The safety of anti PD-1 therapeutics for the treatment of melanoma

INTRODUCTION

The introduction of immunotherapies into clinical practice has substantially improved the prognosis of metastatic melanoma patients as well as patients suffering from other cancers. The two FDA-approved checkpoint inhibitors against PD-1 (nivolumab and pembrolizumab) have been shown to significantly improve patient survival while being less toxic than previous treatment options. Areas covered: The current scientific literature on safety and adverse events (AEs) related to anti-PD-1 therapies has been investigated with special attention to case reports and to the latest results announced at the major clinical cancer and melanoma meetings, including ASCO (American Society of Clinical Oncology), ESMO (European Society of medical Oncology) and EADO (European Association of Dermato-Oncology) annual meetings. Expert opinion: Even though anti-PD-1 therapies are better tolerated than conventional chemo- or other immune-therapies, they still induce a plethora of AEs. Given the mechanism of action, it is supposed that most if not all of them are immune related. Fortunately, the majority are mild and manageable. However, due to the increase in patients' life expectancy, there is a substantial need to understand and prevent severe cutaneous, pulmonary, neurological and other AEs which have major impact on the quality of life. The safety profile after long term use of these medications is still unclear. In addition, non-steroid based immune interventions to control autoimmunity are still to be developed.

Rapid detection of HSV with an enzyme-linked virus inducible system™ (ELVIS™) employing a genetically modified cell line

BACKGROUND

Infections with herpes simplex viruses (HSV) are common and may cause severe disease in immunocompromised hosts and in neonates. Isolation of infectious HSV in tissue culture is the most sensitive method of detection, but is not the most rapid. Recently, however, an Enzyme-Linked Virus Inducible System (ELVIS) for rapid detection of HSV in culture has been developed. The system employs genetically engineered baby hamster kidney (BHK) cells (ELVIS cells) whose DNA bears and HSV inducible promoter gene chimerically linked to an E. coli LacZ "reporter" gene. Induction of the promoter by HSV leads to the production of LacZ product, beta-galactosidase, which is readily detected histochemically.

OBJECTIVE

To evaluate these ELVIS cells, as a test for HSV, in comparison with HSV detection in MRC-5 cells in shell vial cultures confirmed by staining with fluorescent antibodies.

STUDY DESIGN

Over a period of one month, 167 specimens submitted to the laboratory for detection of HSV were evaluated. Specimens were inoculated onto MRC-5 cells growing on glass coverslips in each of two shell vials and into two wells of a 24-well cluster plate containing ELVIS cells. MRC-5 shell vial cultures were observed daily for cpe for up to 7 days. With the appearance of cpe, the coverslips were fixed and the cells were typed for HSV-1 and HSV-2 with monoclonal antibodies. Specimens inoculated onto ELVIS cells were incubated for 16-24 h, then substrate was added to stain for beta-galactosidase. ELVIS cells, induced by HSV infection to express beta-galactosidase, stained blue upon reaction with substrate.

RESULTS

Of 167 specimens inoculated onto MRC-5 cells, 13 were excluded because of contamination or toxicity. Among the remaining 154 specimens, 24 were positive for HSV in the MRC-5 shell vials. Of 166 specimens inoculated into the ELVIS cell, all were completed within 24 h. Twenty-three (23) of the 24 shell-vial-positive cultures also were positive on the ELVIS cells. All 23 specimens detected in the ELVIS cells were positive within 24 h, whereas only nine were positive within 24 hours in MRC-5 shell vial cultures. The remaining 15 became positive after 24 h. Specimens positive for viruses other than HSV-1 or HSV-2 were not positive on the ELVIS cells.

CONCLUSIONS

The ELVIS assay for HSV is simple to perform, is rapid, sensitive, and specific. The assay detects both HSV-1 and HSV-2. No antibodies are required unless typing, which can be done on the ELVIS cells, is necessary.