Multiple Investigational Approaches Show Promise for Lupus

VIENNA — It may have been a while since there have been any major breakthroughs in the treatment of systemic lupus erythematosus (SLE), but there are high hopes that this is a situation that may be about to change, experts agreed at the recent European Alliance of Associations for Rheumatology (EULAR) 2024 Annual Meeting.

“It’s an incredibly vivid area of development,” Laurent Arnaud, MD, PhD, professor of rheumatology at the University of Strasbourg in Strasbourg, France, said during one of the first sessions of the meeting. He reported that there were at least 17 phase 2 and 14 phase 3 trials that were expected to start within the next few years, all with investigational agents that target different immune cells or pathways that have been implicated in the pathogenesis of SLE.

In a systematic review published last year, Arnaud and coauthors found that there were 92 investigational biologic or novel targeted agents in various phases of clinical testing. This included B-cell–targeting agents such as ianalumab, plasma cell-targeting agents such as daratumumab, and drugs with novel mechanisms of action such as KPG-818, which targets the CRL4-Cereblon (CRBN) E3 ubiquitin ligase complex. Phase 2 data on all three of these investigational agents were presented during various sessions at EULAR 2024, all with positive results, suggesting that their further development in SLE is worth pursuing.

There are of course “many more candidates in the pipeline,” Arnaud said. “I’m very happy that I think we are going to see great days for lupus right in front of our eyes.”

Targeting B Cells

Drugs that target B cells have been at the forefront of lupus treatment for several years, as David Isenberg, MD, professor of rheumatology at University College London, London, pointed out during an interview for EULAR TV.

“It’s clearly important to target the cells which are likely to be causing the problem in lupus, and in the main, that tends to be B cells,” he said.

Isenberg, who is renowned for his work with the B-cell–targeting agent rituximab, added: “But we know that obviously T cells integrate with B cells, so anything which interrupts the link between the T cell and the B cell is likely to be important.”

Chimeric Antigen Receptor (CAR) T-Cell Therapy ‘Revolution’

One new way of targeting B cells is with CAR T-cell therapy, which David D’Cruz , MD, PhD, a consultant rheumatologist for Guy’s and St. Thomas’ Hospital NHS Foundation Trust in London, picked as one of the “most striking” topics highlighted at EULAR 2024.

This is “truly personalized medicine,” D’Cruz said. This is an autologous therapy because a patient’s T cells are removed by leukapheresis, transfected with a CAR T vector directed against a component of the B cell, and then returned to them.

“I do feel that we’re on the cusp of a major revolution,” D’Cruz told Medscape Medical News. Not only in lupus but also in other rheumatic conditions that have proved really difficult to treat, such as systemic sclerosis and myositis, he said.

“Basically, it’s a very powerful B-cell–depleting tool, but it’s much more profound B-cell–depleting tool than, for example, rituximab or belimumab,” explained D’Cruz. “What you’re doing is reprogramming T cells to attack the B cells.”

Although rituximab and belimumab clear all the B cells in the circulation, there are still some cells left behind in the bone marrow, “and it’s very difficult to get rid of those,” D’Cruz said. “What CAR T-cell therapy appears to do is wipe out all the CD19-positive B cells everywhere, in the blood and the tissue. So you get a really profound B-cell depletion.”

Eric Morand, MBBS, PhD, head of rheumatology at Monash Health in Melbourne, Australia, told Medscape Medical News that there was obviously “a lot of buzz” about CAR T-cell therapy.

“We’re waiting to see if the exciting data from Erlangen can be reproduced in other centers with other CAR T products to show that it is a universal effect. We haven’t seen that yet, but I think we will by next year.”

Cost and expertise are two major considerations and potential limiting factors, however, as D’Cruz and Isenberg both pointed out in separate interviews with Medscape Medical News.

D’Cruz said: “It’s very expensive, it takes a while, and it doesn’t always work is what I’m hearing. It’s usually successful, but again, a little bit depends on the technique and the people doing the process.”

