A practical guide to the handling and administration of talimogene laherparepvec in Europe

Cancer therapy with the viral and bacterial pathogens: The past enemies can be considered the present allies

Cancer continues to be one of the leading causes of mortality worldwide despite significant advancements in cancer treatment. Many difficulties have arisen as a result of the detrimental consequences of chemotherapy and radiotherapy as a common cancer therapy, such as drug inability to penetrate deep tumor tissue, and also the drug resistance in tumor cells continues to be a major concern. These obstacles have increased the need for the development of new techniques that are more selective and effective against cancer cells. Bacterial-based therapies and the use of oncolytic viruses can suppress cancer in comparison to other cancer medications. The tumor microenvironment is susceptible to bacterial accumulation and proliferation, which can trigger immune responses against the tumor. Oncolytic viruses (OVs) have also gained considerable attention in recent years because of their potential capability to selectively target and induce apoptosis in cancer cells. This review aims to provide a comprehensive summary of the latest literature on the role of bacteria and viruses in cancer treatment, discusses the limitations and challenges, outlines various strategies, summarizes recent preclinical and clinical trials, and emphasizes the importance of optimizing current strategies for better clinical outcomes.

Intravesical instillation-based mTOR-STAT3 dual targeting for bladder cancer treatment

BACKGROUND

Recent intravesical administration of adenoviral vectors, either as a single injection or in combination with immune checkpoint inhibitors, exemplified by cretostimogene grenadenorepvec and nadofaragene firadenovec, has demonstrated remarkable efficacy in clinical trials for non-muscle invasive bladder cancer. Despite their ability to induce an enhanced immune reaction within the lesion, the intracellular survival signaling of cancer cells has not been thoroughly addressed.

METHODS

An analysis of the prognostic data revealed a high probability of therapeutic efficacy with simultaneous inhibition of mTOR and STAT3. Considering the challenges of limited pharmaco-accessibility to the bladder due to its pathophysiological structure and the partially undruggable nature of target molecules, we designed a dual siRNA system targeting both mRNAs. Subsequently, this dual siRNA system was encoded into the adenovirus 5/3 (Ad 5/3) to enhance in vivo delivery efficiency.

RESULTS

Gene-targeting efficacy was assessed using cells isolated from xenografted tumors using a single-cell analysis system. Our strategy demonstrated a balanced downregulation of mTOR and STAT3 at the single-cell resolution, both in vitro and in vivo. This approach reduced tumor growth in bladder cancer xenograft and orthotopic animal experiments. In addition, increased infiltration of CD8+ T cells was observed in a humanized mouse model. We provided helpful and safe tissue distribution data for intravesical therapy of siRNAs coding adenoviruses.

CONCLUSIONS

The bi-specific siRNA strategy, encapsulated in an adenovirus, could be a promising tool to augment cancer treatment efficacy and overcome conventional therapy limitations associated with "undruggability." Hence, we propose that dual targeting of mTOR and STAT3 is an advantageous strategy for intravesical therapy using adenoviruses.

Oncolytic virotherapy in cancer treatment: challenges and optimization prospects

Oncolytic viruses (OVs) are emerging cancer therapeutics that offer a multifaceted therapeutic platform for the benefits of replicating and lysing tumor cells, being engineered to express transgenes, modulating the tumor microenvironment (TME), and having a tolerable safety profile that does not overlap with other cancer therapeutics. The mechanism of OVs combined with other antitumor agents is based on immune-mediated attack resistance and might benefit patients who fail to achieve durable responses after immune checkpoint inhibitor (ICI) treatment. In this Review, we summarize data on the OV mechanism and limitations of monotherapy, which are currently in the process of combination partner development, especially with ICIs. We discuss some of the hurdles that have limited the preclinical and clinical development of OVs. We also describe the available data and provide guidance for optimizing OVs in clinical practice, as well as a summary of approved and promising novel OVs with clinical indications.

