Final safety and HRQoL results of the phase II/III Act.In.Sarc study with preoperative NBTXR3 plus radiotherapy versus radiotherapy in locally advanced soft-tissue sarcoma

ABSTRACT

PURPOSE

XXXX(Anonymized) demonstrated that the first-in-class radioenhancer NBTXR3, activated by preoperative radiotherapy, doubled the rate of pathological complete response after resection compared with preoperative radiotherapy alone in adult patients with locally advanced soft tissue sarcoma of the extremity or trunk wall (16.1% versus 7.9%, P=0.045), and more patients achieved R0 resections (77.0% versus 64.0%, P=0.042). These are the toxicity and health-related quality of life (HRQoL) results.

METHODS AND MATERIALS

XXXX(Anonymized) randomized eligible patients 1:1 to either NBTXR3 (single intratumoral injection, volume equivalent to 10% of baseline tumor volume, at 53.3 g/L) activated by external-beam radiotherapy (EBRT) (Arm A) or EBRT alone (Arm B) (50 Gy in 25 fractions), followed by surgery in both arms. Here, we report the safety analyses in the all-treated population with a long-term follow-up of at least two-years, and HRQoL in the intention-to-treat full analysis set.

RESULTS

During the on-treatment period serious adverse events (SAEs) of all grades related to NBTXR3 occurred in 10.1% (9/89) of patients (Arm A), SAEs related to radiotherapy occurred in 5.6% (5/89) (Arm A) versus 5.6% (5/90) (Arm B); and post-surgery hospitalization due to SAEs occurred in 15.7% (14/89) (Arm A) versus 24.4% (22/90) (Arm B). During the follow-up period, post-treatment SAEs (regardless of relationship) occurred in 13.5% (12/89) (Arm A) versus 24.4% (22/90) (Arm B). NBTXR3 did not negatively impact on HRQoL, during the follow-up period, there was an improvement in most mean Toronto Extremity Salvage Score, EuroQol-5 Dimension (EQ-5D), EQ5D02-EQ Visual Analog Scale, Reintegration to Normal Living Index, and Musculoskeletal Tumor Rating Scale scores.

CONCLUSIONS

NBTXR3 did not negatively impact safety or HRQoL. Long-term safety results reinforce the favorable benefit-risk ratio of NBTXR3 plus radiotherapy.