DataSheet_1_Photochemical Internalization Enhanced Vaccination Is Safe, and Gives Promising Cellular Immune Responses to an HPV Peptide-Based Vaccine in a Phase I Clinical Study in Healthy Volunteers.pdf

Background and AimsPhotochemical internalization (PCI) is a technology for inducing release of endocytosed antigens into the cell cytosol via a light-induced process. Preclinical experiments have shown that PCI improves MHC class I antigen presentation, resulting in strongly enhanced CD8+ T-cell responses to polypeptide antigens. In PCI vaccination a mixture of the photosensitizing compound fimaporfin, vaccine antigens, and an adjuvant is administered intradermally followed by illumination of the vaccination site. This work describes an open label, phase I study in healthy volunteers, to assess the safety, tolerability, and immune response to PCI vaccination in combination with the adjuvant poly-ICLC (Hiltonol) (ClinicalTrials.gov Identifier: NCT02947854).
MethodsThe primary objective of the study was to assess the safety and local tolerance of PCI mediated vaccination, and to identify a safe fimaporfin dose for later clinical studies. A secondary objective was to analyze the immunological responses to the vaccination. Each subject received 3 doses of HPV16 E7 peptide antigens and two doses of Keyhole Limpet Hemocyanin (KLH) protein. A control group received Hiltonol and vaccine antigens only, whereas the PCI groups in addition received fimaporfin + light. Local and systemic adverse effects were assessed by standard criteria, and cellular and humoral immune responses were analyzed by ELISpot, flow cytometry, and ELISA assays.
Results96 healthy volunteers were vaccinated with fimaporfin doses of 0.75–50 µg. Doses below 17.5 µg were safe and tolerable, higher doses exhibited local tolerability issues in some study subjects, mainly erythema, and pain during illumination. There were few, and only mild and expected systemic adverse events. The employment of PCI increased the number of subjects exhibiting a T-cell response to the HPV peptide vaccine about 10-fold over what was achieved with the antigen/Hiltonol combination without PCI. Moreover, the use of PCI seemed to result in a more consistent and multifunctional CD8+ T-cell response. An enhancement of the humoral immune response to KLH vaccination was also observed.
ConclusionsUsing PCI in combination with Hiltonol for intradermal vaccination is safe at fimaporfin doses below 17.5 µg, and gives encouraging immune responses to peptide and protein based vaccination.

研究背景与目的
光化学内化（Photochemical internalization, PCI）是一种通过光诱导过程，将内吞抗原释放至细胞胞浆的技术。临床前实验表明，PCI可增强主要组织相容性复合体I类（MHC class I）抗原呈递，进而显著增强CD8+ T细胞对多肽抗原的应答。在PCI疫苗接种中，需将光敏化合物菲莫泊芬（fimaporfin）、疫苗抗原与佐剂的混合物皮内给药，随后对接种部位进行光照照射。本研究针对健康受试者开展一项开放标签I期临床试验，旨在评估联合佐剂poly-ICLC（Hiltonol）的PCI疫苗接种的安全性、耐受性与免疫应答（临床试验注册号：ClinicalTrials.gov编号：NCT02947854）。

研究方法
本研究的主要目的为评估PCI介导疫苗接种的安全性与局部耐受性，并确定适用于后续临床研究的菲莫泊芬安全剂量；次要目的为分析疫苗接种后的免疫应答。每名受试者接受3剂HPV16 E7肽抗原与2剂钥孔戚血蓝蛋白（Keyhole Limpet Hemocyanin, KLH）蛋白。对照组仅接受Hiltonol与疫苗抗原，PCI组则额外接受菲莫泊芬联合光照照射。采用标准化评估准则评估局部与全身不良事件，并通过酶联免疫斑点试验（ELISpot）、流式细胞术（flow cytometry）与酶联免疫吸附试验（ELISA）分析细胞免疫与体液免疫应答。

研究结果
96名健康受试者接受了剂量为0.75~50μg的菲莫泊芬疫苗接种。剂量低于17.5μg时安全性与耐受性良好，更高剂量在部分受试者中出现局部耐受性问题，主要表现为光照时的红斑与疼痛。全身不良事件极少，且仅为轻度、预期内的反应。与仅使用抗原/Hiltonol组合（未使用PCI）的方案相比，PCI的应用使对HPV肽疫苗产生T细胞应答的受试者数量增加约10倍。此外，PCI的使用似乎可诱导更具一致性且多功能的CD8+ T细胞应答。同时，KLH疫苗接种的体液免疫应答也得到增强。

研究结论
将PCI与Hiltonol联合用于皮内疫苗接种，在菲莫泊芬剂量低于17.5μg时安全性良好，可为肽类与蛋白类疫苗接种带来令人鼓舞的免疫应答效果。