Ondanks positieve bevindingen in fase II-onderzoek naar de orale CB2-agonist lenabasum, werd het primaire eindpunt van de fase III-studie RESOLVE-1 niet bereikt bij patiënten met diffuus cutane systemische sclerose (dcSSc).
Van de 375 patiënten met dcSSc die werden gerandomiseerd naar lenabasum, tweemaal daags 5 of 20 mg, of placebo, waren de ACR CRISS-scores na 52 weken “hoog en vergelijkbaar” in alle 3 de groepen, met mediane scores rond de 0,8 zonder significante verschillen. Secundaire uitkomsten, waaronder veranderingen in de gemodificeerde Rodnan-huidscore, HAQ-DI en FVC percentage voorspeld, waren ook vergelijkbaar in de drie groepen.
Robert Spiera (Weill Cornell Medical College, New York, VS) presenteerde de bevindingen op het EULAR 2021 Virtual Congress en merkte op dat de effectiviteitsuitkomsten in de placebogroep veel hoger waren dan verwacht, wat het moeilijk maakte om een behandeleffect te onderscheiden bovenop wat werd gezien in de placebogroep.
Robert Spiera bespreekt de bevindingen van de fase III-studie RESOLVE-1 (7:11)
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Interview transcript
The phase III RESOLVE-1 lenabasum trial was a double-blinded randomized placebo-controlled trial in patients with diffuse systemic sclerosis looking at a novel strategy, which was a cannabinoid-2 receptor agonist in the treatment of systemic sclerosis. So this was a nice strategy in that a cannabinoid-2 receptor engagement initiates resolution of the inflammatory response and has had antifibrotic effects, both in-vivo systems and in in-vitro systems. And in our phase II study, we saw efficacy signals that were encouraging. So this was the 375-patient 76-site international trial in which patients were randomized to treatment with either lenabasum 5 milligrams twice daily, 20 milligrams twice daily, or a placebo, with the primary endpoint being the comparison of 20 milligrams twice daily, our highest-dose group, with placebo with regard to the CRISS response. We selected the combined response index in systemic sclerosis as our primary outcome. A couple of points that are important about the trial design that made it very relevant in real-world practice was that, number one, we enrolled patients with either less than three-year disease or even up to six years of disease. And in that latter group, they had to have a substantial modified Rodnan skin score of greater than 15. But more importantly, we allowed background therapy, and that was at the discretion of the individual investigator at various sites. So that was heterogeneous, but the vast majority of our patients were on background therapy. And the primary outcome, which was whether lenabasum afforded more improvement in the CRISS score than would placebo, was not met. We cannot show the treatment with lenabasum was superior to treatment with placebo. Importantly, patients in the placebo arm who were on background therapy had a very high CRISS response, as did patients on active drug. So we didn’t demonstrate efficacy of lenabasum, but there may have been issues related to how our placebo group did and possibly, a ceiling effect of lenabasum. Well, this was a very large clinical trial, probably the largest prospective randomized placebo-controlled trial looking at scleroderma holistically as opposed to just, let’s say, interstitial lung disease. But this is the largest prospective trial done in this disease, and it was done in the backdrop of a moving landscape, in terms of what has been used as background therapies. And by allowing background therapies, we may have blunted an ability to see an effect of lenabasum. So some of the most striking findings relate not necessarily even to lenabasum’s effect but how well background therapy fared for our patients. In particular, about half of our patients were on background mycophenolate, and that seemed to have a very important impact on disease outcomes, including the overall combined response index in systemic sclerosis and the forced vital capacity percent predicted more specifically. And this was surprising to us. We didn’t model this expecting the degree of a CRISS response in our placebo group, but the landscape has changed in terms of how much mycophenolate is now being used in the treatment of systemic sclerosis. And right now, we’re engaged in ongoing analysis looking at the relative impact of mycophenolate, as opposed to other therapies that were used as background therapy in this trial. But it looks like mycophenolate is really emerging as an important player in systemic sclerosis, maybe surprisingly better than