Biosafety and biohazard considerations of HSV-1-based oncolytic viral immunotherapy

Oncolytic viral immunotherapies are agents which can directly kill tumor cells and activate an immune response. Oncolytic viruses (OVs) range from native/unmodified viruses to genetically modified, attenuated viruses with the capacity to preferentially replicate in and kill tumors, leaving normal tissue unharmed. Talimogene laherparepvec (T-VEC) is the only OV approved for patient use in the United States; however, during the last 20 years, there have been a substantial number of clinical trials using OV immunotherapies across a broad range of cancers. Like T-VEC, many OV immunotherapies in clinical development are based on the herpes simplex virus type 1 (HSV-1), with genetic modifications for tumor selectivity, safety, and immunogenicity. Despite these modifications, HSV-1 OV immunotherapies are often treated with the same biosafety guidelines as the wild-type virus, potentially leading to reduced patient access and logistical hurdles for treatment centers, including community treatment centers and small group or private practices, and healthcare workers. Despite the lack of real-world evidence documenting possible transmission to close contacts, and in the setting of shedding and biodistribution analyses for T-VEC demonstrating limited infectivity and low risk of spread to healthcare workers, barriers to treatment with OV immunotherapies remain. With comprehensive information and educational programs, our hope is that updated biosafety guidance on OV immunotherapies will reduce logistical hurdles to ensure that patients have access to these innovative and potentially life-saving medicines across treatment settings. This work reviews a comprehensive collection of data in conjunction with the opinions of the authors based on their clinical experience to provide the suggested framework and key considerations for implementing biosafety protocols for OV immunotherapies, namely T-VEC, the only approved agent to date.

Therapy with oncolytic viruses: progress and challenges

Oncolytic viruses (OVs) are an emerging class of cancer therapeutics that offer the benefits of selective replication in tumour cells, delivery of multiple eukaryotic transgene payloads, induction of immunogenic cell death and promotion of antitumour immunity, and a tolerable safety profile that largely does not overlap with that of other cancer therapeutics. To date, four OVs and one non-oncolytic virus have been approved for the treatment of cancer globally although talimogene laherparepvec (T-VEC) remains the only widely approved therapy. T-VEC is indicated for the treatment of patients with recurrent melanoma after initial surgery and was initially approved in 2015. An expanding body of data on the clinical experience of patients receiving T-VEC is now becoming available as are data from clinical trials of various other OVs in a range of other cancers. Despite increasing research interest, a better understanding of the underlying biology and pharmacology of OVs is needed to enable the full therapeutic potential of these agents in patients with cancer. In this Review, we summarize the available data and provide guidance on optimizing the use of OVs in clinical practice, with a focus on the clinical experience with T-VEC. We describe data on selected novel OVs that are currently in clinical development, either as monotherapies or as part of combination regimens. We also discuss some of the preclinical, clinical and regulatory hurdles that have thus far limited the development of OVs.

Glioblastoma microenvironment and its reprogramming by oncolytic virotherapy

Glioblastoma (GBM), a highly aggressive form of brain tumor, responds poorly to current conventional therapies, including surgery, radiation therapy, and systemic chemotherapy. The reason is that the delicate location of the primary tumor and the existence of the blood-brain barrier limit the effectiveness of traditional local and systemic therapies. The immunosuppressive status and multiple carcinogenic pathways in the complex GBM microenvironment also pose challenges for immunotherapy and single-targeted therapy. With an improving understanding of the GBM microenvironment, it has become possible to consider the immunosuppressive and highly angiogenic GBM microenvironment as an excellent opportunity to improve the existing therapeutic efficacy. Oncolytic virus therapy can exert antitumor effects on various components of the GBM microenvironment. In this review, we have focused on the current status of oncolytic virus therapy for GBM and the related literature on antitumor mechanisms. Moreover, the limitations of oncolytic virus therapy as a monotherapy and future directions that may enhance the field have also been discussed.

[Oncolytic virotherapy in head and neck cancer]

OBJECTIVE

Oncolytic viruses (OV) infect and kill cancer cells and elicit an antitumoral immune response. With their potential to break through tumor immunoresistance, OV might be a future combination treatment option in patients with advanced head and neck cancer (HNC). Modes of action, biological modifications, handling and side effects of OV for treatment of HNC are reviewed. Results of preclinical and clinical trials are reported.

