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a patient affected by rheumatoid arthritis developed a squamous - cell carcinoma probably due to abatacept , according to naranjo algorithm .
the case describes this adverse reaction for the first time and highlights the need for additional studies to establish the long - term risk profile of abatacept .
abatacept is a fusion protein composed of the extracellular domain of cytotoxic t - lymphocyte antigen 4 ( ctla-4 ) and the fc region of the human immunoglobulin g1 ( igg1 ) that acts as a selective t - cell costimulation modulator .
therapeutic indications of abatacept include rheumatoid arthritis ( ra ) not responding to traditional disease - modifying antirheumatic drugs ( dmards ) and refractory active polyarticular juvenile idiopathic arthritis ( jia ) .
summary of product characteristics ( spc )   for abatacept reports the possibility of basal - cell carcinoma and skin papilloma as uncommon events , lymphoma and malignant lung neoplasm as rare events .
we describe the case of a patient who developed a squamous - cell carcinoma ( scc ) of the tongue after 1 year of treatment with abatacept for refractory ra .
the case was reported by the university hospital of sassari ( aouss ) to the  sardinian regional center of pharmacovigilance  , unit of clinical pharmacology , university hospital of cagliari ( aouca ) , as provided by the project entitled  development of a pharmacovigilance network in sardinia  .
as biologics are newer drugs , there is a lack of long - term safety data .
a 50-year - old woman with a long history of ra presented a tongue ulcer after 1 year of therapy with abatacept 750 mg every 4 weeks intravenously and leflunomide 20 mg / day .
the tongue ulcer was subjected to biopsy and histopathology revealed  moderately differentiated scc of the lateral left border of the tongue .  in view of the possible role of abatacept in the development of the adverse reaction , therapy with this drug was discontinued .
symptoms included stiffness and arthritis of metacarpophalangeals , proximal interphalangeal joints of the hand , metatarsal interphalangeals , ankle and left knee joints .
the patients had no comorbidities , apart from a history of allergy to penicillin , wool , dermatophagoides farinae and pteronyssinus , crustaceans , and peas .
the patient was treated up to 2005 with low doses of methylprednisolone and sulfasalazine ( 500 mg thrice daily , orally ) .
therapy with methotrexate i m was started and discontinued after 2 months for urticarial rush . in december 2005 , the patient started therapy with adalimumab ( 40 mg twice weekly ) , leflunomide ( 20 mg , orally , one tablet every 2 days ) , and celecoxib ( up to 200 mg twice daily , as needed ) . from may 2008 ,
the patient switched to once - weekly treatment with adalimumab and daily treatment with leflunomide . in october 2009 , therapy with adalimumab was suspended due to respiratory difficulty and urticarial rush following drug injection .
the patient started receiving etanercept ( 50 mg weekly ) but therapy was suspended 3 months later due to insurgence of urticarial reactions and respiratory difficulty . from april 2010 to august 2011 , the patient was treated with abatacept 750 mg monthly in association with leflunomide 20 mg daily ( reduced to 20 mg every 2 days from march 2011 ) , achieving clinical remission . in september 2011 , after histopathology confirmation of scc of the tongue , therapy with abatacept was discontinued . from september 2011 to june 2012 , the patient was treated with leflunomide 20 mg / day and methylprednisolone as needed . from june 2012 ,
therapy included methotrexate ( 10 mg / week , subcutaneously , augmented to 15 mg / week from december 2012 ) , calcium folinate 10 mg / week , leflunomide 20 mg / day , risedronate sodium ( 75 mg every 2 weeks ) , calcium carbonate and cholecalciferol ( vitamin d3 ) 500 mg + 440 ui ( 2 tablets daily from december 2011 ) , methylprednisolone , and nonsteroidal anti - inflammatory drugs as needed .
the patient had no personal history of risk factors for scc of the tongue : she was not a smoker at the moment of observation ( albeit being an occasional smoker in her youth , smoking a cigarette every few days ) and her alcohol intake was restricted to one glass of wine during meals in rare occasions .
