KESIMPTA resources
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Prescribing information (external link)
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KESIMPTA®▼ (ofatumumab) safety profile and side effects
KESIMPTA is indicated for the treatment of adult patients with relapsing forms of multiple sclerosis (RMS) with active disease defined by clinical or imaging features.1
All patient imagery on this webpage is fictional and used for illustrative purposes only.1
Women of childbearing potential should use effective contraception (methods that result in less than 1% pregnancy rates) while receiving KESIMPTA and for 6 months after the last administration.
Please refer to the Summary of Product Characteristics (SmPC) for full safety information.
Overall safety profiles up to 8 years2
Safety population in a pooled analysis
Overall population (N=2531)
Included participants receiving ≥1 KESIMPTA doses in:
ASCLEPIOS I/II, APOLITOS, APLIOS, ARTIOS or the umbrella extension study ALITHIOS3–8
Recently diagnosed (≤3 years) treatment-naïve subgroup (RDTN) (N=546)
Included participants receiving ≥1 KESIMPTA doses in:
ASCLEPIOS I/II or ALITHIOS3,7,8
Overall safety profiles up to 8 years2
Overall population (N=2,531) | RDTN subgroup (N=546) | |||
Adverse event (AE) | n (%) | EAIR (95% CI) | n (%) | EAIR (95% CI) |
Participants with at least one AE | 2,368 (93.6) | 128.46 (123.39–133.74) | 512 (93.8) | 121.65 (111.56–132.66) |
Participants with at least one serious adverse event (SAE) | 425 (16.8) | 3.94 (3.58–4.33) | 96 (17.6) | 3.67 (3.00–4.48) |
AEs leading to KESIMPTA discontinuation | 167 (6.6) | - | 55 (10.1) | - |
Serious infections | 140 (5.5) | 1.21 (1.03–1.43) | 34 (6.2) | 1.21 (0.86–1.69) |
Serious infections (excluding COVID-19) | 94 (3.7) | 0.80 (0.66–0.98) | 19 (3.4) | 0.66 (0.42–1.04) |
Serious COVID-19 infections | 53 (2.1) | 0.45 (0.34–0.59) | 18 (3.3) | 0.62 (0.39–0.99) |
Injection-related reactions | 819 (32.4) | 9.54 (8.91–10.22) | 142 (26.0) | 6.35 (5.39–7.49) |
Injection-site reactions | 346 (13.7) | 3.28 (2.95–3.64) | 92 (16.8) | 3.65 (2.97–4.47) |
Deaths | 15* (0.59) | - | 8† (1.4) | - |
Malignancies | 40 (1.6) | 0.33 (0.25–0.46) | 11 (2.0) | 0.38 (0.21–0.68) |
Adapted from Pardo G, et al. 2026.2
Exposure-adjusted incidence rate (EAIR) per 100 patient-years (PYs) of AEs and SAEs with up to 8 years of KESIMPTA treatment remained consistent with that in the ASCLEPIOS I/II trials, in the overall population including the RDTN subgroup2
EAIRs for AEs including serious infections and malignancies did not increase over time in the overall safety population and the RDTN subgroup2
The RDTN subgroup refers to patients who were recently diagnosed (≤3 years) and treatment-naïve.2
EAIR per 100 PYs is defined as the expected number of patients with the given event over 100 years of exposure to a treatment, assuming the event rate is constant over time. This is estimated by Poisson regression where participants' time is taken until first event occurrence, or the last day the patient was at risk, for those who did not have the event.2
Treatment-emergent AEs recorded in ASCLEPIOS3