METHODS

Publications and clinical trials dealing with OV and HNC were searched in PubMed and international platforms for clinical study records. Studies on preclinical and clinical trials regarding oncolytic Herpes Simplex Virus (HSV), Adenovirus, Vacciniavirus and Reovirus were selected.

RESULTS

Enhanced infection and killing of tumor cells through capsid and genome modifications of OV were reported in recent preclinical studies. Most of the clinical studies were phase-I/II trials. In phase III studies, tumor regression and prolonged survival were observed after treatment with oncolytic HSV, Adenoviruses and Reoviruses. In most trials, OV were combined with chemoradiotherapy or immunotherapy.

CONCLUSION

In the published studies, OV treatment of HNC patients was safe, often well tolerated and showed promising results with regard to response and survival, especially in combination with chemoradiotherapy or checkpoint inhibitors.

Dermoscopy as response evaluation tool for cutaneous malignant melanoma metastases treated with Talimogene Laherparepvec: a prospective feasibility study

BACKGROUND

Currently, the response of cutaneous melanoma metastases (CMM) to treatment with Talimogene Laherparepvec (T-VEC) is evaluated by clinical examination, macroscopic lesion photography and 3-monthly PET-CT scans. When a complete response (CR) is suspected, biopsies are taken for histopathological confirmation.

OBJECTIVES

We set out to investigate the feasibility of dermoscopy in monitoring the response to T-VEC in a pilot study.

METHODS

Six patients with CMM treated with T-VEC monotherapy were enrolled in the pilot study. Patients were treated with T-VEC according to protocol and the response was monitored with clinical examination, macroscopic lesion photography and 3-monthly PET-CT scans. For this study, 1-3 cutaneous metastases per patient were selected. Macroscopic and dermoscopic pictures of these metastases were taken at baseline, prior to each treatment with T-VEC and prior to histological biopsy. The pictures were evaluated by two investigators, using a color-based pattern classification.

RESULTS

In total 11 CMM were dermoscopically assessed, 93% was located on the extremities. Four metastases had a blue pattern, two metastases had a pink pattern, three metastases had a brown pattern and two metastases had mixed pattern. Metastases with a pink pattern harbored glomerular and arborizing vessels that diminished and vanished during treatment T-VEC, indicating CR. The remaining metastases did not show changes on a dermoscopic level that were not also seen on macroscopic level. Five patients achieved CR to T-VEC, one patient is still on treatment.

CONCLUSIONS

These results suggest that for CMM with a pink pattern, dermoscopy can provide additional information regarding the response to T-VEC. For cutaneous metastases with a blue, brown or a mixed pattern, dermoscopy did not provide additional information on top of the information obtained through physical examination and lesion photography. More studies would be needed to determine the exact role of dermoscopy in the evaluation of CMM.

External Validation of a Dutch Predictive Nomogram for Complete Response to T-VEC in an Independent American Patient Cohort

PURPOSE

Talimogene Laherparepvec (T-VEC) is a modified herpes simplex virus type-1 used as intralesional immunotherapy in stage IIIB-IVM1a melanoma patients. Recently, Stahlie et al. published a predictive model for complete response (CR) to T-VEC. This study was designed to validate this model externally in an independent, American patient cohort.

METHODS

In total, 71 stage IIIB-IVM1a melanoma patients treated with T-VEC at Moffitt Cancer Center were included. A second nomogram was built incorporating the same predictive factors: tumor size (diameter of largest metastasis), type of metastases (cutaneous, subcutaneous and nodal), and number of metastases (cutoff: < 20 and > 20). Predictive accuracy was assessed through calculation of overall performance, discriminative ability, and calibration.

RESULTS

The two cohorts were similar in many clinicopathologic factors and only differing in tumor mutational status and use of systemic therapy prior to T-VEC. In the validation cohort, 37 (52%) patients showed CR, 22 (31%) partial response (PR), 2 (5.6%) stable disease (SD), and 10 (15%) progressive disease (PD). Of those who demonstrated a CR, 16 (43%) recurred. Overall performance was good (0.164), and discriminative power resulted in fair discriminative ability (0.827). The calibration curve showed slight underestimation for predicted probabilities > 0.15 and slight overestimation <0.15.

