Citations

Introduction: The safety and efficacy of direct oral anticoagulants (DOACs) compared to vitamin K antagonists (VKAs) remain unknown in patients with BMI ≥ 40 kg/m 2 . We aim to evaluate the risk of recurrent VTE and major bleeding in patients with a BMI ≥ 40 when started on DOACs versus VKAs. Methods: We conducted a systematic literature search according to PRISMA guidelines to identify studies using the terms: “venous thromboembolism”, “Vitamin K antagonists” and “direct oral anticoagulants”. After the screening, We extracted the data till May 2023 in a data extraction sheet. Our inclusion criteria were: adult patients, morbidly obese (BMI ≥ 40 kg/m 2 ), who were on DOACs or VKAs for VTE or atrial fibrillation. We used a variance-weighted random-effects model to analyze data on DOACs vs. VKAs, estimating event rates and odds ratios while assessing heterogeneity. Data were analyzed using the ‘meta’ package in R. Results: Our analysis included a total of 16 studies (n= 62704 patients). Obese patients on DOACs had a significant reduction in the risk of recurrent VTEs compared to VKAs OR 0.72 (95% CI: 0.59 - 0.88, I2 :19%). Also, DOACs were associated with a lower risk of major bleeding compared to VKAs in morbidly obese patients (OR = 0.65, 95% CI: 0.58 - 0.74, I2 :0%). For non-major bleeding, although the statistical significance was not reached, a consistent trend favoring DOACs was observed (OR = 0.76, 95% CI: 0.47-1.21). (Figure1) Conclusions: Among morbidly obese patients (BMI ≥ 40), DOACs are associated with a significantly lower risk of recurrent VTEs, and major bleeding compared to VKA. For non-major bleeding, there was a trend favoring DOACs over VKA. Increased recruitment of obese patients in clinical trials is needed to provide us with robust data for informed clinical decision-making.

e19503 Background: The risk of venous thromboembolic events (VTE) despite mandatory thromboprophylaxis (TPx) in patients with multiple myeloma (MM) receiving contemporary lenalidomide (Len)-based regimens is not well-defined. Methods: Medline, Embase, and CENTRAL databases were queried to identify phase 1-3 clinical trials of Len-based regimens with mandatory TPx published until April 2018. Random effects meta-analysis was performed using CMAv3 software to obtain crude, and per 100 patient-cycle incidence rate (IR). Prespecified subgroup analyses were performed to obtain IR for VTE by (1) line of treatment (newly diagnosed [ND], relapsed/refractory [RR] and maintenance [Mx] phase) and (2) different Len-based regimens. Results: We screened 1069 citations and analyzed data from 43 trials with 8696 patients, including 17 in ND, 23 in RR and 3 in Mx phase. 12 out of 43 were Phase 3 randomized controlled trials. The overall incidence of VTE in 8696 patients was 4.6% (95% CI, 3.7-5.8%), with 1.0 event (95% CI, 0.7-1.4%) per 100 patient cycles. In patients with NDMM (n = 3295), 193 (5.9%) experienced VTE with a pooled IR of 0.9 (95% CI, 0.3-2.3) per 100 patient-cycle. Among RRMM patients (n = 3981), 251 (6.3%) experienced VTE with a pooled IR of 1.0 (95% CI, 0.4-2.3) per 100 patient-cycle. The incidence of VTE was highest with the following triplet regimens: Rd + Proteasome inhibitor (PIs) and Rd + Anthracycline (Ac) [+/- Vincristine], with the latter having a high risk of VTE regardless of the treatment phase (table). With Len Mx (n = 1420), 38 (2.7%) patients had VTE, with a pooled IR of 0.2 (95% CI, 0-2.1) per 100 patient-cycle. Conclusions: Patients with MM undergoing treatment with Len-based regimens remain at risk of VTE despite current TPx strategies. The estimates of VTE IR provided by this analysis can guide clinicians in assessing treatment-related risk of VTE in this setting. [Table: see text]

