CRISPR-Cas9 In Vivo Gene Editing of KLKB1 for Hereditary Angioedema

BACKGROUND

Hereditary angioedema is a rare genetic disease that leads to severe and unpredictable swelling attacks. NTLA-2002 is an in vivo gene-editing therapy based on clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9. NTLA-2002 targets the gene encoding kallikrein B1 (KLKB1), with the goal of lifelong control of angioedema attacks after a single dose.

METHODS

In this phase 1 dose-escalation portion of a combined phase 1-2 trial of NTLA-2002 in adults with hereditary angioedema, we administered NTLA-2002 at a single dose of 25 mg, 50 mg, or 75 mg. The primary end points were the safety and side-effect profile of NTLA-2002 therapy. Secondary and exploratory end points included pharmacokinetics, pharmacodynamics, and clinical efficacy determined on the basis of investigator-confirmed angioedema attacks.

RESULTS

Three patients received 25 mg of NTLA-2002, four received 50 mg, and three received 75 mg. At all dose levels, the most common adverse events were infusion-related reactions and fatigue. No dose-limiting toxic effects, serious adverse events, grade 3 or higher adverse events, or clinically important laboratory findings were observed after the administration of NTLA-2002. Dose-dependent reductions in the total plasma kallikrein protein level were observed between baseline and the latest assessment, with a mean percentage change of -67% in the 25-mg group, -84% in the 50-mg group, and -95% in the 75-mg group. The mean percentage change in the number of angioedema attacks per month between baseline and weeks 1 through 16 (primary observation period) was -91% in the 25-mg group, -97% in the 50-mg group, and -80% in the 75-mg group. Among all the patients, the mean percentage change in the number of angioedema attacks per month from baseline through the latest assessment was -95%.

CONCLUSIONS

In this small study, a single dose of NTLA-2002 led to robust, dose-dependent, and durable reductions in total plasma kallikrein levels, and no severe adverse events were observed. In exploratory analyses, reductions in the number of angioedema attacks per month were observed at all dose levels. (Funded by Intellia Therapeutics; ClinicalTrials.gov number, NCT05120830.).

Clinical Pharmacology and Translational Considerations in the Development of CRISPR-Based Therapies

Genome editing holds the potential for curative treatments of human disease, however, clinical realization has proven to be a challenging journey with incremental progress made up until recently. Over the last decade, advances in clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) systems have provided the necessary breakthrough for genome editing in the clinic. The progress of investigational CRISPR therapies from bench to bedside reflects the culmination of multiple advances occurring in parallel, several of which intersect with clinical pharmacology and translation. Directing the CRISPR therapy to the intended site of action has necessitated novel delivery platforms, and this has resulted in special considerations for the complete characterization of distribution, metabolism, and excretion, as well as immunogenicity. Once at the site of action, CRISPR therapies aim to make permanent alterations to the genome and achieve therapeutically relevant effects with a single dose. This fundamental aspect of the mechanism of action for CRISPR therapies results in new considerations for clinical translation and dose selection. Early advances in model-informed development of CRISPR therapies have incorporated key facets of the mechanism of action and have captured hallmark features of clinical pharmacokinetics and pharmacodynamics from phase I investigations. Given the recent emergence of CRISPR therapies in clinical development, the landscape continues to evolve rapidly with ample opportunity for continued innovation. Here, we provide a snapshot of selected topics in clinical pharmacology and translation that has supported the advance of systemically administered in vivo and ex vivo CRISPR-based investigational therapies in the clinic.

Isotope signature and elemental characteristics of subsurface formations around deep-laying coal seams probed by means of atomic and nuclear-based techniques

A systematic investigation on the isotopic and elemental signature, for both stable and radioactive elements, and mineral contents was performed to examine the characteristics of subsurface formations collected at different depths between 3.962 km and 4.115 km around deep-laying coal seams located under the Marmarica plateau in Egypt. Concentrations of major and minor oxides (Na₂O, MgO, Al₂O₃, SiO₂, SO₃, K₂O, CaO, TiO₂, MnO, ΣFeO + Fe₂O₃, SrO, ZrO₂, and BaO) were determined by X-ray fluorescence and dependencies among these concentrations revealed the type and sort of the formations. Organic contents were determined by Fourier Transform infrared spectroscopy to investigate the variation of the CO/CC bonding ratio with depth. Rare earth elements (REE), specifically Y, Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu were determined by inductively coupled plasma mass spectrometry while actinoids were detected by the radioactive decay of its daughter nuclei. The results showed a high trapping of REE elements and actinoids in layers above the coal seams which indicates the occurrence of aqueous flow followed by possible sorption in these layers. The mobility of the fluid was investigated using the process radioactive decay series between Ra226 and Ac228 from one side and their daughters from the other side.

