Alexandra M. Adams

Background: The emergence of checkpoint inhibitors (CPIs) has significantly improved survival outcomes in later-stage melanoma. However, the efficacy of these treatments remains limited, with around 50% of later-stage melanoma patients experiencing recurrence. As variable response rates to CPIs persist, the development of cancer vaccines has emerged as a potential strategy to augment antitumor immune responses. Results: This review compares two promising personalized therapeutic cancer vaccine trials in advanced melanoma: Elios Therapeutics’ Tumor Lysate (TL) vaccine and Moderna’s mRNA-4157 vaccine. The TL vaccine, which utilizes yeast cell wall particles (YCWPs) loaded with autologous tumor lysate, and the mRNA-4157 vaccine, which encodes up to 34 patient-specific neoantigens, both aim to stimulate robust tumor-specific immune responses. Both trials were phase 2b randomized studies, with Elios Therapeutics’ trial employing a double-blind, placebo-controlled design, while Moderna’s was open-label. Both trials had roughly equivalent sample sizes (n = 187 and n = 157, respectively) with similar demographics and disease characteristics. The TL trial reported improvements in disease-free survival (DFS) with a hazard ratio (HR) of 0.52 (p < 0.01) over 36 months, whereas the mRNA-4157 trial demonstrated improvements in recurrence-free survival (RFS) with an HR of 0.56 (p = 0.053) over 18 months. The TL vaccine exhibited lower rates of related grade 3 adverse events (<1%) compared to the mRNA vaccine (12%). Key differences between the two trials include the use of CPIs, with 100% of patients in the mRNA trial receiving pembrolizumab versus 37% of the patients in the TL trial receiving either an anti-PD-1 or anti-CTLA-4. The production processes also varied significantly, with the mRNA vaccine requiring individualized sequencing and a 9-week production time, while the TL vaccine utilized tumor lysate with a 1–3-day production time. Conclusions: While both vaccines demonstrated promising efficacy, future phase 3 trials are needed to further evaluate their potential as adjuvant therapies for melanoma. This review highlights the comparative strengths and limitations of these vaccine platforms, providing insight into the evolving landscape of adjuvant cancer vaccines.

Purpose Despite curative-intent treatment, recurrence is common for patients with colorectal cancer (CRC). Currently, prediction of disease recurrence and prognostication following surgery is based upon vague clinical factors and more precise and dynamic biomarkers for risk stratification and treatment decisions are urgently needed. Circulating tumor DNA (ctDNA) is a promising biomarker for patients undergoing treatment for resectable CRC. Methods In this review, we provide an overview of the data supporting current uses of ctDNA for CRC, including localized CRC and resectable colorectal liver metastases (CLM), as well as descriptions of important ongoing clinical trials using ctDNA in the care of patients with CRC. Results The detection of ctDNA following curative-intent therapy is associated with disease recurrence, and multiple trials are investigating its role in determining need and duration for adjuvant therapy for localized CRC. In addition, ctDNA reliably predicts prognosis for patients with CLM, with trials underway studying ctDNA-guided treatment sequencing and intensity. Conclusion The detection of ctDNA is a sensitive and dynamic biomarker for disease recurrence in CRC. Many investigations are underway into ctDNA’s potential role in surveillance and treatment algorithms, and it has the potential to become a critical biomarker to determine individualized strategies for treatment sequencing, choice, and duration of therapies.

Immunotherapy has revolutionized the treatment of melanoma, yet survival remains poor for patients with metastatic disease. The autologous tumor lysate, particle-loaded, dendritic cell (TLPLDC) vaccine has been shown to be safe adjuvant therapy for patients with resected stage III/IV melanoma who complete the primary vaccine series. Here, we describe an open-label trial of patients with metastatic melanoma treated with TLPLDC vaccine in addition to standard of care (SoC) therapies. The TLPLDC vaccine is created by loading autologous tumor lysate into yeast cell wall particles, which are phagocytosed by autologous dendritic cells ex vivo. Patients who recurred while enrolled in a phase IIb trial of adjuvant TLPLDC vaccine (crossover cohort) and patients with measurable metastatic melanoma cohort were offered TLPLDC vaccine along with SoC therapies. Tumor response was measured by RECIST 1.1 criteria. Overall survival (OS) and progression-free survival (PFS) were estimated by intention-to-treat analysis. Fifty-four patients were enrolled (28 in crossover cohort; 26 in metastatic melanoma cohort). The vaccine was well-tolerated with no grade ≥3 adverse events when given with SoC therapies to include checkpoint inhibitors, BRAF/MEK inhibitors, tyrosine kinase inhibitors, intralesional therapy and/or radiation. In the crossover arm, OS was 76.5% and PFS was 57.1% (median follow-up of 13.9 months). In the metastatic melanoma arm, OS was 85.7% and PFS was 52.2% (median follow-up 8.5 months). The TLPLDC vaccine is well-tolerated and safe in combination with SoC therapies. Future trials will determine the efficacy of TLPLDC in combination with SoC therapies in metastatic melanoma.