Background Thromboprophylaxis is routinely used with lenalidomide‐based regimens in multiple myeloma because of a substantial risk of venous thromboembolism (VTE). However, little is known about the incidence of VTE with contemporary lenalidomide‐based regimens. The objective of the current study was to estimate the incidence of VTE despite thromboprophylaxis with currently used lenalidomide‐based regimens in patients with myeloma. Methods The Ovid MEDLINE, Embase, and Cochrane databases were queried from study inception to January 2019 for keywords to cover the following concepts: “lenalidomide,” “venous thromboembolism,” and “multiple myeloma.” Phase 1, 2, and 3 clinical trials evaluating lenalidomide‐based regimens with thromboprophylaxis were included. The pooled incidence rate of VTE was estimated using a random‐effects model. Results The search generated 1372 citations, with 51 clinical trials and 9069 patients included for analysis. The most common thromboprophylaxis agents were aspirin, low‐molecular‐weight heparin or warfarin, administered either per risk‐stratification or at investigators' discretion. The pooled incidence of VTE in trials of patients who had newly diagnosed and relapsed/refractory myeloma was 6.2% (95% CI, 5.4%‐7.1%) over median treatment durations ranging from 2 to 34 cycles, which translated into 1.2 VTE events per 100 patient‐cycles (95% CI, 0.9‐1.7 VTE events per 100 patient‐cycles). Among contemporary regimens, the risk of VTE was low with combined lenalidomide and low‐dose dexamethasone (0.2 [95% CI, 0.1‐0.6] events/100 patient‐cycles) and lenalidomide maintenance (0.0 [95% CI, 0.0‐0.7] events per 100 patient‐cycles). VTE risk was higher with combined lenalidomide and low‐dose dexamethasone plus proteasome inhibitors (1.3 [95% CI, 0.7‐2.3] events per 100 patient‐cycles). Conclusions Despite adequate thromboprophylaxis, lenalidomide‐based regimens have a substantial risk of VTE in controlled clinical trial settings. Further studies are needed on new thromboprophylaxis strategies with regimens that have a high VTE risk.

Abstract Background: Sickle cell disorder (SCD) and transfusion dependent beta-thalassemia (TDT) are inherited disorders of β-globin genes leading to ineffective erythropoiesis, hemolysis and multi-organ damage. Though allogenic hematopoietic cell transplantation (allo-HCT) in the only potentially curative therapy, lack of full HLA-matched donor, increased risk of myeloablative conditioning (MAC) regimen related toxicity, poor prognosis in older age groups (>14 years), and a high risk of infections and graft versus host disease (GVHD) culminating into a high transplant related mortality (TRM) preclude HCT as a treatment option for many patients. Gene therapy has been proposed as a relatively new treatment option for these monogenic disorders. It involves transfection of harvested CD34+ hematopoietic stem cells (HSC) with viral vector to transfer a normal beta globin gene, which are then transplanted back to the autologous donor. However, the available data on gene therapy is extremely variable. The purpose of this review is to evaluate the risks and outcomes of SCD and TDT patients undergoing gene therapy. Methods: A systematic search of databases using PubMed, Embase, Web of science, Cochrane database and Clinicaltrials.gov was performed on with no restrictions of language or time period. A total of 4312 articles were identified and after duplicates removal, 3508 articles were screened for relevance. Clinical studies reporting the most recent follow up results about the efficacy and safety of gene therapy in patients with hemoglobinopathies were considered for inclusion. Their quality assessment was done using the Cochrane tool, and bias was evaluated regarding the study selection, performance, detection, attrition and the reporting of the clinical trials. RESULTS (table-1): Only 7 articles qualified for the strict selection criteria with an N of 47: six studies were phase I trials (Cavazzana, M. et al 2010, Boulad, F. et al 2013, Marktel, S. et al 2017, Kwiatkowski, J. et al 2017, Cavazzana, M. et al 2017, Kanter, J. et al 2017) and one was a phase III trial (Walters, M. et al 2017). Thirty five patients (74.4%) had TDT while 12 patients (25.5%) had SCD. All these patients did not have a suitable HLA-matched HCT donor. The length of follow up was heterogeneous owing to the step wise enrollment of participants and ranged from 2-36 months. Except for 4 cases, the age of included population was >13 years. Lentivirus BB305 encoding the HbAT87Q globin gene was used for gene delivery in 81% patients (n=38). The normal beta globin gene was transduced in remaining 9 TDT cases and it involved transduction using TNS 9.3.55 vector in two cases and with GLOBE lentivirus in 7 cases. MAC with busulfan was used in 81% cases (n=38), while treosulfan+thiotepa was used in 7 cases. The non-myeloablative (NMA) conditioning with busulfan was used in only 2 cases (both TDT). Bone marrow harvest was the source of HSCs in all SCD cases. Except for 3 SCD cases in HGB-204 trial and 3 TDT cases in HGB-207 which measured the potential improvement in outcome by an increase in DP-VCN, the range of drug vector copy number (DP-VCN) was 0.3-1.5 copies per diploid genome. The total hemoglobin (HB) level at last follow up was reported for 62% cases (n=29) and it was >8.8 g/dl in all cases. Twenty-one (60%) thalassemia cases were in a transfusion (Tx) free state at last follow up, including the 7 cases (20%) who developed a complete independence from transfusions. No such Tx-free state was noted in SCD cases although they developed a reduction in the Tx-requirement and 75% SCD cases (n=9) had a 30-100% reduction in the frequency of VOCs. All the cases were alive at their recent follow up with manageable toxicity form conditioning. Acceptable safety until the median follow-up from the 7 trials was established in all cases, with no reported development of post-treatment leukemia or new malignancy in these trials. DISCUSSION: In this largest series of gene therapy for the treatment of hemoglobinopathies (to our knowledge), we find it to be clinically effective in terms of reduction in transfusion needs; data to suggest an improved OS and disease free survival is promising, however long term data is awaited. Gene therapy appears to bypass the limitations faced by allo-HCT especially a high early TRM. Randomized trials reporting the efficacy and safety outcomes with longer follow ups are urgently required. Disclosures No relevant conflicts of interest to declare.