ASCLEPIOS I and II study design:1,3
Two double-blind, double-dummy, Phase III trials
Participants had RMS
Participants were randomised to receive subcutaneous (SC) KESIMPTA (20 mg every 4 weeks after 20 mg loading doses at Days 1, 7, and 14) (n=946) or oral teriflunomide (14 mg daily) for up to 30 months (n=936)‡
Treatment-emergent AEs recorded in ASCLEPIOS3
KESIMPTA (N=946) | Teriflunomide (N=936) | |
Any AEs | 791 (83.6) | 788 (84.2) |
Any SAEs | 86 (9.1) | 74 (7.9) |
Most common AEs | ||
Injection-related reactions (systemic)§ | 195 (20.6) | 143 (15.3) |
Nasopharyngitis | 170 (18.0) | 156 (16.7) |
Headache | 126 (13.3) | 116 (12.4) |
Injection-site reaction (local) | 103 (10.9) | 52 (5.6) |
Upper respiratory tract infection | 97 (10.3) | 120 (12.8) |
Urinary tract infection | 97 (10.3) | 78 (8.3) |
Back pain | 72 (7.6) | 58 (6.2) |
Fatigue | 71 (7.5) | 72 (7.7) |
Influenza | 62 (6.6) | 59 (6.3) |
Nausea | 61 (6.4) | 64 (6.8) |
Blood IgM decreased | 56 (5.9) | 21 (2.2) |
Alopecia | 54 (5.7) | 138 (14.7) |
Arthralgia | 49 (5.2) | 44 (4.7) |
Diarrhoea | 49 (5.2) | 111 (11.9) |
Pain in extremity | 46 (4.9) | 66 (7.1) |
Depression | 45 (4.8) | 48 (5.1) |
Hypertension | 35 (3.7) | 55 (5.9) |
Paraesthesia | 27 (2.9) | 52 (5.6) |
Adapted from Hauser SL, et al. 2020.3
Treatment discontinuations in ASCLEPIOS3
In the ASCLEPIOS trials, treatment discontinuations due to AEs were similar between patients treated with KESIMPTA (5.7%, n=54/946) and teriflunomide (5.2%, n=49/936).3
Discontinuations due to systemic injection reactions were rare, with only 0.1% (n=1/946) reported for KESIMPTA and none reported for teriflunomide.3
Adverse reactions in the SmPC1
| Infections and infestations | |
| Very common | Upper respiratory tract infections¶ Urinary tract infections‖ |
| Common | Oral herpes |
| Immune system disorders | |
| Not known | Hypersensitivity reactions** |
| General disorders and administration site conditions | |
| Very common | Injection-site reactions (local) |
| Injury, poisoning and procedural complications | |
| Very common | Injection-related reactions (systemic) |
| Gastrointestinal disorders | |
| Common | Nausea, vomiting†† |
| Investigations | |
| Common | Blood IgM decreased |
Adapted from KESIMPTA (ofatumumab) Summary of Product Characteristics.1
Please refer to the SmPC for full safety information.1
Frequency is categorised as: Very common (≥1/10); common (≥1/100 to <1/10); uncommon (≥1/1000 to <1/100); rare (≥1/10,000 to <1/1000); very rare (<1/10,000).1
Learn more about B-cell depletion data
Safety considerations and precautions1
Please refer to the SmPC for full safety information.1
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Contraindications1
Hypersensitivity to the active substance or to any of the excipients in KESIMPTA
Patients in a severely immunocompromised state
Severe active infection until resolution
Known active malignancy
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Traceability1
In order to improve the traceability of biological medicinal products, the name and the batch number of the administered product should be clearly recorded.
