The American Society of Clinical Oncology (ASCO) 2026 Annual Meeting saw the presentation of several abstracts and presentations highlighting the latest advances in solid tumour research.
Merck & Co has been shoring up its pipeline for the upcoming loss of exclusivity on its oncology blockbuster Keytruda (pembrolizumab), and had data releases at ASCO 2026 centred on several assets, including the antibody drug conjugate (ADC) sacituzumab tirumotecan in endometrial cancer. Nonetheless, data presentations like one from a Phase II study evaluating Keytruda in combination with radiotherapy for head and neck squamous cell carcinoma, continued to highlight the PD-1 inhibitor’s far-reaching impact in oncology.
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Here are some of the highlights from notable trials in solid tumours discussed at ASCO 2026.
Keytruda with radiotherapy bests SOC in HPV+ HNSCC
Conducted by the University of California San Diego in collaboration with Merck & Co, the open-label randomised Phase II KEYCHAIN (NCT03383094) trial evaluated the efficacy of concurrent and adjuvant Keytruda (pembrolizumab) in combination with radiotherapy versus the standard of care, cisplatin plus radiotherapy, in patients with unresected, non-metastatic, unfavourable-risk p16-positive head and neck squamous cell carcinoma (HNSCC).
Keytruda demonstrated a meaningful improvement in progression-free survival (PFS) relative to cisplatin, satisfying the trial’s pre-specified significance threshold (one-sided p <0.15). The efficacy-evaluable population comprised 102 patients, 50 receiving Keytruda and 52 receiving cisplatin, with median follow-up of 36.5 and 25.4 months for Keytruda and cisplatin respectively. In both arms, most patients presented with oropharyngeal primary tumours (94% and 96% in the Keytruda and cisplatin groups, respectively). Notably, the cisplatin arm had a higher prevalence of T4 and N2–N3 disease, though the difference was not statistically significant. Patients treated with Keytruda achieved a two-year PFS rate of 84% (95% CI: 74–96%), compared with 70% (95% CI: 58–85%) among those receiving cisplatin-based chemoradiotherapy (HR 0.58, 95% CI: 0.25–1.33; one-sided p = 0.09). The overall survival (OS) benefit was even more pronounced with two-year rates of 98% (95% CI: 94–100%) and 85% (95% CI: 76–96%) in the Keytruda and SOC arms, respectively (HR 0.34, 95% CI: 0.09–1.31; two-sided p = 0.11). Regarding the safety profile, in the Keytruda arm Grade ≥3 treatment-related adverse events were reported in 36% of patients vs 46% observed with cisplatin. These results support advancement of pembrolizumab plus radiotherapy into Phase III evaluation.
Keytruda is expanding its footprint in locally advanced HNSCC, building on last year’s landmark FDA approval for patients with locally advanced HNSCC with a PD-L1 combined positive score (CPS) ≥1, covering its use as neoadjuvant monotherapy followed by adjuvant treatment with radiotherapy with or without cisplatin. NCCN guidelines restrict its use to resectable disease explicitly excluding p16-positive oropharyngeal HNSCC. This leaves patients managed non-surgically, approximately 40% of the locally advanced HNSCC population, outside the reach of approved immune checkpoint inhibitors (ICIs), according to GlobalData’s Head and Neck Squamous Cell Carcinoma: Eight-Market Drug Forecast and Market Analysis 2024–34 (GDHCHT669).
The KEYCHAIN findings are particularly noteworthy in the context of a difficult clinical landscape: six prior Phase III trials evaluating ICIs alongside definitive chemoradiotherapy in locally advanced HNSCC, JAVELIN HN100, GORTEC REACH, PembroRad, KEYNOTE-412, NRG HN004, and IMvoke010, all missed their primary endpoints. The rationale for continued investigation remains compelling. With over 63,000 locally advanced HNSCC cases diagnosed across six major markets in 2024 alone, the patient population is large and the unmet need significant as chemoradiotherapy carries high recurrence rates, leaving a significant proportion of patients without durable disease control. The advancement of pembrolizumab into Phase III evaluation for the non-surgical locally advanced setting represents a critical and long-awaited next step.
