Long-term evaluation of the novel radioenhancer NBTXR3 plus radiotherapy in patients with locally advanced soft tissue sarcoma treated in the phase II/III Act.In.Sarc trial

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Background: NBTXR3, a novel radioenhancer activated by radiotherapy (RT) demonstrated superior efficacy, as preoperative treatment, in patients with locally advanced soft tissue sarcoma (LA STS), compared to RT alone. Primary endpoint of pCR rate was 16% vs 8% (p=0.044) and R0 margin rate was 77% vs 64% (p=0.042) (Bonvalot et al. Lancet Oncol. 2019). No modification of the early safety profile of RT was observed, leading to market authorization. Here we report on the long-term safety, limb function and quality of life. Methods: This phase II/III randomized (1:1), international trial included adult patients with LA STS of the extremity or trunk wall, requiring preoperative RT (NCT02379845). Patients were treated with either a single intratumoral injection of NBTXR3 (volume equivalent to 10% of tumor volume, at 53.3g/L) plus EBRT (arm A), or EBRT alone (arm B) (50 Gy in 25 fractions), followed by surgery. The primary and main secondary efficacy endpoints were previously reported. Safety of NBTXR3+RT, as preoperative treatment, was evaluated as secondary endpoint. We present the safety analyses done in the “all treated population”, with data recorded during at least a two-year follow-up. Important parameters related to HR-QoL, including functional outcome were studied using the EQ-5D, RNLI, TESS and MSTS questionnaires. Results: Patients had at least two-year follow-up and the lost to follow-up rate was very low (1.9%). RT-related SAEs were observed in 11.2% (10/89) vs 13.3% (12/90) in A vs B. Post-treatment AEs, any grade, were observed in 51.7% (46/89) vs 57.8% (52/90) and serious post-treatment AEs in 13.5% (12/89) vs 24.4% (22/90) of patients in A vs B. Second primary cancer was observed in 1 patient in arm A and 6 patients in arm B. Long-term safety continues to demonstrate that NBTXR3 plus RT has no impact on post-surgical wound complications (24.7% vs 36.7%, A vs B). Furthermore, the evaluation of radiation late toxicities in limbs such as fibrosis (4.5% vs 7.7%), arthrosis (2.2% vs 0.0%) and edema (6.7% vs 2.2%) that may alter limb function showed no difference between arms. Accordingly, HR-QoL evaluation yielded no difference in functional outcome. In addition, the intratumoral injection of NBTXR3 did not induce cancer cell seeding at the former tumor site. Finally, sequelae or chronic tissue disturbances at the former tumor localization were similar in both treatment arms, confirming that the increase of energy dose deposit and the physical presence of NBTXR3 did not impact post-treatment limb functions. Conclusions: The long-term safety results demonstrate that the addition of NBTXR3 to EBRT neither added toxicity nor modified the bystander effect of RT. The results presented here associated with the efficacy data reported previously reinforce the favorable benefit-risk ratio of the use of NBTXR3 in patients with LA STS. Clinical trial information: NCT02379845.

Efficacy and safety of CT-P6 versus reference trastuzumab in HER2-positive early breast cancer: updated results of a randomised phase 3 trial

PURPOSE

Neoadjuvant CT-P6, a trastuzumab biosimilar, demonstrated equivalent efficacy to reference trastuzumab in a phase 3 trial of HER2-positive early-stage breast cancer (EBC) (NCT02162667). We report post hoc analyses evaluating pathological complete response (pCR) and breast pCR alongside additional efficacy and safety measures.

METHODS

Following neoadjuvant treatment and surgery, patients received adjuvant CT-P6 or trastuzumab (6 mg/kg) every 3 weeks for ≤ 1 year.

RESULTS

In total, 271 and 278 patients received CT-P6 and trastuzumab, respectively. pCR and breast pCR rates were comparable between treatment groups regardless of age, region, or clinical stage. Overall, 47.6% (CT-P6) and 52.2% (trastuzumab) of patients experienced study drug-related treatment-emergent adverse events (TEAEs), including 17 patients reporting heart failure (CT-P6: 10; trastuzumab: 7). Two CT-P6 and three trastuzumab patients discontinued adjuvant treatment due to TEAEs.

CONCLUSION

Adjuvant CT-P6 demonstrated comparable efficacy and safety to trastuzumab at 1 year in patients with HER2-positive EBC, supporting CT-P6 and trastuzumab comparability.

NBTXR3, a first-in-class radioenhancer hafnium oxide nanoparticle, plus radiotherapy versus radiotherapy alone in patients with locally advanced soft-tissue sarcoma (Act.In.Sarc): a multicentre, phase 2-3, randomised, controlled trial

BACKGROUND

Pathological complete response to preoperative treatment in adults with soft-tissue sarcoma can be achieved in only a few patients receiving radiotherapy. This phase 2-3 trial evaluated the safety and efficacy of the hafnium oxide (HfO₂) nanoparticle NBTXR3 activated by radiotherapy versus radiotherapy alone as a pre-operative treatment in patients with locally advanced soft-tissue sarcoma.

