In this JCO Article Insights episode, host Joseph Mathew summaries Pancreatic Adenocarcinoma: Long-Term Outcomes of Adjuvant Therapy in the ESPAC4 Phase III Trial, by Palmer, et al published December 5, 2024.

Transcript

Joseph Mathew:

Hello and welcome to the Journal of Clinical Oncology Article Insights. I'm your host, Joseph Mathew, and today we will be discussing the article "Long-Term Survival in Resected Pancreatic Ductal Adenocarcinoma with Adjuvant Gemcitabine plus Capecitabine Compared to Modified FOLFIRINOX from the ESPAC-4 and the PRODIGE 24 Trials" by Dr. Palmer et al.

To summarize the relevant evidence, the ESPAC-4 was a European phase 3 multicenter randomized clinical trial published in 2017 comparing adjuvant gemcitabine and capecitabine (GemCap) with gemcitabine monotherapy following macroscopic margin-negative resections for operable pancreatic ductal adenocarcinoma (PDAC). The trial had included non-metastatic patients aged 18 years or older, World Health Organization (WHO) performance scores of 2 or less, creatinine clearance of at least 50 mL/min, and a life expectancy of over three months who had not received any prior anticancer treatment. Patients who had undergone R2 resections were selectively excluded.

Eligible participants were randomized 1:1 within 12 weeks of pancreatectomy to one of the two treatment arms, with chemotherapy initiated within two weeks from the date of randomization. The regimens involved six cycles, each lasting four weeks, for an overall duration of 24 weeks. In the monotherapy arm, gemcitabine dosed at 1 g/m² was given as an intravenous infusion once a week for three weeks, followed by one week off. In the GemCap arm, capecitabine dosed at 1660 mg/m² was added to gemcitabine, given daily for three weeks, followed by one week off. Patients were followed up every three months, with the primary endpoint being overall survival (OS). The study showed that at a median follow-up of 43.2 months, GemCap was associated with a significantly longer OS than gemcitabine alone.

Subsequently, in 2018, the Phase 3 randomized PRODIGE 24 trial was conducted in centers across France and Canada, comparing adjuvant modified FOLFIRINOX (mFOLFIRINOX) with gemcitabine in a similar subset of patients with resected PDAC and reported longer OS with the mFOLFIRINOX regimen. This study, however, had more restrictive eligibility criteria when compared to ESPAC-4, including patients aged under 80 years, WHO performance status of 0 or 1, with no significant cardiovascular disease, and a postoperative serum CA 19-9 of less than 180 U/mL. There was hence a subset of ESPAC-4 patients who did not meet the eligibility criteria for mFOLFIRINOX as set by the PRODIGE 24.

The present study was conducted to estimate the overall 5-year survival rates for patients of ESPAC-4 receiving GemCap and gemcitabine, further stratifying survival in either arm according to the status of the surgical margins (R status) and the resected nodes (N status), and also to investigate whether GemCap retained a survival benefit over gemcitabine in PRODIGE 24-ineligible patients.

A total of 732 patients, evenly distributed between both arms, were followed up for a median period of 104 months. Adjuvant GemCap was found to retain its survival advantage over gemcitabine, with a significantly longer median OS of 31.6 months when compared to 28.4 months with gemcitabine alone.

Further subgroup analysis was performed with reference to the resection margins and the nodal status. As a reminder, in the ESPAC-4 trial, 60% of patients were found to have microscopically positive margins (an R1 resection), and 80% were node-positive. The difference in survival was greater in patients undergoing microscopic margin-negative resections (R0) who experienced a median OS of 49.9 months with GemCap when compared to 32.2 months with gemcitabine. Node-negative patients also had a significantly greater 5-year OS rate with GemCap of 59% versus 53% with gemcitabine monotherapy. However, it is important to note that no significant difference in survival outcomes was observed in margin-positive (R1) or node-positive patients in the two arms.

The investigators also evaluated GemCap in the subgroup of 193 patients (comprising 26.4% of the ESPAC-4 cohort) who were not considered to have met the eligibility criteria for PRODIGE 24. The survival benefit of combination therapy was retained in this group, with patients receiving GemCap experiencing a median survival of 25.9 months compared to 20.7 months with adjuvant gemcitabine.

Although cross-trial comparisons have limited validity, good agreement was noted in adverse grade 3 or greater toxicity associated with the control gemcitabine arms of ESPAC-4 and PRODIGE 24, serving as the basis for a qualitative comparison of toxicities between mFOLFIRINOX and GemCap. Neutropenia was more prevalent in the GemCap arm, affecting 40.8% of patients compared to 28.4% with mFOLFIRINOX. However, granulocyte colony-stimulating factor (G-CSF) was administered to 62.2% of patients in PRODIGE 24. Palmar-plantar erythrodysesthesia (PPE) was also more prevalent with GemCap. Patients on mFOLFIRINOX were more likely to observe grade 3 or greater fatigue, diarrhea, nausea and vomiting, sensory peripheral neuropathy, and paresthesias.

The investigators concluded that GemCap was the standard adjuvant treatment for patients with PDAC undergoing an upfront resection who were not feasible for mFOLFIRINOX. Further exploratory analysis revealed that patients under the age of 70 who had undergone a microscopic margin-negative (R0) resection for node-negative PDAC were likely to derive an OS benefit from the addition of capecitabine to gemcitabine in the adjuvant setting. In contrast, mFOLFIRINOX would be more effective than gemcitabine in patients with positive margins (R1) or involved nodes, as per the PRODIGE 24 trial.

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Journal of Clinical Oncology (JCO) Podcast

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