CONCLUSIONS

The original model as well as the validation model show comparable and good predictive accuracy. The validation model reinforces the conclusion that for the best response to T-VEC, it should be used early on in the course of the disease, when the tumor burden is cutaneous with smaller diameter and fewer of metastases.

Is there still a role for talimogene laherparepvec (T-VEC) in advanced melanoma? An indirect efficacy comparison of T-VEC plus ipilimumab combination therapy versus T-VEC alone as salvage therapy in unresectable metastatic melanoma

BACKGROUND

Talimogene laherparepvec (T-VEC) improves overall survival (OS) in unresectable stage IIIB/C-IV melanoma T-VEC may have synergistic effects with CTLA-4 inhibitors In the absence of a trial comparing T-VEC and ipilimumab (T-VEC + IPI) to T-VEC, we applied a novel indirect comparison method using extrapolated OS curves to estimate OS outcomes in a simulated trial comparing both regimens in stage IIIB/C-IV unresectable melanoma.

RESEARCH DESIGN AND METHODS

Two trials with extractable OS curves for a T-VEC versus T-VEC + IPI comparison were identified. Outcomes were adjusted for heterogeneity in prognostic factors using a calculated adjustment factor. T-VEC and adjusted/unadjusted T-VEC+IPI curves were plotted with 95% CIs.

RESULTS

Unadjusted indirect OS comparison of T-VEC versus T-VEC + IPI revealed no significant difference up to 15 months. Extrapolation beyond 15 months showed significant survival benefits for T-VEC + IPI over T-VEC, confirmed in adjusted analyses. The expected OS percentage at 48 months is 32.0% (95% CI = 26.6-37.3) for T-VEC, 60.0% (95% CI = 46.2-69.1) for unadjusted, and 81.1% (95% CI = 72.3-85.9) for adjusted T-VEC + IPI.

CONCLUSIONS

Our novel indirect comparison suggests that T-VEC + IPI may demonstrate a significantly improved OS versus T-VEC alone. Findings may portend a possible role for the addition of T-VEC to advanced melanoma treatment regimens in select patients as salvage therapy.

Talimogene Laherparepvec (T-VEC) for the Treatment of Advanced Locoregional Melanoma After Failure of Immunotherapy: An International Multi-Institutional Experience

BACKGROUND

Talimogene laherparepvec (T-VEC) is an oncolytic virus approved for the treatment of unresectable, recurrent melanoma. The role of T-VEC after progression on systemic immunotherapy (IO) remains undefined. The goal of this study was to characterize the efficacy of T-VEC after failure of IO in patients with unresectable metastatic melanoma.

METHODS

An international, multi-institutional review of AJCC version 8 stage IIIB-IV melanoma patients treated with T-VEC after failure of IO was performed at six centers from October 2015-December 2020. Primary outcome was in-field response; secondary outcomes included analyses of in-field and overall progression-free survival (PFS) and in-field and overall disease-free survival (DFS) after a complete response. Subset analysis of T-VEC initiation sequentially after or concurrently with IO was performed.

RESULTS

Of 112 patients, median age at T-VEC initiation was 69 years (range 21-93); 65 (58%) were male. Before T-VEC, 57% patients received one IO regimen, 42% received two or more, with most patients (n = 74, 66%) receiving T-VEC sequential to IO. Most were stage 3C (n = 51, 46%) at T-VEC initiation, 29 (26%) received injections to nodal disease. Over median follow-up of 14 months, in-field response at final T-VEC injection was 37% complete (CR), 14% partial (PR). T-VEC initiation sequentially or concurrently did not significantly affect in-field response (p = 0.26). Median in-field PFS was 15 months (95% confidence interval 4.6-NE). Median overall DFS after CR was 32 months (95% confidence interval 17-NE).

CONCLUSIONS

T-VEC after failure of IO is effective in unresectable, metastatic stage IIIB-IV melanoma. T-VEC initiation sequentially or concurrently did not significantly affect in-field response.

