Novel cannabinoid receptor 1 inverse agonist CRB-913 enhances efficacy of tirzepatide, semaglutide, and liraglutidein the diet-induced obesity mouse model

OBJECTIVE

Incretin receptor agonists are now standard of care in treating obesity. Their efficacy and tolerability might be further improved by combining them with compounds that offer orthogonal mechanisms of action. The cannabinoid type 1 receptor (CB1R) is a clinically validated therapeutic target in obesity, and several experimental CB1R inverse agonists have been shown to induce weight loss.

METHODS

This study characterizes a novel CB1R inverse agonist (CRB-913) with similar preclinical potency to rimonabant but markedly reduced brain penetration. CRB-913 was tested as monotherapy and in combination with tirzepatide, semaglutide, or liraglutide in the diet-induced obesity (DIO) mouse model for body weight reduction.

RESULTS

CRB-913 demonstrated enhanced plasma exposure (3.8-fold larger area under the curvelast ) and reduced brain levels (9.5-fold lower area under the curvelast ) than rimonabant. CRB-913 monotherapy yielded a dose-dependent decrease in body weight in DIO mice reaching -22% within 18 days. In further DIO studies in combination with tirzepatide, semaglutide, or liraglutide, CRB-913 (2.5 mg/kg) resulted in -32.6%, -28.8%, and -16.8% decreases in body weight on Day 18, respectively, with concomitant improvements in body fat content, liver triglycerides, and liver fat deposits.

CONCLUSIONS

CRB-913 in combination with incretin analogues could deliver meaningful improvements over current standards of care for obesity and related conditions.

Evaluation of adjusted international normalized ratio goal in patients with HeartMate 3 left ventricular assist devices

BACKGROUND

The HeartMate3 left ventricular assist device (HM3 LVAD) has shown a low incidence of thrombosis, but bleeding risk is as high as 43%. We aim to describe the impact of lower international normalization ratio (INR) goal on clinical outcomes.

METHODS

In February 2019, our tertiary care institution lowered INR goal in HM3 patients from manufacturer recommendations to 1.8-2.2 and retrospectively analyzed the data. Two cohorts were compared: patients with lower INR goal upon implant (De novo) and those with subsequently lowered INR goal (Adjusted). The Adjusted group also served as its own historical control. Both groups continued aspirin 81 milligrams daily per manufacturer recommendations. The primary outcomes were incidences of bleed and thrombosis events within 12 months. Secondary outcomes included survival free of disabling stroke or reoperation to remove or replace the device and Rosendaal time in therapeutic range (TTR) over 12 months.

RESULTS

Thirty-one patients were evaluated for inclusion with 26 meeting criteria. Within 12 months, incidence of bleeding events was 25% and 28.6% in the De novo and Adjusted groups, respectively. Incidence of thrombotic events within 12 months was 0% in the De novo group and 7.1% in the Adjusted group. Twelve-month survival free of disabling stroke or reoperation to remove or replace the device was higher over 12 months for patients in the De novo group (91.7% vs. 78.6%). Median 12-month TTR was 36%, which was primarily attributable to subtherapeutic deviations.

CONCLUSIONS

A lower INR goal may be safe when initiated De novo following implantation of the HM3. This study informs the need for larger prospective studies.

Bedside ultrasound of the internal jugular vein to assess fluid status and right ventricular function: The POCUS-JVD study

BACKGROUND

Accurate estimation of fluid status is important in the management of heart failure patients, however, the current methods for bedside assessment can be unreliable or impractical for daily use.

METHODS

Non-ventilated patients were enrolled immediately prior to scheduled right heart catheterization (RHC). Using M-mode, IJV maximum (Dmax) and minimum (Dmin) anteroposterior diameters were measured during normal breathing, while supine. Respiratory variation in diameter (RVD) was calculated as [(Dmax - Dmin)/Dmax] in percentage. Collapsibility with sniff maneuver (COS) was assessed. Lastly, inferior vena cava (IVC) was assessed. Pulmonary artery pulsatility index (PAPi) was calculated. Data was obtained by five investigators.

