PRIME STUDY
A randomized, open-label, active-controlled, multicentre, phase 3 study1,2

  • Primary Endpoint
  • Secondary Endpoints
Improved PFS in patients with RAS wild-type tumours treated with Vectibix + FOLFOX vs.
FOLFOX alone1,3
Progression-free survival in patients with RAS wild-type tumours1,3
Kaplan-Meier Curve of Progression-Free Survival (PFS) for Vectibix + FOLFOX (n=259) and FOLFOX (n=253) in patients with wild-type RAS mCRC.1,3 Proportion of event-free patients from 0 to 100 percent. Treatment duration from 0 to 24 months. In the primary-analysis patient population, the median PFS for patients in the Vectibix + FOLFOX treatment arm was 10.1 months (95% CI: 9.3-12.0) vs. 7.9 months (95% CI: 7.2-9.3) in the FOLFOX arm.1,3 Patients in the Vectibix + FOLFOX arm had significant improvement in PFS over those in the FOLFOX arm (HR: 0.72, 95% CI: 0.58–0.90 [P=0.004*]).1,3 Kaplan-Meier Curve of Progression-Free Survival (PFS) for Vectibix + FOLFOX (n=259) and FOLFOX (n=253) in patients with wild-type RAS mCRC.1,3 Proportion of event-free patients from 0 to 100 percent. Treatment duration from 0 to 24 months. In the primary-analysis patient population, the median PFS for patients in the Vectibix + FOLFOX treatment arm was 10.1 months (95% CI: 9.3-12.0) vs. 7.9 months (95% CI: 7.2-9.3) in the FOLFOX arm.1,3 Patients in the Vectibix + FOLFOX arm had significant improvement in PFS over those in the FOLFOX arm (HR: 0.72, 95% CI: 0.58–0.90 [P=0.004*]).1,3

Adapted from the Vectibix Product Monograph1 and Douillard et al.3
* P values from the retrospective analysis by RAS status were not adjusted for multiplicity testing.

CI, confidence interval; FOLFOX, infusional 5-fluorouracil, leucovorin, and oxaliplatin; HR, hazard ratio; PFS, progression-free survival; RAS, Rat sarcoma viral oncogene homologue.

Vectibix + FOLFOX was associated with improved OS vs. FOLFOX alone in patients with RAS wild-type tumours1,3
Overall survival in patients with RAS wild-type tumours1,3
Kaplan-Meier Curve of Overall Survival (OS) for Vectibix + FOLFOX (n=259) and FOLFOX (n=253) in patients with wild-type RAS mCRC.1, Proportion of alive patients from 0 to 100 percent. Treatment duration from 0 to 36 months.1 Patients in the Vectibix + FOLFOX arm had significant improvement in OS over those in the FOLFOX arm (HR: 0.78, 95% CI: 0.62–0.99 [P=0.04*]), with median OS of 26 months (95% CI: 21.7-30.4) and 20.2 months (17.7-23.1) for Vectibix + FOLFOX and FOLFOX alone arms, respectively.<sup>1</sup> Kaplan-Meier Curve of Overall Survival (OS) for Vectibix + FOLFOX (n=259) and FOLFOX (n=253) in patients with wild-type RAS mCRC.1, Proportion of alive patients from 0 to 100 percent. Treatment duration from 0 to 36 months.1 Patients in the Vectibix + FOLFOX arm had significant improvement in OS over those in the FOLFOX arm (HR: 0.78, 95% CI: 0.62–0.99 [P=0.04*]), with median OS of 26 months (95% CI: 21.7-30.4) and 20.2 months (17.7-23.1) for Vectibix + FOLFOX and FOLFOX alone arms, respectively.<sup>1</sup>

Adapted from the Vectibix Product Monograph1 and Douillard et al.3
* P values from the retrospective analysis by RAS status were not adjusted for multiplicity testing.

59% response rate observed with Vectibix + FOLFOX vs. 46% with FOLFOX alone1
Treatment response in patients with wild-type (WT) RAS mCRC. Key results of overall response rate (ORR) for Vectibix + FOLFOX and FOLFOX treatment arms. Percentage of patients with response (%) from 0 to 70 percent. 1 ORR in Vectibix + FOLFOX arm: 59%. ORR in FOLFOX arm: 46%.1 Treatment response in patients with wild-type (WT) RAS mCRC. Key results of overall response rate (ORR) for Vectibix + FOLFOX and FOLFOX treatment arms. Percentage of patients with response (%) from 0 to 70 percent. 1 ORR in Vectibix + FOLFOX arm: 59%. ORR in FOLFOX arm: 46%.1

Adapted from the Vectibix Product Monograph.1

CI, confidence interval; FOLFOX, infusional 5-fluorouracil, leucovorin, and oxaliplatin; HR, hazard ratio; OS, overall survival; PFS, progression-free survival; RAS, Rat sarcoma viral oncogene homologue; WT, wild-type.

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STUDY DESIGN
BASELINE
CHARACTERISTICS
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Baseline characteristics*

In patients with WT RAS mCRC receiving Vectibix + FOLFOX vs. FOLFOX alone (n=512):1

Characteristics Vectibix + FOLFOX (n=259) FOLFOX alone (n=253)
Age
Mean (years) 60.5 59.8
Range (years) 27-81 24-82
Gender
Male (n) 173 158
Female (n) 86 95
Ethnicity
White (%) 91 92
Primary Tumour Type
Colon (%) 66 65
Rectal (%) 34 35

* Baseline disease characteristics were generally balanced between treatment arms.1

Patient eligibility:2
  • ≥18 years old with previously untreated metastatic adenocarcinoma of the colon or rectum.
  • Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0–2.
  • Prior chemotherapy:
    • Fluorouracil-based adjuvant chemotherapy allowed if disease recurrence occurred 6 months after completion.
    • Prior oxaliplatin not allowed.
  • At least one measurable lesion (≥20 mm).

