T cells are known as the most potent killer cells of the immune system, designed by nature to prevent unwanted challenges. The first class of therapeutic products harnessing the power of T cells for target-specific treatment of oncological diseases was bispecific antibodies. The first T-cell engaging bispecific antibodies that obtained approval were catumaxomab and blinatumomab 1,2. Eight years later, the first chimeric antigen receptor (CAR)-T cells received regulatory approval 3. CART cells are the cellular interpretation of T-cell engaging therapies and have shown remarkable clinical results. CART cells belong to the regulatory group of advanced therapy medicinal products (ATMPs). Due to the cell-/gene-based complex nature, ATMPs are far more challenging to develop than other, more defined, medicinal products. Despite very encouraging clinical results, there have been many setbacks in the development of ATMPs during the past 20 years. Therefore, the approval of the first two CARTs KYMRIAH and YESCARTA is highly encouraging for the field. In this article we review the current landscape of CARTs as a special class of ATMPs. This comprises the pathway to approval including the use of dedicated regulatory tools and challenges that were faced during the procedure. Furthermore, we highlight important future trends in the field.
Biomarkers are widely used at every stage of drug discovery and development. Utilisation of biomarkers has a potential to make drug discovery, development and approval processes more efficient. An overview of the current global regulatory landscape is presented in this article with particular emphasis on the validation and qualification of biomarkers, as well as legal framework for companion diagnostics. Furthermore, this article shows how the number of approved drugs with at least 1 biomarker used during development (biomarker acceptance) is affected by the recent advances in the biomarker regulations. More than half of analysed approvals were supported by biomarker data and there has been a slight increase in acceptance of biomarkers in recent years, even though the growth is not continuous. For certain pharmacotherapeutic groups, approvals with biomarkers are more common than without. Examples include immunosuppressants, immunostimulants, drugs used in diabetes, antithrombotic drugs, antineoplastic agents and antivirals. As a conclusion, potential benefits, challenges and opportunities of using biomarkers in drug discovery and development in the current regulatory landscape are summarised and discussed.
The trifunctional antibody (trAb) catumaxomab is characterized by a unique ability to bind three different cell types: tumor cells; T-cells; and accessory cells. It binds to epithelial cell adhesion molecule (EpCAM) on tumor cells, the CD3 antigen on T-cells, and to type I, IIa, and III Fcγ receptors (FcγRs) on accessory cells (e.g. natural killer cells, dendritic cells, and macrophages). Catumaxomab exerts its anti-tumor effects via T-cell-mediated lysis, antibody-dependent, cell-mediated cytotoxicity, and phagocytosis via activation of FcγR-positive accessory cells. Catumaxomab represents a self-supporting system, as no additional immune cell activation is required for tumor eradication. The efficacy and safety of catumaxomab have been demonstrated in a pivotal phase II/III study in malignant ascites (MA) and supporting phase I/II studies. It is administered as four intraperitoneal (i.p.) infusions of 10, 20, 50, and 150 µg on days 0, 3, 7, and 10, respectively. Catumaxomab was approved for the i.p. treatment of MA in patients with EpCAM-positive carcinomas where standard therapy is not available or no longer feasible in the European Union in April 2009. It is the first trAb and the first drug in the world approved specifically for the treatment of MA. Catumaxomab was awarded the Galen of Pergamon Prize, which recognizes pharmacological research for developing new and innovative drugs and diagnostics, in the specialist care category in 2010. The use of catumaxomab in other indications and additional routes of administration are currently being investigated to further exploit its therapeutic potential in EpCAM-positive carcinomas.
The trifunctional antibody catumaxomab is a targeted immunotherapy for the intraperitoneal treatment of malignant ascites. In a Phase II/III trial in cancer patients (n = 258) with malignant ascites, catumaxomab showed a clear clinical benefit vs. paracentesis and had an acceptable safety profile. Human antimouse antibodies (HAMAs), which could be associated with beneficial humoral effects and prolonged survival, may develop against catumaxomab as it is a mouse/rat antibody. This post hoc analysis investigated whether there was a correlation between the detection of HAMAs 8 days after the fourth catumaxomab infusion and clinical outcome. HAMA-positive and HAMA-negative patients in the catumaxomab group and patients in the control group were analyzed separately for all three clinical outcome measures (puncture-free survival, time to next puncture and overall survival) and compared to each other. There was a strong correlation between humoral response and clinical outcome: patients who developed HAMAs after catumaxomab showed significant improvement in all three clinical outcome measures vs. HAMA-negative patients. In the overall population in HAMA-positive vs. HAMA-negative patients, median puncture-free survival was 64 vs. 27 days (p < 0.0001; HR 0.330), median time to next therapeutic puncture was 104 vs. 46 days (p = 0.0002; HR 0.307) and median overall survival was 129 vs. 64 days (p = 0.0003; HR 0.433). Similar differences between HAMA-positive and HAMA-negative patients were seen in the ovarian, nonovarian and gastric cancer subgroups. In conclusion, HAMA development may be a biomarker for catumaxomab response and patients who developed HAMAs sooner derived greater benefit from catumaxomab treatment.
Gene editing technologies such as CRISPR/Cas9 have emerged as an attractive tool not only for scientific research but also for the development of medicinal products. Their ability to induce precise double strand breaks into DNA enables targeted modifications of the genome including selective knockout of genes, correction of mutations or precise insertion of new genetic material into specific loci. Gene editing‐based therapies hold a great potential for the treatment of numerous diseases and the first products are already being tested in clinical trials. The treatment indications include oncological malignancies, HIV, diseases of the hematopoietic system and metabolic disorders. This article reviews ongoing preclinical and clinical studies and discusses how gene editing technologies are altering the gene therapy landscape. In addition, it focusses on the regulatory challenges associated with such therapies and how they can be tackled during the drug development process.
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