Efficacy and safety of tisagenlecleucel (Tisa-cel) in adult patients (Pts) with relapsed/refractory follicular lymphoma (r/r FL): Primary analysis of the phase 2 Elara trial

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Background: Most pts with r/r FL experience multiple relapses and progressively worse clinical outcomes with each line of therapy, underlining a need for novel therapies. Tisa-cel has demonstrated durable responses and manageable safety in adult pts with r/r diffuse large B-cell lymphoma. Here we report the primary analysis of ELARA, an international, single-arm phase 2 trial of tisa-cel in adult pts with r/r FL. Methods: Eligible pts (≥18 y) had r/r FL (grades [Gr] 1-3A) after ≥2 lines of therapy or had failed autologous stem cell transplant. Bridging therapy was permitted followed by disease assessment prior to tisa-cel infusion. Pts received tisa-cel (0.6-6×108 CAR+ viable T cells) after lymphodepleting chemotherapy. The primary endpoint was complete response rate (CRR) by central review per Lugano 2014 criteria. Secondary endpoints included overall response rate (ORR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), safety, and cellular kinetics. Predefined primary analysis occurred when ≥90 treated pts had ≥6 mo of follow-up. Results: As of September 28, 2020, 98 pts were enrolled and 97 received tisa-cel (median follow-up, 10.6 mo). At study entry, median age among treated pts was 57 y (range, 29-73), 85% had stage III-IV disease, 60% had a FLIPI score ≥3, 65% had bulky disease, and 42% had LDH > upper limit of normal. The median number of prior therapies was 4 (range, 2-13); 78% of pts were refractory to their last treatment (76% to any ≥2 prior regimens) and 60% progressed within 2 y of initial anti-CD20–containing treatment. Of 94 pts evaluable for efficacy, the CRR was 66% (95% CI, 56-75) and the ORR was 86% (95% CI, 78-92). CRRs/ORRs were comparable among key high-risk subgroups. Estimated DOR (CR) and PFS rates at 6 mo were 94% (95% CI, 82-98) and 76% (95% CI, 65-84), respectively. Of 97 pts evaluable for safety, 65% experienced Gr ≥3 adverse events within 8 weeks post-infusion, most commonly neutropenia (28%) and anemia (13%). Any-grade cytokine release syndrome (per Lee scale) occurred in 49% of pts (Gr ≥3, 0%). Any-grade neurological events (per CTCAE v4.03) occurred in 9% of pts (Gr 3, 0%; Gr 4, 1 pt and recovered). Three pts died from progressive disease. Cellular kinetic parameters for tisa-cel were estimated using transgene levels (by qPCR) in peripheral blood. Cmax and AUC0-28d were similar between responders (CR or partial response) and non-responders (stable or progressive disease). Maximum transgene levels were reached by a median of 10 days in responders and 12.9 days in non-responders; transgene persistence was detected up to 370 days and 187 days, respectively. Conclusions: These data demonstrate the efficacy and acceptable safety of tisa-cel in pts with r/r FL, including high-risk pts after multiple lines of prior therapy, and suggest that tisa-cel may be a promising therapy for pts with r/r FL. Clinical trial information: NCT03568461.

