Citations

Abstract Multiple myeloma (MM) makes up approximately 10% of all hematologic malignancies, with increasing incidence worldwide. Though treatment options for newly diagnosed patients have evolved in recent years, they are not curative, and relapse is common with 2,500-3,000 relapsed or refractory (R/R) MM US patients seeking novel treatments, annually. Cereblon (CRBN)-binding Ikaros and Aiolos (I/A) protein degraders (i.e., lenalidomide (LEN) and pomalidomide (POM)) have had great success in treating MM. However, due to the unstable chiral nature of the CRBN-binding moiety, common to these molecules, many exist as racemic mixtures (1:1 mixture of interconverting (R)- and (S)-enantiomers). A growing body of evidence suggests that the (S)- enantiomer is the active anticancer species, while the (R)-enantiomer is inactive and potentially results in undesired activity. The ability to stabilize the active (S)- enantiomer represents a potential strategy to improve therapeutic outcomes. We are developing SP-3164, the deuterium-stabilized (S)-enantiomer of avadomide (AVA), an I/A-degrading molecular glue which has been studied in over 400 patients, demonstrating safety and activity in hematologic diseases. Our in vitro data demonstrate that SP-3164 more potently and rapidly degrades the cancer-promoting transcription factors, I/A, compared to LEN, POM, and AVA, while the stabilized (R)-enantiomer, SP-3165, neither binds CRBN nor degrades I/A. In preliminary in vivo studies, SP-3164 elicited significant tumor growth inhibition (TGI). Here, we investigate the activity of SP-3164 in MM, compared to established treatment regimens. SP-3164’s potential to degrade Aiolos in MM.1S cells was compared to SP-3165, AVA, and POM. SP-3164 rapidly and robustly degraded Aiolos in a time- and dose-dependent manner, more potently than AVA and POM, while SP-3165 demonstrated minimal Aiolos degradation. To investigate the effect of SP-3164 on cell survival, we treated NCI-H929 cells with SP-3164 (0.1 µM, 1 µM, and 10 µM) and SP-3165 (1 µM) and assessed apoptosis by flow cytometry. SP-3164 induced dose-dependent early and late apoptosis after 72 hours, while SP-3165 showed no induction of apoptosis. SP-3164’s in vivo activity was assessed and compared to SP-3165, LEN, and POM in an NCI-H929 mouse xenograft model. SP-3164 showed significant TGI as a single agent while SP-3165 seemed to support tumor growth. LEN and POM demonstrated minimal TGI. When combined with dexamethasone (DEX), SP-3164 had improved TGI compared to the combination of POM+DEX. These preclinical data demonstrate that SP-3164 is a potent CRBN-binding molecular glue with the ability to rapidly degrade cancer-promoting transcription factors and induce apoptosis in vitro. In vivo, SP-3164 has superior single agent and combination activity compared to approved molecular glues. These data support the continued development as a novel therapy in MM. Citation Format: Aundrietta D. Duncan, Daniela Y. Santiesteban, Nadeem Q. Mirza, Steve Horrigan, Sheila DeWitt, Vincent Jacques, P. Leif Bergsagel. SP-3164, a novel molecular glue degrader with activity in preclinical models of multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6253.

