# Ofatumumab

Source: https://onco.cc/drugs/ofatumumab/  
OnCo record `ofatumumab` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Ofatumumab (Arzerra) is a fully human anti-CD20 antibody for chronic lymphocytic leukaemia, used with chlorambucil in untreated patients or alone after other drugs have failed; the same molecule is sold as Kesimpta for multiple sclerosis.

## Summary

Ofatumumab received accelerated FDA approval in October 2009 for CLL refractory to fludarabine and alemtuzumab, then full approvals with chlorambucil in previously untreated CLL where fludarabine is inappropriate (COMPLEMENT-1, 2014: longer progression-free survival than chlorambucil alone), as extended treatment in recurrent or progressive CLL after response (PROLONG, 2016) and with fludarabine and cyclophosphamide in relapsed CLL (COMPLEMENT-2, 2016). The EU granted conditional authorisation in 2010; the marketing authorisation was later withdrawn for commercial reasons and Arzerra is now supplied in many countries through a compassionate programme, while Kesimpta (subcutaneous ofatumumab) is marketed for multiple sclerosis. Hepatitis B reactivation and progressive multifocal leukoencephalopathy carry boxed warnings.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-09-10
- Also known as: Kesimpta (multiple sclerosis formulation)
- Tags: nci-list
- Brand: Arzerra
- Modality: Monoclonal antibody (anti-CD20, fully human IgG1)
- Mechanism: Binds a distinct small- and large-loop epitope of CD20 close to the membrane, giving potent complement-dependent cytotoxicity as well as antibody-dependent cellular cytotoxicity against B cells.
- Approvals: US 2009: CLL refractory to fludarabine and alemtuzumab (accelerated); US 2014: Previously untreated CLL with chlorambucil; later extended treatment and relapsed CLL with fludarabine and cyclophosphamide; EU 2010: CLL refractory to fludarabine and alemtuzumab (conditional; authorisation since withdrawn)

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Ofatumumab
- US label (DailyMed): https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=ofatumumab
- NCI drug page: https://www.cancer.gov/about-cancer/treatment/drugs/ofatumumab

## Connected records

- drugs: [Obinutuzumab](https://onco.cc/drugs/obinutuzumab/), [Rituximab](https://onco.cc/drugs/rituximab/)
- cancers: [Chronic lymphocytic leukaemia](https://onco.cc/cancers/cll/)
- technologies: [Monoclonal antibodies](https://onco.cc/technologies/monoclonal-antibody/)
- targets: [CD20](https://onco.cc/targets/cd20/)
- companies: [Genmab](https://onco.cc/companies/genmab/), [Novartis](https://onco.cc/companies/novartis/)
- trials: [RESONATE](https://onco.cc/trials/resonate/)

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