Safety and efficacy of tisagenlecleucel (tisa-cel) plus pembrolizumab (pembro) in patients (pts) with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL): Updated analysis of the phase 1b PORTIA study

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Background: Tisa-cel showed durable responses and manageable safety in pts with r/r DLBCL in the phase 2 JULIET trial. High baseline programmed cell death 1 (PD-1) expression associated with higher probability of no response (Schuster et al. NEJM 2019). Here we report an updated analysis of PORTIA, a phase 1b, multicenter, open-label study of tisa-cel plus pembro in pts with r/r DLBCL. Methods: Eligible pts (≥18 y) had r/r DLBCL after ≥2 lines of therapy and relapsed after or were not candidates for autologous stem cell transplant (autoSCT). Patients received a single tisa-cel infusion on Day 1 and were enrolled in 1 of 3 cohorts that initiated pembro (200 mg q 21 days, for up to 6 doses) on either Days +15, +8, or –1. Primary endpoints were incidence of dose-limiting toxicities (DLTs) and overall response rate (ORR; complete response [CR] and partial response [PR]). Secondary endpoints included duration of response, progression-free survival, overall survival, safety, and cellular kinetics. Results: As of November 9, 2020, 15 pts were enrolled and 12 received tisa-cel (n = 4 pts for each Days +15, +8, and –1 cohorts; median follow-up, 4 mo). At study entry, the median age among treated pts was 62 y (range, 35-79), 100% had an International Prognostic Index score ≥2, 67% had ≥3 prior lines of therapy, 58% had stage IV disease, 58% had lactate dehydrogenase > ULN, and 42% had prior autoSCT. All 12 pts had ≥1 AE. Grade ≥3 AEs suspected to be related to tisa-cel and/or pembro were neutropenia (n = 4); neutrophil count decreased (n = 3); febrile neutropenia, lymphocyte count decreased, malnutrition (each n = 2); anemia, leukopenia, diarrhea, white blood count decreased, liver function tests increased, thrombocytopenia, hepatitis, and cytokine release syndrome (CRS; each n = 1). No neurotoxicity or DLTs were observed. Among the Day +15, +8, and –1 cohorts (each n = 4), the ORR was 50% (2/4; CR n = 0, PR n = 2), 25% (1/4; CR n = 1, PR n = 0), and 25% (1/4; CR n = 1, PR n = 0; longer follow-up is needed for n = 2 pts), respectively. Tisa-cel exposure and peak expansion were consistent with JULIET, with a trend toward delayed expansion in the Day –1 cohort (n = 4). There was no sign of secondary expansion following pembro administration regardless of the number of doses. Compared with JULIET, lower CRS severity and frequency and lower cytokine profiles were observed for all 3 cohorts. Conclusions: The combination of tisa-cel plus pembro was feasible and showed manageable safety. The lack of improved efficacy in PORTIA with the addition of pembro compared with tisa-cel alone may be related to more pts with ≥3 prior lines of therapy (67% vs 51%, respectively), and/or pts with more advanced disease in PORTIA. Additional studies with larger patient cohorts are needed to determine the value of adding PD-1 inhibitors to CAR-T cell therapy in pts with r/r DLBCL. Clinical trial information: NCT03630159.

Abstract CT162: The phase 1b PORTIA study: Safety and efficacy of tisagenlecleucel plus pembrolizumab in patients with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL)

Introduction: Pembrolizumab (pembro) has shown clinical activity in r/r DLBCL after failing tisagenlecleucel (tisa), an autologous anti-CD19 chimeric antigen receptor (CAR)-T therapy (Chong et al. Blood. 2017).

Methods: PORTIA is a phase 1b, multicenter, open-label trial investigating the safety and efficacy of tisa plus pembro in adult patients (pts) with r/r DLBCL. Pts receive a single tisa IV infusion (target: 0.6-6.0×108 cells) on Day (D)1 and pembro at 200mg every 21 days, for up to 6 doses. Pembro was started on D15 post tisa in Cohort 1, with the option of moving to D8 (Cohort 2) or D22 based on safety profile and dose-limiting toxicities (DLTs). Primary endpoints: proportion of pts receiving pembro per schedule, incidence of DLTs (dose-timing selection phase), overall response rate (dose-expansion phase).

Results: As of 5 March 2019, 5 patients were screened for Cohort 1; 4 pts were enrolled. Median age was 54 (range, 35-79). Median follow-up after tisa infusion was 46 days (range, 36-85). Pts received 1.7-3.0×108 CAR-positive T cells and 1, 2, 2, and 4 pembro doses, respectively, with no delays. All 4 pts experienced ≥1 adverse event (AE), with no exacerbation or recurrence of tisa-related AEs post pembro infusion. No pembro-related AEs, DLTs or grade 3/4 treatment-related AEs (TRAEs) were observed (Table 1). All pts experienced initial expansion between D6-15 post-tisa infusion; overall exposure is consistent with that observed in the JULIET trial. Two pts discontinued pembro treatment (after 1 and 2 doses, respectively) due to disease progression. With limited follow-up, 1 partial response has been observed.

