Camilla Qvortrup

Effects of KRAS, BRAF, NRAS, and PIK3CA mutations on the efficacy of cetuximab plus chemotherapy in chemotherapy-refractory metastatic colorectal cancer: a retrospective consortium analysis

BACKGROUND Following the discovery that mutant KRAS is associated with resistance to anti-epidermal growth factor receptor (EGFR) antibodies, the tumours of patients with metastatic colorectal cancer are now profiled for seven KRAS mutations before receiving cetuximab or panitumumab. However, most patients with KRAS wild-type tumours still do not respond. We studied the effect of other downstream mutations on the efficacy of cetuximab in, to our knowledge, the largest cohort to date of patients with chemotherapy-refractory metastatic colorectal cancer treated with cetuximab plus chemotherapy in the pre-KRAS selection era. METHODS 1022 tumour DNA samples (73 from fresh-frozen and 949 from formalin-fixed, paraffin-embedded tissue) from patients treated with cetuximab between 2001 and 2008 were gathered from 11 centres in seven European countries. 773 primary tumour samples had sufficient quality DNA and were included in mutation frequency analyses; mass spectrometry genotyping of tumour samples for KRAS, BRAF, NRAS, and PIK3CA was done centrally. We analysed objective response, progression-free survival (PFS), and overall survival in molecularly defined subgroups of the 649 chemotherapy-refractory patients treated with cetuximab plus chemotherapy. FINDINGS 40.0% (299/747) of the tumours harboured a KRAS mutation, 14.5% (108/743) harboured a PIK3CA mutation (of which 68.5% [74/108] were located in exon 9 and 20.4% [22/108] in exon 20), 4.7% (36/761) harboured a BRAF mutation, and 2.6% (17/644) harboured an NRAS mutation. KRAS mutants did not derive benefit compared with wild types, with a response rate of 6.7% (17/253) versus 35.8% (126/352; odds ratio [OR] 0.13, 95% CI 0.07-0.22; p<0.0001), a median PFS of 12 weeks versus 24 weeks (hazard ratio [HR] 1.98, 1.66-2.36; p<0.0001), and a median overall survival of 32 weeks versus 50 weeks (1.75, 1.47-2.09; p<0.0001). In KRAS wild types, carriers of BRAF and NRAS mutations had a significantly lower response rate than did BRAF and NRAS wild types, with a response rate of 8.3% (2/24) in carriers of BRAF mutations versus 38.0% in BRAF wild types (124/326; OR 0.15, 95% CI 0.02-0.51; p=0.0012); and 7.7% (1/13) in carriers of NRAS mutations versus 38.1% in NRAS wild types (110/289; OR 0.14, 0.007-0.70; p=0.013). PIK3CA exon 9 mutations had no effect, whereas exon 20 mutations were associated with a worse outcome compared with wild types, with a response rate of 0.0% (0/9) versus 36.8% (121/329; OR 0.00, 0.00-0.89; p=0.029), a median PFS of 11.5 weeks versus 24 weeks (HR 2.52, 1.33-4.78; p=0.013), and a median overall survival of 34 weeks versus 51 weeks (3.29, 1.60-6.74; p=0.0057). Multivariate analysis and conditional inference trees confirmed that, if KRAS is not mutated, assessing BRAF, NRAS, and PIK3CA exon 20 mutations (in that order) gives additional information about outcome. Objective response rates in our series were 24.4% in the unselected population, 36.3% in the KRAS wild-type selected population, and 41.2% in the KRAS, BRAF, NRAS, and PIK3CA exon 20 wild-type population. INTERPRETATION While confirming the negative effect of KRAS mutations on outcome after cetuximab, we show that BRAF, NRAS, and PIK3CA exon 20 mutations are significantly associated with a low response rate. Objective response rates could be improved by additional genotyping of BRAF, NRAS, and PIK3CA exon 20 mutations in a KRAS wild-type population. FUNDING Belgian Federation against Cancer (Stichting tegen Kanker).

Clinical trial enrollment, patient characteristics, and survival differences in prospectively registered metastatic colorectal cancer patients.

Trial accrual patterns were examined to determine whether metastatic colorectal cancer (mCRC) patients enrolled in trials are representative of a general cancer population concerning patient characteristics and survival.

Biweekly cetuximab and irinotecan as third-line therapy in patients with advanced colorectal cancer after failure to irinotecan, oxaliplatin and 5-fluorouracil

BACKGROUND Standard weekly cetuximab and irinotecan (CetIri) is an effective regimen in heavily pretreated patients with advanced colorectal cancer (ACRC). Inspired by a pharmacokinetic study demonstrating no differences between weekly and biweekly cetuximab, we present the results of 74 consecutive patients treated with biweekly CetIri. METHODS Biweekly CetIri schedule: cetuximab 500 mg/m(2), first course was given as a 120-min infusion followed 1 h later by irinotecan 180 mg/m(2) as a 30-min infusion. Subsequent courses of cetuximab were given in 60 min, immediately followed by irinotecan-resulting in an overall treatment time of 90 min. RESULTS All patients had ACRC resistant to 5-fluorouracil and irinotecan and 95% to oxaliplatin. Median age was 63 years, median performance status was 0. Median duration of therapy was 4.3 months. Response rate was 25%. Median progression-free survival and overall survival were 5.4 months and 8.9 months, respectively, comparable to own historical controls receiving weekly CetIri. Grade 3-4 toxicity was rare (skin 7%, nail 3%, diarrhoea 10%, fatigue 3%, neutropenia 9%). One patient experienced severe allergic reaction. CONCLUSION Salvage therapy with simplified biweekly CetIri is a convenient, effective and well-tolerated regimen in heavily pretreated patients with ACRC. A confirmatory phase II study is ongoing.