ECOG, Eastern Cooperative Oncology Group (ECOG); FOLFOX, infusional 5-fluorouracil, leucovorin, and oxaliplatin; mCRC, metastatic colorectal cancer; RAS, Rat sarcoma viral oncogene homologue; WT, wild-type.

PRIME was a randomized, open-label, active-controlled, multicentre, phase 3 study with the following study design1
  • 1183 patients with previously untreated mCRC
  • Prospectively analyzed by tumour KRAS (exon 2) status, which was evaluable in 1096 patients (92.6%)
  • 512 patients were determined to have wild-type RAS tumours
  • A predefined retrospective subset analysis evaluated the treatment effect of Vectibix plus FOLFOX compared with FOLFOX alone in patients with wild-type RAS mCRC
Patients with previously untreated mCRC (N=1183) were randomized 1:1 to one of two groups: Vectibix Q2W + FOLFOX Q2W (n=593) or FOLFOX Q2W (n=590).1 The primary endpoint was progression-free survival, while secondary endpoints consisted of overall survival, objective response rate, and safety. Duration of treatment was until disease progression, intolerance, or other reason (death, withdrawal, etc). 1 Tumours from the intention to treat (ITT) patient population were prospectively analyzed by tumour mutation status of KRAS (exon 2). In the Vectibix Q2W + FOLFOX Q2W treatment arm, 325 patients had wild-type KRAS, and 221 patients had mutant KRAS. Out of the FOLFOX alone treatment arm, 331 patients had wild-type KRAS tumours, and 219 patients had KRAS mutation on exon 2. 1 Tumours from both treatment arms were further analyzed for biomarker status through additional retrospective analysis for the status of KRAS (exon 3, 4) and NRAS (exon 2, 3, 4). 1 In the Vectibix Q2W + FOLFOX Q2W treatment arm, 259 patients had wild-type RAS and 272 patients had RAS mutations.3 [4A, p6] Out of the FOLFOX alone treatment arm, 253 patients had wild-type RAS tumours and 276 were determined to have RAS mutations.3 The mutation analysis was performed as Vectibix is not indicated for patients with mutant RAS (KRAS/NRAS) or for whom RAS status is unknown. The dosing administration for FOLFOX Q2W consisted of oxaliplatin 85 mg/m2 and leucovorin 200 mg/m2 (or equivalent) intravenous (IV) infusion followed by fluorouracil 400 mg/m2 IV bolus every 2 weeks on day 1, and fluorouracil 600 mg/m2 22-hour continuous infusions every 2 weeks on days 1 and 2. Vectibix dosing consisted of panitumumab 6 mg/kg IV infusion every 2 weeks on day 1, administered before FOLFOX.2 Patients with previously untreated mCRC (N=1183) were randomized 1:1 to one of two groups: Vectibix Q2W + FOLFOX Q2W (n=593) or FOLFOX Q2W (n=590).1 The primary endpoint was progression-free survival, while secondary endpoints consisted of overall survival, objective response rate, and safety. Duration of treatment was until disease progression, intolerance, or other reason (death, withdrawal, etc). 1 Tumours from the intention to treat (ITT) patient population were prospectively analyzed by tumour mutation status of KRAS (exon 2). In the Vectibix Q2W + FOLFOX Q2W treatment arm, 325 patients had wild-type KRAS, and 221 patients had mutant KRAS. Out of the FOLFOX alone treatment arm, 331 patients had wild-type KRAS tumours, and 219 patients had KRAS mutation on exon 2. 1 Tumours from both treatment arms were further analyzed for biomarker status through additional retrospective analysis for the status of KRAS (exon 3, 4) and NRAS (exon 2, 3, 4). 1 In the Vectibix Q2W + FOLFOX Q2W treatment arm, 259 patients had wild-type RAS and 272 patients had RAS mutations.3 [4A, p6] Out of the FOLFOX alone treatment arm, 253 patients had wild-type RAS tumours and 276 were determined to have RAS mutations.3 The mutation analysis was performed as Vectibix is not indicated for patients with mutant RAS (KRAS/NRAS) or for whom RAS status is unknown. The dosing administration for FOLFOX Q2W consisted of oxaliplatin 85 mg/m2 and leucovorin 200 mg/m2 (or equivalent) intravenous (IV) infusion followed by fluorouracil 400 mg/m2 IV bolus every 2 weeks on day 1, and fluorouracil 600 mg/m2 22-hour continuous infusions every 2 weeks on days 1 and 2. Vectibix dosing consisted of panitumumab 6 mg/kg IV infusion every 2 weeks on day 1, administered before FOLFOX.2

Adapted from the Vectibix Product Monograph,1 Douillard et al.,2 and Douillard et al.3

* Vectibix is not indicated for patients with mutant RAS (KRAS/NRAS) or for whom RAS status is unknown.

FOLFOX, infusional 5-fluorouracil, leucovorin, and oxaliplatin; ITT, intention to treat; IV, intravenous; KRAS, Kirsten rat sarcoma viral oncogene homologue; mCRC, metastatic colorectal cancer; MT, mutant; NRAS, Neuroblastoma RAS viral oncogene homologue; Q2W, every 2 weeks; RAS, Rat sarcoma viral oncogene homologue; WT, wild-type.