Table 1.TRAEs and Grade 3/4 AEs Observed in Day 15 Cohort Interim ReadAdverse EventPatients With Grade 3/4 AE, n (%)Patients With Grade 3/4 AE, n (%)Patients With Grade 3/4 TRAE, n (%)Anemia1 (25)a00Cytokine release syndrome01 (25)a0Pancreatitis1 (25)a00Tachycardia01 (25)a0AE, adverse event; TRAE, treatment-related adverse event.aAnemia developed on D14 after tisa infusion but preceding pembro initiation, and again on D36 while the pt was on pembro (during the time from first pembro administration to 30 days after the last pembro administration date). Pancreatitis developed on D28 in the same pt. Both are likely related to lymphoma progression.bOne pt developed grade 2 cytokine release syndrome according to the Lee scale (D7-11) and concomitant sinus tachycardia, both attributed to tisa and resolved prior to pembro infusion; no neurological events occurred.

Conclusions: PD-1 blockade with pembro was feasible and showed a manageable safety profile in the first 4 pts. No DLTs or clinically significant exacerbation of AEs were observed. Efficacy and safety data for Cohorts 1 and 2 (D15 and D8) with longer follow-up will be presented at the congress.

Clinical trial information: NCT03630159

Citation Format: Ulrich Jaeger, Nina Worel, Joseph P. McGuirk, Peter A. Riedell, Isabelle Fleury, Peter Borchmann, Simon Newsome, Ahmed M. Abdelhady, Alessandra Forcina, Lida Bubuteishvili Pacaud, Edmund K. Waller. The phase 1b PORTIA study: Safety and efficacy of tisagenlecleucel plus pembrolizumab in patients with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT162.

Primary angiosarcoma of the breast: Case report of a rare vascular tumor

This is a case report of a woman in her sixth decade of life diagnosed with primary angiosarcoma of the breast using mammography and ultrasound, confirmed with imaging-guided biopsy, and finally treated with surgery and radiation. Imaging studies obtained and discussed include mammography, ultrasonography, and MRI. Further discussion on the presenting symptoms, useful imaging modalities, and treatment options takes place. It is important to consider primary angiosarcoma of the breast, though rare, in any woman presenting with a palpable breast mass and, if feasible, an MRI will be most helpful in the diagnosis of this rare tumor.

MicroRNA155 Expression in Relation to BDCAF Scored Behçet's Disease in an Egyptian Patients' Sample

Objective:

To discover the possibility of using microRNA155 (miRNA155) expression level as a biomarker of Behçet's Disease (BD) activity or remission.

Methods:

Thirty BD patients’ white blood cells (WBCs) miRNA155 expression was measured and compared to WBCs miRNA155 expression in 15 healthy subjects. Assessment of disease activity was done using Behçet's Disease Current Activity Form (BDCAF).

Results:

miRNA155 expression significantly decreases with the increase of BD activity scored by BDCAF.

Conclusion:

Increased miRNA155 may be used as a biomarker of BD remission and thus in the disease follow up. There could be a prospect of treating the disease via microRNA 155 effect enhancement.

Efavirenz Inhibits the Human Ether-A-Go-Go Related Current (hERG) and Induces QT Interval Prolongation in CYP2B6*6*6 Allele Carriers

BACKGROUND

Efavirenz (EFV) has been associated with torsade de pointes despite marginal QT interval lengthening. Since EFV is metabolized by the cytochrome P450 (CYP) 2B6 enzyme, we hypothesized that EFV would lengthen the rate-corrected QT (QTcF) interval in carriers of the CYP2B6*6 decreased functional allele.

OBJECTIVE

The primary objective of this study was to evaluate EFV-associated QT interval changes with regard to CYP2B6 genotype and to explore mechanisms of QT interval lengthening.

METHODS

EFV was administered to healthy volunteers (n = 57) as a single 600 mg dose followed by multiple doses to steady-state. Subjects were genotyped for known CYP2B6 alleles and ECGs and EFV plasma concentrations were obtained serially. Whole-cell, voltage-clamp experiments were performed on cells stably expressing hERG and exposed to EFV in the presence and absence of CYP2B6 expression.

