Abstract Introduction Ofatumumab (Kesimpta®) is a subcutaneous CD20-targeting antibody approved in Germany in 2021 for the treatment of relapsing multiple sclerosis (RMS). After careful instruction, patients can administer the treatment themselves. We previously reported data of 101 patients (Klimas et al. in Nervenarzt 94:923–933, 2023). The objective of this longitudinal study is to explore the tolerability and acceptability of ofatumumab from a patient perspective over a follow up period of 6 months. Methods In this prospective observational real-world study, we report follow up data of 81 patients. We evaluated sociodemographic data, disease duration, duration and side effects of ofatumumab use, expanded disability status scale (EDSS), Beck Depression Inventory II (BDI-II), Short-Form 36 (SF-36), Fatigue Scale of Motor and Cognitive Functions (FSMC), and modified Multiple Sclerosis Functional Composite Test (MSFC). In addition, we asked for subjective treatment outcomes, such as impact on quality of life, walking distance, concentration, mood, medication adherence, fatigue and the subjective course of MS on a numerical rating scale (1 = very negative; 5 = very positive). Furthermore, treatment discontinuations were recorded. Results The average duration of ofatumumab treatment was 10 months. In comparison to previous published data of our cohort, patients reported a significant increase in headache (10% up to 26%, p = 0.004) and limb pain (5% up to 26%, p < 0.001) as persistent side effects after the injections. More patients reported a very positive effect (p < 0.0001) on quality of life. 4 confirmed relapses occurred but no EDSS worsening, and no treatment discontinuations were documented during the observation period. Discussion As previously described, our prospective study indicates that patients have a good tolerability of ofatumumab, precisely because of the mild and few side effects at the first administration. However, the longer the observation period, the more headaches and limb pain occurred after the injections. Despite this, patients’ subjective quality of life improved. There were no discontinuations during the follow-up period, with the limitation of a high loss to follow-up.