7018 Background: MF is a life-limiting malignancy characterized by marrow fibrosis, splenomegaly, and progressive cytopenias. JAK2 inhibitors can reduce spleen volume, which is considered a surrogate for disease response. For example, ≥10% SVR on ruxolitinib (RUX) is associated with improved OS among patients with platelet (PLT) counts ≥100×109/L. RUX cannot be administered at full dose in patients with lower PLTs, and it is not known whether the association between SVR and OS persists in such patients. PAC is a JAK1-sparing inhibitor of JAK2/IRAK1/ACVR1 that demonstrated SVR benefit vs BAT (including RUX) in PERSIST-2, which enrolled MF patients with PLTs ≤100×109/L. Here we present a retrospective landmark OS analysis of the relationship between SVR and OS on PERSIST-2. Methods: This analysis includes PERSIST-2 patients who were alive and on study at the start of the 12-week SVR window (study week 10) on PAC 200 mg BID or BAT. Spleen volume was assessed radiographically (MRI or CT). OS was evaluated among SVR responders vs non-responders within each treatment arm using different SVR thresholds (≥35%, ≥20%, ≥10%, > 0%) and a landmark analysis methodology. OS was compared using the log-rank test. Results: Among patients on PAC (n = 89), any SVR ( > 0%) at 12 weeks was significantly associated with improved survival (HR = 0.08 [95% CI: 0.01, 0.51], P = 0.0007). Among all SVR response thresholds, SVR ≥10% demonstrated the greatest separation in OS curves between responders vs. non-responders on PAC, with no deaths on study among 65 responders compared to 5 deaths among 24 non-responders (HR = 0.0 [95% CI: 0.0, 0.14], P < 0.0001). By contrast, SVR did not predict OS benefit on BAT (n = 84), including RUX (n = 39). For example, 11% (3/28) of patients on BAT who achieved SVR ≥10% died compared to a similar number (14%, 8/56) of non-responders (HR = 0.63 [95% CI: 0.17, 2.37], P = 0.49). Of the 28 patients on BAT who achieved SVR ≥10%, 23 (82%) were treated with RUX. Among these 23 patients, most patients were receiving low-dose RUX at the time of the landmark: 78% were on ≤10 mg BID and 43% were on £5 mg BID. By contrast, the median relative dose intensity on PAC was 100% (200 mg BID) through week 12 among both SVR ≥10% responders and non-responders. Conclusions: In MF patients with PLTs ≤100×109/L, achieving SVR on full-dose PAC was associated with significant OS benefit. By contrast, this association was not found with BAT, even though most responders were on RUX, albeit at low doses. As PAC can be given at full dose regardless of PLT count, it is possible that PAC may offer a unique survival advantage for MF patients with moderate or severe thrombocytopenia who achieve spleen reduction. Clinical trial information: NCT02055781 .

7016 Background: Many patients (pts) with myelofibrosis (MF) experience anemia resulting from disease or JAK inhibitor therapy. The open-label, phase 2 ACE-536-MF-001 study (NCT03194542) evaluated the safety and efficacy of luspatercept (LUSPA) for the treatment of MF-related anemia. Methods: Eligible pts comprised 4 cohorts based on transfusion dependence (TD, defined as receiving 4–12 red blood cell [RBC] units/84 days [d] immediately up to cycle 1 d 1) and stable ruxolitinib (RUX) treatment; cohort 1: no TD, no RUX; cohort 2: TD, no RUX; cohort 3A: no TD, RUX; cohort 3B: TD, RUX. Pts received subcutaneous LUSPA 1.0 mg/kg (1.33 mg/kg for pts in cohort 3B expansion) with titration up to 1.75 mg/kg in 21-d cycles. Disease response was assessed at d 169 and treatment extended for pts showing clinical benefit; pts were followed for ≥ 3 years (y) post last dose. The primary endpoint was anemia response (defined as 84 consecutive d: ≥ 1.5 g/dL hemoglobin [Hgb] from baseline without transfusion [cohorts 1 and 3A] or RBC transfusion-free [cohorts 2 and 3B]); secondary endpoints included duration of response (DOR), transfusion frequency, change in Hgb level, and symptom response. Results: Of 95 pts in the ITT group, the most common reason for treatment discontinuation was lack of clinical benefit at d 169 (n = 28). Median (range) age was 71.0 (50–89) y. Most (54.7%) pts had primary MF, intermediate-risk 2 disease (75.8%), and > 2 y since initial diagnosis (74.7%). Median prior RUX therapy was 18.1 months (cohorts 3A/3B) and 84.7% of pts had baseline transfusion burden 6–12 units/84 d (cohorts 2/3B). Mean treatment duration was 42.8 weeks. Cohort 3B had the highest anemia response rate with 26.3% (95% CI, 13.4–43.1) of pts transfusion independent during the primary treatment period and 31.6% (95% CI, 17.5–48.7) transfusion independent during the entire treatment period; median (range) DOR was 448 d (85–1582). In cohort 3B: 19 (50.0%) pts had reduced transfusion burden by ≥ 50% during the primary treatment period; 8 (21.1%) pts achieved mean Hgb increase ≥ 1.5 g/dL from baseline throughout the entire treatment period and 6 (15.8%) achieved a mean ≥ 50% reduction in symptom score from baseline. Overall, 47.4% of pts had ≥ 1 treatment-related adverse event (TRAE), most frequently hypertension (17.9%, 5.3% grade ≥ 3); 3.2% of pts had a serious TRAE. One TRAE led to LUSPA discontinuation. Two (2.1%) pts had transformation to acute myeloid leukemia. Nine pts died on treatment from: post-procedural hemorrhage, pneumonia, intracranial hemorrhage, septic shock, ischemic stroke, multiple organ dysfunction syndrome, renal failure, pneumonitis, and myelofibrosis (n = 1 each); no deaths were considered related to the study drug. Conclusions: In pts with MF, the safety profile of LUSPA was consistent with previous studies and efficacy results showed promising improvements in anemia and transfusion burden in all cohorts. Clinical trial information: NCT03194542 .