RESULTS

Total 176 patients were enrolled. Mean BMI was 30.5 kg/m2, LVEF 14-69% (range), 38% with LVEF ≤35%. The POCUS of IJV could be performed in all patients in <5 min. Increasing RAP demonstrated progressive increase in IJV and IVC diameters. For high filling pressure (RAP ≥10 mmHg), an IJV Dmax ≥1.2 cm or IJV-RVD < 30% had specificity >70%. Combining the POCUS of IJV to physical examination improved the combined specificity to 97% for RAP ≥10 mmHg. Conversely, a finding of IJV-COS was 88% specific for normal RAP (<10 mmHg). An IJV-RVD <15% is suggested as a cutoff for RAP ≥15 mmHg. The performance of IJV POCUS was comparable to IVC. For RV function assessment, IJV-RVD < 30% had 76% sensitivity and 73% specificity for PAPi <3, while IJV-COS was 80% specific for PAPi ≥3.

CONCLUSION

POCUS of IJV is an easy to perform, specific and reliable method for volume status estimation in daily practice. An IJV-RVD < 30% is suggested for estimation of RAP ≥10 mmHg and PAPi <3.

Covid-19 positive donor utilization for heart transplantation: The new frontier for donor pool expansion

BACKGROUND

Hearts from COVID-19 positive donors (CPD) are being utilized for heart transplantation by some centers; however, this is in the setting of the lack of guidelines or robust evidence. The paucity of evidence is reflected in the recent Organ Procurement and Transplantation Network (OPTN) communication describing CPD utilization as an "unknown risk."

METHODS AND RESULTS

We analyzed the UNOS database for adult heart transplants performed between January 2021 to December 2022, and CPD comprised of a significant percentage of donors, being used in >10% of recipients in some UNOS regions. Between July 2022 and December 2022, 7.9% of heart transplants were with CPD, and in the same period Hepatitis C positive donors accounted for 7.1% and donation after circulatory death (DCD) accounted for 10.3%.

CONCLUSION

If the transplant community comes up with a standardized approach and guidance in using CPD hearts, this could provide an effective donor pool expansion strategy.

Abstract 706: CRB-601, an avβ8 blocking antibody, prevents activation of TGFb and exhibits anti-tumor activity associated with immune cell remodeling of the tumor microenvironment

Background: Transforming growth factor-beta (TGFβ) is a promising immunotherapeutic target in cancer given the association of increased TGFβ signaling in the tumor microenvironment (TME) with immune cell exclusion, and poor clinical outcomes. TGFβ is expressed as a latent form (L-TGFβ) and presented on cell surfaces by L-TGFβ binding proteins (e.g. GARP and LRRC33) as part of the large latent complex, whereupon it is activated by binding to integrins, including integrin αvβ8. Corbus Pharmaceuticals is developing a humanized monoclonal antibody, CRB-601, that binds with high specificity and affinity to αvβ8 and blocks the critical interaction with L-TGFβ that promotes an immune excluded phenotype.

Methods: Tumor growth was evaluated in mice bearing orthotopically implanted murine breast cancer EMT6 or colon cancer MC38 and treated with CRB-601, anti-PD1 antibody, or the combination. αvβ8 receptor occupancy (RO) was measured ex vivo in dissociated tumors by flow cytometry (FC). Tumor-infiltrating immune cell populations were characterized by FC, and pSMAD2/3 was measured by Western blot.