RESULTS

EFV demonstrated a gene-dose effect and exceeded the FDA criteria for QTcF interval prolongation in CYP2B6*6/*6 carriers. The largest mean time-matched differences ∆∆QTcF were observed at 6 hours (14 milliseconds; 95% CI [1; 27]), 12 hours (18 milliseconds; 95% CI [-4; 40]), and 18 hours (6 milliseconds; 95% CI [-1; 14]) in the CYP2B6*6/*6 genotype. EFV concentrations exceeding 0.4 μg/mL significantly inhibited outward hERG tail currents (P < 0.05).

CONCLUSIONS

This study demonstrates that homozygous carriers of CYP2B6*6 allele may be at increased risk for EFV-induced QTcF interval prolongation via inhibition of hERG.

Losartan may inhibit the progression of liver fibrosis in chronic HCV patients

BACKGROUND

Abundant experimental evidence indicates overproduction of angiotensin II in the injured liver, and a role in stimulation of hepatic stellate cell (HSC) activation and fibrogenesis thereby, representing an attractive antifibrotic target. The aim of this study was to examine the antifibrotic effect of losartan on histopathologic level in chronic HCV patients.

METHODS

A prospective study on fifty patients with chronic HCV and liver fibrosis proved by liver biopsy was conducted. They included patients who did not respond (n=36) or comply (n=2) or receive therapy due to established cirrhosis (n=10), or refused to receive (n=2) combined interferon and ribavirin therapy. They were divided randomly into 2 groups. The 1(st) group (n=25) was given losartan 50 mg OD for 1 year and the 2(nd) group (25 patients) was given silymarin, 140 mg t.i.d., (silymarin group). Liver biopsy was done at baseline and 1 year from the onset of treatment (end of study).

RESULTS

In the second liver biopsy after 1 year, the decrease in fibrosis stage was significantly different between losartan group and silymarin group (a decrease of 1.88±0.96 (50.9%) vs. 0.45±0.93 (11.7%), respectively; P<0.01). In patients treated with losartan, regression in fibrosis stage was observed in 14/16 patients vs. 2/11 in silymarin group (P<0.01). No differences were observed in inflammation grades in both groups. A significant increase in albumin and prothrombin levels and a decrease in systolic blood pressure were found in losartan but not in silymarin group (P=0.009, 0.001 & 0.018 respectively and P=0.158, 0.603 & 0.288, respectively).

CONCLUSIONS

Histopathological scores showed that losartan had an inhibitory effect on progression and even led to regression of fibrosis stage but had no effect on the grade of inflammation.

Population pharmacogenetic-based pharmacokinetic modeling of efavirenz, 7-hydroxy- and 8-hydroxyefavirenz

The purpose of this study was to determine the demographic and pharmacogenetic covariates that influence the disposition of efavirenz (EFV) and its major metabolites. A population pharmacokinetic (PK) model was developed from a randomized, cross-over, drug-interaction study in healthy male Korean subjects (n = 17). Plasma concentrations of EFV and its hydroxy-metabolites (0-120 hours) were measured by LC/MS/MS. Genomic DNA was genotyped for variants in the cytochrome P450 (CYP) 2A6, 2B6, 3A5, and MDR1 genes. A PK model was built in a stepwise procedure using nonlinear mixed effect modeling in NONMEM 7. The covariate model was built using the generalized additive modeling and forward selection-backward elimination. Model-based simulations were performed to predict EFV steady-state concentrations following 200, 400, and 600 mg daily oral dose among different CYP2B6 genotypes. The final model included only CYP2B6 genotype as a covariate that predicts EFV clearance through the formation of 8-OH EFV that represented 65% to 80% of EFV clearance. The total clearance of EFV in CYP2B6*6/*6 genotype was ∼30% lower than CYP2B6*1/*1 or CYP2B6*1/*6 alleles (P < .001). Clopidogrel reduced both formation and elimination clearances of 8-OH EFV by 22% and 19%, respectively (P = .033 and .041). Other demographics and genotype of accessory CYP pathways did not predict EFV or metabolites PK. CYP2B6 genotype was the only significant predictor of EFV disposition. The developed model may serve as the foundation for further exploration of pharmacogenetic-based dosing of EFV.