Hurst Susan, Ryan Anne M, Ng Chee-Keng, McNally James M, Lorello Leslie G, Finch Gregory L, Leach Michael W, Ploch Stephen A, Fohey Josh A, Smolarek Teresa A
Pharmacodynamics and Metabolism, Pfizer Worldwide Research and Development, Eastern Point Road, Groton, CT, 06340, USA,
BioDrugs. 2014 Oct;28(5):451-9. doi: 10.1007/s40259-014-0103-4.
Trastuzumab (Herceptin(®)) is a humanized monoclonal antibody (mAb) that binds to the HER2 protein. PF-05280014 is being developed as a potential biosimilar to trastuzumab products marketed in the United States (trastuzumab-US) and European Union (trastuzumab-EU). Nonclinical studies were designed to evaluate the similarity of PF-05280014 to trastuzumab-US and trastuzumab-EU using in vitro structural and functional analyses, and in vivo pharmacokinetic and immunogenicity assessments.
Peptide mapping was utilized to determine structural similarity. Functional similarity was assessed via an in vitro tumor cell growth inhibition assay. CD-1 male mice were administered a single-dose (0, 1, 10, or 100 mg/kg) of PF-05280014, trastuzumab-US, or trastuzumab-EU. Mice were monitored for clinical signs and body weight changes over a 4-month period. At approximately 720, 1,080, 1,440, 2,160, and 2,880 h post-dose, terminal blood samples were collected and assayed for PF-05280014, trastuzumab-US, or trastuzumab-EU concentrations and anti-drug antibodies (ADA). Values for C max, area under the concentration time curve (AUC), clearance (CL), volume of distribution (V ss), half-life (t ½), and the presence of ADA were determined.
In this report, peptide mapping of PF-05280014, trastuzumab-US, and trastuzumab-EU showed similar chromatographic profiles in a side-by-side analysis. The tumor cell growth inhibition of PF-05280014 was similar to trastuzumab-US and trastuzumab-EU. C max and AUC0-∞ values in mice were similar and dose-dependent across the mAbs at all doses, and CL and V ss values were similar and dose-independent. The CL values across doses ranged from 0.193 to 0.350 mL/h/kg (PF-05280014), from 0.200 to 0.346 mL/h/kg (trastuzumab-US), and from 0.193 to 0.335 mL/h/kg (trastuzumab-EU). V ss values across doses ranged from 84.9 to 120 mL/kg (PF-05280014), 86.7 to 130 mL/kg (trastuzumab-US), and 85.4 to 116 mL/kg (trastuzumab-EU). The incidence of ADA was low (~10%) and also similar across all dose levels and the three mAbs. The lower exposure generally observed in ADA-positive animals did not impact the overall PK interpretation. All animals survived to their scheduled terminal blood collection with no mAb-related differences in body weight gain or clinical signs.
PF-05280014, trastuzumab-US, and trastuzumab-EU were well tolerated during the 4-month observation period following a single dose of up to 100 mg/kg. PF-05280014, trastuzumab-US, and trastuzumab-EU showed similar structural properties, tumor cell growth inhibition properties, and PK profiles. The incidence of ADA was low and similar across the three mAbs. The results of these studies support the development of PF-05280014 as a proposed biosimilar to Herceptin.
曲妥珠单抗（赫赛汀（®））是一种与人表皮生长因子受体2（HER2）蛋白结合的人源化单克隆抗体（mAb）。PF-05280014正被开发为一种潜在的生物类似药，用于对标在美国上市的曲妥珠单抗产品（美国曲妥珠单抗）和欧盟上市的曲妥珠单抗产品（欧盟曲妥珠单抗）。非临床研究旨在通过体外结构和功能分析以及体内药代动力学和免疫原性评估，来评价PF-05280014与美国曲妥珠单抗和欧盟曲妥珠单抗的相似性。
采用肽图分析确定结构相似性。通过体外肿瘤细胞生长抑制试验评估功能相似性。给CD-1雄性小鼠单次注射（0、1、10或100mg/kg）PF-05280014、美国曲妥珠单抗或欧盟曲妥珠单抗。在4个月的时间内监测小鼠的临床症状和体重变化。在给药后约720、1080、1440、2160和2880小时采集终末血样，检测PF-05280014、美国曲妥珠单抗或欧盟曲妥珠单抗的浓度以及抗药物抗体（ADA）。测定最大血药浓度（Cmax）、药时曲线下面积（AUC）、清除率（CL）、稳态分布容积（Vss）、半衰期（t½）以及ADA的存在情况。
在本报告中，PF-05280014、美国曲妥珠单抗和欧盟曲妥珠单抗的肽图在平行分析中显示出相似的色谱图。PF-05280014对肿瘤细胞生长的抑制作用与美国曲妥珠单抗和欧盟曲妥珠单抗相似。小鼠体内的Cmax和AUC0-∞值在所有剂量下对三种单克隆抗体而言均相似且呈剂量依赖性，CL和Vss值相似且与剂量无关。各剂量下的CL值范围为0.193至0.350mL/（h·kg）（PF-05280014）、0.200至0.346mL/（h·kg）（美国曲妥珠单抗）以及0.193至0.335mL/（h·kg）（欧盟曲妥珠单抗）。各剂量下的Vss值范围为84.9至120mL/kg（PF-05280014）、86.7至130mL/kg（美国曲妥珠单抗）以及85.4至116mL/kg（欧盟曲妥珠单抗）。ADA的发生率较低（约10%），在所有剂量水平和三种单克隆抗体之间也相似。ADA阳性动物中普遍观察到的较低暴露量并未影响总体药代动力学解释。所有动物均存活至预定的终末血样采集时间，在体重增加或临床症状方面没有与单克隆抗体相关的差异。
在单次给药高达100mg/kg后的4个月观察期内，PF-05280014、美国曲妥珠单抗和欧盟曲妥珠单抗耐受性良好。PF-05280014、美国曲妥珠单抗和欧盟曲妥珠单抗显示出相似的结构特性、肿瘤细胞生长抑制特性和药代动力学特征。ADA的发生率较低，且在三种单克隆抗体之间相似。这些研究结果支持将PF-05280014开发为赫赛汀的生物类似药。