Isenberg said: “CAR T-cell therapy is, I think, very exciting because it does look to be quite promising. But as it costs 350,000 euros per patient, I don’t think that it is going to be widely adopted.”

Even if it could be afforded by certain centers in the West, he added, this just would not be feasible in poorer nations. “So, we’ve got to find other effective, cheaper ways to go,” Isenberg said.

“I think there are some very interesting ideas with monoclonal antibodies which target at least two different targets — one on the B cell, one on the T cell — and that could well be the way to take this forward,” he suggested.

Ianalumab ‘Double Blocking’ B Cells

Another way could be to develop more potent B-cell–depleting drugs, as Nancy Agmon-Levin , MD, head of the Clinical Immunology, Angioedema and Allergy Unit, Lupus and Autoimmune Diseases Clinic, at Sheba Medical Center, Tel Aviv University in Tel Aviv, Israel, reported during one of the clinical abstract sessions at EULAR 2024.

Agmon-Levin presented data on 67 individuals with SLE who had participated in a multicenter phase 2 study of ianalumab, a fully human immunoglobulin (Ig) G1 monoclonal antibody that results in a “double blocking of the B-cell lineage.”

Ianalumab targets the B-cell–activating factor receptor (BAFFR), but what makes it distinct from other BAFF-targeting drugs is that it has had a fructose molecule removed from its Fc portion, which renders it more likely to trigger antibody-dependent cellular cytotoxicity.

“This is a B-cell depletion therapy,” Agmon-Levin said, but it also blocks BAFFR-mediated survival of B cells, so the subsequent recuperation process of BAFFR-expressing B cells is affected, leading to continued B-cell depletion.

The phase 2 study she presented consisted of an initial 28-week, double-blind period, during which time participants had been randomly allocated to receive either subcutaneous injections of ianalumab 300 mg or a matching placebo every 4 weeks. This was followed by a 24-week, open-label period where all participants were treated with ianalumab, and then an off-treatment, minimal follow-up period that lasted up to 68 weeks, with continued data collection for safety.

The primary outcome measure was a composite of meeting criteria for the SLE Responder Index 4 and a sustained reduction in corticosteroid use at 28 weeks. This was achieved in 15 of the 34 (44.1%) people treated with ianalumab vs only 3 (9.1%) of the 33 people who had been given a placebo.

Agmon-Levin reported that the effect on this outcome was sustained to the end of the open-label period, at 1 year, in 15 (45.5%) of 33 participants who had continued treatment with ianalumab and achieved in 13 (40.6%) of 32 participants who had switched from placebo to ianalumab treatment.

Moreover, longer durations of treatment were associated with a host of improved outcomes, Agmon-Levin said: “Treatment was improved along the 52 weeks, and we can see from the LLDAS [Lupus Low Disease Activity State], DORIS [Definition Of Remission In SLE], and SRI-6 and -8 that as you continue the therapy, you improve the outcomes.”

The potential benefits of ianalumab in the treatment of SLE and lupus nephritis will now be further examined in the phase 3 SIRIUS-SLE1 , SIRIUS-SLE2, and SIRIUS-LN trials, which are estimated to provide initial results in 2027 and complete in early 2029 or 2030.

Targeting Plasma Cells With Daratumumab

Another drug showing signs that it might be useful as a treatment for SLE is daratumumab, as Tobias Alexander, MD, of Charité — Universitätsmedizin Berlin, Berlin, reported during one of the late-breaking abstract sessions at EULAR 2024.

“Daratumumab is a human, first-in-class anti-CD38 antibody that efficiently depletes plasma cells,” Alexander said. CD38 is both a receptor and an enzyme, and while it is found on the surface of most immune cells, it’s particularly expressed by plasma cells, he added.

Daratumumab is not a total newcomer, however, as it’s already approved for the treatment of multiple myeloma under the trade name Darzalex. The rationale for using it in SLE comes from two case reports, Alexander explained. The first, published in 2020 in The New England Journal of Medicine, involved two patients with severe and life-threatening lupus who were given off-label treatment for a period of 4 weeks and experienced good clinical and serologic responses. The second, published last year in Nature Medicine, involved six patients with refractory lupus nephritis, five of whom had a clinical response at 6 months.

