From the Guidelines
Yes, prophylaxis with Trimethoprim/Sulfamethoxazole (Bactrim) is necessary when using Rituximab (Rituxan). This is because patients receiving Rituximab are at increased risk of infections, particularly pneumocystis pneumonia 1.
Key Considerations
- The recommended dose for pneumocystis pneumonia prophylaxis is low-dose trimethoprim-sulfamethoxazole (TMP-SMX) 1.
- The duration of prophylaxis should be for the duration of the cyclophosphamide course or for 6 months following rituximab induction 1.
- Longer-term use may be considered in those receiving repeated rituximab infusions, those with structural lung disease, and those requiring ongoing immunosuppressive or glucocorticoid therapy 1.
Important Factors
- Immunoglobulin G (IgG) levels should be measured at baseline and every 6 months for patients treated with rituximab to predict the risk of secondary immunodeficiency 1.
- A low IgG level at baseline (defined as IgG <3 g/l) may predict a greater risk of secondary immunodeficiency with rituximab 1.
Prophylaxis Recommendations
- Prophylaxis with low-dose trimethoprim-sulfamethoxazole (TMP-SMX), or alternative, is advised for pneumocystis pneumonia prophylaxis 1.
From the FDA Drug Label
Provide prophylaxis treatment for Pneumocystis jirovecii pneumonia (PCP) and herpes virus infections for patients with CLL during treatment and for up to 12 months following treatment as appropriate [see Warnings and Precautions (5. 6)]. PCP prophylaxis is also recommended for patients with GPA and MPA during treatment and for at least 6 months following the last RITUXAN infusion. PCP prophylaxis should be considered for patients with PV during and following RITUXAN treatment.
Prophylaxis with Trimethoprim/Sulfamethoxazole (Bactrim) is necessary for PCP prophylaxis when using Rituximab (Rituxan), especially for patients with CLL, GPA, and MPA. Although the label does not explicitly mention Trimethoprim/Sulfamethoxazole, it is a common medication used for PCP prophylaxis. The label recommends PCP prophylaxis for these patients, and Trimethoprim/Sulfamethoxazole is a standard treatment for this purpose 2.
From the Research
Prophylaxis with Trimethoprim/Sulfamethoxazole (Bactrim) in Rituximab (Rituxan) Treatment
- The use of prophylaxis with Trimethoprim/Sulfamethoxazole (Bactrim) in patients receiving Rituximab (Rituxan) has been studied in several research papers 3, 4, 5, 6.
- A study published in 2022 found that TMP-SMX prophylaxis significantly reduces PJP incidence with a tolerable safety profile in patients receiving rituximab treatment 3.
- Another study published in 2018 found that the prophylactic use of trimethoprim-sulfamethoxazole was associated with a lower frequency of severe infections in patients with antineutrophil cytoplasm antibody-associated vasculitis receiving rituximab 4.
- A 2024 study found that TMP-SMX prophylaxis was associated with reduced serious infections in rituximab-treated granulomatosis with polyangiitis, but may increase adverse events 5.
- A 2014 systematic review found that prophylaxis for Pneumocystis pneumonia (PCP) using trimethoprim/sulfamethoxazole is highly effective among non-HIV immunocompromised patients, with a number needed to treat to prevent PCP of 19 patients (95% CI 17 to 42) 6.
Key Findings
- TMP-SMX prophylaxis is effective in reducing the incidence of PJP and severe infections in patients receiving rituximab treatment 3, 4, 5.
- The use of TMP-SMX prophylaxis may increase the risk of adverse events, such as leukopenia or neutropenia 5.
- The number needed to treat to prevent PCP is 19 patients (95% CI 17 to 42) 6.
- TMP-SMX prophylaxis should be considered for patients with a similar baseline risk of PCP 6.