A comparison between anorganic bone and collagen-preserving bone xenografts for alveolar ridge preservation: systematic review and future perspectives

After tooth extraction, dimensional changes affect the alveolar socket, leading to loss in alveolar bone height and width. Histological modifications also occur, with initial formation of a blood clot that is replaced with granulation tissue and subsequently with a provisional connective tissue matrix. Spontaneous healing ends with socket filling with woven bone, which is gradually replaced with lamellar bone and bone marrow. Adequate alveolar ridge dimensions and bone quality are required to assure optimal stability and osseointegration following dental implant placement. When a tooth is extracted, alveolar ridge preservation (ARP) procedures are an effective method to prevent collapse of the post-extraction socket. Heterologous bone is widely chosen by clinicians for ARP, and anorganic bone xenografts (ABXs) made bioinert by heat treatment represents the most used biomaterial in clinical applications. Collagen-preserving bone xenografts (CBXs) made of porcine or equine bone are fabricated by less invasive chemical or enzymatic treatments to remove xenogenic antigens, and these are also effective in preserving post-extraction sites. Clinical differences between anorganic bone substitutes and collagen-preserving materials are not well documented in the literature but understanding these differences could clarify how processing protocols influence biomaterial behavior in situ. This systematic review of the literature compares the dimensional changes and histological features of ABXs versus CBXs in ridge preservation procedures to promote awareness of different bone xenograft efficacies in stimulating the healing of post-extraction sockets.

POS0246 SEQUENTIAL RITUXIMAB AND MEPOLIZUMAB IN EOSINOPHILIC GRANULOMATOSIS WITH POLYANGIITIS

Background

Rituximab (RTX) is an effective remission-induction treatment in ANCA-associated vasculitides (AAVs). Some reports have suggested that it might be effective also in Eosinophilic Granulomatosis with Polyangiitis (EGPA), to induce and maintain remission of vasculitic manifestations [1,2]. However, its effects for preventing respiratory relapses seem to be poor. Mepolizumab (Mepo) (both 100 and 300mg/month) is effective in improving respiratory manifestations and lung function, while partially controlling also systemic activity [3,4]. Isolated case reports further indicate that the sequential therapy with RTX and Mepo might be effective [5-7].

Objectives

The study aimed to investigate the efficacy and safety of a therapeutic regimen based on sequential RTX and Mepo for the control of EGPA.

Methods

A multicenter, retrospective, cohort study was conducted on adult patients diagnosed with EGPA according to the ACR classification criteria [8] or MIRRA trial criteria [3]. Only patients who received induction therapy with RTX (any dosage), and subsequent treatment with Mepo (100-300 mg/4 weeks) within 12 months from last RTX administration were included. Patients receiving other induction therapies between RTX and Mepo were excluded. The effectiveness of sequential RTX and Mepo was assessed in terms of disease activity (by the Birmingham Vasculitis Activity Score, BVAS) and daily corticosteroid dosage. Safety data were also collected.

Results

Thirty-four EGPA patients treated with sequential RTX and Mepo were included (59% females, median age of 51 years (IQR 40-58); 41% ANCA positive).

In most cases (26/34; 76%), RTX was started at the dosage of 1g q2w, and all except two patients had active disease at time of RTX beginning [median BVAS of 9 (IQR 6-14)]. Specifically, most patients started RTX for the control of systemic manifestations (19/34; 56%), or of both systemic and respiratory symptoms (11/34; 32%). All except one patient were receiving oral corticosteroids, at a median dosage of 25 mg/day (10-38).

Mepo was started after a median of 14 months (6-23) from RTX initiation and after a median of 5 months (IQR 3-11) from the last RTX administration. Mepo was used at the dosage of 100mg/4 weeks in 32/34 (94%), mostly for the control of respiratory manifestations (25/34, 74%). At the time of starting Mepo, the median BVAS was 4 (2-8), and median prednisolone dose 10 mg/day (7-15). After a median follow-up of 28 months (IQR 23-33) from starting Mepo, the median BVAS decreased to 1.5 (IQR 0-4) and the median corticosteroid dosage to 5 mg/day (2.5-5), with 7/34 (21%) patients being off steroids. At last follow-up, most patients were off-RTX (28/34), typically due to stable disease remission (20/34; 59%).

Both RTX and Mepo were well-tolerated; 5 patients had adverse events on RTX (none serious), and 5 on Mepo (including one serious infection).

Conclusion

Sequential use of RTX and Mepo seems to be effective for remission induction and maintenance in EGPA.

