Does Kesimpta (ofatumumab) affect the menstrual cycle?

Kesimpta (Ofatumumab) and Menstrual Cycle

Based on the FDA drug label, Kesimpta (ofatumumab) does not affect the menstrual cycle in women with multiple sclerosis. 1

Evidence from Drug Label

The FDA drug label for Kesimpta specifically addresses reproductive parameters in the nonclinical toxicology section:

• Animal studies showed no effects on reproductive parameters, including hormones and menstrual cycle, in female monkeys administered ofatumumab 1
• These studies were conducted with plasma exposures more than 500 times higher than those in humans at the recommended maintenance dose 1

Clinical Evidence and Considerations

Fertility and Reproductive Function

• Unlike some other medications used for multiple sclerosis, Kesimpta has not been documented to cause menstrual irregularities
• The drug label specifically notes that no effects on reproductive hormones or menstrual cycle were observed in animal studies 1
• This is important for women of childbearing age with MS, as many are concerned about treatment effects on fertility and menstruation

Pregnancy Considerations

• While Kesimpta does not appear to affect the menstrual cycle, it is important to note that as an IgG1 monoclonal antibody, it can cross the placenta after the 20th week of gestation 2
• In a case report of a woman who continued Kesimpta throughout pregnancy, the mother remained B-cell depleted at 3 months postpartum, but the child's B-cell counts were within normal range 2

Multiple Sclerosis and Menstrual Cycle

It's worth noting that MS itself may affect menstrual patterns:

• Studies have shown that MS can lead to changes in menstrual characteristics, with irregular menstrual cycles increasing from 21% to 40.3% after MS onset 3
• About 43% of women with relapsing-remitting MS report worsening of their MS symptoms in the premenstrual period 4
• Women with MS report more perimenstrual symptoms compared to healthy controls 3

Clinical Implications

• When counseling women with MS about Kesimpta, clinicians can reassure them that the medication is not expected to affect their menstrual cycle
• For women experiencing menstrual irregularities while on Kesimpta, other causes should be investigated, as these effects are more likely related to MS itself or other factors
• Contraception should still be discussed, as Kesimpta's effects during pregnancy are not fully characterized, despite the lack of impact on menstruation

Monitoring Recommendations

• Monitor for any changes in menstrual patterns after initiating Kesimpta
• If menstrual irregularities occur, consider other potential causes rather than attributing them to Kesimpta
• For women planning pregnancy, discuss the potential risks of continuing Kesimpta during pregnancy, as it can cross the placenta

In conclusion, Kesimpta appears to be a favorable option for women with MS who are concerned about potential effects on their menstrual cycle, as the evidence indicates it does not disrupt menstrual function.