Results: CRB-601 exhibited dose dependent tumor growth inhibition (TGI) in the EMT6 tumor model. TGI activity at 0.3mg/kg biw dose was 22.0 ± 3.8 %, and reached maximum antitumor activity at a dose between 3 mg/kg biw (41.3 ± 8.4%) and 10 mg/kg biw (48.4 ± 8.4 %). TGI was significantly augmented in combination with anti-PD1. These effects were associated with changes in TME immune cell populations, as characterized by marked increases in infiltrating T cells, NK cells and M1 polarized macrophages, thereby converting immune excluded EMT6 tumors to immune cell-inflamed tumors. Efficacy correlated with cell surface αvβ8 occupancy by CRB-601 as measured by FC in CD45- EMT6 tumor cells, increasing with CRB-601 dose from 5.5 ± 0.4% at 0.3 mg/kg to a maximum of 75.6 ± 23.8% at 10 mg/kg. CRB-601 treatment downregulated phosphorylation of SMAD proteins pSMAD2 and pSMAD3, consistent with blockade of the canonical TGFβ signaling pathway. When combined with anti-PD1, CRB-601 induced a T-cell memory response. In the MC38 model, mice cured by the combination treatment survived long term (&gt;40 mo). Naïve mice adoptively transferred with splenocytes from these mice gained tumor-specific antitumor activity and rejected MC38 tumor cell inoculation. These splenocytes contained an immune cell population of IFN-γ producing cytotoxic T cells with a repertoire consistent with MC38 antigen recognition.

Conclusions: CRB-601 is a potent and selective integrin αvβ8 blocking monoclonal antibody that can overcome tumor immune exclusion and enhance the activity of immune checkpoint inhibitors. CRB-601 antitumor activity correlated to increased αvβ8 RO and downregulation of TGFβ signaling. Investigational New Drug (IND) enabling studies are in progress.

Citation Format: Daqing Wang, Vaishali Shinde, Maneesh Singh, Rachael Brake, Andrew Kolodziej. CRB-601, an avβ8 blocking antibody, prevents activation of TGFb and exhibits anti-tumor activity associated with immune cell remodeling of the tumor microenvironment [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 706.

Patterns and outcomes of COVID-19 donor utilization for heart transplant

BACKGROUND

The outcomes following COVID-19 positive donor (CPD) utilization for heart transplant are unknown.

METHODS

UNOS database was analyzed for heart transplants performed from the declaration of COVID-19 pandemic until September 30, 2022.

RESULT

Since the onset of pandemic, there were 9876 heart transplants reported. COVID-19 antigen or NAT results were available in 7698 adult donors within 14 days of donation, of which 177 (2.3%) were positive. There was no difference in recipient demographics, including age (COVID positive donor vs. negative: 55 vs. 56 years, p = .2) and BMI. Listing status 1 and 2 were similar in both groups (7% vs. 10% and 48% vs. 49% respectively, p = .4). Durable and temporary mechanical support were similar in both groups pre-transplant (both groups 33%, p = .9). There was no difference in days on the waitlist (median 31 days, p = .9). Simultaneous renal transplant rates were similar (11% vs. 10%, p = .9). CPD utilization has increased since the onset of the pandemic, and the adoption is present across most UNOS regions. Post-transplant, there was no difference in length of stay (median 16 vs. 17 days, p = .9) and acute rejection episodes prior to discharge (3% vs. 8%, p = .1). In survival analysis of 90-day follow up, number of deaths reported were comparable (5% in both groups, p = .9) Follow-up LVEF was comparable (62% vs. 60%, p = .4).

CONCLUSION

Active COVID-19 infection in donors did not affect survival or rejection rates in the short-term post-heart transplant.