6596 Background: Several previous systematic reviews and meta-analyses have attempted to summarize toxicity of Immune checkpoint inhibitors (ICIs). However, very soon after each one of these reviews has been published, it became outdated. ICIs are currently used in 14 different cancers and data is rapidly evolving from new clinical trials. A living Systematic review, which is defined as a systematic review that is continually updated to incorporate relevant new evidence as it becomes available, is necessary in this situations. Therefore, we performed an updated systematic review and a meta-analysis which will serve as a foundation of a living Systematic review. Methods: MEDLINE, EMBASE and Cochrane were searched to identify phase 2 and 3 RCTs of PD-1/PD-L1 ICIs. Included studies compared either immunotherapy alone or combination with existing standard of care treatment and reported data for AE’s of interest. DerSimonian-Laird random effects Meta-Analysis was performed to derive pooled odds Ratio (OR) estimates for AE’s of interest. An infrastructure of a living systematic review is being developed and it includes monthly literature searches, cumulative meta-analysis and an online reporting platform. Results: We screened 6746 studies and 31 phase 3 and 2 phase 2 RCTs (n = 21,421) were included in the analysis. 22 RCTs used PD-1/PD-L1 ICIs as a single agent and 11 as a combination therapy. Selected toxicity estimates are summarized in a table. Conclusions: The meta-analysis updates previously published toxicity estimates and provides additional information about the risk of toxicities in single versus combination regimens. We have initiated the first living systematic review in oncology that will be continuously updated, incorporating relevant new evidence as it becomes available, and will provide accurate and up to date toxicity estimates to support clinical decision making. [Table: see text]