“On this background, we conducted an investigator-initiated trial, which was an open-label, single-center, proof-of-concept study,” Alexander said. A total of 10 female patients whose ages ranged from 24 to 43 years were included in the phase 2 trial that was dubbed DARALUP. For inclusion, all had to have a Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) of four or more for clinical manifestations, have been treated with at least two prior disease-modifying drugs to no avail, and be anti–double-stranded DNA (anti-dsDNA) antibody positive. Alexander reported that the median baseline SLEDAI-2K score was 12 and ranged from 8 to 20, with the number of prior therapies ranging from two to nine.

Daratumumab was given at a dose of 1800 mg via subcutaneous injection every week for 8 weeks. This is the same dose that is used to treat multiple myeloma, Alexander explained, although the dosing is not stopped. The reason for stopping after 8 weeks in the current trial was to be able to see what happened once the treatment was stopped. The follow-up was for 36 weeks.

Alexander reported that there was a “very dramatic and significant” effect on the primary endpoint of a reduction in anti-dsDNA antibody levels, decreasing from a median of 166.3 U/mL at baseline to 61.1 U/mL at week 12 (P = .002). Alongside, there was a reduction in the SLEDAI-2K score from 12 to 4 within 12 weeks, which was sustained at the 36-week follow-up assessment. Improvements in skin, joint, kidney, and level of proteinuria were also seen.

Although all patients experienced adverse events, none were serious. Infections and infestations (mostly nasopharyngitis, COVID-19, and gastroenteritis) were the most common, experienced by 80% of the participants; 70% had injection site reactions or fatigue, 60% had gastrointestinal symptoms, 50% had a fall of IgG < 5 g/L, 40% had headache, and 20% had back pain.

“This is a positive trial. I think we could demonstrate that [daratumumab] produced very strong, rapid, and durable clinical improvements,” Alexander said. “We think that targeting CD38 is relevant; plasma cells had been depleted based on the reduction of anti-dsDNA antibodies,” he added.

From the audience, however, Peter Nash, MBBS, of Griffith University in Brisbane, Australia, questioned whether the results could be attributed to “a steroid effect” because patients had been treated with oral dexamethasone throughout the study.

Alexander noted that steroid use had been part of the treatment schedule but acknowledged it was a possible confounder.

“I think we can be confident that [daratumumab] had a major effect on plasma cells decreasing…because we see that also the vaccine titers decreased,” Alexander said. “Time will tell, but even more important is the durability of the responses over time, which you don’t achieve under steroids.”

KPG-818’s Novel Mechanism of Action

Elsewhere at EULAR 2024, positive results of another phase 2 study involving a drug with an entirely different mechanism of action, KPG-818, were reported in a poster presentation. KPG-818 modulates CRBN, which results in the degradation of two transcription factors (Aiolos and Ikaros) that are involved in the development, maturation, and proliferation of innate and adaptive immune cells and have been linked to genetic risk in SLE, according to the poster’s authors. It is currently in development for the treatment of SLE, Behçet disease, inflammatory bowel disease, multiple myeloma, and non-Hodgkin lymphoma.

Yao Wang, MD, chief medical officer of KPG-818’s developer Kangpu Biopharmaceuticals, Hefei, China, and associates found that oral doses of 0.15 or 0.6 mg KPG-818 were “generally well-tolerated” and produced immunomodulatory changes that could be beneficial in people with SLE over a 12-week treatment period.

“Only two new agents have been approved for the treatment of SLE in the past five decades in USA and Europe,” Wang and team wrote, which highlights “a significant unmet need for more effective and safe treatment options.”

They believe that KPG-818 might well fit the bill based on the results of their study, in which 35 of 37 recruited patients completed the treatment. Compared with placebo, they observed reduced numbers of total B cells, Aiolos+ T and B cells, and increased T_reg cells.

SLEDAI-2K and Cutaneous Lupus Erythematosus Disease Area and Severity Index activity scores in the 0.15-mg group were improved relative to baseline and placebo.