Lenabasum Reduces Porphyromonas gingivalis-Driven Inflammation

The aim of this study was to evaluate the potential anti-inflammatory and anti-resorptive effects of lenabasum in the context of Porphyromonas gingivalis (Pg)-induced inflammation. Lenabasum or ajulemic acid (1',1'-dimethylheptyl-THC-11-oic-acid), a synthetic analog of THC-11-oic acid, has already demonstrated anti-inflammatory properties for the treatment of several inflammatory diseases. In vitro, the cytocompatibility of lenabasum was evaluated in human oral epithelial cells (EC), oral fibroblasts and osteoblasts by metabolic activity assay. The effect of lenabasum (5 µM) treatment of Pg-LPS- and P. gingivalis-infected EC on the pro- and anti-inflammatory markers was studied through RTqPCR. In vivo, lenabasum was injected subcutaneously in a P. gingivalis-induced calvarial abscess mouse model to assess its pro-healing effect. Concentrations of lenabasum up to 5 µM were cytocompatible in all cell types. Treatment of Pg-LPS and Pg-infected EC with lenabasum (5 µM; 6 h) reduced the gene expression of TNF-α, COX-2, NF-κB, and RANKL, whereas it increased the expression of IL-10 and resolvin E1 receptor respectively (p < 0.05). In vivo, the Pg-elicited inflammatory lesions' clinical size was significantly reduced by lenabasum injection (30 µM) vs untreated controls (45%) (p < 0.05). Histomorphometric analysis exhibited improved quantity and quality of bone (with reduced lacunae) and significantly reduced calvarial soft tissue inflammatory score in mice treated with lenabasum (p < 0.05). Tartrate-resistant acid phosphatase activity assay (TRAP) also demonstrated decreased osteoclastic activity in the treatment group compared to that in the controls. Lenabasum showed promising anti-inflammatory and pro-resolutive properties in the management of Pg-elicited inflammation, and thus, its potential as adjuvant periodontal treatment should be further investigated.

Abstract 5611: CRB-601: A highly potent and selective integrin αvβ8 blocking antibody with anti-tumoral properties

TGFβ is a secreted protein produced by tumors that promotes cancer progression primarily via the suppression of both the innate and adaptive immune systems. This makes TGFβ a promising immunotherapeutic target in cancer. It is ubiquitously expressed in a latent (L-TGFβ) form and the latent form has been shown to promote an immune suppressive phenotype within the tumor microenvironment. Integrin αvβ8 specifically binds to L-TGFβ. This interaction is essential for the activation of L-TGFβ-mediated signals in a variety of immune cell types. Interestingly, it has been recently shown that integrin αvβ8-mediated TGFβ activation can active directly through L-TGFβ and does not require the release of active TGFβ (1). Inhibition of integrin αvβ8-mediated TGFβ activation has been shown to block immunosuppressive regulatory T cell differentiation and enhance the recruitment of cytotoxic T cells into the tumor microenvironment (2). Here, we demonstrate by Surface Plasmon Resonance (SPR) that CRB-601, our selective inhibitor of integrin αvβ8 monoclonal antibody candidate, has a high affinity and specificity for the integrin αvβ8 complex. Moreover, in comparison to competitor molecules, such as ADWA-11, CRB-601 substantially blocks TGFβ activation in a reporter cell assay system. Additionally, using syngeneic mouse models, we evaluated the anti-tumoral properties of CRB-601 as a monotherapy, as well as in combination with immune checkpoints therapies. Findings from this study highlight the importance of integrin αvβ8 blockade in mediating the immune landscape within the tumor and leads to an enhanced response to immune checkpoint therapy. In conclusion, CRB-601 is a potent and selective integrin αvβ8 blocking monoclonal antibody that enhances the activity of immune checkpoint inhibitors in vivo and holds promise as a potential combination partner for immunotherapy. Investigational New Drug (IND) enabling studies are currently underway.

References: 1: Campbell MG. et al. (2020) Cyro-EM reveals integrin-mediated TGF-β activation without release from latent TGF-β. Cell 180, 490-501. 2: Mariathasan S. et al. (2018) TGFbeta attenuates tumour response to PD-L1 blockade by contributing to exclusion of T cells. Nature 554, 544-48.

Citation Format: Andrew Kolodziej, Eric Haines, Richard Morse, Eugene Zhukovsky. CRB-601: A highly potent and selective integrin αvβ8 blocking antibody with anti-tumoral properties [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5611.

Outcomes of Heart Failure in COVID-19 Patients: An Appalachian Experience

Background

The Southeastern rural areas of the USA have a higher prevalence of heart failure (HF). Coronavirus disease 2019 (COVID-19) infection is associated with poor outcomes in patients with HF. Our study aimed to compare the outcomes of hospitalized HF patients with and without COVID-19 infection specifically in rural parts of the USA.

Methods

We conducted a retrospective cohort study of HF patients with and without COVID-19 hospitalized in Southeastern rural parts of the USA by using the Appalachian Regional Healthcare System. Analyses were stratified by waves from April 1, 2020 to May 31, 2021, and from June 1, 2021 to October 19, 2021.

