Highlight
– The phase III TRYBECA‑1 trial (NCT03665441) randomized 512 patients with advanced pancreatic ductal adenocarcinoma (PDAC) to eryaspase plus standard second‑line chemotherapy versus chemotherapy alone and showed no improvement in overall survival (OS).
– Median OS was 7.5 months with eryaspase plus chemotherapy versus 6.7 months with chemotherapy alone (HR 0.92, 95% CI 0.76–1.11; P = .374). PFS and ORR were also not significantly different.
– Grade ≥3 adverse events (neutropenia, asthenia, anemia) were somewhat more frequent in the eryaspase arm; no new safety signals were reported.
Background: disease burden and rationale
Pancreatic ductal adenocarcinoma is a lethal malignancy with limited effective systemic therapies in the advanced/metastatic setting. First‑line regimens such as FOLFIRINOX or gemcitabine‑nab‑paclitaxel provide modest survival benefits, but progression is common and second‑line options yield limited incremental benefit. The biological rationale for asparagine depletion in cancer therapy derives from the metabolic dependence that some malignancies have on extracellular asparagine. L‑asparaginase depletes circulating asparagine and has proven activity in acute lymphoblastic leukemia; however, its systemic use in solid tumors has been limited by immunogenicity and toxicity.
Eryaspase is L‑asparaginase encapsulated within allogeneic erythrocytes, intended to prolong enzyme activity, reduce immune recognition, and potentially allow combination with myelosuppressive chemotherapy. Earlier phase studies suggested that eryaspase could achieve sustained asparagine depletion with an acceptable safety profile, motivating the phase III TRYBECA‑1 study to test whether adding eryaspase to standard second‑line chemotherapy improves clinical outcomes in advanced PDAC.
Study design
TRYBECA‑1 (ClinicalTrials.gov identifier NCT03665441) was an international, randomized, open‑label phase III trial enrolling adults (≥18 years) with PDAC whose disease progressed on or after first‑line chemotherapy. Key eligibility criteria included adequate organ function and ECOG performance status appropriate for second‑line therapy. Patients were randomized 1:1 to:
– Eryaspase plus chemotherapy (investigator’s choice between gemcitabine/nab‑paclitaxel or fluorouracil/leucovorin with irinotecan or nanoliposomal irinotecan), or
– Chemotherapy alone (same regimen options).
Treatment schedule (4‑week cycles): eryaspase 100 U/kg IV on days 1 and 15; gemcitabine 1000 mg/m2 and nab‑paclitaxel 125 mg/m2 IV on days 1, 8, 15; irinotecan 180 mg/m2 (or nanoliposomal irinotecan 70 mg/m2) IV on days 1 and 15; 5‑FU 2400 mg/m2 as a 46‑hour infusion with a bolus of 400 mg/m2 and leucovorin 400 mg/m2 IV on days 1 and 15. Treatment continued until disease progression or unacceptable toxicity.
The primary endpoint was overall survival (OS). Secondary endpoints included progression‑free survival (PFS), objective response rate (ORR), and safety.
Key findings
Population and follow‑up
A total of 512 patients were randomized (n = 255 to eryaspase plus chemotherapy; n = 257 to chemotherapy alone). Baseline characteristics were reported as balanced between arms. There were 420 deaths observed during follow‑up.
Overall survival (primary endpoint)
– Median OS: 7.5 months (eryaspase + chemotherapy) versus 6.7 months (chemotherapy alone).
– Hazard ratio (HR) for death: 0.92 (95% CI, 0.76–1.11); P = .374.
This difference was not statistically significant and the confidence interval crossed 1.0, indicating no reliable evidence for an OS benefit with the addition of eryaspase in this population.
Progression‑free survival and response
– Median PFS: 3.7 months (eryaspase arm) versus 3.4 months (control); HR 0.88 (95% CI, 0.73–1.07); P = .196.
– Objective response rate (ORR): 16.1% (eryaspase) versus 12.5% (control); odds ratio 1.35 (95% CI, 0.81–2.24).
PFS and ORR numerically favored the experimental arm, but these differences were small and did not achieve statistical significance. The magnitude of any PFS or response improvement was modest and unlikely to translate into meaningful survival benefit based on these data.
Safety
Adverse events (AEs) of grade ≥3 were generally consistent with chemotherapy effects, but certain events were more frequent with eryaspase addition:
– Neutropenia: 25.4% (eryaspase) versus 20.3% (control)
– Asthenia (severe fatigue): 16.9% versus 13.8%
– Anemia: 17.3% versus 12.2%
No unexpected safety signals unique to eryaspase were reported in the primary results. The encapsulation strategy was developed to mitigate hypersensitivity and other asparaginase‑related toxicities; the safety profile in TRYBECA‑1 appears broadly consistent with prior experience, though with modestly higher hematologic toxicity rates.
Interpretation and clinical implications
TRYBECA‑1 is a well‑powered, randomized phase III evaluation of eryaspase added to standard second‑line chemotherapy in unselected patients with advanced PDAC. The trial’s negative primary result — no OS advantage — argues that eryaspase, as administered in this protocol and in this broad population, does not improve survival outcomes and should not proceed to routine clinical use for this indication.