METHODS

Act.In.Sarc is a phase 2-3 randomised, multicentre, international trial. Adults (aged ≥18 years) with locally advanced soft-tissue sarcoma of the extremity or trunk wall, of any histological grade, and requiring preoperative radiotherapy were included. Patients had to have a WHO performance status of 0-2 and a life expectancy of at least 6 months. Patients were randomly assigned (1:1) by an interactive web response system to receive either NBTXR3 (volume corresponding to 10% of baseline tumour volume at a fixed concentration of 53·3 g/L) as a single intratumoural administration before preoperative external-beam radiotherapy (50 Gy in 25 fractions) or radiotherapy alone, followed by surgery. Randomisation was stratified by histological subtype (myxoid liposarcoma vs others). This was an open-label study. The primary endpoint was the proportion of patients with a pathological complete response, assessed by a central pathology review board following European Organisation for Research and Treatment of Cancer guidelines in the intention-to-treat population full analysis set. Safety analyses were done in all patients who received at least one puncture and injection of NBTXR3 or at least one dose of radiotherapy. This study is registered with ClinicalTrials.gov, number NCT02379845, and is ongoing for long-term follow-up, but recruitment is complete.

FINDINGS

Between March 3, 2015, and Nov 21, 2017, 180 eligible patients were enrolled and randomly assigned and 179 started treatment: 89 in the NBTXR3 plus radiotherapy group and 90 in the radiotherapy alone group. Two patients in the NBTXR3 group and one patient in the radiotherapy group were excluded from the efficacy analysis because they were subsequently discovered to be ineligible; thus, a total of 176 patients were analysed for the primary endpoint in the intention-to-treat full analysis set (87 in the NBTXR3 group and 89 in the radiotherapy alone group). A pathological complete response was noted in 14 (16%) of 87 patients in the NBTXR3 group and seven (8%) of 89 in the radiotherapy alone group (p=0·044). In both treatment groups, the most common grade 3-4 treatment-emergent adverse event was postoperative wound complication (eight [9%] of 89 patients in the NBTXR3 group and eight [9%] of 90 in the radiotherapy alone group). The most common grade 3-4 adverse events related to NBTXR3 administration were injection site pain (four [4%] of 89) and hypotension (four [4%]) and the most common grade 3-4 radiotherapy-related adverse event was radiation skin injury in both groups (five [6%] of 89 in the NBTXR3 group and four [4%] of 90 in the radiotherapy alone group). The most common treatment-emergent grade 3-4 adverse event related to NBTXR3 was hypotension (six [7%] of 89 patients). Serious adverse events were observed in 35 (39%) of 89 patients in the NBTXR3 group and 27 (30%) of 90 patients in the radiotherapy alone group. No treatment-related deaths occurred.

INTERPRETATION

This trial validates the mode of action of this new class of radioenhancer, which potentially opens a large field of clinical applications in soft-tissue sarcoma and possibly other cancers.

FUNDING

Nanobiotix SA.

Bevacizumab (BEV) plus second-line taxane (TAX) or other chemotherapy (CT) for triple-negative breast cancer (TNBC): Subgroup analysis of RIBBON-2

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Background: In three randomized trials in the first-line metastatic breast cancer (MBC) setting, combining BEV with CT significantly improved progression-free survival (PFS; primary endpoint) and objective response rate (ORR) vs. CT alone. BEV also showed a significant PFS benefit in the second-line MBC setting (RIBBON-2) when combined with TAX or other CT. We analyzed data from the subgroup of patients (pts) with TNBC in RIBBON-2.

Methods: Eligible pts had MBC that had progressed on first-line CT without BEV. Second-line CT (TAX, gemcitabine, capecitabine, or vinorelbine) was chosen before 2:1 randomization to CT with either BEV (10 mg/kg q2w or 15 mg/kg q3w) or placebo (PLA). All pts could receive BEV at progression. The primary endpoint was PFS.

Results: RIBBON-2 included 684 pts; 159 (23%) had TNBC and of these, 67 (42%) received TAX with BEV/PLA. Baseline characteristics were broadly similar in the two treatment arms. In an exploratory analysis of pts with TNBC, BEV + CT led to significantly improved PFS and ORR vs. CT alone, and a trend toward improved overall survival (OS). The magnitude of the effect was particularly pronounced in pts receiving TAX CT.

Conclusions: Pts with TNBC derive significant ORR and PFS benefit from BEV combined with second-line CT. Despite the small sample size, there was a trend (HR 0.624; p = 0.0534) toward OS benefit in pts treated with BEV, especially with TAX CT.

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Human parvovirus B19: prevalence of viral DNA in volunteer blood donors and clinical outcomes of transfusion recipients

BACKGROUND AND OBJECTIVES

Blood donor units are not screened for human parvovirus B19 (B19) even though it can be acquired via blood products. We estimated the prevalence of B19 in a US volunteer blood donor population and determined the clinical outcomes of transfusion recipients.

MATERIALS AND METHODS

Donor units were screened for B19 DNA by PCR, and positive units analyzed by EIA for B19 Ig. Unit usage was determined and recipient chart review conducted.

RESULTS

B19 DNA was detected in 11/9, 568 allogeneic units (0.1%), of which 3 had no measurable B19 Ig. One individual developed anemia consistent with B19 infection after receiving a DNA+ unit lacking B19 Ig.

CONCLUSIONS

The apparent low incidence of disease in patients transfused with B19 DNA+ components may be due to coexistence of neutralizing antibodies in donors and/or recipients.