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Introduction: Cancer immunotherapy has seen tremendous strides in the past 15 years, with the introduction of several novel immunotherapeutic agents. Nevertheless, as clinical practice has shown, significant challenges remain with a considerable number of patients responding sub-optimally to available therapeutic options. Research has demonstrated the important immunoregulatory role of the tumor microenvironment (TME), with the potential to either hinder or promote an effective anti-tumor immune response. As such, scientific efforts have focused on investigating novel candidate immunomodulatory agents with the potential to alter the TME toward a more immunopotentiating composition., Areas Covered: Herein, we discuss the novel investigational toll-like receptor 9 agonist tilsotolimod currently undergoing phase II and III clinical trials for advanced refractory cancer, highlighting its mode of action, efficacy, tolerability, and potential future applications in the treatment of cancer. To this effect, we conducted an exhaustive Web of Science and PubMed search to evaluate available research on tilsotolimod as of August 2021., Expert Opinion: With encouraging early clinical results demonstrating extensive TME immunomodulation and abscopal effects on distant tumor lesions, tilsotolimod has emerged as a potential candidate immunomodulatory agent with the possibility to augment currently available immunotherapy and provide novel avenues of treatment for patients with advanced refectory cancer.

Malignant melanoma (MM) exhibits a high propensity for central nervous system dissemination with ~50% of metastatic MM patients developing brain metastases (BM). Targeted therapies and immune checkpoint inhibitors have improved overall survival for MM patients with BM. However, responses are usually of short duration and new agents that effectively penetrate the blood brain barrier (BBB) are needed. Here, we report a MM patient with BM who experienced an exceptional response to E6201, an ATP-competitive MEK1 inhibitor, on a Phase 1 study, with ongoing near-complete response and overall survival extending beyond 8 years. Whole exome and transcriptome sequencing revealed a high mutational burden tumor (22 mutations/Megabase) with homozygous BRAF V600E mutation. Correlative preclinical studies demonstrated broad activity for E6201 across BRAF V600E mutant melanoma cell lines and effective BBB penetration in vivo. Together, these results suggest that E6201 may represent a potential new treatment option for BRAF-mutant MM patients with BM.

Importance: A phase 2 trial comparing talimogene laherparepvec plus ipilimumab vs ipilimumab monotherapy in patients with advanced unresectable melanoma found no differential benefit in progression-free survival (PFS) but noted objective response rates (ORRs) of 38.8% (38 of 98 patients) vs 18.0% (18 of 100 patients), respectively., Objective: To perform an economic evaluation of talimogene laherparepvec plus ipilimumab combination therapy vs ipilimumab monotherapy., Design, Setting, and Participants: For PFS, cost-effectiveness and cost-utility analyses using a 2-state Markov model (PFS vs progression or death) was performed. For ORRs, cost-effectiveness analysis of the incremental cost of 1 additional patient achieving objective response was performed. In this setting based on a US payer perspective (2017 US dollars), participants were patients with advanced unresectable melanoma., Main Outcomes and Measures: The PFS life-years and PFS quality-adjusted life-years were determined, and the associated incremental cost-effectiveness ratios (ICERs) and incremental cost-utility ratios (ICURs) were estimated. Also estimated was the ICER per 1 additional patient (out of 100 treated patients) achieving objective response. Base-case analyses were validated by sensitivity analyses., Results: In PFS analyses, the cost of talimogene laherparepvec plus ipilimumab ($494 983) exceeded the cost of ipilimumab monotherapy ($132 950) by $362 033. The ICER was $2 129 606 per PFS life-years, and the ICUR was $2 262 706 per PFS quality-adjusted life-year gained. Probabilistic sensitivity analyses yielded an ICER of $1 481 208 per PFS life-year gained and an ICUR of $1 683 191 per PFS quality-adjusted life-year gained. In 1-way sensitivity analyses, the PFS hazard ratio and the utility of response were the most influential parameters. Talimogene laherparepvec plus ipilimumab has a 50% likelihood of being cost-effective at a willingness-to-pay threshold of $1 683 191 per PFS quality-adjusted life-year gained. In ORR analyses, talimogene laherparepvec plus ipilimumab ($474 904) vs ipilimumab alone ($132 810), a $342 094 difference, yielded an ICER of $1 629 019 per additional patient achieving objective response. In subgroup analyses by disease stage and BRAFV600E mutation status, ICERs ranged from $1 069 044 to $17 104 700 per 1 additional patient achieving objective response., Conclusions and Relevance: The cost to gain 1 additional progression-free quality-adjusted life-year, 1 additional progression-free life-year, or to have 1 additional patient attain objective response is about $1.6 million. This amount may be beyond what payers typically are willing to pay. Combination therapy of talimogene laherparepvec plus ipilimumab does not offer an economically beneficial treatment option relative to ipilimumab monotherapy at the population level. This should not preclude treatment for individual patients for whom this regimen may be indicated.

The patient was enrolled in a research study assessing liquid biopsies, which allowed a repeat liquid biopsy testing and analysis post-treatment. For comprehensive evaluation, the original surgically resected clival biopsy sample underwent additional tumor profile assays accompanied by a plasma liquid biopsy. In patients harboring these malignancies, an empiric palliative therapy of docetaxel or paclitaxel, used in parallel with gemcitabine (combined with either carboplatin or irinotecan), is often the preferred regimen used for poor-risk patients with a grim prognosis. Potentially, if other first-line treatment failure occurred, the patient could be considered for a clinical trial that is enrolling patients with ataxia telangiectasia-mutated mutations. [Extracted from the article]