A randomized, placebo-controlled phase 2 study of ganitumab or conatumumab in combination with FOLFIRI for second-line treatment of mutant KRAS metastatic colorectal cancer

BACKGROUND

Targeted agents presently available for mutant KRAS metastatic colorectal cancer (mCRC) are bevacizumab and aflibercept. We evaluated the efficacy and safety of conatumumab (an agonistic monoclonal antibody against human death receptor 5) and ganitumab (a monoclonal antibody against the type 1 insulin-like growth factor receptor) combined with standard FOLFIRI chemotherapy as a second-line treatment in patients with mutant KRAS mCRC.

PATIENTS AND METHODS

Patients with mutant KRAS metastatic adenocarcinoma of the colon or rectum refractory to fluoropyrimidine- and oxaliplatin-based chemotherapy were randomized 1 : 1 : 1 to receive intravenous FOLFIRI plus conatumumab 10 mg/kg (Arm A), ganitumab 12 mg/kg (Arm B), or placebo (Arm C) Q2W. The primary end point was progression-free survival (PFS).

RESULTS

In total, 155 patients were randomized. Median PFS in Arms A, B, and C was 6.5 months (HR, 0.69; P = 0.147), 4.5 months (HR, 1.01; P = 0.998), and 4.6 months, respectively; median overall survival was 12.3 months (HR, 0.89; P = 0.650), 12.4 months (HR, 1.27; P = 0.357), and 12.0 months; and objective response rate was 14%, 8%, and 2%. The most common grade ≥3 adverse events in Arms A/B/C included neutropenia (30%/25%/18%) and diarrhea (18%/2%/10%).

CONCLUSIONS

Conatumumab, but not ganitumab, plus FOLFIRI was associated with a trend toward improved PFS. Both combinations had acceptable toxicity.

Phase 1 study of ganitumab (AMG 479), a fully human monoclonal antibody against the insulin-like growth factor receptor type I (IGF1R), in Japanese patients with advanced solid tumors

PURPOSE

This study was to investigate the safety and tolerability of ganitumab in Japanese patients with advanced solid tumors.

METHODS

Patients were enrolled into 1 of 3 dose cohorts (6, 12, or 20 mg/kg) of single-agent ganitumab administered intravenously every 2 weeks. Dose-limiting toxicity (DLT) was assessed for the first 28 days. The primary objectives were to assess the safety, tolerability, and pharmacokinetics (PK) of ganitumab in Japanese patients with advanced solid tumors. An exploratory pharmacodynamic analysis was done to investigate the relationship between exposure and changes in the level of circulating factors in IGF1R pathway (IGFBP-3 and total IGF-1).

RESULTS

Nineteen patients with ECOG performance status 0-1 (6 in cohort 1 and 3, 7 in cohort 2) received at least 1 dose of ganitumab. Median age was 58.0 years. Tumor types included: breast (4), gastric (3), rectal (2), NSCLC (2), thymic (2), and other cancers (6). No DLTs were observed. The most common grade ≥3 adverse events were neutropenia (21 %), leukopenia (16 %) and lymphopenia (11 %). There was a trend of dose-dependency on severity of thrombocytopenia, but not on that of neutropenia. No neutralizing anti-ganitumab antibodies were detected during this study. Dose-linearity on PK of ganitumab was indicated in the dose range. Tumor response was assessed for 19 patients. Stable disease as best response was reported in 7 patients.

CONCLUSIONS

Ganitumab up to 20 mg/kg was tolerable in Japanese patients with advanced solid tumors. The safety and PK profiles were similar to those previously observed in non-Japanese patients.

The insulin receptor/insulin-like growth factor receptor family as a therapeutic target in oncology

Over the past decade, encouraging preclinical and early clinical data concerning the relevance of the insulin receptor/insulin-like growth factor (IGF) receptor family to neoplasia led to ambitious clinical trial programs of more than a dozen drug candidates that target these receptors. These candidates include antireceptor antibodies, antiligand antibodies, receptor-specific tyrosine kinase inhibitors, and agents such as picropodophyllin and metformin that have novel mechanisms of action. Several recently reported phase III clinical trials of anti-IGF-I receptor antibodies have been disappointing and are sufficient to disprove the hypothesis that the antibodies tested have large favorable impacts on unselected patients with cancer. However, many of these trials were designed prior to recent insights concerning pathophysiology and predictive biomarkers. Future studies are required, but it will be important to optimize their design rather than simply repeat the approaches taken to date.

The insulin and insulin-like growth factor receptor family in neoplasia: an update

Although several early phase clinical trials raised enthusiasm for the use of insulin-like growth factor I receptor (IGF1R)-specific antibodies for cancer treatment, initial Phase III results in unselected patients have been disappointing. Further clinical studies may benefit from the use of predictive biomarkers to identify probable responders, the use of rational combination therapies and the consideration of alternative targeting strategies, such as ligand-specific antibodies and receptor-specific tyrosine kinase inhibitors. Targeting insulin and IGF signalling also needs to be considered in the broader context of the pathophysiology that relates obesity and diabetes to neoplasia, and the effects of anti-diabetic drugs, including metformin, on cancer risk and prognosis. The insulin and IGFI receptor family is also relevant to the development of PI3K-AKT pathway inhibitors.