Oncolytic virus therapy in cancer: A current review

In view of the advancement in the understanding about the most diverse types of cancer and consequently a relentless search for a cure and increased survival rates of cancer patients, finding a therapy that is able to combat the mechanism of aggression of this disease is extremely important. Thus, oncolytic viruses (OVs) have demonstrated great benefits in the treatment of cancer because it mediates antitumor effects in several ways. Viruses can be used to infect cancer cells, especially over normal cells, to present tumor-associated antigens, to activate "danger signals" that generate a less immune-tolerant tumor microenvironment, and to serve transduction vehicles for expression of inflammatory and immunomodulatory cytokines. The success of therapies using OVs was initially demonstrated by the use of the genetically modified herpes virus, talimogene laherparepvec, for the treatment of melanoma. At this time, several OVs are being studied as a potential treatment for cancer in clinical trials. However, it is necessary to be aware of the safety and possible adverse effects of this therapy; after all, an effective treatment for cancer should promote regression, attack the tumor, and in the meantime induce minimal systemic repercussions. In this manuscript, we will present a current review of the mechanism of action of OVs, main clinical uses, updates, and future perspectives on this treatment.

T-VEC for stage IIIB-IVM1a melanoma achieves high rates of complete and durable responses and is associated with tumor load: a clinical prediction model

BACKGROUND

Talimogene laherparepvec (T-VEC) is a genetically modified herpes simplex type 1 virus and known as an effective oncolytic immunotherapy for injectable cutaneous, subcutaneous and nodal melanoma lesions in stage IIIB-IVM1a patients. This study set out to identify prognostic factors for achieving a complete response that can be used to optimize patient selection for T-VEC monotherapy.

METHODS

Patients with stage IIIB-IVM1a melanoma, treated with T-VEC at the Netherlands Cancer Institute between 2016-12 and 2020-01 with a follow-up time > 6 months, were included. Data were collected on baseline characteristics, responses and adverse events (AEs). Uni- and multivariable analyses were conducted, and a prediction model was developed to identify prognostic factors associated with CR.

RESULTS

A total of 93 patients were included with a median age of 69 years, median follow-up time was 16.6 months. As best response, 58 patients (62%) had a CR, and the overall response rate was 79%. The durable response rate (objective response lasting > 6 months) was 51%. Grade 1-2 AEs occurred in almost every patient. Tumor size, type of metastases, prior treatment with systemic therapy and stage (8Th AJCC) were independent prognostic factors for achieving CR. The prediction model includes the predictors tumor size, type of metastases and number of lesions.

CONCLUSIONS

This study shows that intralesional T-VEC monotherapy is able to achieve high complete and durable responses. The prediction model shows that use of T-VEC in patients with less tumor burden is associated with better outcomes, suggesting use earlier in the course of the disease.

Injectables in Head and Neck Cutaneous Melanoma Treatment

Head and neck cutaneous melanomas pose many treatment challenges. Intratumoral injectables offer local and possibly systemic therapy in unresectable lesions. Talimogene laherparepvec, an injectable oncolytic type 1 herpes simplex virus, can improve durable response rates compared with systemic granulocyte-macrophage colony-stimulating factor therapy in patients with stage IIIB to IVM1a unresectable melanoma. These benefits were most noticed in lower-stage subsets and treatment naive patients. Efficacy of talimogene laherparepvec was maintained in patients with head and neck melanoma. Talimogene laherparepvec plus systemic immunotherapies is being studied, with promising preliminary data. Numerous ongoing clinical trials are investigating other viral and nonviral injectables.

Oncolytic Virotherapy in Solid Tumors: The Challenges and Achievements

Oncolytic virotherapy (OVT) is a promising approach in cancer immunotherapy. Oncolytic viruses (OVs) could be applied in cancer immunotherapy without in-depth knowledge of tumor antigens. The capability of genetic modification makes OVs exciting therapeutic tools with a high potential for manipulation. Improving efficacy, employing immunostimulatory elements, changing the immunosuppressive tumor microenvironment (TME) to inflammatory TME, optimizing their delivery system, and increasing the safety are the main areas of OVs manipulations. Recently, the reciprocal interaction of OVs and TME has become a hot topic for investigators to enhance the efficacy of OVT with less off-target adverse events. Current investigations suggest that the main application of OVT is to provoke the antitumor immune response in the TME, which synergize the effects of other immunotherapies such as immune-checkpoint blockers and adoptive cell therapy. In this review, we focused on the effects of OVs on the TME and antitumor immune responses. Furthermore, OVT challenges, including its moderate efficiency, safety concerns, and delivery strategies, along with recent achievements to overcome challenges, are thoroughly discussed.

