each marker. All tests of association were conducted at a 2-sided α = 0.05. Clinical Results: Sixty-six pts (23 male, 43 female; median age 62 years \(3382\) ) were enrolled. Based on FL International Prognostic Index, 12% had low-risk disease (0-1 risk factors [RF]); 55%, intermediate-risk disease (2 RFs); and 33%, high-risk disease (3-5 RFs). Forty-six pts (69.7%) were chemonaive and 20 pts (30.3%) had ≥ 1 prior chemotherapy. The median overall exposure was 10.8 months (mo; 1–57 mo). Of 58 pts who received ≥1 dose of ENZ, 2 (3.4%) had complete response, and 15 (25.9%) had partial response (overall RR = 29.3%). The median PFS was 15.2 mo (95% confidence interval [CI] 11.1–25.7 mo). DoR median was 20.5 mo (95% CI 9.1–31.5 mo). Seven pts (10.6%) discontinued treatment due to adverse events (AEs), of which 5 (7.6%) were possibly drug related: bronchitis, prolonged QTc interval, abdominal distention, colitis, and skin rash. Four pts (6.1%) had drug-related serious AEs: grade (Gr) 3 bronchitis, Gr 2 vision, Gr 2 diarrhea, Gr 2 pancreatitis. There were no drug-related deaths. To date, 5 pts remain on treatment and have been on treatment 3.5–5 years. Correlative Results: Tumor tissue was obtained from 28 pts. Patient demographics and overall RR were well balanced between protocol and correlative study populations. No significant associations with RR or PFS were observed for any FL-specific markers. Significant associations were observed between low cytoplasmic PKCβ2 and increased RR (median H score cutpoint 151.5, odds ratio (OR) [95%CI] = 0.027 [0.001-0.656], p=0.027) (Table 1, Figure 1). Significant associations were also observed between PFS and both cytoplasmic PKCβ2 and cytoplasmic pS6 using median H score cutpoint (Table 1). Conclusions: ENZ has clinical activity and is well tolerated in pts with grade 1/2 FL. Low cytoplasmic PKCβ2 was significantly associated with increased RR and longer PFS; high cytoplasmic pS6 was significantly associated with longer PFS. The correlative results are hypothesis generating given the study9s size and nonrandomized nature. Disclosures: Hermann:Eli Lilly and Company: Research Funding. Hsi:Eli Lilly and Company: Research Funding. Hamid:Eli Lilly and Company: Employment. Myrand:Eli Lilly and Company: Employment. Lin:Eli Lilly and Company: Employment. Thornton:Eli Lilly and Company: Employment. Shi:Eli Lilly and Company: Employment. Nguyen:Eli Lilly and Company: Employment.