Randomized Trial of Irinotecan and Cetuximab With or Without Vemurafenib in BRAF-Mutant Metastatic Colorectal Cancer (SWOG S1406).

PURPOSE: BRAFV600E mutations are rarely associated with objective responses to the BRAF inhibitor vemurafenib in patients with metastatic colorectal cancer (CRC). Blockade of BRAFV600E by vemurafenib causes feedback upregulation of EGFR, whose signaling activities can be impeded by cetuximab. METHODS: One hundred six patients with BRAFV600E-mutated metastatic CRC previously treated with one or two regimens were randomly assigned to irinotecan and cetuximab with or without vemurafenib (960 mg PO twice daily). RESULTS: Progression-free survival, the primary end point, was improved with the addition of vemurafenib (hazard ratio, 0.50, P = .001). The response rate was 17% versus 4% (P = .05), with a disease control rate of 65% versus 21% (P < .001). A decline in circulating tumor DNA BRAFV600E variant allele frequency was seen in 87% versus 0% of patients (P < .001), with a low incidence of acquired RAS alterations at the time of progression. RNA profiling suggested that treatment benefit did not depend on previously established BRAF subgroups or the consensus molecular subtype. CONCLUSION: Simultaneous inhibition of EGFR and BRAF combined with irinotecan is effective in BRAFV600E-mutated CRC.

Phase IB/II Randomized Study of FOLFIRINOX Plus Pegylated Recombinant Human Hyaluronidase Versus FOLFIRINOX Alone in Patients With Metastatic Pancreatic Adenocarcinoma: SWOG S1313.

PURPOSE: Pegylated recombinant human hyaluronidase (PEGPH20) degrades hyaluronan (HA) and, in combination with chemotherapy, prolongs survival in preclinical models. The activity of PEGPH20 with modified fluorouracil, leucovorin, irinotecan, and oxaliplatin (mFOLFIRINOX) was evaluated in patients with metastatic pancreatic cancer (mPC). MATERIALS AND METHODS: Patients had untreated mPC, a performance status of 0 to 1, and adequate organ function. Tumor HA status was not required for eligibility. After a phase Ib dose-finding study of mFOLFIRINOX plus PEGPH20, the phase II open-label study randomly assigned patients (1:1) to the combination arm or to mFOLFIRINOX alone (n = 138). The primary end point was overall survival (OS). RESULTS: PEGPH20 dosages of 3 µg/kg every 2 weeks were more tolerable than twice-weekly dosages used in the phase I study, so 3 µg/kg every 2 weeks was the phase II dosage. An amendment instituted enoxaparin prophylaxis in the PEGPH20 combination arm as a result of increased thromboembolic (TE) events. The planned interim futility analysis when 35 deaths (of 103 analyzable patients) occurred resulted in an OS hazard ratio (HR) of 2.07 that favored the control arm, and the study was closed to accrual. The treatment-related grade 3 to 4 toxicity was significantly increased in the PEGPH20 combination arm relative to control (odds ratio, 2.7; 95% CI, 1.1 to 7.1). The median OS in the mFOLFIRINOX arm was 14.4 months (95% CI, 10.1 to 15.7 months) versus 7.7 months (95% CI, 4.6 to 9.3 months) in the PEGPH20 combination arm. CONCLUSION: Addition of PEGPH20 to mFOLFIRINOX seems to be detrimental in patients unselected for tumor HA status. This combination caused increased toxicity (mostly GI and TE events) and resulted in decreased treatment duration compared with mFOLFIRINOX alone. The median OS in the mFOLFIRINOX control arm (14.4 months) is, to our knowledge, the longest yet reported and can be considered for patients with good PS.

Cetuximab Combined With Induction Oxaliplatin and Capecitabine, Followed by Neoadjuvant Chemoradiation for Locally Advanced Rectal Cancer: SWOG 0713.

BACKGROUND: Neoadjuvant chemoradiation (NCRT) is standard treatment for locally advanced rectal cancer. Pathologic complete response (pCR) has associated with improved survival. In modern phase III trials of NCRT, pCR ranges from 10% to 20%. Cetuximab improves response in KRAS (KRAS proto-oncogene) wild type (wt) metastatic colorectal cancer. S0713 was designed to assess improvement in pCR with additional use of cetuximab with induction chemotherapy and NCRT for locally advanced, KRAS-wt rectal cancer. PATIENTS AND METHODS: Patient eligibility: stage II to III biopsy-proven, KRAS-wt rectal adenocarcinoma; no bowel obstruction; adequate hematologic, hepatic and renal function; performance status of 0 to 2. Target enrollment: 80 patients. TREATMENT: induction chemotherapy with wCAPOX (weekly capecitabine and oxaliplatin) and cetuximab followed by the same regimen concurrent with radiation (omitting day 15 oxaliplatin). If fewer than 7 pCRs were observed at planned interim analysis after 40 patients received all therapy, the study would close. Eighty eligible patients would provide 90% power given a true pCR rate > 35% at a significance of 0.04. The regimen would lack future interest if pCR probability was ≤ 20%. RESULTS: Between February 2009 and April 2013, 83 patients registered. Four were ineligible and 4 not treated, leaving 75 evaluable for clinical outcomes and toxicity, of whom 65 had surgery. Of 75 patients, 20 had pCR (27%; 95% confidence interval [CI], 17%-38%); 19 (25%) had microscopic cancer; 36 (48%) had minor/no response (including 10 without surgery). Three-year disease-free survival was 73% (95% CI, 63%-83%). CONCLUSION: Our trial did not meet the pCR target of 35%. Toxicity was generally acceptable. This regimen cannot be recommended outside the clinical trial setting.

Phase 2 study of MK-2206, an allosteric inhibitor of AKT, as second-line therapy for advanced gastric and gastroesophageal junction cancer: A SWOG cooperative group trial (S1005).

BACKGROUND: The AKT inhibitor MK-2206 at a dose of 60 mg every other day was evaluated in gastric/gastroesophageal junction cancers. METHODS: Patients who had progressed after first-line treatment were eligible. Pertinent eligibility criteria included adequate organ function, a fasting serum glucose level ≤ 150 mg/dL, and less than grade 2 malabsorption or chronic diarrhea. MK-2206 was given orally (60 evaluable patients required). The primary endpoint was overall survival, and a median survival of 6.5 months (power, 89%; significance level, 0.07) was considered encouraging for further investigation. RESULTS: Seventy patients were included in the final analyses. The median age was 59.8 years (range, 30.4-86.7 years); 70% were male, 89% were white, and 7% were Asian. There were 2 deaths possibly related to the study drug (cardiac arrest and respiratory failure). Grade 4 adverse events included hyperglycemia, anemia, and lung infection (1 each). Grade 3 adverse events occurred in < 5% of patients except for fatigue (6%). Other adverse events (all grades) included anemia (17%), anorexia (30%), diarrhea (26%), fatigue (50%), hyperglycemia (30%), nausea (40%), vomiting (22%), dry skin (19%), maculopapular rash (30%), and acneiform rash (13%). The response rate was 1%, the median progression-free survival was 1.8 months (95% confidence interval, 1.7-1.8 months), and the median overall survival was 5.1 months (95% confidence interval, 3.7-9.4 months) CONCLUSIONS: MK-2206 as second-line therapy was well tolerated by an unselected group of patients with gastric/gastroesophageal junction cancers, but it did not have sufficient activity (response rate, 1%; overall survival, 5.1 months) to warrant further testing in this population.