NEO-GAP: A phase II single-arm prospective feasibility study of neoadjuvant gemcitabine/cisplatin/nab-paclitaxel for resectable high-risk intrahepatic cholangiocarcinoma.
Authors: Maithel Shishir K. , Javle Milind M. , Mahipal Amit , Lin Bruce Shih-Li , Akce Mehmet , Switchenko Jeffrey M. , Rupji Manali , Tran Cao Hop , Cleary Sean P. , Rocha Flavio G. 
Published: June 2022

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Background: Given a high recurrence rate, surgical resection for localized intrahepatic cholangiocarcinoma (IHCC) is curative in only 30-35% of patients. BILCAP has established a standard of care for adjuvant therapy with monotherapy capecitabine. Gemcitabine, cisplatin and nab-paclitaxel combination chemotherapy (GAP) was associated with a response rate of 45% in biliary cancer and 20% of patients who were previously inoperable underwent margin negative resection. Based on these data, we conducted a neoadjuvant study of GAP for resectable but high-risk IHCC. Methods: A multi-institutional prospective single-arm phase II trial was conducted for patients with resectable high-risk disease, as defined by tumor size > 5cm, multiple tumors, presence of radiographic major vascular invasion, and lymph node involvement. Patients were administered 4 cycles (3 months) of preoperative GAP (gemcitabine 800 mg/m2, cisplatin 25 mg/m2 and nab-paclitaxel 100 mg/m2 on days 1 and 8 of a 21-day cycle) prior to an attempt at curative-intent surgical resection. The primary endpoint was completion of all therapy, including both preoperative chemotherapy and resection. Secondary endpoints were toxicity, radiologic response according to Response Evaluation Criteria in Solid Tumor (RECIST) criteria, RFS, and OS. Thirty evaluable patients provided 73% power to reject a null therapy completion rate of 50%, with a target completion rate of 70% using a one-sided exact test with a Type I error of 0.05. Results: Thirty-seven patients were screened and 30 evaluable patients were enrolled. The trial was sequentially activated at each of the 4 sites from 09/18-02/21 and the final patient was enrolled in 09/21. Median age was 60.5 years and 40% were female. Twenty-three patients (77%, 90% CI: 60.6-88.5%; p = 0.0026) completed all preoperative chemotherapy and underwent surgical resection. Ten patients (33%) experienced grade 3-4 treatment-related adverse events, the most common being neutropenia and diarrhea; 47% required at least one dose reduction. Partial response rate was 23% and disease control rate was 90% (PD: 10%, PR: 23%, SD: 67%). Of the 23 patients who successfully underwent surgical resection, 2 (9%) had minor postoperative complications. Median size of largest tumor was 5.5cm, median number of tumors was 3, and 39% were lymph node positive. Median length of hospital stay was 4 days. There was zero treatment related mortality. Conclusions: This study met its primary endpoint and demonstrated that neoadjuvant gemcitabine/cisplatin/nab-paclitaxel is feasible and safe prior to resection of intrahepatic cholangiocarcinoma and does not adversely impact perioperative outcomes. Continued follow-up for RFS and OS with this treatment strategy is underway and larger validation studies are planned. Clinical trial information: NCT03579771.