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Treatment of severely immunocompromised patients1
Patients in a severely immunocompromised state must not be treated until the condition resolves
It is not recommended to use other immunosuppressants concomitantly with KESIMPTA except corticosteroids for symptomatic treatment of relapses
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Vaccinations1
All immunisations should be administered according to immunisation guidelines at least 4 weeks prior to initiation of KESIMPTA for live or live-attenuated vaccines and, whenever possible, at least 2 weeks prior to initiation of KESIMPTA for inactivated vaccines
KESIMPTA may interfere with the effectiveness of inactivated vaccines
The safety of immunisation with live or live-attenuated vaccines following KESIMPTA therapy has not been studied. Vaccination with live or live-attenuated vaccines is not recommended during treatment and after discontinuation until B-cell repletion. The median time to B-cell recovery to the lower limit of normal (defined as 40 cells/μl) or baseline value is 24.6 weeks post treatment discontinuation based on data from Phase III studies
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Pregnancy and family planning1
Women of childbearing potential should use effective contraception (methods that result in less than 1% pregnancy rates) while receiving KESIMPTA and for 6 months after the last administration of KESIMPTA, as there is a limited amount of data from the use of KESIMPTA in pregnant women
Treatment with KESIMPTA should be avoided during pregnancy unless the potential benefit to the mother outweighs the potential risk to the foetus
KESIMPTA may cross the placenta and cause foetal B-cell depletion based on findings from animal studies
The use of KESIMPTA in women during lactation has not been studied. It is unknown whether KESIMPTA is excreted in human milk. In humans, excretion of IgG antibodies in milk occurs during the first few days after birth, and decreases to low concentrations soon afterwards. Consequently, a risk to the breastfed child cannot be excluded during this short period. Afterwards, KESIMPTA could be used during breastfeeding if clinically needed. However, if the patient was treated with KESIMPTA up to the last few months of pregnancy, breastfeeding can be started immediately after birth
There are no data on the effect of KESIMPTA on human fertility
Non-clinical data did not indicate potential hazards for humans based on male and female fertility parameters assessed in monkeys
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Vaccination of infants born to mothers treated with KESIMPTA during pregnancy1
In infants of mothers treated with KESIMPTA during pregnancy, live or live-attenuated vaccines should not be administered before the recovery of B-cell counts has been confirmed. Depletion of B-cells in these infants may increase the risks from live or live-attenuated vaccines
Inactivated vaccines may be administered as indicated prior to recovery from B-cell depletion; however, assessment of vaccine immune responses, including consultation with a qualified specialist, should be considered to determine whether a protective immune response was mounted
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Infections1
It is recommended to evaluate the patient’s immune status prior to initiating therapy
Based on its mode of action and available clinical experience, KESIMPTA has the potential for an increased risk of infections. Administration should be delayed in patients with an active infection until the infection is resolved
KESIMPTA must not be given to patients in a severely immunocompromised state (e.g. significant neutropenia or lymphopenia)
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Progressive multifocal leukoencephalopathy (PML)1
Since John Cunningham virus infection resulting in PML has been observed in patients treated with anti-CD20 antibodies, other MS therapies and KESIMPTA at substantially higher doses in oncology indications, physicians should be vigilant for medical history of PML and for any clinical symptoms or magnetic resonance imaging findings that may be suggestive of PML. If PML is suspected, treatment with KESIMPTA should be suspended until PML has been excluded
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Hepatitis B virus (HBV) reactivation1
HBV reactivation has occurred in patients treated with anti-CD20 antibodies, which in some cases resulted in fulminant hepatitis, hepatic failure and death
Patients with active HBV disease should not be treated with KESIMPTA. HBV screening should be performed in all patients before initiation of treatment. As a minimum, screening should include hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (HBcAb) testing. These can be complemented with other appropriate markers as per local guidelines. Patients with positive HBV serology (either HBsAg or HBcAb) should consult a liver disease expert before the start of treatment and should be monitored and managed following local medical standards to prevent HBV reactivation
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Injection-related reactions1
- Patients should be informed that systemic injection‑related reactions could occur, generally within 24 hours and predominantly following the first injection
