We previously evidenced a reduced response to i.v. pamidronate in Q15STM1 mutation carriers (Q15STM1+) with Pagets disease of bone (PDB). In order to confirm and extend this observation, we investigated the effect of Q15STM1 mutation and polymorphisms in three genes associated with PDB (TNFRSF11A; OPTN; TNFRSF11B) on the response to bisphosphonates. First, a retrospective study was performed in 335 patients treated with i.v. clodronate (CLN) 1500 mg/6 months (n=84), i.v. pamidronate (PAM) 60 mg/6 months (n=75), risedronate (RIS) 30 mg/day for 2 months (n=57), neridronate (NER) 200 mg i.m. or i.v. (n=61) and zoledronate (ZOL) 4 mg or 5 mg i.v. (n=48). Overall, Q15STM1+ patients had an increased disease severity and a reduced response to CLN or PAM than Q15STM1− patients. Despite carriers of TNFRSF11A rs1805034 CC genotype had increased PDB severity, there was no association between this genotype and the response to any treatment. Conversely, there was an increased prevalence of TT carriers of rs1561570 (OPTN) in non-responders to CLN. Normalization after the first CLN course was achieved in 69% of CC vs 42% of TT carriers despite no significant differences in disease extension or activity, especially in Q15STM1− patients. A similar but not significant trend was observed for PAM. Conversely, RIS, ZOL and NER were effective in most patients. We then designed a prospective analysis in patients treated with iv ZOL 5 mg (n=130) or NER 200 mg (n=70) and followed-up for more than 3 years. Even though most patients achieved biochemical remission after the first NER course for more than 12 months, there was a trend for an earlier relapse in Q15STM1+ vs Q15STM1−patients. Conversely most ZOL treated patients achieved biochemical remission independent of Q15STM1 mutation and did not need retreatment. These results suggest that PDB patients with Q15STM1 mutation may require a more aggressive treatment regimen for long-term disease remission.
17 May 2014 - 20 May 2014