Posters Assess Quality of Trastuzumab, Denosumab Biosimilars in Cancer

Posters from the American Society of Clinical Oncology’s annual meeting showed the safety and efficacy of a trastuzumab biosimilar and a denosumab biosimilar in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer and bone metastases, respectively.

Real-World Data on Trastuzumab Biosimilar

Data from a Brazilian, national, multicenter, observational, prospective real-world study analyzed the use of Zedora, known as Ogivri (trastuzumab-dkst) in the United States and was the first oncology biosimilar approved in Brazil.

The investigators enrolled 126 or 170 of patients with early-stage HER2-positive breast cancer who received at least 1 dose of a the biosimilar as adjuvant therapy and presented preliminary data on 42. The safety of the biosimilar was determined by the occurrence of adverse events as reported by the patients.

The median age of the 42 patients was 48.5 years and 78.6% of them had a node-negative disease. Most patients had tumors that were positive for hormone-receptors, 71.4% had estrogen-receptor-positive disease and 57.1% had progesterone-receptor-positive disease. A majority of patients (59.5%) underwent conservative surgery and 40.5% underwent a mastectomy.

Invasive ductal carcinoma was the most frequent histological breast cancer subtype, accounting for 97.6% of cases. Overall, 25.0% of the patients received solely a trastuzumab biosimilar and 68.8% received combination therapy with the biosimilar and pertuzumab. Also, 6.3% received the reference product in neoadjuvant therapy.

At least 1 adverse event was reported by 59.5% of patients, of which 2 events were considered serious. Grade 3 or 4 adverse events accounted for 35.7% of the reported events and no deaths occurred. The researchers said that the nature and severity of adverse events was consistent with the known safety profile of the reference product.

Phase 3 Denosumab Biosimilar Study

Investigators conducted a phase 3 trial assessing the safety and efficacy of a QL1206, the first denosumab biosimilar, compared to the reference product (Prolia) in patients with solid tumors and bone metastases.

For inclusion, the patients had to be between the 18 and 80 years old and have an Eastern Cooperative Oncology Group performance status between 0 and 2. Each patient was randomly assigned to receive subcutaneous administration of the biosimilar or the reference product and were followed for 53 weeks.

In total, 717 patients were included and 357 received the biosimilar while 360 received the originator. The median percentage changes at week 13 were -75.2% urinary N-telopeptide/creatinine ratio (uNTX/uCr) for the biosimilar and -75.8% for the originator. The number of treatment-emergency adverse events between the biosimilar and originator groups was similar (n = 332/356 vs 348/361, respectively). The proportions of positive anti-drug antibody, neutralizing antibody, and pharmacokinetic characteristics was also comparable between the groups.

Reference

1. Cardoso ACF, Gagliato DDM, Brito NM, et al. A prospective real-world study to assess the effectiveness and safety of trastuzumab biosimilar in the adjuvant treatment of HER2-positive breast cancer: Preliminary safety results. Presented at: ASCO 2022; June 3-7, 2022; Chicago, Illinois. Abstract e12524.
2. Li H, Huang Y, Zhang L, et al. A multicenter, randomized, double-blind, phase III trial comparing denosumab biosimilar QL1206 and denosumab in patients with bone metastases from solid tumors. Presented at: ASCO 2022; June 3-7, 2022; Chicago, Illinois. Abstract 2526.