Merck & Co’s sacituzumab tirumotecan strengthens its position in endometrial cancer
Merck & Co recently announced positive topline results from TroFuse-005, a randomized, open-label, global Phase III clinical trial. The study is evaluating Merck & Co/Kelun’s sacituzumab tirumotecan (sac-TMT), a trophoblast cell surface antigen 2 (TROP2)-directed antibody drug conjugate (ADC), versus physician’s choice chemotherapy in certain patients with advanced or recurrent endometrial cancer (EC) who had previously received platinum-based chemotherapy and anti-programmed cell death 1 protein (PD-1)/anti-programmed cell death ligand 1 (PD-L1) therapy.
EC is the most common gynecologic cancer worldwide and makes up an estimated 90% of all uterine cancers. According to GlobalData’s Endometrial Cancer: Epidemiology Forecast to 2030 report, the total number of diagnosed incident cases of EC in the eight major markets (8MM: US, France, Germany, Italy, Spain, UK, Japan, and Canada) will grow from 129,810 in 2026 to 133,690 in 2030. In pre-specified interim analysis, sac-TMT met both primary endpoints of overall survival (OS) and progression-free survival (PFS) and met the key secondary endpoint of objective response rate.
From a competitive perspective, sac-TMT’s closest direct rival is Gilead’s Trodelvy (sacituzumab govitecan), another TROP2-directed ADC being evaluated in ASCENT-GYN-01 in a very similar post-platinum, post-anti-PD-1 or -PD-L1 patient population. However, Merck & Co now appears ahead on timing, with the first positive global Phase III OS and PFS readout in this setting. This first-mover advantage could be commercially meaningful if the company files quickly and obtains regulatory approval before the readout of ASCENT-GYN-01.
Commercially, this readout is also important for Merck & Co’s broader oncology strategy. sac-TMT gives Merck & Co a post-Keytruda (pembrolizumab) growth asset in a disease area where Keytruda has already moved into the first line. This could allow the company to build a treatment continuum in EC, with Keytruda-based therapy used earlier and sac-TMT positioned after platinum and immunotherapy progression. It also supports Merck & Co’s wider ADC ambitions. According to GlobalData’s clinical trial database, sac-TMT is being evaluated in 22 ongoing Phase III trials across several tumour types. In addition, human epidermal growth factor receptor 2 (HER2)-directed ADCs remain relevant mainly for biomarker-selected EC. AstraZeneca/Daiichi Sankyo’s Enhertu (trastuzumab deruxtecan) is available for HER2-positive (IHC 3+) solid tumours, while BioNTech/DualityBio’s trastuzumab pamirtecan is in Phase III for HER2-expressing recurrent EC, but sac-TMT may have broader utility if it does not require mandatory biomarker selection. According to GlobalData’s analyst consensus forecast, global sales of sac-TMT are expected to reach $2.2bn, whereas Trodelvy will reach $2.4bn by 2030. If sac-TMT delivers a clear OS advantage with manageable haematologic and gastrointestinal toxicity, it could become a new standard after platinum-based therapy and immunotherapy in advanced or recurrent EC. Merck & Co has also received a Commissioner’s National Priority Voucher (CNPV) for sac-TMT, which could substantially shorten the FDA review timeline once the company submits its regulatory application. For Merck & Co, the value is not limited to EC; the trial result helps validate the Kelun-partnered TROP2 ADC platform and strengthens Merck & Co’s attempt to build a post-Keytruda loss-of-exclusivity oncology growth engine.
