SAPHNELO (anifrolumab) is a first-in-class, fully human monoclonal antibody that binds to subunit 1 of the type I interferon (IFN) receptor, blocking the activity of type I IFN. Type I IFNs, such as IFN-alpha, IFN-beta, and IFN-kappa, are cytokines involved in regulating the inflammatory pathways implicated in SLE. SAPHNELO is approved to treat SLE in more than 60 countries worldwide, including the US, EU and Japan, with reviews ongoing in other countries. 

The study involved 536 patients randomized to receive either anifrolumab 300 mg or placebo across the TULIP-1/-2 trials and their long-term extension (LTE) demonstrated comparable baseline frequencies of low lymphocytes, hemoglobin, and platelets between treatment groups. Over the course of treatment, anifrolumab consistently led to higher rates of lymphocyte normalization compared to placebo, with significant differences observed as early as Week 12 and sustained through Week 208. Similarly, a greater proportion of anifrolumab-treated patients achieved normalized Hb levels by Week 52 and Week 208 relative to placebo. However, the rates of platelet normalization showed no significant difference between the two groups at these time points.

Furthermore, withdrawal rates by Week 208 were notably lower among anifrolumab recipients who initially presented with low lymphocytes, Hb, or platelets compared to their placebo counterparts. This suggests that anifrolumab's treatment efficacy in improving hematological parameters may contribute to better patient retention and tolerance over the long term.

Analyses focusing on patients with initially low baseline levels revealed a strong association between normalization of lymphocytes, Hb, and platelets by Week 52 and positive treatment response assessed by BICLA criteria. Responders consistently exhibited higher rates of normalized lymphocyte counts throughout the LTE period compared to non-responders, highlighting the potential clinical relevance of these hematological improvements in predicting overall treatment efficacy in SLE. However, such a correlation was less evident for Hb and platelet normalization.

KOL insights

“POS0024 showed that patients receiving long-term anifrolumab treatment were more likely to normalize their SLE-related lymphopenia and anemia compared with placebo (ie, standard therapy alone).” – Expert Opinion

Conclusion

Currently, the biologics approved by the US FDA as adjunct therapies for SLE patients are BENLYSTA and SAPHNELO. In contrast, the use of RITUXIMAB for treating SLE is considered off-label.

SAPHNELO and BENLYSTA are competitors in the SLE market, each aiming for a significant market share. BENLYSTA has an advantage because it is approved for both adults and children, while SAPHNELO is only approved for adults. Additionally, BENLYSTA offers a subcutaneous injection option, making it more convenient and boosting its revenue, whereas SAPHNELO is limited to intravenous administration. By 2034, BENLYSTA and SAPHNELO are projected to generate around USD 1 billion and USD 760 million, respectively, in the United States.