Suicidal behaviour and CFTR modulators: A case series and WHO database disproportionality analysis.

Background: A highly effective therapy involving elexacaftor, tezacaftor, and ivacaftor (ETI) for cystic fibrosis (CF) patients has recently raised safety concerns regarding potential psychiatric disorders. The manuscript reports cases of suicide attempts in patients receiving ETI and investigates putative causality using the WHO spontaneous reporting database.

Methods: First, four cases of suicide attempts/self-injury are described. Second, a disproportionality analysis was conducted using spontaneous reports collected in Vigibase through the standardised MedDRA Query (narrow version) "Suicide/Self-injury" and ETI exposure. Reporting Odds Ratio (ROR) was calculated for the main and subgroup (i/suicide attempt, ii/suicidal ideation) analyses. Sensitivity analyses were performed with variations in exposure, to ivacaftor/lumacaftor to assess the intrinsic psychiatric risk of CF patients, and paracetamol as a positive control for suicide attempt and a negative one for suicidal ideation. Exposure to reduced-dose ETI was studied to evaluate the dose-gradient effect.

Results: Four cases of suicide attempt/self-injury occurred 3 to 13 months after ETI initiation in CF patients and were reported to the Bordeaux Pharmacovigilance centre. Aside, in Vigibase, ETI is associated with an increased likelihood of reporting suicidal behaviour (ROR 2.5, 95 % CI[2.1; 2.8]). A signal of disproportionate reporting was found for the subgroup of suicide attempts (1.4, 95 % CI[1.2; 1.8]), unlike ivacaftor/lumacaftor, which was associated only with the risk of reporting suicidal ideation. Significant ROR values were also found for reduced-dose ETI for all psychiatric effects studied except suicide attempt.

Conclusions: ETI exposure is related with increased reporting of suicidal behaviour. A potential dose-dependent effect merits further investigation.