Ultrasound-guided Intralesional Injection of Talimogene laherparepvec (Imlygic) for Advanced Melanoma: Technical Note on a Preliminary Experience

PURPOSE

To evaluate the safety and feasibility of ultrasound-guided intralesional injection of Talimogene laherparepvec (Imlygic, T-VEC) in patients with advanced non-palpable melanoma.

MATERIALS AND METHODS

Fourteen consecutive patients (mean age, 67.9 years ± 13.0; range, 40-88; 12 males) with unresectable, locally advanced melanoma underwent ultrasound-guided intralesional injections of T-VEC (July 2016-March 2020) into subcutaneous lesions. Tumor response to the injection was evaluated at the last follow-up. Technical success and complication rates were recorded.

RESULTS

The T-VEC injection was technically successful in all patients with all lesions successfully punctured (100%). The mean number of lesions, injection cycles, and injection volumes were 4.1 ± 2.6 (1-9), 6.5 ± 3.0 (3-12), and 2.6 mL ± 1.4 (1-4 mL), respectively. During the follow-up period (mean, 21.0 months ± 13.4; range 1-43.6 months), complete remission, partial remission, persistent disease, and disease progression were observed in 6 (42.9%), 3 (21.4%), 1 (7.1%), and 4 (28.6%) patients, respectively. Post-treatment symptoms observed in 9 patients (64.3%), including fever (n = 2), fatigue (n = 1), headache (n = 1), pain (n = 1), mouth sores (n = 1), and flu-like symptoms (n = 3). No injection-related complications occurred in all procedures.

CONCLUSION

Intralesional injection of T-VEC for non-palpable metastases under ultrasound guidance is safe and feasible in patients with advanced melanoma.

Intratumoural immunotherapies for unresectable and metastatic melanoma: current status and future perspectives

The emergence of human intratumoural immunotherapy (HIT-IT) is a major step forward in the management of unresectable melanoma. The direct injection of treatments into melanoma lesions can cause cell lysis and induce a local immune response, and might be associated with a systemic immune response. Directly injecting immunotherapies into tumours achieves a high local concentration of immunostimulatory agent while minimising systemic exposure and, as such, HIT-IT agents are associated with lower toxicity than systemic immune checkpoint inhibitors (CPIs), enabling their potential use in combination with other therapies. Consequently, multiple HIT-IT agents, including oncolytic viruses, pattern-recognition receptor agonists, injected CPIs, cytokines and immune glycolipids, are under investigation. This review considers the current clinical development status of HIT-IT agents as monotherapy and in combination with systemic CPIs, and the practical aspects of administering and assessing the response to these agents. The future of HIT-IT probably lies in its use in combination with systemic CPIs; data from Phase 2 trials indicate a synergy between HIT-IT and CPIs. Data also suggest that the addition of HIT-IT to a CPI might generate responses in CPI-refractory tumours, thereby overcoming resistance and addressing a current unmet need in unresectable and metastatic melanoma for treatment options following progression after CPI treatment.

Delivery and Biosafety of Oncolytic Virotherapy

In recent years, oncolytic virotherapy has emerged as a promising anticancer therapy. Oncolytic viruses destroy cancer cells, without damaging normal tissues, through virus self-replication and antitumor immunity responses, showing great potential for cancer treatment. However, the clinical guidelines for administering oncolytic virotherapy remain unclear. Delivery routes for oncolytic virotherapy to patients vary in existing studies, depending on the tumor sites and the objective of studies. Moreover, the biosafety of oncolytic virotherapy, including mainly uncontrolled adverse events and long-term complications, remains a serious concern that needs to be accurately measured. This review provides a comprehensive and detailed overview of the delivery and biosafety of oncolytic virotherapy.