e13119 Background: Tyrosine kinase inhibitors (TKIs) are routinely used in the treatment of metastatic RCC and Sunitinib is approved for the use in adjuvant setting. Arterial thromboembolic events (ATEs) have been described with these agents, although the overall risk remains unclear. We did a systematic review and meta-analysis to determine the incidence associated with the use of FDA approved TKIs used in treatment of RCC. Methods: PubMed, EMBASE, Cochrane Central and Scopus databases were searched to identify phase 2 and 3 RCTs of TKI therapy in RCC. Trials were included if they reported ATEs defined as arterial thrombosis, cerebral ischemia or infarction, myocardial ischemia and myocardial infarction. The DerSimonian-Laird random effects meta-analysis was performed using CMAv3 software to derive pooled estimates of incidence rates of ATEs with its 95% confidence interval (CI). I2 statistic was computed to express the percentage of the total observed variability due to study heterogeneity. Risk for bias was assessed using the Cochrane Collaboration’s tool. Results: 1755 studies retrieved in the initial search, and 13 phase 2 and 3 clinical trials (n = 4983) were included in the quantitative analysis. The trials had open label design which can potentially result in bias. Risk of bias was low in all other domains. TKIs used for the treatment of RCC included sunitinib (n = 2632), sorafenib (n = 981), cabozantinib (n = 78), pazopanib (n = 844), axitinib (n = 189) and tivozanib (n = 259). The incidence of ATEs with the use of TKIs was 2.9% (95% CI: 2-3%). Cabozantinib was associated with the highest rate of ATEs (11.5%, 95% CI: 6-21%), followed by sunitinib (2.6%, 95% CI:2-3%) pazopanib (2.6%, 95% CI:2-4%) and axitinib (2.1%, 95% CI: 1-6%). The TKI with lowest event rate of ATE was tivozanib (0.8%, 95% CI:0.2-3%). Conclusions: The use of TKIs is associated with increased risk of developing ATEs. Clinicians should be aware of the possibility of increased ATEs and counsel the patients about this increased risk to enhance the process of informed decision making.

e13096 Background: Several studies have reported the association between atrial fibrillation (AF) and malignant cancer. Recently, results from a large cohort within the Women’s Health Study showed increased incident risk of breast, colon and lung cancer in patients with AF. Therefore, we performed a systematic review to assess the available evidence and a meta-analysis to define the strength of this association. Methods: MEDLINE, Cochrane and Scopus databases were searched for all prospective studies that reported the association between AF and presence of cancer. The HR for incident risk of common cancers was recorded (Breast, Lung, Colorectal) in patients with and without AF. Lung cancer was excluded because the data required for the analysis was not consistently reported. The DerSimonian-Laird random effects meta-analysis was performed to derive pooled Hazard Ratio (HR) estimates for incident risk of colorectal and breast cancer in patients with AF. Q-test was used to assess between-study heterogeneity; I2 statistic was computed to expresses the percentage of the total observed variability due to study heterogeneity. Results: A total of 390,479 participants in 3 prospective studies were included in the analysis. Mean age of participants was 66.3 ± 6.5 with mean follow up for 12.6 years. Patients with atrial fibrillation had 27% more risk of developing colorectal cancer [HR 1.27 (1.07-1.51) p < 0.005, I2= 73%] and 14% more risk of developing breast cancer [HR 1.14 (1.03-1.26) p = 0.01, I2= 37%] as compared to those without atrial fibrillation. Applying these hazard ratios to age adjusted yearly incidence ratios from 2000-2015, one in 5824 new onset AF cases will develop CRC and one in 7474 new onset AF cases will develop breast cancer. Conclusions: There is small but statistically significant increase in risk of subsequent diagnosis of colorectal or breast cancer diagnosis in patients with AF. Shared risk factors such as old age or systemic disease processes may explain this association. While the results of this analysis raise interesting questions for future search, these results should not be used as basis to initiate cancer screening for an occult cancer in a patient with AF.