References

[1]Emmi, Ann Rheum Dis, 2018

[2]Teixeira, RMD Open, 2019 3. Wechsler, NEJM, 2017

[4]Bettiol, Arthritis Rheumatol, 2021

[5]Shiroshita, Respir Med Case Rep, 2018

[6]Higashitani, Mod Rheumatol Case Rep, 2021

[7]Afiari, Cureus 2020

[8]Masi, Arthritis Rheum, 1990

Table 1.

Effectiveness of sequential RTX and Mepo in the 34 patients included in the study

RTX beginningMepo beginningLast follow-upMedian time elapsed (IQR)-14 months (6-23) from RTX beginning28 months (23-33) from Mepo beginningDosage1g q2w (26/34);100mg/4 weeks (32/34)6 patients off Mepo; 28 patients off RTX375mg/m2 for 4 weeks (8/34)300mg/4 weeks (2/34)Reason for treatment beginning (manifestations)Systemic (19/34);Respiratory (25/34);-Systemic + respiratory (11/34);Systemic (4/34);Only respiratory (3/34);Remission maintenance (5/34)Other (1/34)BVAS (median, IQR)9 (6-14)4 (2-8)1.5 (0-4)Prednisolone dosage (median, IQR), mg/day25 (10-38)10 (7-15)5 (2.5-5)

Disclosure of Interests

Alessandra Bettiol: None declared, Maria Letizia Urban: None declared, Federica Bello: None declared, Davide Fiori: None declared, Irene Mattioli: None declared, Giuseppe Lopalco: None declared, Florenzo Iannone: None declared, Allyson Egan: None declared, Luca Moroni: None declared, Lorenzo Dagna Consultant of: Consultation honoraria from GSK outside the current work, Marco Caminati: None declared, Simone Negrini: None declared, Paolo Cameli: None declared, Marco Folci: None declared, Paola Toniati: None declared, Roberto Padoan: None declared, Oliver Flossmann: None declared, Roser Solans-Laqué: None declared, Laura Losappio: None declared, Jan Schroeder Consultant of: Advisory Board fees from AstraZeneca and GSK, Marc André: None declared, Laura Moi: None declared, paola parronchi Consultant of: Consultation honoraria from GSK and Novartis, Fabrizio Conti: None declared, Savino Sciascia: None declared, David Jayne Consultant of: Consultant for Astra-Zeneca, Aurinia, BMS, Boehringer-Ingelheim, Chemocentryx, Chugai, CSL, GSK, Infla-RX, Janssen, Novartis, Roche/Genentech, Takeda and Vifor, Augusto Vaglio Consultant of: Consultation honoraria from GSK outside the current work, Giacomo Emmi Consultant of: Consultation honoraria from GSK outside the current work

Mepolizumab for Eosinophilic Granulomatosis with Polyangiitis (EGPA): a European multicenter observational study

OBJECTIVE

Mepolizumab proved efficacious for eosinophilic granulomatosis with polyangiitis (EGPA, former Churg-Strauss) at the dosage of 300mg/4 weeks in the randomized controlled MIRRA trial. Few successful real-life experiences with the dosage approved for severe eosinophilic asthma (100mg/4 weeks) were recently reported. We retrospectively assessed the effectiveness and safety of mepolizumab 100 and 300mg/4 weeks in a large European EGPA cohort.

METHODS

We included all EGPA patients treated with mepolizumab at the recruiting centres in 2015-2020. Treatment response was evaluated from month 3 through 24 (T3-T24) after mepolizumab starting. Complete response (CR) was defined as no disease activity (Birmingham Vasculitis Activity Score, BVAS=0) and a prednisone dose ≤4mg/day. Respiratory outcomes included asthma and ear-nose-throat (ENT) exacerbations.

RESULTS

We included 203 patients, of whom 191 at stable dosage (158 mepolizumab 100mg/4 weeks, 33 300mg/4 weeks). At T3, 25 patients (12.3%) had a CR. CR rates increased to 30.4% and 35.7% at T12 and T24 and were comparable between mepolizumab 100 and 300mg/4 weeks. Mepolizumab led to a significant reduction in BVAS, prednisone dose, eosinophil counts from T3 through T24, with no significant differences between 100 and 300 mg/4weeks. Eighty-two patients (40.4%) experienced asthma exacerbations [57/158 (36%) on 100mg/4 weeks; 17/33 (52%) on 300mg/4 weeks]. Thirty-one (15.3%) experienced ENT exacerbations. Forty-four patients (21.7%) experienced adverse events, most being non-serious (38/44).

CONCLUSION

Mepolizumab both at 100 and 300mg/4 weeks is effective for EGPA. The two dosages should be compared in the setting of a controlled trial.