Review of talimogene laherparepvec: A first-in-class oncolytic viral treatment of advanced melanoma

Talimogene laherparepvec (T-VEC) is an oncolytic virus based on herpes simplex virus type 1 approved for intralesional treatment of advanced melanoma. In this article, we review the clinical literature on T-VEC for advanced melanoma and provide a practical approach to using T-VEC in the dermatologic surgery and oncology clinic. PubMed was used to conduct a systematic literature review of articles describing the structure, basic science, and clinical and therapeutic properties of T-VEC. The national clinical trials database was also searched for T-VEC clinical trials. Phase I to III clinical trials and early real-world experience have shown the efficacy of T-VEC in advanced melanoma as single or combination therapy with tolerable adverse effects. We conclude that with a standardized clinical approach and training, dermatologists can pave the way in using T-VEC and future oncolytic virus therapies in appropriate clinical scenarios.

Stabilization and formulation of a recombinant Human Cytomegalovirus vector for use as a candidate HIV-1 vaccine

Live attenuated viral vaccine/vector candidates are inherently unstable and infectivity titer losses can readily occur without defining appropriate formulations, storage conditions and clinical handling practices. During initial process development of a candidate vaccine against HIV-1 using a recombinant Human Cytomegalovirus vector (rHCMV-1), large vector titer losses were observed after storage at 4 °C and after undergoing freeze-thaw. Thus, the goal of this work was to develop candidate frozen liquid formulations of rHCMV-1 with improved freeze-thaw and short-term liquid stability for potential use in early clinical trials. To this end, a virus stability screening protocol was developed including use of a rapid, in vitro cell-based immunofluorescence focus assay to quantitate viral titers. A library of ∼50 pharmaceutical excipients (from various known classes of additives) were evaluated for their effect on vector stability after freeze-thaw cycling or incubation at 4 °C for several days. Certain additives including sugars and polymers (e.g., trehalose, sucrose, sorbitol, hydrolyzed gelatin, dextran 40) as well as removal of NaCl (lower ionic strength) protected rHCMV-1 against freeze-thaw mediated losses in viral titers. Optimized solution conditions (e.g., solution pH, buffers and sugar type) slowed the rate of rHCMV-1 titer losses in the liquid state at 4 °C. After evaluating various excipient combinations, three new candidate formulations were designed and rHCMV-1 stability was benchmarked against both the currently-used and a previously reported formulation. The new candidate formulations were significantly more stable in terms of reducing rHCMV-1 titer losses after 5 freeze-thaw cycles or incubation at 4 °C for 30 days. This case study highlights the utility of semi-empirical design of frozen liquid formulations of a live viral vaccine candidate, where protection against infectivity titer losses due to freeze-thaw and short-term liquid storage are sufficient to enable more rapid initiation of early clinical trials.

Development of a Nursing Policy for the Administration of an Oncolytic Virus in the Outpatient Setting

OBJECTIVE

To describe the development of a nursing policy for the administration of oncolytic viruses in therapeutic clinical trials and the unique challenges for infection control and nursing.

DATA SOURCE

Journal articles, web-based resources, peer-reviewed literature.

CONCLUSION

Early nursing involvement and inclusion of multidisciplinary hospital departments facilitated the creation of a nursing policy that maintained fidelity to the research protocol and minimized potential risk to nursing staff. A total of 18 doses of oncolytic viruses were administered with no inadvertent exposures to staff or other patients of the oncolytic virus.

IMPLICATIONS FOR NURSING PRACTICE

Nursing should be involved at the initiation of a clinical trial to determine whether policies need to be created or changed to maintain the integrity of the research protocol while ensuring the safety of staff and patients.

Biodistribution, shedding, and transmissibility of the oncolytic virus talimogene laherparepvec in patients with melanoma

Background

Talimogene laherparepvec (T-VEC) is an intralesionally delivered, modified herpes simplex virus type-1 oncolytic immunotherapy. The biodistribution, shedding, and potential transmission of T-VEC was systematically evaluated during and after completion of therapy in adults with advanced melanoma.

Methods

In this phase 2, single-arm, open-label study, T-VEC was administered into injectable lesions initially at 10⁶ plaque-forming units (PFU)/mL, 10⁸ PFU/mL 21 days later, and 10⁸ PFU/mL every 14 (±3) days thereafter. Injected lesions were covered with occlusive dressings for ≥1 week. Blood, urine, and swabs from exterior of occlusive dressings, surface of injected lesions, oral mucosa, anogenital area, and suspected herpetic lesions were collected throughout the study. Detectable T-VEC DNA was determined for each sample type; infectivity was determined for all swabs with detectable T-VEC DNA.