Results

Of the 14,379 patients hospitalized with HF, 6% had concomitant COVID-19 infection. We found that HF patients with COVID-19 had higher mortality rate compared to those without COVID-19 (21.8% versus 3.8%, respectively, P < 0.01). Additionally, hospital resource utilization was significantly higher in HF patients with COVID-19 compared to HF patients without COVID-19 with intensive care unit (ICU) utilization of 21.6% versus 13.8%, P < 0.01, mechanical ventilation use of 17.3% versus 6.2%, P < 0.01, and vasopressor/inotrope use of 16.8% versus 7.9%, P < 0.01. A lower percentage of those with COVID-19 were discharged home compared to those without a COVID-19 diagnosis (63.4% versus 72.0%, respectively). There was a six-fold greater odds of dying in the first wave and seven-fold greater odds of dying in the second wave.

Conclusions

Our study confirms previous findings of poor outcome in HF patients with COVID-19. There is a need for review of healthcare resources in rural hospitals which already face numerous healthcare challenges.

CTLA-4 and CD28 genes' polymorphisms and renal cell carcinoma susceptibility in the Polish population--a prospective study

Polymorphisms in co-stimulatory genes are associated with susceptibility to several malignances such as breast cancer, cervical cancer and chronic lymphocytic leukemia, but have been scarcely investigated in renal cell cancer (RCC). A total of 310 RCC patients and 518 controls were genotyped for single-nucleotide polymorphisms (SNPs) in the CTLA-4 and CD28 genes: CTLA-4c.49A>G (rs231775), CTLA-4g.319C>T (rs5742909), CTLA-4g.*6230G>A (CT60; rs3087243), CTLA-4g.*10223G>T (Jo31; rs11571302), CD28c.17+3T>C (rs3116496) and CD28c.-1042G>A (rs3181098). The distribution of the alleles, genotypes and haplotypes in the CTLA-4 and CD28 genes were similar in the RCC patients and in the controls. However, among the patients with a clear cell RCC (CCRCC), the G allele carriers of CT60 and Jo31 SNPs were overrepresented, and the overrepresentation became significant for the carriers of CT60[G] allele in CCRCC patients with necrosis in the primary tumor (P = 0.046). The CTLA-4c.49A>G[A]/CTLA-4g.319C>T[C]/CT60[A]/Jo31[T]/CD28c.17+3T>C[T]/ CD28c.1042G>A[G] haplotype was associated with an approximately threefold increased risk of primary tumor necrosis in CCRCC patients (P corrected = 0.0000007) and with the advanced stage of disease (IV) (P corrected = 0.001). When stratified by gender, CD28c.-1042G>A[GG] genotype was more frequent in the female CCRCC patients compared with healthy women (P = 0.042). Polymorphisms in the CTLA-4 and CD28 genes, in particular considered together as haplotypes, were associated with increased risk of CCRCC, especially with necrosis and with the advanced stage of disease. The CD28c.-1042G>A SNP modulates the risk of CCRCC in women. These findings indicate that the associations of the CTLA-4 and CD28 polymorphisms with the risk of renal cancer are worth further study in a larger group of patients.

Treatment of single peripheral pulmonary emboli: patient outcomes and factors associated with decision to treat

BACKGROUND

Increasing use of computed tomography pulmonary angiography together with higher-resolution scanners has increased the detection of peripheral filling defects. Physicians face the dilemma of whether to treat patients with these findings, especially single defects. The aims of this study were to compare the outcomes of treated and untreated patients with single peripheral filling defects (SPFD) and identify factors associated with treatment.

METHODS

All cases with SPFDs over 66 months in a single institution were identified. Patient and treatment information were abstracted and data on 90-day mortality and postdischarge venous thromboembolism (VTE) were collected.