we thought it might be. And one prespecified analysis we looked at specifically was to look at the effects on outcomes, including forced vital capacity and the CRISS score based on different treatment assignments. And mycophenolate clearly had a very significant impact on outcomes in this study, more than we anticipated. And we did allow background therapy in the phase II study, as well, but it was a much smaller study. And there are issues related to the duration of mycophenolate before you enter the trial that seemed to have an effect on how lenabasum performed as a background therapy and what impact mycophenolate had specifically, or other background therapy, for that matter. So if you had been a relatively new starter to mycophenolate when you entered this trial– you had to be on a stable dose of mycophenolate for a few months prior to entry– but if you were somebody who had been on mycophenolate for a longer period of time– so this would be a scleroderma patient on mycophenolate not doing well enough, perhaps a couple of years into therapy with mycophenolate– those patients, if you watch them over time, seemed to receive less benefit from continued mycophenolate. And, indeed, in that subgroup, if you looked at how lenabasum impacted their forced vital capacity, it seemed that there was a beneficial impact on the change in forced vital capacity in those patients, not just on mycophenolate but on background immunosuppressive therapies in general, with regard to how the FVC changed over time. If you looked at newer starters to background immunosuppressive therapies in general, or mycophenolate specifically, it seemed that the background therapy had more impact in those patients who were newer starters to mycophenolate. So that actually is an important point that will even have implications towards trial design. It’s very disappointing when you do a large well-designed trial like this and don’t see an effect of the study intervention, although there were clues there. I still feel it’s ethical in patients with progressive systemic sclerosis to have background therapy allowed in the context of a clinical trial, particularly one of the duration that we’re talking about, a one-year trial. This actually indirectly supported that concept, that we clearly saw an impact on background immunosuppressive therapy or immunomodulatory therapy. But that does make it a higher bar for any additional therapy to show benefit because you’re having such good responses from the background immunomodulatory therapy in general and mycophenolate specifically.
Hij legde uit dat de patiënten tijdens deelname aan het onderzoek immuunsuppressieve achtergrondtherapie mochten krijgen, zolang deze gedurende ten minste 8 weken voorafgaand aan de studie stabiel was, om zo een betere afspiegeling te kunnen geven van de real-world klinische praktijk. Dit betrof de meerderheid van de patiënten in elke groep, tussen 78% en 89%, waarbij ongeveer de helft van de patiënten in elke groep mycofenolaatmofetil gebruikte, en ongeveer een derde van de patiënten twee of meer immuunsuppressieve therapieën.
Deze achtergrondtherapie, en specifiek mycofenolaatmofetil, leken de resultaten aanzienlijk te beïnvloeden. In een vooraf gespecificeerde analyse bleek gebruik van mycofenolaatmofetil op baseline significant geassocieerd te zijn met de ACR CRISS-score. Dit bracht de onderzoekers ertoe post-hocanalyses uit te voeren waaruit bleek dat patiënten die het middel gebruikten een grotere verbetering van de ACR CRISS-score hadden dan degenen die geen immuunsuppressieve therapie kregen (0,94 vs. 0,35 punten).
Dit voordeel van mycofenolaatmofetil nam echter af met de duur van het gebruik, waarbij patiënten die het meer dan 2 jaar hadden gebruikt, een minder grote verbetering van de ACR CRISS-score lieten zien dan patiënten die het korter hadden gebruikt. Dit was ook het geval voor de FVC percentage voorspeld, en post-hocanalyse liet zien dat patiënten die mycofenolaatmofetil gedurende meer dan 2 jaar gebruikten, meer kans hadden op een stabiel (binnen 5%) FVC percentage voorspeld over 1 jaar als ze lenabasum namen ten opzichte van placebo, namelijk 64% versus 35%. Deze bevindingen moeten echter worden bevestigd in vervolgonderzoek.
Lenabasum werd goed verdragen met minder ernstige bijwerkingen in vergelijking met de placebogroep en zonder therapiegerelateerde bijwerkingen die leidden tot stopzetting van de behandeling.
Provided by Medicine Matters rheumatology; ©2021 Springer Healthcare Ltd, part of the Springer Nature Group.
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