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.).

The autoimmune rheumatological presentation of Common Variable Immunodeficiency Disorders with an overview of genetic testing.

Primary immunodeficiency Disorders (PIDS) are rare, mostly monogenetic conditions which can present to a number of specialties. Although infections predominate in most PIDs, some individuals can manifest autoimmune or inflammatory sequelae as their initial clinical presentation. Identifying patients with PIDs can be challenging, as some can present later in life. This is often seen in patients with Common Variable Immunodeficiency Disorders (CVID), where symptoms can begin in the sixth or even seventh decades of life. Some patients with PIDs including CVID can initially present to rheumatologists with autoimmune musculoskeletal manifestations. It is imperative for these patients to be identified promptly as immunosuppression could lead to life-threatening opportunistic infections in these immunocompromised individuals. These risks could be mitigated by prior treatment with subcutaneous or intravenous (SCIG/IVIG) immunoglobulin replacement or prophylactic antibiotics. Importantly, many of these disorders have an underlying genetic defect. Individualized treatments may be available for the specific mutation, which may obviate or mitigate the need for hazardous broad-spectrum immunosuppression. Identification of the genetic defect has profound implications not only for the patient but also for affected family members, who may be at risk of symptomatic disease following an environmental trigger such as a viral infection. Finally, there may be clinical clues to the underlying PID, such as recurrent infections, the early presentation of severe or multiple autoimmune disorders, as well as a relevant family history. Early referral to a clinical immunologist will facilitate appropriate diagnostic evaluation and institution of treatment such as SCIG/IVIG immunoglobulin replacement. This review comprises three sections; an overview of PIDs, focusing on CVID, secondly genetic testing of PIDs and finally the clinical presentation of these disorders to rheumatologists.

The complexities of decision-making associated with on-demand treatment of hereditary angioedema (HAE) attacks.

BACKGROUND: Hereditary angioedema (HAE) is characterized by debilitating attacks of tissue swelling in various locations. While guidelines recommend the importance of early on-demand treatment, recent data indicate that many patients delay or do not treat their attacks. OBJECTIVE: This survey aimed to investigate patient behavior and evaluate the key factors that drive on-demand treatment decision-making, as reported by those living with HAE. METHODS: People living with HAE were recruited by the US Hereditary Angioedema Association (HAEA) to complete a 20-minute online survey between September 6, and October 19, 2022. RESULTS: Respondents included 107 people with HAE, 80% female, 98% adults (≥ 18 years). Attack management included on-demand therapy only (50%, n = 53) or prophylaxis with on-demand therapy (50%, n = 54). Most patients (63.6%) reported that they did not carry on-demand treatment at all times when away from home. The most common reason for not carrying on-demand treatment when away from home was 'prefer to treat at home' (72.1%). Overall, 86% of respondents reported delaying on-demand treatment, despite recognizing the initial onset of an HAE attack and despite 97% of patients agreeing that it is important to recover quickly from an HAE attack. Reasons for non-treatment or treatment delay included 'the attack is not severe enough to treat' (91.9% and 88.0%, respectively), 'cost of treatment' (31.1% and 40.2%, respectively), anxiety about refilling the prescription for on-demand treatment quickly (31.1% and 37.0%, respectively), the pain (injection or burning) associated with their on-demand treatment (18.9% and 28.3%, respectively), the lack of a suitable/private area to administer on-demand treatment (17.6% and 27.2%, respectively), lack of time to prepare on-demand treatment (16.2% and 16.3%, respectively), and a 'fear of needles' (13% and 12.2%, respectively). Survey findings from the patient perspective revealed that when on-demand treatment was delayed, 75% experienced HAE attacks that progressed in severity, and 80% reported longer attack recovery. CONCLUSIONS: Survey results highlight that decision-making regarding on-demand treatment in HAE is more complicated than expected. The burden associated with current parenteral on-demand therapies is often the cause of treatment delay, despite acknowledgment that delays may result in progression of HAE attacks and longer time to recovery.