Chemotherapy-induced peripheral neuropathy in patients treated with taxanes and platinum derivatives

Abstract Background. Chemotherapy with taxanes and platinum compounds has resulted in substantial survival benefits both in adjuvant and metastatic settings. However, as a side effect, such chemotherapy may cause peripheral neuropathy (CIPN) which may result in discontinuation of treatment, and if it persists after treatment completion, has a negative impact on quality of life (QoL). Results. Symptoms of CIPN are sensory, like pain, numbness, and tingling, typically located in the hands and feet. For oxaliplatin, there is an acute form of CIPN, resulting in paraesthesias in the mouth and throat during or shortly after the infusion triggered by exposure to cold. Risks factors for CIPN include preexisting neuropathy, either from treatment with other neurotoxic agents, or from comorbid conditions. The incidence of CIPN is related to dose per cycle, cumulative dose, and duration of infusion. While cisplatin-induced neuropathy is irreversible, CIPN induced by taxanes may persist for several years in about 30% of patients. Evidence from the literature is suggestive that CIPN is likely to be negatively associated with QoL. No agents have been identified to be recommended for the prevention of CIPN. For treatment of CIPN, the best available data supports a moderate recommendation for treatment with duloxetine and evidence is inconclusive regarding the use of tricyclic antidepressants (such as nortriptyline), gabapentin, and a compounded topical gel containing baclofen, amitriptyline HCL, and ketamine. Conclusion. Research is still needed to predict which patients are at high risk of developing CIPN during treatment and in whom CIPN will persist after completion of chemotherapy.

High expression of microRNA-625-3p is associated with poor response to first-line oxaliplatin based treatment of metastatic colorectal cancer

The backbone of current cytotoxic treatment of metastatic colorectal cancer (mCRC) consists of a fluoropyrimidine together with either oxaliplatin (XELOX/FOLFOX) or irinotecan (XELIRI/FOLFIRI). With an overall objective response rate of approximately 50% for either treatment combination, a major unsolved problem is that no predictors of response to these treatments are available. To address this issue, we profiled 742 microRNAs in laser‐capture microdissected cancer cells from responding and non‐responding patients receiving XELOX/FOLFOX as first‐line treatment for mCRC, and identified, among others, high expression of miR‐625‐3p, miR‐181b and miR‐27b to be associated with poor clinical response. In a validation cohort of 94 mCRC patients treated first‐line with XELOX, high expression of miR‐625‐3p was confirmed to be associated with poor response (OR = 6.25, 95%CI [1.8; 21.0]). Independent analyses showed that miR‐625‐3p was not dysregulated between normal and cancer samples, nor was its expression associated with recurrence of stage II or III disease, indicating that miR‐625‐3p solely is a response marker. Finally, we also found that these miRNAs were up‐regulated in oxaliplatin resistant HCT116/oxPt (miR‐625‐3p, miR‐181b and miR‐27b) and LoVo/oxPt (miR‐181b) colon cancer cell lines as compared with their isogenic parental cells. Altogether, our results suggest an association between miR‐625‐3p and response to first‐line oxaliplatin based chemotherapy of mCRC.

Age-dependent improvement in median and long-term survival in unselected population-based Nordic registries of patients with synchronous metastatic colorectal cancer

BACKGROUND In metastatic colorectal cancer (mCRC) trials, median survival has increased from 6 months to above 20 months during the previous decades. Uncertainty exists in how this survival improvement has translated to the general mCRC population. PATIENTS AND METHODS Survival data from patients with synchronous mCRC were collected from the Norwegian (1980-2008), Swedish (1996-2008) and Danish (2001-09) cancer registries. RESULTS A total of 29 628 patients were identified. From 1980-1985 to 2006-2008, median survival increased from 5 to 10 months for Norwegian patients. Three-year survival increased from 7% to 21% and 5-year survival from 4% to 9%. For patients <60 years, median survival was doubled to 16 months, 3-year survival increased fourfold up to 28% and 5-year survival threefold up to 14%. Similar improvements were seen in Sweden and Denmark. In all countries, the improved outcome was seen especially for younger patients and much less for patients >75 years of age. CONCLUSION An increase in median and long-term survival over time was found in unselected population-based registries of patients with synchronous mCRC. The improved outcome in survival was especially seen in younger patients, raising concerns over our ability to adapt available treatment options for elderly patients.

Review on adjuvant chemotherapy for rectal cancer – why do treatment guidelines differ so much?