- Symptoms most frequently observed in RMS clinical studies include fever, headache, myalgia, chills, fatigue, nausea and vomiting, and were predominantly (99.8%) mild to moderate in severity. There were no life-threatening systemic injection‑related reactions reported in RMS clinical studies
- Additional systemic injection‑related reactions reported in the post-marketing setting include rash, urticaria, dyspnoea and angioedema (e.g., tongue, pharyngeal or laryngeal swelling), and rare cases which were reported as anaphylaxis. While there were some cases which were serious and resulted in discontinuation of KESIMPTA treatment, there were also serious cases where patients were able to continue KESIMPTA treatment without further incidents
- Some systemic injection‑related reaction symptoms may be clinically indistinguishable from Type 1 acute hypersensitivity reactions (IgE-mediated). A hypersensitivity reaction may present during any injection, although typically would not present with the first injection. For subsequent injections, more severe symptoms than previously experienced, or new severe symptoms, should prompt consideration of a potential hypersensitivity reaction. Patients with known IgE-mediated hypersensitivity to KESIMPTA must not be treated with KESIMPTA
- Only limited benefit of premedication with steroids was seen in RMS clinical studies. Injection-related reactions can be managed with symptomatic treatment, should they occur. Therefore, use of premedication is not required
- Injection site reaction (local) symptoms observed in clinical studies included erythema, swelling, itching and pain
- The first injection should be performed under the guidance of an appropriately trained healthcare professional
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Other immunosuppressive or immune-modulating therapies1
The risk of additive immune system effects should be considered when co-administering immunosuppressive therapies with KESIMPTA
When initiating KESIMPTA after other immunosuppressive therapies with prolonged immune effects or initiating other immunosuppressive therapies with prolonged immune effects after KESIMPTA, the duration and mode of action of these medicinal products should be taken into account because of potential additive immunosuppressive effects
*Including the following: sudden death (n=1), oesophageal adenocarcinoma (n=1), ventricular fibrillation (n=1), completed suicide (n=1), gastric ulcer perforation (n=1), COVID-19 (n=2), COVID-19 pneumonia (n=1), COVID-19/COVID-19 pneumonia (n=1), COVID-19 pneumonia/pneumothorax (n=1), pneumonia/septic shock (n=1), injury (n=1), intestinal metastasis (n=1), ovarian epithelial cancer (n=1), cerebrovascular disorder (n=1).³
†Sudden death (n=1), oesophageal adenocarcinoma (n=1), ventricular fibrillation (n=1), completed suicide (n=1), COVID-19/COVID-19 pneumonia (n=1), COVID-19 (n=2), aortic dissection (n=1).³
‡Patients in the teriflunomide arm received a matching placebo injection to ensure blinding (double-dummy design).3
§Only reactions or symptoms that occurred within 24 hours after injection are included (i.e., time to onset of reaction ≤24 hours).3
¶Grouping of preferred terms (PTs) was considered for adverse drug reaction (ADR) frequency determination and includes the following: nasopharyngitis, upper respiratory tract infection, influenza, sinusitis, pharyngitis, rhinitis, viral upper respiratory infection, tonsillitis, acute sinusitis, pharyngotonsillitis, laryngitis, pharyngitis streptococcal, viral rhinitis, sinusitis bacterial, tonsillitis bacterial, viral pharyngitis, viral tonsillitis, chronic sinusitis, nasal herpes and tracheitis.1
‖Grouping of PTs was considered for ADR frequency determination and includes the following: urinary tract infection, cystitis, Escherichia urinary tract infection, asymptomatic bacteriuria and bacteriuria.1
**Reported during post-marketing experience.1
††Nausea and vomiting have been reported in association with systemic injection-related reactions.1
ADR, adverse drug reaction; AE, adverse event; COVID-19, coronavirus disease 2019; EAIR, exposure-adjusted incidence rate; HBcAb, hepatitis B core antibody; HBsAg, hepatitis B surface antigen; HBV, hepatitis B virus; IgE, immunoglobulin E; IgG, immunoglobulin G; IgM, immunoglobulin M; PML, progressive multifocal leukoencephalopathy; PT, preferred term; PY, patient-year; RDTN, recently diagnosed treatment-naïve; RMS, relapsing forms of multiple sclerosis; SAE, serious adverse event; SC, subcutaneous; SmPC, summary of product characteristics.
References
KESIMPTA (ofatumumab) Summary of Product Characteristics.
Pardo G, et al. P9.006. American Academy of Neurology Annual Meeting. 18–22 April 2026, Chicago, IL, US.
Hauser SL, et al. N Engl J Med 2020;383(6):546–557 and supplementary material.
Kira JI, et al. Mult Scler 2022;28:1229–1238.
Bar-Or A, et al. Mult Scler 2022;28:910–924.
Bove R, et al. P791. European Committee for Treatment and Research in Multiple Sclerosis Annual Congress. 24–26 September 2025, Barcelona, Spain.
Hauser SL, et al. Mult Scler 2023;29:1452–1464.
Hauser SL, et al. Mult Scler 2022;28:1576–1590.
UK | June 2026 | 443397-2
Adverse events should be reported. Reporting forms and information can be found at www.mhra.gov.uk/yellowcard. Adverse events should also be reported to Novartis online through the pharmacovigilance intake (PVI) tool at www.novartis.com/report, or alternatively email [email protected] or call 01276 698370.
