HIPEC + FLOT vs. FLOT Alone in Patients With Gastric Cancer and GEJ (PREVENT)

This is a multicenter, randomized, controlled, open-label study including patients with localized and locally advanced diffuse and mixed type adenocarcinoma of the stomach and Type II/III GEJ scheduled to receive perioperative chemotherapy combined with intraoperative HIPEC procedure.

The scope of the trial is to evaluate the efficacy as well as the safety and tolerability of the combination of perioperative chemotherapy combined with an intraoperative HIPEC for resectable diffuse and mixed type gastric and GEJ (types II/III) adenocarcinoma. Intraoperative hyperthermic chemoperfusion is summarized under the abbreviation HIPEC in the following.

Patients with localized and locally advanced diffuse or mixed type adenocarcinoma of the stomach and Type II/III GEJ (i.e. ≥cT3 any N or any T N-positive) with exclusion of distant metastases and after receiving neoadjuvant FLOT- therapy will be included in this trial after a central review.

All enrolled patients will have received 3-6 pre-operative cycles (de-escalation or dose modification allowed) of biweekly FLOT (Docetaxel 50 mg/m² in 250 ml NaCl 0.9%, iv over 1 h; Oxaliplatin 85 mg/m² in 500 ml G5%, iv over 2h; Leucovorin 200 mg/m² in 250 ml NaCl 0.9%, iv over 30 min; 5-FU 2600 mg/m², iv over 24 h, q2wk) in the preoperative treatment phase.

After completion of neoadjuvant FLOT- therapy followed by pre-operative tumor assessment, (also including diagnostic laparoscopy prior to start of FLOT), patients without disease progression (expected to be approximately 90% of the patients) will be included into the trial, stratified by initial clinical stage (N- vs. N+), histological type of tumor (Lauren classification diffuse vs. mixed) and study site.

Patients will be randomized 1:1 to receive either postoperative FLOT (Arm A) or postoperative FLOT + intraoperative HIPEC (Arm B).

Arm A (FLOT) Surgery in Arm A is planned to occur 4 to 6 weeks after d1 of last FLOT. Surgery is carried out in kind of gastrectomy, transhiatal extended gastrectomy. Following surgery, patients will receive four further 2-week treatment cycles FLOT in the post-operative treatment phase. Post-operative treatment should start 6 to 8 weeks, but at maximum 12 weeks after surgery.

Arm B (FLOT/ HIPEC) Surgery in Arm B is planned to occur 4 to 6 weeks after d1 of last FLOT. Surgery is carried out in kind of gastrectomy, transhiatal extended gastrectomy. Surgery will be combined with an intraoperative Hyperthermic IntraPEritoneal Chemoperfusion (HIPEC) including cisplatin solution administered at a temperature of 42°C for 90 minutes. Following surgery, patients will receive four further 2-week treatment cycles FLOT in the post-operative treatment phase. Post-operative treatment should start 6 to 8 weeks, but at maximum 12 weeks after surgery.

In both of the arms, tumor assessments (CT or MRI) are performed before randomization prior to surgery, and then every 3 months (radiological tumor assessment) thereafter until progression/relapse, death or end of follow-up. A change from CT into MRI in the follow up period is possible at any time.

During treatment, clinical visits (blood cell counts, detection of toxicity) occur prior to every treatment dose. Safety of FLOT/ HIPEC will be monitored continuously by careful monitoring of all adverse events (AEs) and serious adverse events (SAEs) reported.

The phase III design starts with a safety run-in phase. After 20 patients had curatively intended resection in Arm B, an interim safety analysis is performed that shows feasibility, safety, and tolerability of Arm B planned at the time 8 weeks after the 20th patient in Arm B had curatively intended resection. It is not planned to discontinue recruitment for the interim safety analysis.

• Comparison of Overall survival (OS) in both arms [Time frame: from randomization up to 5 years]
• Comparison of Overall survival rates at 3 and 5 years in both arms [Time frame: 3 and 5 years after randomization]
• Comparison of peritoneal relapse rate at 2 and 3 years in both arms [Time frame: 2 and 3 years after surgery]
• PFS/DFS rates at 2, 3 & 5 years [Time frame: 2, 3 & 5 years after randomization]
• Rate of surgical serious adverse events (SAEs) [Time frame: After randomization of the patient until 30 days after last study-specific treatment]
• OS and PFS/DFS (medians and rates) according to subgroup (diffuse vs. mixed and gastric vs. GEJ type II/III) [Time frame: from randomization up to 5 years]
• Patient reported outcomes: Quality of life EORTC QLQ C30 questionnaire [Time frame: From date of screening until the date of first documented progression or last visit before date of death from any cause, whichever came first, assessed 8 weeks +/- 7 days until EOT, afterwards every 3 months up to 2 years after last patient in]
• Patient reported outcomes: Quality of life EORTC QLQ STO22 questionnaire [Time frame: From date of screening until the date of first documented progression or last visit before date of death from any cause, whichever came first, assessed 8 weeks +/- 7 days until EOT, afterwards every 3 months up to 2 years after last patient in]
• Patient reported outcomes: VAS pain assessment form [Time frame: From date of screening until the date of first documented progression or last visit before date of death from any cause, whichever came first, assessed 8 weeks +/- 7 days until EOT, afterwards every 3 months up to 2 years after last patient in]
• Rate of post-operative morbidity/mortality at day 30 after surgery acc. to Clavien-Dindo classification [Time frame: at day 30 after surgery]