Alternative dosing schedules for cetuximab: a role for biweekly administration?

Evaluating the Time Toxicity of Cancer Treatment in the CCTG CO.17 Trial

PURPOSE

The time spent in pursuing treatments for advanced cancer can be substantial. We have previously proposed a pragmatic and patient-centered metric of these time costs-which we term time toxicity-as any day with physical health care system contact. This includes outpatient visits (eg, bloodwork, scans, etc), emergency department visits, and overnight stays in a health care facility. Herein, we sought to assess time toxicity in a completed randomized controlled trial (RCT).

METHODS

We conducted a secondary analysis of the Canadian Cancer Trials Group CO.17 RCT that evaluated weekly cetuximab infusions versus supportive care alone in 572 patients with advanced colorectal cancer. Initial results reported a 6-week improvement in median overall survival (OS) with cetuximab (6.1 v 4.6 months). Subsequent analyses reported that benefit was restricted to patients with K-ras wild-type tumors. We calculated patient-level time toxicity by analyzing trial forms. We considered days without health care contact as home days. We compared medians of time measures across arms and stratified results by K-ras status.

RESULTS

In the overall population, median time toxic days were higher in the cetuximab arm (28 v 10, P < .001) although median home days were not statistically different between arms (140 v 121, P = .09). In patients with K-ras-mutated tumors, cetuximab was associated with almost numerically equal home days (114 days v 112 days, P = .571) and higher time toxicity (23 days v 11 days, P < .001). In patients with K-ras wild-type tumors, cetuximab was associated with more home days (186 v 132, P < .001).

CONCLUSION

This proof-of-concept feasibility study demonstrates that measures of time toxicity can be extracted through secondary analyses of RCTs. In CO.17, despite an overall OS benefit with cetuximab, home days were statistically similar across arms. Such data can supplement traditional survival end points in RCTs. Further work should refine and validate the measure prospectively.

Discovery of A Novel EGFR-Targeting Antibody-Drug Conjugate, SHR-A1307, for the Treatment of Solid Tumors Resistant or Refractory to Anti-EGFR Therapies

Although inhibiting EGFR-mediated signaling proved to be effective in treating certain types of cancers, a quickly evolved mechanism that either restores the EGFR signaling or activates an alternative pathway for driving the proliferation and survival of malignant cells limits the efficacy and utility of the approach via suppressing the EGFR functionality. Given the fact that overexpression of EGFR is commonly seen in many cancers, an EGFR-targeting antibody-drug conjugate (ADC) can selectively kill cancer cells independently of blocking EGFR-mediated signaling. Herein, we describe SHR-A1307, a novel anti-EGFR ADC, generated from an anti-EGFR antibody with prolonged half-life, and conjugated with a proprietary toxin payload that has increased index of EGFR targeting-dependent versus EGFR targeting-independent cytotoxicity. SHR-A1307 demonstrated strong and sustained antitumor activities in EGFR-positive tumors harboring different oncogenic mutations on EGFR, KRAS, or PIK3CA. Antitumor efficacy of SHR-A1307 correlated with EGFR expression levels in vitro and in vivo, regardless of the mutation status of EGFR signaling mediators and a resultant resistance to EGFR signaling inhibitors. Cynomolgus monkey toxicology study showed that SHR-A1307 is well tolerated with a wide therapeutic index. SHR-A1307 is a promising therapeutic option for EGFR-expressing cancers, including those resistant or refractory to the EGFR pathway inhibitors.

Epithelial growth factor receptor (EGFR)-inhibition for relief of neuropathic pain-A case series

Background Neuropathic pain remains a significant challenge with unsatisfactory therapeutic options. Its pathogenesis may involve the neuropathic triad of neuronal, glial and immune cells. Communication between these cells is possibly perpetuated by mitogen-activated protein kinase (MAPK)-signaling. For several years, we successfully treated a rectal cancer patient with the epithelial growth factor receptor (EGFR)-inhibitor cetuximab, for debilitating neuropathic pain due to progressive malignant invasion of the sacral plexus. Here, we report the effect of treatment with various EGFR-inhibitors in five additional patients with severe and long-standing, therapy-resistant neuropathic pain. Methods All patients had well-documented neuropathic pain syndromes with the following etiologies: inflammatory polyneuropathy, complex regional pain syndrome type 1, radiculopathy after failed back surgery, malignant invasion of the sacral plexus by bladder cancer, and phantom limb pain. All patients were given intravenous (extracellular) EGFR-inhibitors (cetuximab, panitumumab) initially, and switched to oral (intracellular) agents (gefitinib, erlotinib) after an analgesic effect was obtained. Results Four of the five patients responded, all within 24h of intravenous administration, with a mean decrease in worst pain from 9 to 1 on a 10-point scale. All four EGFR-inhibitors were effective. The clinical courses, including patient-reported pain relief, are prospectively documented with 78-219 days follow-up for those who responded to treatment. Toxicities were transient and manageable. Conclusions/implications EGFR-inhibition resulted in dramatic relief of neuropathic pain. A plausible biological explanation involves the interruption of MAPK-signaling. The role of EGFR-inhibition as a target for the treatment of neuropathic pain appears promising and warrants investigation.