“The proof-of-concept findings suggest a favorable benefit/risk ratio in SLE for KPG-818,” Wang and coauthors said, supporting its further development in SLE.

Need for Treatments

Isenberg told Medscape Medical News that both daratumumab and KPG-818 would be welcome additions as treatment options if further trials proved their worth.

“The great frustration about lupus is that, compared to patients with rheumatoid arthritis, the choice has been so limited,” Isenberg said. Aside from rituximab (Rituxan) and belimumab (Benlysta), which are used with certain restrictions, there are no other biologic targeted treatments available in the United Kingdom. Anifrolumab (Saphnelo) has a license in the United States and some European countries but is not yet available for him to use in his practice.

Daratumumab and KPG-818 are “different types of molecules, and if they work that will be great. It would be nice to have the choice,” Isenberg said. “Whether they will be as effective as I think rituximab is, I don’t know, but these are some very encouraging results.”

Of course, these are all phase 2 trials, and the “big problem” is that such positive results do not always translate when it comes to phase 3, as D’Cruz told Medscape Medical News.

“Until a few years ago, there had been about 25 or 30 industry-led trails, and they’d all failed, except for belimumab and anifrolumab,” D’Cruz said. These drugs were found to work and be generally safe in phase 1 and 2 trials, but “when they come to phase 3, they all seem to fail, and we don’t know why.”

These are large global studies, D’Cruz added, observing that problems with patient selection, steroid use, and choice of outcome measures were possible factors for why the EXPLORER and LUNAR studies had shown no benefit for rituximab despite the drug being widely used to treat SLE.

Isenberg, who has coauthored an article on the topic of why drugs seem to fail at the final hurdle, noted: “I think it has a lot to do with the nature of the disease. It’s a complicated disease.” From having “savvy physicians doing the trials for you” to the placebo response, there are “a whole bunch or reasons why these things haven’t worked in lupus.”

Morand commented: “We’ve got many programs in phase 2 and 3, and because there’s so many, they’re all facing recruitment challenges, and as a consequence of so much activity, every program is going a little slower than hoped for.”

As for other drugs on the horizon, Morand noted: “We’re very optimistic about things like litifilimab and deucravacitinib; that’s two examples that are in phase 3. Earlier in the program of development, [there are] a huge range of targets being addressed. The future looks bright. But we might have to wait a while.”

Arnaud has consulted for AstraZeneca, AbbVie, Alpine Immune Sciences, Biogen, Bristol Myers Squibb, Boehringer Ingelheim, Chugai Pharmaceutical, GlaxoSmithKline, Grifols, Janssen, Kezar Life Sciences, LFB, Lilly, Medac, Merck, Novartis, Pfizer, Roche, and UCB. Isenberg has served as an adviser to Merck Serono, AstraZeneca, Eli Lilly, Servier, and ImmuPharma. Any honoraria received is passed on to a local arthritis charity connected to his hospital. D’Cruz has served as a consultant and advisory board member for GlaxoSmithKline and CSL Vifor. Morand has received research support, consultancy fees, or both from multiple pharmaceutical companies paid to his institution including AbbVie, Amgen, AstraZeneca, Biogen, Bristol Myers Squibb, Eli Lilly, EMD Serono, Dragonfly, Genentech, GlaxoSmithKline, Janssen, Novartis, RemeGen, Takeda, UCB, and Zenas. The ianalumab trial presented by Agmon-Levin was sponsored by Novartis Pharma AG; however, she reported having no conflicts of interest. The DARALUP study was an investigator-initiated trial supported by Janssen. Alexander has received consulting fees, study support, honoraria, and travel grants from various pharmaceutical companies including AbbVie, Amgen, AstraZeneca, Bayer, GlaxoSmithKline, Janssen, and Lilly. Nash has consulted for The Rheumatology Education Group Consultants. The KPG-818 study reported by Wang was sponsored by Kangpu Biopharmaceuticals.

Sara Freeman is a medical journalist and writer based in London. She is a regular contributor to Medscape Medical News, Medscape News UK, and other specialist healthcare media outlets.