Rituximab
| Evidence Level: L1 | Predicted Indications: 10 |
Table of Contents
Rituximab: From Rheumatoid Arthritis and B-Cell Lymphomas to Follicular Lymphoma
One-Sentence Summary
Rituximab is an anti-CD20 monoclonal antibody, originally used for B-cell non-Hodgkin lymphoma and rheumatoid arthritis. The TxGNN model predicts it may be effective for Follicular Lymphoma, which is close to an on-label use. The data compiled for this report include 43 clinical trials (several Phase 3) and 20 publications, including a 2025 randomized Phase 3 trial.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Rheumatoid arthritis, non-Hodgkin lymphoma, mantle cell lymphoma and other B-cell neoplasms (from the knowledge graph; the Singapore licence records contain no indication text) |
| Predicted New Indication | Follicular lymphoma |
| TxGNN Prediction Score | 96.08% |
| Evidence Level | L1 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 8 |
| Recommended Decision | Proceed with Guardrails |
Why is This Prediction Reasonable?
Detailed mechanism of action data are not available in the data compiled for this report. Based on known pharmacology, rituximab binds the CD20 antigen on B cells. It is understood to act through antibody-dependent cellular cytotoxicity, complement-dependent cytotoxicity and direct induction of apoptosis.
Follicular lymphoma is a B-cell non-Hodgkin lymphoma, and its malignant cells express CD20. It therefore falls within a disease class where rituximab is already used. This is closer to on-label or near-label use than to true repurposing. The prediction is supported by Phase 3 trials and a 2025 randomized trial of early rituximab monotherapy versus watchful waiting.
Other predicted indications in the data (ranks 2-10) vary widely. Some are CD20-positive B-cell neoplasms with plausible rationale, such as mature B-cell neoplasms, MALT lymphomas and Burkitt lymphoma. Others lack any mechanistic basis, such as "metastatic neoplasm" and malignant spiradenoma, a sweat gland carcinoma. The "metastatic neoplasm" score likely reflects a broad ontology term.
Clinical Trial Evidence
The table lists the most relevant trials for follicular lymphoma, prioritising trials with rituximab as the direct subject.
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT00078598 | Phase 3 | Unknown | 506 | Rituximab vs iodine-131 tositumomab in relapsed follicular NHL; status unknown, so reliability is uncertain |
| NCT01724021 | Phase 3 | Completed | 743 | Subcutaneous vs intravenous rituximab in DLBCL or follicular NHL; addresses route and patient preference rather than efficacy |
| NCT02303119 | Phase 3 | Completed | 221 | Two rituximab administration strategies (IV/SC) in first-line, low tumour burden follicular lymphoma |
| NCT02569996 | Phase 3 | Completed | 124 | Long-term rituximab maintenance in advanced follicular lymphoma after response to first-line therapy |
| NCT00991211 | Phase 3 | Completed | 549 | Bendamustine plus rituximab vs CHOP plus rituximab, first-line indolent and mantle cell lymphoma |
| NCT00012051 | Phase 3 | Completed | 340 | Rituximab with sequential chemotherapy and autologous transplant in relapsed B-cell NHL |
| NCT05100862 | Phase 3 | Active, not recruiting | 799 | Zanubrutinib plus anti-CD20 vs lenalidomide plus rituximab in relapsed/refractory follicular or marginal zone lymphoma |
| NCT00238238 | Phase 2 | Completed | 97 | Rituximab vs lenalidomide vs the combination in recurrent follicular NHL |
| NCT05783609 | Phase 2 | Recruiting | 100 | Epcoritamab plus rituximab, first-line follicular lymphoma; rituximab is a combination backbone |
| NCT05371093 | Phase 3 | Active, not recruiting | 231 | Axicabtagene ciloleucel vs standard care in relapsed/refractory follicular lymphoma; rituximab is likely part of the comparator |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 40306831 | 2025 | Randomized Phase 3 | Lancet Haematol | Long-term results: early rituximab monotherapy vs watchful waiting in asymptomatic, low tumour burden advanced follicular lymphoma; earlier results showed improved time to new treatment |
| 38041532 | 2024 | Systematic review / network meta-analysis | Cancer | Maintenance and consolidation strategies in untreated advanced follicular lymphoma |
| 40884311 | 2025 | Review | Br J Haematol | Chemo-free approaches; rituximab-lenalidomide supported from second line |