Abstract Pathogenic protein-truncating variants of RAD51C, which plays an integral role in promoting DNA damage repair, increase the risk of breast and ovarian cancer. A large number of RAD51C missense variants of uncertain significance (VUS) have been identified, but the effects of the majority of these variants on RAD51C function and cancer predisposition have not been established. Here, analysis of 173 missense variants by a homology-directed repair (HDR) assay in reconstituted RAD51C−/− cells identified 30 nonfunctional (deleterious) variants, including 18 in a hotspot within the ATP-binding region. The deleterious variants conferred sensitivity to cisplatin and olaparib and disrupted formation of RAD51C/XRCC3 and RAD51B/RAD51C/RAD51D/XRCC2 complexes. Computational analysis indicated the deleterious variant effects were consistent with structural effects on ATP-binding to RAD51C. A subset of the variants displayed similar effects on RAD51C activity in reconstituted human RAD51C-depleted cancer cells. Case–control association studies of deleterious variants in women with breast and ovarian cancer and noncancer controls showed associations with moderate breast cancer risk [OR, 3.92; 95% confidence interval (95% CI), 2.18–7.59] and high ovarian cancer risk (OR, 14.8; 95% CI, 7.71–30.36), similar to protein-truncating variants. This functional data supports the clinical classification of inactivating RAD51C missense variants as pathogenic or likely pathogenic, which may improve the clinical management of variant carriers. Significance: Functional analysis of the impact of a large number of missense variants on RAD51C function provides insight into RAD51C activity and information for classification of the cancer relevance of RAD51C variants.

The global burden of paediatric and congenital heart disease (PCHD) is substantial. We propose a novel public health framework with recommendations for developing effective and safe PCHD services in low-income and middle-income countries (LMICs). This framework was created by the Global Initiative for Children’s Surgery Cardiac Surgery working group in collaboration with a group of international rexperts in providing paediatric and congenital cardiac care to patients with CHD and rheumatic heart disease (RHD) in LMICs. Effective and safe PCHD care is inaccessible to many, and there is no consensus on the best approaches to provide meaningful access in resource-limited settings, where it is often needed the most. Considering the high inequity in access to care for CHD and RHD, we aimed to create an actionable framework for health practitioners, policy makers and patients that supports treatment and prevention. It was formulated based on rigorous evaluation of available guidelines and standards of care and builds on a consensus process about the competencies needed at each step of the care continuum. We recommend a tier-based framework for PCHD care integrated within existing health systems. Each level of care is expected to meet minimum benchmarks and ensure high-quality and family centred care. We propose that cardiac surgery capabilities should only be developed at the more advanced levels on hospitals that have an established foundation of cardiology and cardiac surgery services, including screening, diagnostics, inpatient and outpatient care, postoperative care and cardiac catheterisation. This approach requires a quality control system and close collaboration between the different levels of care to facilitate the journey and care of every child with heart disease. This effort was designed to guide readers and leaders in taking action, strengthening capacity, evaluating impact, advancing policy and engaging in partnerships to guide facilities providing PCHD care in LMICs.