e12545 Background: Palbociclib(P), Ribociclib(R) and Abemaciclib(A) in combination with Endocrine therapy (ET) have demonstrated progression free survival (PFS) in patients with metastatic hormone receptor positive, HER2-negative breast cancer as compared to ET alone. In the absence of head to head clinical trials and to provide clinical guidance, we performed an indirect comparison for P, R and A using network Meta-Analysis (NMA). Methods: MEDLINE, EMBASE and the Cochrane Library were searched to identify RCTs comparing P+ET, R+ET, A+ ET vs ET alone. NMA for PFS and toxicity endpoints was conducted using a multivariate random-effects meta-regression, using a consistency model, as described by White and colleagues. We used a frequentist approach and provided a point estimate from the network and a 95% CI from the frequency distribution of the estimate. We also estimated the relative ranking of the different treatments for each outcome using the distribution of the ranking probabilities and the surface under the cumulative ranking curves (SUCRA). Risk of bias was assessed using Cochrane Collaboration tool. Results: 8 RCTs were identified including 4580 patients. Risk of bias was low. 5 RCTs tested CDK 4/6 inhibitors in endocrine naive and 2 in the refractory setting, while MONALESSA-3 included patients both with endocrine naive and endocrine resistant disease. In the endocrine naïve patients, PFS for P was similar when compared indirectly with R (HR, 0.95, 95% CI 0.67-1.35) or A (HR, 1.00, 95% CI 0.62-1.61). Similarly, indirect comparison between R vs A did not show any statistical significant (HR, 0.95, 95% CI 0.62-1.45). In endocrine refractory patients, P showed no difference when compared indirectly to A (HR 1.12, 95% CI 0.67-1.87) or R (HR 0.98, 95% CI 0.52-1.86). R vs A did not show any statistically significant PFS either (HR, 1.14, 95% CI 1.61-4.51). P was ranked first in terms of PFS in frontline setting (SUCRA of 70.5) while R ranked first in the refractory setting (SUCRA of 39.5). QT prolongation was reported for R only. P caused more neutropenia while A caused more fatigue, anemia and diarrhea, although the results were not statistically significant. Conclusions: The efficacy of using either palbociclib, ribociclib or abemaciclib in combination with ET was similar in terms of PFS in either endocrine naïve or resistant disease. Palbociclib causes more neutropenia, abemaciclib causes more fatigue, anemia and diarrhea while ribociclib causes QT prolongation.

Background: Poly (ADP-ribose) polymerases (PARPs) are a highly conserved family of enzymes whose main function is to preserve genomic integrity following DNA damage. PARP inhibitors (PARPi) are increasingly used in cancers with deficiencies in homologous recombination. Clinical trials in breast and ovarian cancers have led to several FDA approvals in recent years, and their use in clinical practice is continuing to rise. It is thus necessary to assess their adverse event (AE) profile. Method: Literature search was performed using Ovid MEDLINE, EMBASE, CENTRAL, and Scopus (inception through October 26, 2018). Eligible studies were phase 3, randomized, controlled trials that compared single agent PARPi to placebo or standard treatment. Number of patients treated and AEs reported were recorded. Observed incidence of AE was reported with 95% CI. Heterogeneity was evaluated using Cochran Q statistic and I2 statistics quantified the proportion of heterogeneity not due to chance. Results: Databases revealed 869 references. Of these, 6 were eligible: 2 in breast cancer (OlympiAD, EMBRACA) and 4 in ovarian cancer (NOVA, ARIEL3, SOLO1, SOLO2). PARPi included niraparib (NOVA), olaparib (OlympiAD, SOLO1, SOLO2), rucaparib (ARIEL3), and talazoparib (EMBRACA). Of 1,685 patients who received PARPi, incidence of any AE, regardless of grade, was 98.5% (95% CI, 97.2–99.2%). Common AEs were: nausea (incidence rate, 68.9% and 95% CI, 58.7%–77.5%), fatigue (56.3%, 45.3%–66.8%), anemia (46.3%, 37.2%–55.8%), vomiting (33.7%, 29.5%–38.3%), neutropenia (24.7%, 15.3%–37.4%), headache (23.9%, 19.9%–28.4%), and reduced appetite (21.7%, 19.3%–24.3%). Myeloid neoplasms were rare (1.2%, 0.7%–1.9%). Incidence of grade 3 or higher AE was 44.3% (30.2%–59.5%) and often related to myelosuppression, specifically anemia (24.7%, 15.3%–37.4%), neutropenia (10.7%, 6.6%–16.9%), and thrombocytopenia (5.0%, 1.7%–14.0%). Incidence of serious AE was 24.3% (19.4%–29.9%); dose interruption occurred in 53.3% (41.2%–65.0%) and dose reduction occurred in 39.2% (23.6%–57.4%). 10% (7.4%–13.6%) of patients discontinued therapy due to AE. Death due to AE was rare; less than 1% (0.4%, 0.2%–0.8%) in all trials. Conclusion: Myelosuppression and gastrointestinal toxicities were the most commonly reported AE in 6 randomized phase 3 trials of PARPi for breast and ovarian cancers. Therapy was rarely discontinued due to AE. It remains to be seen whether these results will be reflected in clinical practice.