| 28628883 | 2017 | Review | Cancer Treat Rev | Pros and cons of rituximab maintenance in follicular lymphoma |
| 32236519 | 2020 | Review | Blood | Lenalidomide plus rituximab as an effective chemo-free option in first-line and relapsed disease |
| 31814159 | 2020 | Review | Am J Hematol | 2020 update on diagnosis and management of follicular lymphoma |
| 31346132 | 2019 | Review | Oncologist | Recent and emerging therapies and unmet needs |
| 34105813 | 2021 | Review | Hematol Oncol | High-risk follicular lymphoma; rituximab chemotherapy improved survival and maintenance improved PFS |
| 21958083 | 2012 | Review | Leuk Lymphoma | Facts and controversies of maintenance rituximab |
| 29542329 | 2018 | Review | Expert Rev Hematol | Treatment of relapsed follicular lymphoma in the rituximab era |
Singapore Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN09946P | MabThera Concentrate for Solution for Infusion 500 mg/50 ml | Injection | Not stated in the licence data |
| SIN13718P | MabThera Concentrate for Solution for Infusion 100 mg/10 ml | Infusion, solution concentrate | Not stated in the licence data |
| SIN15023P | MabThera Solution for Subcutaneous Injection 1400 mg | Injection, solution | Not stated in the licence data |
| SIN15671P | Truxima Concentrate for Solution for Infusion 10 mg/ml | Infusion, solution concentrate | Not stated in the licence data |
| SIN15969P | Rixathon Concentrate for Solution for Infusion 500 mg/50 ml | Infusion, solution concentrate | Not stated in the licence data |
Three further registrations exist: Rixathon 100 mg/10 ml (SIN15970P) and Ruxience 500 mg/50 mL and 100 mg/10 mL (SIN16452P, SIN16451P). All 8 licences are valid single-ingredient products, and none has been cancelled. Both intravenous and subcutaneous formulations are available.
Cytotoxicity
Rituximab is a targeted monoclonal antibody (anti-CD20 immunotherapy), not a conventional cytotoxic chemotherapy.
| Item | Content |
|---|---|
| Cytotoxicity Classification | Targeted therapy (anti-CD20 monoclonal antibody) |
| Myelosuppression Risk | Please refer to the package insert warnings and precautions |
| Emetogenicity Classification | Please refer to the package insert warnings and precautions |
| Monitoring Items | CBC with differential and B-cell counts; hepatitis B screening before treatment is generally advised (a literature report in the data notes viral reactivation, including HCV flares, after rituximab-based treatment) |
| Handling Protection | Please refer to the package insert and local institutional policy |
Safety Considerations
- Drug Interactions: The interaction query returned 90 entries (first 20 reviewed here). Major interactions include adalimumab, baricitinib, deferiprone and samarium (153Sm) lexidronam. Moderate interactions include other immunosuppressive or biologic agents (alemtuzumab, azathioprine, anakinra, alefacept), chloramphenicol, zidovudine, roflumilast, palifermin and strontium-89 chloride. Moderate interactions with the tetanus toxoid and anthrax vaccines are also listed. Zinc salts are minor. Combining rituximab with other immunosuppressants raises infection concerns, and vaccine response may be blunted.
Label warnings and contraindications are not available in the compiled data. Please refer to the package insert for full safety information.
Conclusion and Next Steps
Decision: Proceed with Guardrails
Rationale: Follicular lymphoma is a CD20-positive B-cell lymphoma, a class in which rituximab is already established. Multiple Phase 3 trials and a 2025 randomized trial support its use. Because this is near on-label use, the main gaps concern the Singapore labelling and safety documentation, not efficacy.
To proceed, the following is needed:
- The HSA package insert, to confirm the approved indications and obtain warnings and contraindications. This is currently a blocking data gap.
- Detailed mechanism of action data from DrugBank.
- Confirmation of follicular lymphoma as a labelled indication for each Singapore product.
- A monitoring plan covering infusion reactions, hepatitis B screening, infections and immunosuppressant co-medication.
- Subtype-specific review for other B-cell categories. Mature B-cell neoplasms, Burkitt lymphoma and MALT lymphomas have supportive rationale, while "metastatic neoplasm" and malignant spiradenoma lack a rationale and should be held.
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.