the patient had a familial history of ra ( cousin of the mother ) and lung cancer ( first- grade cousin , 68 years old ) . in september 2011 , following the histopathology report , the patient was admitted to hospital and subjected to left glossectomy , left cervical lymphadenectomy , and reconstruction of the intraoral defect using a myomucosal flap from the buccinator muscle .
surgical pathology report showed resection margins were free of involvement and reactive lymph nodes were metastasis - free .
laboratory test results showed normal except for mild neutropenia and relative lymphocytosis : neutrophils 1.49  10/ml ( 1.88 ) , 23.3% ( 3580 ) , and lymphocytes 3.59  10/ml ( 1.54 ) .
six and 10 months after surgery , no clinical , echography , or computed tomography ( ct ) signs of relapse were observed .
the case was reported to the italian regulatory authority ( report number of italian spontaneous - reporting database : 157854 ) and to the manufacturer of the drug .
guidelines for submitting adverse event reports for publication    in order to offer a clearer differential diagnosis for the event . applying naranjo algorithm   and world health organization ( who ) algorithm of uppsala monitoring centre , the score generated suggested that the adverse reaction was probable due to abatacept and to leflunomide .
other causes of scc of the tongue were considered rather unlikely , as suggested by personal and familial history of the patient .
the adverse reaction had a reasonable time relationship to abatacept intake and could be speculated as an adverse reaction arising from long - term use ( type c according to edwards and aronson , 2000 ) .
on the basis of available evidence , the adverse reaction described seems to be more probably due to abatacept than leflunomide , as therapy with leflunomide does not seem to be associated to insurgence of malignancies , according to data from large european registers .
in fact , even if an increase in the risk of pancreatic cancer was hypothesized on the basis of seven cases detected in the german biologics register ( rabbit ) , this risk was not confirmed by a subsequent replication analysis conducted on the national biologics registers in the uk and sweden .
to the best of our knowledge , this adverse reaction during therapy with abatacept has not been previously reported : although spc for abatacept   does report incidence of malignancies ( in particular , basal - cell carcinoma and skin papilloma as uncommon events ; lymphoma and malignant lung neoplasm as rare events ) , specific cases of scc of the tongue associated to use of this drug have not been described until now .
spc for abatacept   states that  the potential role of abatacept in the development of malignancies , including lymphoma , in humans is unknown .
 a cochrane review on efficacy and safety of abatacept in patients with ra   outlined the necessity of long - term studies and postmarketing surveillance to assess harms and sustained efficacy of abatacept .
this necessity was also confirmed by the overview of cochrane reviews on biologics for ra : even though the review did not show statistically significant difference between patients receiving abatacept and placebo with regard to safety , the authors outlined the lack of precise information about rare side effects , including certain types of cancer .
the recent network meta - analysis and cochrane overview   showed that abatacept seemed to be associated with significantly fewer serious infections and serious adverse events compared to other biologics .
however , a limitation of this review is the choice of limiting inclusion to rcts and their open label extensions , whereas long - term observational studies , including population - based registries , could provide better estimates of the long - term safety of biologics .
the authors outlined the urgent need for more research addressing the issue of rare or long - term adverse effects of biologics . a recent systematic review and meta - analysis   showed no statistically significant increased risk of malignancy among ra patients treated with biologic response modifiers ( brms ) compared with other dmards or with placebo in rcts with a duration of at least 6 months .
based on the case presented , our opinion is that a relation between therapy with abatacept and onset of the scc of the tongue is plausible .
active postmarketing surveillance is essential to a better understanding of the safety profile of this drug .
even if the limitation of being a single case report must be taken into account , given the urgent necessity of collecting more information on the possible relation between malignancies and abatacept , we believe this work could be a valid contribution to the existing literature .
key clinical messagea patient affected by rheumatoid arthritis developed a squamous - cell carcinoma probably due to abatacept , according to naranjo algorithm . 
 the case describes this adverse reaction for the first time and highlights the need for additional studies to establish the long - term risk profile of abatacept .