Rituximab associated with mycophenolate: the LUNAR trial experienceFernando Fervenza, Rochester, USA

Chairs: David Jayne, Cambridge, UKVladimir Tesar, Prague, Czech Republic

Prof. Fernando FervenzaDivision of Nephrology and Hypertension

Mayo ClinicRochester, Minnesota

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So, my role in

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the presentation is to discuss

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the results of the LUNAR trial and I have the disclosures

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that the trial was conducted by Genentech and Biogen. The results of the trial have alreadybeen published, almost a year ago in Arthritis Rheumatism.

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The background of why LUNAR was conducted was based on the fact that rituximab, which isa chimeric CD20 antibody, has proven effective in a number of autoimmune diseases and islabelled for the treatment of rheumatoid arthritis and ANCA vasculitis. In a small number ofuncontrolled trials in lupus nephritis, it has been suggested that rituximab could also bepotentially effective in patients with lupus nephritis in view of the fact that we have such pooroutcomes in this population and the use of rituximab may improve the outcome.

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The primary objective of LUNAR was to test the efficacy and the safety of rituximab ascompared to placebo when added to the background standard therapy of patients treatedwith prednisone and MMF.

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The design of LUNAR: Briefly patients were treated with prednisone and MMF. They received1-2 g of methyl prednisone at day 1 and they were then randomised either to continueprednisone and MMF or to receive rituximab on top of the prednisone and MMF therapy.Patients were started on 0.75 mg of prednisone orally to a maximum of 60 mg/day. The dosewas started to be tapered at day 16 and the aim was that by week-16 prednisone dose hadto be 10 or less mg/kg per day. MMF was started at 500 mg 3 times/day aiming to reach atarget dose of 3000 mg/day.

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The inclusion criteria is briefly described here. There were patients who had a diagnosis oflupus according to the ACR criteria. They should have had a class III or class IV lupusnephritis but the coexistence of a class V lesion was allowed. Proteinuria should be more than1 g determined by a protein/creatinine ratio. Patients who had more than 50% ofglomerulosclerosis or more than 50% interstitial fibrosis as well as a creatinine clearance lessthan 25 ml/min or other significant involvement of lupus like retinitis, poorly controlledseizures, stroke or patients on dialysis were excluded from enrolment.

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The primary endpoint of this study was a little complex as a primary endpoint and it wasbased on the patients who achieved a renal response. The definition of either complete,partial or non-response is represented in this slide. The complete response that is defined asa patient that at week 52 had a normalisation of serum creatinine or less than 15% greater

than the baseline if the day 1 serum creatinine was indeed in the normal range. Also thosepatients had to have inactive urinary sediment and have a urine protein creatinine ratio ofless than 0.5. The partial remission was defined by a serum creatinine of less than 15% of thebaseline, above the baseline, no worsening of urinary sediment and a 50% improvement inthe urine protein creatinine ratio defined as: if the baseline was less than 3, then the urineprotein creatinine ratio should go down to less than 1 and if the baseline was more than 3,than the urine protein creatinine had to be less than 3. No response was achieving neithercomplete nor partial remission. This study was an intention-to-treat analysis so any patientwas recruited was counted.

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There was a number of secondary endpoints that involved a portion of patients who achievedcomplete remission at week 52, time to complete remission, change in the SF36 physical scoreand also there were some physiological measurements like the change in anti-dsDNA andchange in complement levels from baseline to week 52.

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The study was powered on the assumption that there would be a 20% more completeremission rate in the rituximab group versus the placebo group and there would be a 5%better number of partial remissions in the rituximab group than the partial response group.Based on that, it was calculated that recruiting 140 patients, randomising on a one to oneratio, would give a 90% power to detect significance for this study.

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This is how the patients were disposed. In fact, 144 patients were recruited, 72 patientswent into the placebo arm and 72 patients in the rituximab arm. By the end of week 52, 88%of the patients in the placebo arm and 93% in the rituximab arm were still being followed asper protocol.

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The baseline characteristics are summarised in this slide. It was a young patient populationwith an average age of about 30 years. The majority of the patients was female and racewas equally divided between whites, blacks and Hispanics. One thing that is important, atleast to me, is to realise that in this study 75% of the patients roughly were recruited incentres in the United States. An equal number of patients, approximately 50%, were treatedat entry into the study with an ACE or an ARB.

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Baseline proteinuria was around 4 g. Serum creatinine was normal and this was reflected byan eGFR of close to 90 ml/min. Regarding the renal biopsy, the majority of the patients had aclass IV lupus nephritis, a third of the patients had class III lupus nephritis and a third of thepatients also had a class V lupus lesion associated.

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Here are the main results of the study. Basically, to cut a long story short, there was nodifference in the rate of complete remission in patients treated with placebo or rituximab.There was a 15% increase or a doubling of the number of patients reaching partial remissionbut this was not significant. One of the most concerning results was that approximately 50%of the patients enrolled in LUNAR and treated in centres where perhaps people believe theyknow how to treat this disease could not reach even a partial remission of nephritis.

