A prospective study to assess and quantify the setup errors with cone-beam computed tomography in head-and-neck cancer image-guided radiotherapy treatment.

Introduction: This study was done to quantify the translational setup errors with cone-beam computed tomography (CBCT) in the image-guided radiation therapy (IGRT) treatment of head-and-neck cancer (HNC) patients. Aims: The objective was to quantify the setup errors by CBCT. Methodology: One hundred patients of HNC were enrolled from March 2020 to March 2021 for IGRT treatment. Pretreatment kV-CBCT images were obtained at the first 3 days of irradiations, and setup error corrections were done in the mediolateral (ML), superior-inferior (SI), and anterior-posterior (AP) directions. Subsequently, a weekly kV-CBCT was repeated for whole duration of radiotherapy for the next 6-7 weeks. Adequacy of planning target volume (PTV) margins was assessed by van Herk's formula. Results: Total 630 CBCT scans of 100 patients were analyzed. Setup errors greater than 3 mm and 5 mm were seen in 11.4% and 0.31% of the patients, respectively. Systematic errors and random errors before correction in ML, SI, and AP directions were 0.10 cm, 0.11 cm, and 0.12 cm and 0.24 cm, 0.20 cm, and 0.21 cm, respectively. Systematic errors and random errors after correction in ML, SI, and AP directions were 0.06 cm, 0.07 cm, and 0.07 cm and 0.13 cm, 0.10 cm, and 0.12 cm, respectively. Conclusion: CBCT at the first 3 fractions and then weekly during radiotherapy is effective to detect the setup errors. An isotropic PTV margin of 5 mm over clinical target volume is safe to account for setup errors, however, in the case of close organ at risk, or with IGRT, a PTV margin of 3 mm can be considered.

Rituximab biosimilar for the treatment of diffuse large B-cell lymphoma: a phase 3 randomized study in India.

PURPOSE: Very few studies have demonstrated the rituximab biosimilarity in terms of efficacy, safety, pharmacokinetics, pharmacodynamics, and immunogenicity in patients with diffuse large B-cell lymphoma (DLBCL) in India. Therefore, we compared the efficacy, safety, pharmacokinetic, pharmacodynamic, and immunogenicity of our biosimilar rituximab with the reference rituximab (Ristova, Roche products [India] Pvt. Ltd) in patients with DLBCL in India. METHODS: A phase 3, randomized, assessor-blind, parallel-group, two-arm study was conducted across 28 sites in India. A total of 153 newly diagnosed DLBCL patients were randomized to receive either biosimilar rituximab or reference rituximab. The study drugs were administered at a dose of 375 mg/m2 by intravenous infusion every 3 weeks for six cycles. The primary end point was objective response rate (ORR) at the end of Cycle 6. Secondary end points included: pharmacokinetic, pharmacodynamics, immunogenicity, and safety assessment. RESULTS: The ORR at the end of Cycle 6 was 82.14% in the biosimilar rituximab and 85.71% in the reference rituximab group. The risk difference (90% CIs) was - 3.57 (- 14.80, 7.66). It met the non-inferiority margin of - 20%. The pharmacokinetic and pharmacodynamic parameters were comparable between the two treatment groups. The incidence rate of immunogenicity was very low and similar in both the treatment groups. The safety profile of both the treatments was comparable with no major difference in terms of nature, frequency and severity of TEAEs. CONCLUSION: The study demonstrated the biosimilarity between the biosimilar rituximab and the reference rituximab. Our biosimilar rituximab could add to the cost-effective treatment alternatives for patients with DLBCL in India.