RESULTS

A total of 4906 computed tomography pulmonary angiograms were reviewed. A SPFD was identified in 3.1% (n = 153). Of the 153 patients, 134 met criteria for study inclusion. In 99 of 134 (73.9%) studies, the defect was called a pulmonary embolus (PE) by the initial radiologist. Treatment was administered to 61 of 134 (45.5%) patients; 5 patients died in each group. Postdischarge VTE occurred in 3 treated and 2 untreated patients. In 52 of 153 cases, an additional study was performed. None of the patients with normal ventilation perfusion scan and compression ultrasound received treatment. Immobility (odds ratio [OR]: 3.90, 95% confidence interval [CI]: 1.45-10.60), previous VTE (OR: 3.72, 95% CI: 1.18-11.70), and determination of PE by the radiologist (OR: 24.68, 95% CI: 5.40-112.90) were associated with treatment.

CONCLUSIONS

There was no difference in 90-day mortality or recurrence between treated and untreated patients. The most influential factor associated with treatment was the radiologist's interpretation. When secondary lung imaging studies were negative, no patient received treatment.

A lysine walk to high relaxivity collagen-targeted MRI contrast agents

A strategy for preparing peptide-based magnetic resonance contrast agents with multiple gadolinium chelates is described.

In vivo molecular imaging of acute and subacute thrombosis using a fibrin-binding magnetic resonance imaging contrast agent

BACKGROUND

Plaque rupture with subsequent thrombosis is recognized as the underlying pathophysiology of most acute coronary syndromes and stroke. Thus, direct thrombus visualization may be beneficial for both diagnosis and guidance of therapy. We sought to test the feasibility of direct imaging of acute and subacute thrombosis using MRI together with a novel fibrin-binding gadolinium-labeled peptide, EP-1873, in an experimental animal model of plaque rupture and thrombosis.

METHODS AND RESULTS

Fifteen male New Zealand White rabbits (weight, approximately 3.5 kg) were made atherosclerotic by feeding a high-cholesterol diet after endothelial aortic injury. Plaque rupture was then induced with the use of Russell's viper venom (RVV) and histamine. Subsequently, MRI of the subrenal aorta was performed before RVV, after RVV, and after EP-1873. Histology was performed on regions suggested by MRI to contain thrombus. Nine rabbits (60%) developed plaque rupture and thrombus, including 25 thrombi visually apparent on MRI as "hot spots" after injection of EP-1873. Histological correlation confirmed all 25 thrombi (100%), with no thrombi seen in the other regions of the aorta. In the remaining 6 rabbits (control) without plaque rupture, no thrombus was observed on the MR images or on histology.

CONCLUSIONS

We demonstrate the feasibility of in vivo "molecular" MRI for the detection of acute and subacute thrombosis using a novel fibrin-binding MRI contrast agent in an animal model of atherosclerosis and acute/subacute thrombosis. Potential clinical applications include thrombus detection in acute coronary syndromes and stroke.

Treatment of high-risk superficial bladder cancer with maintenance bacille Calmette-Guérin therapy: preliminary results

OBJECTIVE

To evaluate, in a prospective study, the effects and results of maintenance therapy with bacille Calmette-Guérin (BCG) in treating patients with high-risk superficial bladder cancer.

PATIENTS AND METHODS

In all, 155 patients were enrolled in a randomized study of transurethral resection alone (53) or combined with intravesical BCG (102) as a treatment for superficial bladder cancer. BCG was administered for six consecutive weeks followed by three weekly instillations in months 3, 6, 12, 18, 24, 30 and 36 after resection. Recurrence, progression, prognostic factors and side-effects were assessed and analysed.

RESULTS

After a median (range) follow-up of 23 (6-42) months, 83 of the 102 patients treated with BCG (81%) were disease-free, compared with 24 of the 53 treated with resection alone (45%). There was also a significant difference in tumour progression and time to progression between the trial arms. The disease progressed in eight patients (8%) treated with BCG and in 12 (23%) of those treated by resection alone. Independent risk factors for progression were DNA ploidy status and stage. Only the completion of treatment was predictive of outcome (risk of recurrence) for patients treated with BCG.

CONCLUSION

Maintenance BCG therapy was better than resection alone in reducing the incidence of recurrence and progression in patients with high-risk superficial bladder cancer.