Cetuximab alleviates neuropathic pain despite tumour progression

The authors present the case of a 68-year-old male patient with metastatic rectal cancer. A pelvic recurrence resulted in neuropathic pain, radiating down his left leg. The pain was resistant to standard treatments. However, after nearly 3 years of debilitating pain, the patient experienced dramatic relief just hours after an infusion of the antiepidermal growth factor receptor antibody cetuximab. The analgesic effect lasted for 10-12 days and was repeated roughly every 12 days for three and a half years. To test for placebo effect, the patient received (unknown to him) 20% of his usual cetuximab dose and experienced no pain relief. The dramatic analgesic effect was documented in clinical notes, medication lists and in numeric rating scales even while his cancer was in radiological progression. Mitogen-activated protein kinase (MAPK)-signalling is believed to be an important driver of neuropathic pain and therefore, the authors hypothesise a direct inhibition of MAPK-signalling by cetuximab in neuronal or glial cells.

Phase II study of biweekly cetuximab in combination with irinotecan as second-line treatment in patients with platinum-resistant gastro-oesophageal cancer

BACKGROUND

The purpose of this phase II trial was to evaluate the efficacy and safety of cetuximab and irinotecan as second-line treatment in patients with gastro-oesophageal adenocarcinoma.

PATIENTS AND METHODS

Patients with failure to first-line platinum-based chemotherapy received cetuximab 500 mg/m(2) and irinotecan 180 mg/m(2) every second week until disease progression. Toxicity was evaluated according to The Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) v. 3.0. Antitumour activity was assessed according to Response Evaluation Criteria in Solid Tumours (RECIST) v. 1.0.

RESULTS

Sixty-three patients were enrolled, median age was 60 years, median performance status was 1 (0-1), 35 patients had two or more organs involved. The median number of courses was 5 (range 1-25). Response rate was 11% (6 partial response (PR)) and 37% had stable disease. Median progression free survival was 2.8 months and overall survival (OS) was 6.1 months. Grade 3-4 toxicity included: diarrhoea (6%), fatigue (5%), vomiting (5%) and neutropenia (16%). Two patients developed febrile neutropenia. Forty-six patients (73%) had developed grade 1-2 skin rash. Patients developing skin rash had a prolonged survival with an OS at 7.1 months.

CONCLUSIONS

The combination of cetuximab and irinotecan is active as second-line therapy in patients with gastro-oesophageal cancer. Cetuximab induced skin rash was associated with prolonged survival.

Phase II study of irinotecan and cetuximab given every 2 weeks as second-line therapy for advanced colorectal cancer

BACKGROUND

Irinotecan and weekly cetuximab (I+C) is a standard second-line regimen for metastatic colorectal cancer (mCRC). This study investigated the safety and efficacy of every 2 weeks I+C in patients with mCRC.

PATIENTS AND METHODS

Patients with mCRC refractory to first-line fluoropyrimidine/oxaliplatin regimens and not previously treated with I+C were eligible. Response rate (RR) was the primary endpoint. Cetuximab 500 mg/m(2) and irinotecan 180 mg/m(2) were administered intravenously (I.V.) on day 1 every 2 weeks.

RESULTS

Patient characteristics (n = 31): male (n = 17), median age 62; Eastern Cooperative Oncology Group (ECOG) performance status (PS) ≤1 (n = 30), and PS = 2 (n = 1). Median number of cycles = 3 (range, 1-22). I+C doses were modified in 18 and 12 patients, respectively. Grade 3/4 adverse events: acneiform rash (n = 6); neutropenia (n = 6); and diarrhea (n = 5); there was one grade 5 respiratory failure, possibly related to therapy. Two patients had a partial response, 11 had stable disease, and 18 had progressive disease resulting in an overall RR of 6% and disease control rate of 41.9%. Median overall survival (OS) was 9.3 months (95% CI, 5.1-15), and time to progression (TTP) was 2.4 months (95% CI, 1.3-4.6). K-ras and BRAF mutations were detected in 39% and 9%, respectively, of the patients tested. There was a trend toward longer TTP among patients with wild-type K-ras and BRAF (2.6 vs. 1.7 months; P = 0.16), and OS was significantly longer in those patients (14.1 vs. 5.5 months; P = 0.04).

