On December 17, 2021, the FDA approved VYVGART for the treatment of gMG in adult patients who are AChR-AB+. These patients represent approximately 85% of the total gMG population (Behin et al. New Pathways and Therapeutics Targets in Autoimmune Myasthenia Gravis. J Neuromusc Dis 5. 2018. 265–277). On January 20, 2022, MHLW granted marketing authorization for VYVGART (efgartigimod alfa) for the treatment of adult patients with gMG who are AChR-AB+. With these regulatory milestones, VYVGART is the first-and-only approved neonatal FcRn blocker in the U.S., Japan and the EU.
gMG is a rare and chronic neuromuscular disease characterized by debilitating and potentially life-threatening muscle weakness. VYVGART is a human IgG1 antibody fragment that binds to FcRn, resulting in the reduction of circulating IgG antibodies. The action of AChR autoantibodies at the neuromuscular junction is a key driver of gMG (Howard JF Jr, Utsugisawa K, Benatar M, et al. Safety and efficacy of efficacy of eculizumab in AChR antibody-positive refractory gMG (REGAIN): a phase 3, randomized, double-blind, placebo-controlled, multicenter study. Lancet Neurol. 2017; 16: 976–86).
The approval of VYVGART is based on results from the global Phase 3 ADAPT clinical trial, which were published in the July 2021 issue of The Lancet Neurology.
We integrated input from the gMG community into the ADAPT clinical trial design. Through listening to and learning from the gMG patient community, we understand that every gMG patient experiences the course of disease differently. As a result, we designed a clinical trial to reflect the individualized nature of gMG with a dosing approach that we believe is adapted to each patient’s individual response.
The Phase 3 ADAPT clinical trial was a randomized, double-blind, placebo-controlled, multi-center, global clinical trial evaluating the safety and efficacy of efgartigimod in patients with gMG. A total of 167 adult patients with gMG in North America, Europe and Japan enrolled in the clinical trial and were treated. Patients were eligible to enroll in ADAPT regardless of antibody status, including patients with AChR antibodies and patients where AChR antibodies were not detected. Patients were randomized in a 1:1 ratio to receive efgartigimod or placebo for a total of 26 weeks. ADAPT was designed to enable an individualized treatment approach with an initial treatment cycle followed by a variable number of subsequent treatment cycles.
The ADAPT clinical trial met its primary endpoint, demonstrating that significantly more anti-AChR-AB+ gMG patients were responders on the MG-activities of daily living (MG-ADL) scale following treatment with VYVGART compared with placebo (68% vs. 30%; p<0.0001). Responders were defined as having at least a two-point reduction on the MG-ADL scale sustained for four or more consecutive weeks during the first treatment cycle.
Additionally, there were significantly more responders on the quantitative myasthenia gravis (QMG) scale following treatment with VYVGART compared with placebo (63% vs. 14%; p<0.0001). Responders were defined as having at least a three-point reduction on the QMG scale sustained for four or more consecutive weeks during the first treatment cycle.
As shown in figure 1, minimal symptom expression (MSE) is an increasingly important data point for physicians and patients because it is a measure of symptom-free status. In ADAPT, 40% of patients achieved MSE – or an MG-ADL score of 0 or 1 – at any time during cycle one. The right side shows depth of response. Over half of patients treated with efgartigimod experienced an improvement of five points or more on the MG-ADL scale by week four.
VYVGART had a demonstrated safety profile in the ADAPT clinical trial. The most common adverse events in ADAPT were respiratory tract infection (33% vs 29% placebo), headache (32% vs 29% placebo), and urinary tract infection (10% vs. 5% placebo).
There is a pre-approval access program (PAA) for gMG patients that remains open in the EU, the UK, Hong Kong and Canada for eligible patients.
Commercialization and Regulatory Plans
VYVGART was launched in the U.S. in January 2022, in Japan in May 2022 and in Germany in September 2022 following approval in each region. The European commercial launch of VYVGART is still ongoing.
We have established our own sales force in the U.S., Japan and Europe for VYVGART for the treatment of gMG. We plan to expand our own sales and marketing capabilities and promote our products and product candidates if and when regulatory approval has been obtained in the relevant jurisdictions. For example, we established argenx Canada in the first quarter of 2022 in preparation for a potential Health Canada approval request and if granted commercial launch in Canada. We also established argenx UK in August 2022 in preparation for potential Medicines and Healthcare Products Regulatory Agency (MHRA) approval.
Development and commercialization may also be done through collaborations with third parties. In January 2021, we entered into an exclusive out-license agreement with Zai Lab, a commercial-stage biopharmaceutical company, for the development and commercialization of efgartigimod in Greater China (Zai Lab Agreement). Zai Lab filed for approval in the PRC in the second quarter of 2022. Under the Zai Lab Agreement, we received a $75.0 million upfront payment in the form of 568,182 newly issued Zai Lab shares calculated at a price of $132.0 per share, a $75.0 million guaranteed non-creditable, non-refundable development cost-sharing payment and a $25.0 million milestone payment in connection with FDA approval of VYVGART (Zai Lab Payments). We will also be eligible for tiered royalties based on annual net sales of efgartigimod in Greater China.
In October 2021, we announced an exclusive distribution agreement with Medison to commercialize efgartigimod for gMG in Israel (Medison Agreement). Medison will also be responsible for seeking requisite regulatory approvals, and Medison filed for approval in Israel in the second quarter of 2022. On June 6, 2022 we announced an exclusive multi-regional agreement with Medison to commercialize efgartigimod in 14 countries, including Poland, Hungary, Slovenia, Czech Republic, Romania, Bulgaria, Lithuania, Croatia, Slovakia, Estonia, Latvia, Greece, and Cyprus, for the treatment of adult patients with gMG (Medison Multi-Regional Agreement).
In January 2022, we entered into a partnership agreement with Genpharm, under which Genpharm shall purchase VYVGART from us for the resale in the GCC on an exclusive basis for Genpharm’s own account and own name (Genpharm Agreement).
We intend to sign additional distribution partnerships for other territories.
For a discussion of total revenues by geographic market, please see note 18 “Segment Reporting” in our consolidated financial statements.
Pre-Approval Access Program
We are committed to improving the lives of people suffering from rare diseases. We are driven to discover new treatment approaches in autoimmunity and fueled by the resilience of patients to urgently deliver them. We aim to do this in partnership; we listen to patients, supporters and advocacy communities, and we hear their stories. Their insights guide us as we develop our investigational therapies and motivate us to advance the understanding of rare diseases.
We implemented a PAA on February 21, 2022 through which investigational therapies are made available in certain circumstances to treat gMG patients who are unable to participate in an ongoing clinical trial. As of the date of this Annual Report, the PAA has approved over 150 gMG patients in ten countries. With the approval of VYVGART in the U.S., Japan and EU, the PAA program remains open only in countries where VYVGART is not yet launched or reimbursed.