Findings

Sixty patients received ≥1 dose of T-VEC. During cycles 1–4, T-VEC DNA was detected in blood (98·3% of patients, 36·7% of samples), urine (31·7% of patients, 3·0% of samples) and swabs from injected lesions (100% of patients, 57·6% of samples), exterior of dressings (80% of patients,19·5% of samples), oral mucosa (8·3% of patients, 2·5% of samples), and anogenital area (8·0% of patients, 1·1% of samples). During the safety follow-up period, T-VEC DNA was only detected on swabs from injected lesions (14% of patients, 5.8% of samples). T-VEC DNA was detected in 4/37 swabs (3/19 patients) of suspected herpetic lesions. Among all samples, only those from the surface of injected lesions tested positive for infectivity (8/740 [1·1%]). Three close contacts reported signs and symptoms of suspected herpetic origin; however, no lesions had detectable T-VEC DNA.

Interpretation

Using current guidelines, T-VEC can be administered safely to patients with advanced melanoma and is unlikely to be transmitted to close contacts with appropriate use of occlusive dressings.

Fund

This study was funded by Amgen Inc.: ClinicalTrials.gov, NCT02014441.

A severe case of neuro-Sjögren's syndrome induced by pembrolizumab

BACKGROUND

The prevalence of connective tissue disease (CTD) induced by immune checkpoint inhibitors (CPIs) in the absence of pre-existing autoimmunity is unknown.

CASE PRESENTATION

We report the case of a melanoma patient treated for 8 months with pembrolizumab who developed a subacute ataxic sensory neuronopathy (SNN), including a right trigeminal neuropathy. Salivary gland biopsy showed inflammatory changes suggestive of Sjögren's syndrome, while brain MRI revealed enhancement of the right trigeminal ganglia. A high level of protein and pleocytosis was found in the cerebrospinal fluid, with negative cultures. Nerve conduction studies revealed the absence of sensory nerve action potentials in the upper and lower limbs and reduced motor responses in the upper limbs, fulfilling criteria for SNN. Blood tests revealed an important inflammatory syndrome, hemolytic anemia, elevation of total IgG levels and the presence of ANA autoantibodies specific to anti-SSA (52 and 60 kd). All these elements were absent before the initiation of the treatment with pembrolizumab. Initially, there was a clinical response following intravenous frontline methylprednisone, but the subacute relapse required the introduction of second-line treatment with intravenous immunoglobulins and then rituximab, which led to a quick clinical improvement.

CONCLUSIONS

Herein, we describe the first case of a patient who developed a typical SNN as a complication of severe neuro-Sjögren's syndrome induced by pembrolizumab treatment.

Implementing a Program of Talimogene laherparepvec

BACKGROUND

Oncolytic viruses are genetically engineered or naturally occurring viruses that selectively replicate in cancer cells without harming normal cells. Talimogene laherparepvec (Imlygic^®), the first oncolytic viral therapy approved for treatment of cancer, was approved for treatment of locally advanced melanoma in October 2015.

PURPOSE

As a biologic product, use of T. laherparepvec in the clinical setting requires pretreatment planning and a unique systematic approach to deliver the therapy. The processes we describe herein could be adopted by other centers that choose to prescribe T. laherparepvec.

METHODS

We studied our clinical trial experience with T. laherparepvec before we embarked on using commercially available T. laherparepvec. We created a standard operating procedure (SOP) with multidisciplinary buy-in and oversight from leadership in Infection Control at our institution. We reflected on clinical cases and the actual procedures of administering T. laherparepvec to create the SOP.

RESULTS

The preimplementation planning, patient selection, identification of lesions to treat, the actual procedure, and ongoing assessment of patients are described. Tumoral-related factors that lead to unique challenges are described.

CONCLUSIONS

A process to ensure safe and responsible implementation of a program to administer T. laherparepvec for treatment of melanoma may improve the quality of treatment for patients who suffer from advanced melanoma.