EMERALD-3 data poses the question of global opportunity in intermediate HCC, with Lenvima
In the robustly designed and globally coordinated EMERALD-3 study (NCT05301842), participants were assigned to one of three arms: Arm A included transarterial chemoembolization (TACE) plus AstraZeneca’s STRIDE regimen, Imfinzi (durvalumab) and Imjudo (tremelimumab), plus Eisai’s Lenvima (lenvatinib); Arm B used the same combination without Lenvima, and control Arm C received TACE alone.
A total of 181,761 patients were diagnosed with intermediate (BCLC stage B) hepatocellular carcinoma (HCC) in 2025 across eight major markets (8MM: US, France, Germany, Italy, Spain, UK, Japan, and China) and forecast by GlobalData to increase to 214,757, yet despite a growing patient population, systemic treatment options have remained severely limited, with TACE still the standard of care (SOC) in most regions. While the combination of TACE with lenvatinib and Merck’s Keytruda (pembrolizumab) is approved only in China, it is often used off-label in other countries. Current alternatives include approved first-line therapies for advanced HCC or ongoing clinical trials that have shown positive interim results, both of which are used off-label, underscoring an urgent unmet need for new evidence-based regimens.
Both experimental arms reached their endpoints for progression-free survival (PFS) and showed positive trends for overall survival (OS), demonstrating clear efficacy advances over the TACE control:
Arm B versus C
- TACE + STRIDE (number of participants [n] = 175): median PFS of 12.9 (95% confidence interval [CI]: 10.2–15.9) months with hazard ratio [HR] 0.71 (95% CI: 0.56–0.91) at 75.1% data maturity, and median OS exceeding 43.2 (95% CI: 37.7–not calculable [NC]) months with HR of 0.70 (95% CI: 0.51–0.95) at 45.4% data maturity, and a 24-month survival rate of 68.0% (95% CI: 60.4–74.5).
- TACE control (n = 175): PFS of 8.1 (95% CI: 6.5–10.2) months, and a median OS of 32.9 (95% CI: 24.1–43.2) months, and a 24-month survival rate of 57.8% (95% CI: 50.1–64.9).
Arm A versus C
- TACE + STRIDE + Lenvima (n = 293): median PFS of 13.0 (95% CI: 12.2–16.7) months with HR of 0.7 (95% CI: 0.57–0.86) at 63.8% data maturity, and median OS of 39.5 (95 CI: 34.1–NC) months with an HR of 0.84 (95% CI: 0.65–1.09) at 40.3% data maturity, and a 24-month survival rate of 66.9% (95% CI: 61.0–72.2).
- TACE control (n = 292): PFS of 9.8 (95% CI: 8.0–11.4) months, and a median OS of 34.7 (95% CI: 28.8–NC) months, and a 24-month survival rate of 61.5% (95 CI: 55.4–67.0).
These results spotlight a promising advance for intermediate HCC, but it is important to note that the safety profile and interim OS data favour the triplet regimen (TACE + STRIDE) over the addition of Lenvima, with severe adverse events at 50.9% versus 64.1%, respectively. The questionable benefit and increased toxicity of quadruple therapy raise doubts about its regulatory approval and practical use. Adding another systemic agent may bring diminishing returns and added liver stress, potentially impacting future treatment effectiveness.
Importantly, regulatory authorities remain vigilant, seeking robust long-term OS data before approving regimens that escalate both cost and toxicity. The Phase III EMERALD-1 (NCT03778957) trial studying TACE with durvalumab and bevacizumab for intermediate HCC, which previously demonstrated a median PFS of 15 months and met its primary endpoint, now awaits OS outcomes, which will likely be a key determinant in global regulatory filings. AstraZeneca is already moving forward with global submissions for EMERALD-3, while continuing extended follow-up to mature the survival data, thereby addressing payer and regulatory requirements while aiming to demonstrate sustained clinical benefit.
For patients and clinicians, EMERALD-3 signals a new global era in intermediate HCC, paving the way for broader access to effective treatments for a group long underserved by innovation.
