Patients with recurrent or metastatic HNSCC who had previously received anti-PD-1/L1 plus platinum-based chemotherapy (PBC) were enrolled in the S209 trial. SI-B001 16mg/kg IV was given to patients once a week. The S206 trial enrolled patients with recurrent and metastatic HNSCC who had progressed on previous anti-PD-1/L1 therapy with or without PBC and had received no more than two lines of treatment. 

Patients in the S206 trial were split into two groups: Patients in Group A were given SI-B001 as well as paclitaxel (80mg/m² IV once weekly); patients in Group B were given SI-B001 as well as docetaxel.

As per the updated results of April 2023, 11 patients in the S209 study received SI-B001 as a single agent. It was found that in 10 out of the 11 patients who have had at least one post-baseline tumor assessment, the objective response rate (ORR) was found to be 30%, and a median progression free survival (mPFS) of 2.7 months was observed. In the S206 study consisting of patients who had received SI-B001 along with chemotherapy, it was found that in group A, ORR was 58.2% along with a disease control rate (DCR) of 82.4%, and an mPFS of 5.4 months was observed. In the group B cohort, ORR was 12.5% and mPFS was 1.6 months.

KOL insights

“The latest results reported at this year's ASCO are encouraging. It will be fascinating to observe how SI-B001 does in the subsequent Phase III studies.” -Expert Opinion.

Conclusion

The combination of SI-B001 and paclitaxel yielded promising efficacy findings. This would result in improved anti-tumor efficacy, with an ORR of 58.2% and a DCR of 82.4%. The toxicity of SI-B001, in combination with paclitaxel, was likewise found to be acceptable. The Phase III trial would disclose more about SI-B001's promising prospects in the HNSCC treatment domain