AbstractBackgroundMyelofibrosis (MF)‐associated constitutional symptoms can severely impact health‐related quality of life. Clinical trials in MF traditionally measure symptom response to treatment as a landmark endpoint of total symptom score (TSS) reduction ≥50% from baseline. However, this dichotomous assessment provides a limited view of clinically relevant symptomatic changes. Herein we evaluated longitudinal change from baseline in TSS over the continuous 24‐week period and individual symptom scores to obtain a more comprehensive understanding of symptom benefits experienced by patients with MF receiving therapy.MethodsLongitudinal symptom change was evaluated using mixed‐effect model repeated measure (MMRM) methodology with individual item‐level analyses to complement the interpretation of the landmark symptom results in the completed phase III SIMPLIFY studies of momelotinib in MF. MMRM compared mean change in TSS from baseline with Week 24 using data from all patient visits. Generalized estimating equations were used to estimate item‐level odds ratios using multiple predictive imputations for missing data.ResultsMomelotinib and ruxolitinib groups reported similar overall symptom improvements, with a TSS difference of <1.5 points between groups for each post‐baseline visit in SIMPLIFY‐1. In SIMPLIFY‐2, the improvement in TSS observed in momelotinib‐treated patients was consistent with that observed in SIMPLIFY‐1, whereas progressive TSS deterioration was observed with control. Item‐level scores were heterogeneous in both studies. A similar and greater proportion of momelotinib‐treated patients were categorized as “improved” or “stable” compared with control in SIMPLIFY‐1 and SIMPLIFY‐2, respectively. Odds ratios for between‐group comparison ranged from 0.75 to 1.21 in SIMPLIFY‐1, demonstrating similarity in likelihood of symptom improvement. In SIMPLIFY‐2, the likelihood of symptom improvement in each item was higher in the momelotinib arm.ConclusionsThese findings suggest that momelotinib provides clinically relevant symptom benefits in the JAK inhibitor‐naïve and JAK inhibitor‐exposed settings.

Abstract Background The shared inherited genetic contribution to risk of different cancers is not fully known. In this study, we leverage results from 12 cancer genome-wide association studies (GWAS) to quantify pairwise genome-wide genetic correlations across cancers and identify novel cancer susceptibility loci. Methods We collected GWAS summary statistics for 12 solid cancers based on 376 759 participants with cancer and 532 864 participants without cancer of European ancestry. The included cancer types were breast, colorectal, endometrial, esophageal, glioma, head and neck, lung, melanoma, ovarian, pancreatic, prostate, and renal cancers. We conducted cross-cancer GWAS and transcriptome-wide association studies to discover novel cancer susceptibility loci. Finally, we assessed the extent of variant-specific pleiotropy among cancers at known and newly identified cancer susceptibility loci. Results We observed widespread but modest genome-wide genetic correlations across cancers. In cross-cancer GWAS and transcriptome-wide association studies, we identified 15 novel cancer susceptibility loci. Additionally, we identified multiple variants at 77 distinct loci with strong evidence of being associated with at least 2 cancer types by testing for pleiotropy at known cancer susceptibility loci. Conclusions Overall, these results suggest that some genetic risk variants are shared among cancers, though much of cancer heritability is cancer-specific and thus tissue-specific. The increase in statistical power associated with larger sample sizes in cross-disease analysis allows for the identification of novel susceptibility regions. Future studies incorporating data on multiple cancer types are likely to identify additional regions associated with the risk of multiple cancer types.

Background and Objectives: Laparoscopic cholecystectomy (LC) is one of the most performed surgeries worldwide. Procedure difficulty and patient outcomes depend on several factors which are not considered in the current literature, including the learning curve, generating confusing and subjective results. This study aims to create a scoring system to calculate the learning curve of LC based on hepatobiliopancreatic (HPB) experts’ opinions during an educational course. Materials and Methods: A questionnaire was submitted to the panel of experts attending the HPB course at Research Institute against Digestive Cancer-IRCAD (Strasbourg, France) from 27–29 October 2022. Experts scored the proposed variables according to their degree of importance in the learning curve using a Likert scale from 1 (not useful) to 5 (very useful). Variables were included in the composite scoring system only if more than 75% of experts ranked its relevance in the learning curve assessment ≥4. A positive or negative value was assigned to each variable based on its effect on the learning curve. Results: Fifteen experts from six different countries attended the IRCAD HPB course and filled out the questionnaire. Ten variables were finally included in the learning curve scoring system (i.e., patient body weight/BMI, patient previous open surgery, emergency setting, increased inflammatory levels, presence of anatomical bile duct variation(s), and appropriate critical view of safety (CVS) identification), which were all assigned positive values. Minor or major intraoperative injuries to the biliary tract, development of postoperative complications related to biliary injuries, and mortality were assigned negative values. Conclusions: This is the first scoring system on the learning curve of LC based on variables selected through the experts’ opinions. Although the score needs to be validated through future studies, it could be a useful tool to assess its efficacy within educational programs and surgical courses.