CONCLUSIONS

The RR and TTP were lower than expected and may reflect the reduced dose intensity due to toxicities. While the OS was consistent with previous publications, the efficacy of this combination was not demonstrated.

Biweekly cetuximab and irinotecan as second-line therapy in patients with gastro-esophageal cancer previously treated with platinum

BACKGROUND

Until recently there has been no proven second-line therapy for patients with advanced gastro-esophageal cancer (GEC). Since 2004, Denmark has had a national health program where non-proven therapy can be offered to patients with advanced cancer, after approval by an expert panel appointed by the National Board of Health. This program has accelerated the introduction and implementation of new therapies in Denmark. Inspired by therapy in metastatic colorectal cancer, a combination of cetuximab and irinotecan (Cetiri) was chosen for second-line therapy in GEC patients. We report our experience with Cetiri as second-line therapy in patients with GEC.

METHODS

All patients had histologically confirmed GEC and all patients had progressive disease during or after first-line platinum-containing chemotherapy. The patients received cetuximab 500 mg/m(2) on day 1 and irinotecan 180 mg/m(2) on day 1 every 2nd week until progression or unacceptable toxicity. Toxicity was prospectively evaluated according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 3.0.

RESULTS

From December 2007 to February 2009, 50 consecutive patients received Cetiri as second-line therapy. Median performance status (PS) was 1. The median number of courses was seven. Seven patients (14%) had a partial response. Median progression-free survival (PFS) was 3.3 months and overall survival (OS) was 5.5 months; two patients are still alive without progressive disease. Major toxicities were: diarrhea (8%), fatigue (10%), neutropenia (16%), and febrile neutropenia (2%).

CONCLUSION

Cetiri every two weeks is a convenient and well-tolerated second-line regimen in GEC patients. A promising effect was seen in patients with PS 0-1 and in patients who developed a rash.

Progress in metastatic colorectal cancer: growing role of cetuximab to optimize clinical outcome

The prognosis of metastatic colorectal cancer remains poor despite advances made in recent years, particularly with new treatments directed towards molecular targets. Cetuximab, a chimeric immunoglobulin (Ig)G1 monoclonal antibody that targets the ligand-binding domain of the epidermal growth factor receptor (EGFR), is active in metastatic colorectal cancer. As an IgG1 antibody, cetuximab may exert its antitumour efficacy through both EGFR antagonism and antibody-dependent cell-mediated cytotoxicity. The benefits of cetuximab in metastatic colorectal cancer are well documented in clinical trials and are acknowledged in the approval and licensing of this agent. There is evidence of the role of cetuximab not only in irinotecan-refractory or heavily pretreated patients, but also of the efficacy and safety of the addition of this agent to FOLFIRI (irinotecan/5-fluorouracil/leucovorin) in first-line metastatic colorectal cancer, with an enhanced effect in 5-fluorouracil patients with Kirsten rat sarcoma (KRAS) wild-type tumours. In these patients, a recent meta-analysis of the pooled Cetuximab Combined with Irinotecan in First-Line Therapy for Metastatic Colorectal Cancer (CRYSTAL) and Oxaliplatin and Cetuximab in First-Line Treatment of mCRC (OPUS) patient populations confirms that the addition of cetuximab to first-line chemotherapy achieves a statistically significant improvement in the best overall response, overall survival time, and progression-free survival (PSF) compared with chemotherapy alone. In nonresectable colorectal liver metastases, cetuximab plus FOLFOX-6 (oxaliplatin/5-fluorouracil/leucovorin) or cetuximab plus FOLFIRI increased significantly resectability of liver metastases, including R0 resections. Also, preliminary data indicate that cetuximab can be administered in a more convenient 2-week schedule in combination with standard chemotherapy. Cetuximab is generally well tolerated. Acne-form rash is the most frequent toxicity. Up to the present time, the results obtained with targeted therapy combinations are not as encouraging as initially expected. The identification of biomarkers associated with disease control, including KRAS and BRAF mutation status in patients treated with cetuximab, is changing the current management of metastatic colorectal cancer. Clinical and molecular predictive markers of response are under active evaluation in order to better select patients who could benefit from cetuximab treatment, with the aim of both optimising patient outcomes and avoiding unnecessary toxicities.