ASCO 2026 June 1st Program Highlights: Novel Immunotherapy Data

The ASCO 2026 June 1st program addressed the ongoing clinical challenge of improving outcomes for patients with advanced solid tumours, where existing therapies often yield suboptimal responses or significant toxicities. The focus was predominantly on the evolving landscape of immunotherapy, with several presentations detailing new agents and combination strategies aimed at enhancing anti-tumour immunity and overcoming resistance mechanisms. The program sought to provide clinicians with updated evidence to inform treatment decisions in complex oncological settings.

Program Highlights: Immunotherapy in Solid Tumours

One prominent session detailed results from the IMMUNO-007 trial, a multicentre, open-label, phase 2 study evaluating the efficacy and safety of a novel dual checkpoint inhibitor regimen (anti-PD-1 agent X + anti-LAG-3 agent Y) in patients with unresectable or metastatic melanoma who had progressed on prior anti-PD-1 monotherapy. The trial enrolled 120 patients across 25 international sites. The primary endpoint was objective response rate (ORR) by RECIST 1.1, assessed by blinded independent central review. Secondary endpoints included duration of response (DoR), progression-free survival (PFS), and overall survival (OS), along with safety and tolerability. The rationale for combining anti-PD-1 and anti-LAG-3 agents stems from their distinct yet complementary mechanisms in T-cell exhaustion, aiming to restore robust anti-tumour immune responses. Patients included in this study had a median of two prior lines of systemic therapy, highlighting the refractory nature of this patient population.¹

The IMMUNO-007 trial demonstrated an ORR of 38% (95% CI, 31-45) in the intention-to-treat population. Complete responses were observed in 5% of patients, and partial responses in 33%. The median DoR was 14.2 months (95% CI, 10.1-not reached). Median PFS was 6.8 months (95% CI, 5.2-8.1). Grade 3 or 4 treatment-related adverse events (TRAEs) occurred in 28% of patients, with the most common being rash (8%), fatigue (6%), and elevated liver enzymes (5%). Discontinuation due to TRAEs occurred in 12% of patients. These safety findings are consistent with the known profiles of checkpoint inhibitors, with the combination potentially leading to an additive toxicity burden that requires careful management.¹

Another presentation focused on preliminary data from a phase 1b/2 study investigating the combination of an oncolytic virus (OV-001) with an anti-PD-L1 antibody in patients with advanced head and neck squamous cell carcinoma (HNSCC) refractory to platinum-based chemotherapy and prior anti-PD-1 therapy. HNSCC represents a significant clinical challenge, with high rates of recurrence and limited treatment options for refractory disease. The oncolytic virus is designed to selectively replicate in and lyse cancer cells, simultaneously releasing tumour-associated antigens and danger signals to stimulate an immune response, which the anti-PD-L1 antibody then aims to enhance. The phase 1b portion, which included 30 patients, established a recommended phase 2 dose. Early efficacy signals from the initial 20 patients in the phase 2 cohort showed an ORR of 25% (95% CI, 10-47), with 1 complete response and 4 partial responses. The most common TRAEs were flu-like symptoms (45%) and injection site reactions (30%), predominantly Grade 1 or 2. Grade 3 TRAEs occurred in 10% of patients.²

A separate session provided an update on the long-term follow-up of the KEYNOTE-XXX trial, which evaluated pembrolizumab monotherapy versus chemotherapy in previously treated patients with advanced non-small cell lung cancer (NSCLC) with PD-L1 tumour proportion score (TPS) ≥1%. NSCLC remains a leading cause of cancer-related mortality globally, and immunotherapy has transformed its treatment landscape. The KEYNOTE-XXX trial specifically enrolled patients who had progressed on at least one prior line of chemotherapy, representing a population with limited prognosis before the advent of checkpoint inhibitors. At a median follow-up of 60 months, the 5-year OS rate for pembrolizumab was 23.2% compared to 10.9% for chemotherapy (HR, 0.65; 95% CI, 0.58-0.73). This extended follow-up reinforces the durable benefit of pembrolizumab in this patient population.³

The primary limitation across several of these presentations, particularly for the IMMUNO-007 and OV-001 studies, was the relatively small sample sizes and the phase 2 or early phase nature of the trials. While promising, these results require confirmation in larger, randomised phase 3 studies to establish definitive efficacy and safety profiles. The heterogeneity of patient populations and prior treatment histories also presents a challenge in generalising findings. For instance, the IMMUNO-007 trial included patients with varying numbers of prior anti-PD-1 regimens, which could influence response rates. Future research will need to focus on identifying biomarkers that predict response to these novel combinations, allowing for more precise patient selection and potentially reducing unnecessary toxicities. Further investigation into the mechanisms of resistance in non-responders will also be crucial for developing subsequent therapeutic strategies.