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When you look at the renal response at 52 weeks and using the combined complete pluspartial remission, there was a tendency for rituximab to be of greater benefit than theplacebo group although this did not reach statistical significance.

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The improvement of the renal response was gradual and progressive up to 52 weeks

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but when we looked at the response or the proteinuria in the group, there was no differencealthough this slide does not show you the patients that were markers of autoimmunity likeanti-dsDNA, complement levels responded better also had better response with regards toreduction of proteinuria.

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Regarding the secondary endpoints, the main differences were in fact in the serologicalbiomarkers where patients treated with rituximab had a better response in lowering anti-dsDNA levels and a better response on increasing C3 and C4 complement levels.

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Regarding the steroid dose, there was no significant difference in the cumulative dose in thepatients of the placebo group versus the group that received rituximab. However, there wasa tendency that at the end of this study, of less steroid use in the rituximab arm.

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When the study was re-divided to evaluate race, there was a tendency for African- Americansto respond better to rituximab than to placebo but there was no difference betweenHispanics or Caucasians and the better response in the African-American contingence wasbasically due to the higher degree of partial remission in this patient population.

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Regarding safety one good signal was that adding rituximab to a background of prednisoneor CellCept did not increase the number of serious adverse events or infectious complicationsor other adverse events. Interestingly, the presence of human anti-chimeric antibodies thatare antibodies produced against a foreign toxin like rituximab for example, were present in11% of patients with rituximab but even patients with placebo also developed anti-chimericantibodies.

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Regarding death there were two deaths and both occurred in the rituximab arm. One of apatient of sepsis on day 64 and one of a patient with pneumocystis pneumonia at day 58.This tells us how important it is to do prophylaxis on patients with rituximab again withpneumocystis pneumonia because B cells are essential to keep pneumocystis at bay.

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The conclusions of the LUNAR are the following. To date LUNAR is the largest randomisedplacebo controlled trial to evaluate an intervention in lupus nephritis. Although there werenumerically more responders in the rituximab group, 57 versus 46, the study did not show astatistically significant difference in the primary or clinical secondary endpoints at week 52.Rituximab had a significant effect on the level of anti-dsDNA and complement at week 52,although the clinical significance of this is unclear. Adverse events and serious adverse eventswere similar in frequency between the groups with no new or unexpected safety signals.

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So the question is, what went wrong with LUNAR? This is something that doctor LizLivingstone wrote very eloquently in an editorial that accompanied the results of LUNAR.

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I would like to bring to the appointment that maybe part of the issues come in theassumption of the sample size determination. LUNAR was very tough in the fact that theywere very optimistic in trying to get a rate of complete response in lupus nephritis of 50%.Now anyone who deals with lupus nephritis knows that that is probably a little bit too farbecause no study to my understanding has reached 50% complete remission ever and tounderestimate the reason of partial remission. I'd like to remind you that in fact, the LUNARfound a 15% advantage of partial remission in the patients treated with rituximab versusplacebo. I remind you that a delta of 15% in the endpoint but then including 2133 patientsled the FDA to approve Belimumab in a non-renal lupus study based on much less strongercriteria of proteinuria rather than some questionnaires that are of doubtful significance.

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Another issue is that we have to remember that the use of rituximab was associated not onlywith a significant increase in C3 and C4 complement levels but also in anti-dsDNA levels.

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Using another disease but just as an example, this is a study that we conducted in patientswith membranous nephropathy treated with rituximab. When you look at the anti-PLA2R thatis a marker theoretically of disease activity. You can see that by the 12 months there is asignificant decrease of the levels of the antibody. But still, despite almost disappearance of allthe antibodies in all patients, you still can see that the proteinuria still remains quiteelevated.

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In fact, doctor Remuzzi's group showed in a recent paper again in the patients withmembranous nephropathy treated with rituximab that it takes at least 2-3 years forproteinuria to reach its -. So one of the problems with LUNAR I think and in any study thatuses proteinuria as you endpoint is that 12 months in my view is not enough for you to seethe total effect.

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Lastly there is a perception that just because you want to treat someone that the kidney isgoing to behave as you expect it to. This is a kidney biopsy in a patient again withmembranous nephropathy before and after treatment with rituximab and you can see that inthis second biopsy done two years later, all the subepithelial deposits present here havecompletely disappeared but the glomerular basement membrane is markedly distorted. Assuch, is not a surprise that proteinuria persista ta abiout 1 g/24h but his anti-PLA2R levelsthat were high to begin with had become undetectable for the last 12 months. Thus thepatient had reached immunological remission but proteinuria persist because of damage tothe GBM. So we could argue that to use proteinuria as a definition of remission is completeignorance of the immunological situation. Therefore, and I think Doctor Ferrario is going to talkabout the importance of re-biopsying those patients because we are at the moment trying todesign therapies mainly just looking with one eye =proteinuria. I would argue that re-biopsying these patients and taking into consideration the results of the biopsy together withimmunological results are the way to go into future studies of lupus nephritis. In addition, alonger follow-up is really needed to assess those results.

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Thank you very much.