Cancer diagnosis in a Spanish cohort of multiple sclerosis patients under dimethylfumarate treatment

BACKGROUND

Potential increase of cancer incidence is one of the main safety concerns of the disease-modifying therapies employed in Multiple Sclerosis (MS).

OBJECTIVE

Detailed description of patients who developed cancer among a prospective cohort of Spanish MS patients on dimethyl fumarate (DMF) treatment.

METHODS

We describe patients who developed cancer among a cohort of 886 MS patients on DMF treatment (2681 patient-years), with a median time of exposure of 39.5 months (IQR 23-51.5), who participated in a multicentre and prospective real-world study conducted in 16 Spanish National Health System hospitals from February 2014 to May 2019. Local researchers were periodically contacted by the investigation team to monitor safety issues. Cancer histories were collected from the medical records and the information was updated at July 30^th 2020.

RESULTS

Eight Caucasian women developed cancer, which accounts for 0.9% and an accumulated malignancy rate of 298.39 cases per 100,000 patient-years of DMF exposure. At the time of cancer diagnosis, age was between 33 to 67 years and median time on DMF treatment 16.5 months (range 1-53). Two patients had familiar history of cancer. No specific cancer lines were found (breast cancer in 2 cases, thyroid in 3, urothelial carcinoma, cervix and a progression to leiomyosarcoma from a mitotically active leiomyoma). DMF was withdrawn during cancer treatment in 6 patients and reintroduced later. All cancers except one are in complete remission. The patient with leiomyosarcoma died by cancer progression.

CONCLUSION

A relationship between cancers and DMF is unlikely because the malignancy rate was similar to that of the age-and sex-matched general population, and because of the absence of specific tumour cell lines. Nevertheless, as with other immunosuppressive DMTs, clinicians treating MS should be aware of any potential cancer symptom and demand proper testing.

Pregnancy exposure to disease-modifying drugs in multiple sclerosis: a prospective study

INTRODUCTION

In multiple sclerosis (MS), foetal exposure to disease-modifying drugs (DMDs) carries varying degrees of risk. We sought to analyse the clinical and obstetric outcomes of MS patients (MSp) exposed to DMDs during pregnancy.

PATIENTS AND METHODS

Observational study. We analysed the clinical-obstetric data of a cohort MSp, who became pregnant between 2007-2017. They were prospectively followed up during pregnancy and postpartum.

CONTROL GROUP

healthy pregnant women (HPW) and MSp unexposed to DMDs.

RESULTS

Sixty-eight pregnancies in MSp. Fifty-six HPW. Thirteen MSp were exposed to DMDs during pregnancy. Obstetric outcome: 2 (15%) infants had low birth weight, no preterm deliveries. Fifty-five MSp were not exposed to DMDs: 22 (40%) discontinued DMD before pregnancy, 33(60%) naïve. Five infants (9%) had low birth weight and 7 (12%) were preterm. HPW: 56. Low birth weight 6 (11%), preterm delivery 6 (11%). There were no differences in relapse incidence during pregnancy-puerperium between MSp groups. There were no differences in birth weight, gestation time, delivery-caesarean section. We found no special obstetric morbidity in women exposed to DMDs.

CONCLUSIONS

There were no significant differences in the clinical and obstetric variables analysed between pregnant women exposed to DMDs, unexposed, and HPW.