Several factors may explain the lack of observed benefit.
– Biological heterogeneity: PDAC is metabolically heterogeneous. The therapeutic hypothesis assumes that a clinically meaningful subset of PDACs are dependent on extracellular asparagine, but the trial population was not selected or stratified by biomarkers reflecting asparagine dependence or related metabolic pathways. Without a predictive biomarker, benefit limited to a subset can be diluted in a broad trial.
– Pharmacodynamics and dosing: While erythrocyte encapsulation prolongs enzyme activity, it is critical to achieve sustained, tumor‑relevant asparagine depletion. The clinical report did not present correlative data (in the primary publication) showing consistent systemic and intratumoral asparagine suppression across patients; if depletion varied substantially, efficacy would be reduced.
– Combination with chemotherapy: Eryaspase was combined with two chemotherapy backbones chosen by investigators. Heterogeneity in chemotherapy partners and prior treatments might obscure an interaction effect or limit tolerability that could influence efficacy.
– Immunogenicity and neutralizing antibodies: Traditional asparaginase therapies can elicit antibodies that reduce activity. The erythrocyte‑encapsulation approach is designed to lessen this, but detailed immune‑pharmacologic results were not a focus of the primary report. If anti‑drug responses occurred in a subset, they could attenuate biologic effect.
From a practical clinical standpoint, the results do not support adopting eryaspase in second‑line PDAC. For patients and clinicians, established second‑line options (eg, fluorouracil/leucovorin with nanoliposomal irinotecan in appropriate settings) remain standard, and enrollment in trials testing novel targeted, immunotherapy, or biomarker‑directed strategies continues to be appropriate.
Expert commentary and limitations
Strengths of TRYBECA‑1 include its randomized phase III design, appropriate sample size, and clinically meaningful endpoints. Limitations to consider:
– Lack of biomarker selection: The trial tested a mechanistically targeted metabolic therapy in an unselected population; future efforts should prioritize predictive biomarkers or translational correlative studies to define susceptible subgroups.
– Limited correlative data in the primary report: The published primary analysis focuses on clinical endpoints; detailed pharmacodynamic and immunogenicity data (if collected) will be crucial to interpret negative results and guide future research.
– Heterogeneity of chemotherapy partners and prior therapies may have introduced variability that reduced the ability to detect small-to-moderate treatment effects.
Mechanistically, the concept of targeted metabolic therapy in PDAC remains rational. Tumor metabolic dependencies vary by genotype, microenvironment, and prior therapy. Future trials may be more informative if they integrate metabolic imaging, tumor metabolomics, or genomic surrogates that indicate asparagine addiction. Additionally, earlier line use or combination with agents that modify tumor metabolism might be considered, but any such strategy should be grounded in robust preclinical and translational data.
Conclusion
TRYBECA‑1 demonstrates that adding eryaspase to second‑line chemotherapy in an unselected advanced PDAC population does not improve overall survival, progression‑free survival, or objective response. Adverse events were modestly increased without new safety concerns. These findings do not support further development of eryaspase for unselected second‑line treatment of PDAC. Future research should focus on identifying predictive biomarkers of asparagine dependence and clarifying pharmacodynamic effects in patients before additional clinical testing.
Funding and clinicaltrials.gov
TRYBECA‑1 was conducted under ClinicalTrials.gov identifier NCT03665441. Funding sources and study sponsors are listed in the primary publication (Hammel et al., J Clin Oncol. 2025). The primary report provides the official trial registry number and trial funding disclosure.
References
1) Hammel P, Metges JP, Macarulla Mercade T, Garcia‑Carbonero R, Bouché O, Portales F, Pazo Cid RA, Mineur L, Cubillo Gracian A, Trouilloud I, Guimbaud R, Tougeron D, Reina JJ, Feliu J, Sauri T, Fountzilas C, Lecomte T, Molin Y, Ponz‑Sarvise M, Forget F, Berardi R, Van Cutsem E, Gelsomino F, Tournigand C, Bockorny B, Bachet JB, Marin Vera M, Cuyle PJ, Wasan H, Noel M, Van Laethem JL, Kay R, Youssoufian H, El‑Hariry I, Hidalgo M. TRYBECA‑1: A Randomized Phase III Study of Eryaspase Combined With Chemotherapy Versus Chemotherapy as Second‑Line Treatment in Patients With Advanced Pancreatic Adenocarcinoma. J Clin Oncol. 2025 Dec 10;43(35):3714‑3727. doi: 10.1200/JCO-25-00872. Epub 2025 Nov 4. PMID: 41187298.
2) ClinicalTrials.gov. NCT03665441. TRYBECA‑1: Eryaspase Combined With Chemotherapy Versus Chemotherapy in Second Line Treatment of Advanced PDAC. https://clinicaltrials.gov/study/NCT03665441 (accessed 2025).
Author note
This article summarizes the primary published results of the TRYBECA‑1 randomized phase III trial and provides context and interpretation for practicing clinicians and researchers. Further correlative data and subgroup analyses from the trial investigators will be important to fully understand biological and pharmacologic implications of the negative outcome.