Abstract Background. The use of postoperative adjuvant chemotherapy is controversial for rectal adenocarcinoma. Both international and national guidelines display a great span varying from recommending no adjuvant chemotherapy at all, over single drug 5-fluororuacil (5-FU), to combinations of 5-FU/oxaliplatin. Methods. A review of the literature was made identifying 24 randomized controlled trials on adjuvant treatment of rectal cancer based on about 10 000 patients. The trials were subdivided into a number of clinically relevant subgroups. Results. As regards patients treated with preoperative (chemo) radiotherapy, four randomized studies were found where use of adjuvant chemotherapy showed no benefit in survival. Three trials were found in which a subset of patients received preoperative (chemo) radiotherapy. Two of these trials showed a statistically significant benefit of adjuvant chemotherapy. Twenty trials were identified in which the patients did not receive preoperative (chemo) radiotherapy, including five Asian studies in which a statistically significant benefit from adjuvant chemotherapy was reported. Conclusions. Most of the data found did not support the use of postoperative adjuvant chemotherapy for patients already treated with preoperative (chemo) radiotherapy. For patients not treated preoperatively, several studies support the use of single agent 5-FU chemotherapy. Treatment guidelines seem to differ according to if preoperative chemoradiation is considered of importance for use of adjuvant chemotherapy and if adjuvant colon cancer studies are considered transferrable to rectal cancer patients regardless of the molecular differences.

Tissue MicroRNAs as Predictors of Outcome in Patients with Metastatic Colorectal Cancer Treated with First Line Capecitabine and Oxaliplatin with or without Bevacizumab

Purpose We tested the hypothesis that expression of microRNAs (miRNAs) in cancer tissue can predict effectiveness of bevacizumab added to capecitabine and oxaliplatin (CAPEOX) in patients with metastatic colorectal cancer (mCRC). Experimental Design Patients with mCRC treated with first line CAPEOX and bevacizumab (CAPEOXBEV): screening (n = 212) and validation (n = 121) cohorts, or CAPEOX alone: control cohort (n = 127), were identified retrospectively and archival primary tumor samples were collected. Expression of 754 miRNAs was analyzed in the screening cohort using polymerase chain reaction (PCR) arrays and expression levels were related to time to disease progression (TTP) and overall survival (OS). Significant miRNAs from the screening study were analyzed in all three cohorts using custom PCR arrays. In situ hybridization (ISH) was done for selected miRNAs. Results In the screening study, 26 miRNAs were significantly correlated with outcome in multivariate analyses. Twenty-two miRNAs were selected for further study. Higher miR-664-3p expression and lower miR-455-5p expression were predictive of improved outcome in the CAPEOXBEV cohorts and showed a significant interaction with bevacizumab effectiveness. The effects were strongest for OS. Both miRNAs showed high expression in stromal cells. Higher expression of miR-196b-5p and miR-592 predicted improved outcome regardless of bevacizumab treatment, with similar effect estimates in all three cohorts. Conclusions We have identified potentially predictive miRNAs for bevacizumab effectiveness and additional miRNAs that could be related to chemotherapy effectiveness or prognosis in patients with mCRC. Our findings need further validation in large cohorts, preferably from completed randomized trials.

Characterization and diagnostic evaluation of chronic polyneuropathies induced by oxaliplatin and docetaxel comparing skin biopsy to quantitative sensory testing and nerve conduction studies

Chemotherapy‐induced peripheral neuropathy negatively affects the quality of life for many patients treated with oxaliplatin or docetaxel for gastrointestinal cancer or breast cancer. Symptoms can persist long after treatment and often include neuropathic pain. Our objective was to characterize the neuropathies with regard to symptoms, neurological signs and objective evidence of damage to the structure and function of the peripheral nerves. Furthermore, the diagnostic values of skin biopsy, quantitative sensory testing (QST) and nerve conduction studies (NCS) were compared.

High BRAF Mutation Frequency and Marked Survival Differences in Subgroups According to KRAS/BRAF Mutation Status and Tumor Tissue Availability in a Prospective Population-Based Metastatic Colorectal Cancer Cohort.

RAS and BRAF mutations impact treatment and prognosis of metastatic colorectal cancer patients (mCRC), but the knowledge is based on trial patients usually not representative for the general cancer population. Patient characteristics, treatment and efficacy according to KRAS, BRAF and MSI status were analyzed in a prospectively collected unselected population-based cohort of 798 non-resectable mCRC patients. The cohort contained many patients with poor performance status (39% PS 2-4) and elderly (37% age>75), groups usually not included in clinical trials. Patients without available tissue micro array (TMA) (42%) had worse prognostic factors and inferior survival (all patients; 7m vs 11m, chemotherapy-treated;12m vs 17m). The 92 patients (21%) with BRAF mutation had a poor prognosis regardless of microsatellite instability, but receipt of 1-2nd chemotherapy was similar to wildtype BRAF patients. Median survival in this cohort varied from 1 month in BRAF mutated patients not given chemotherapy to 26 months in wildtype KRAS/BRAF patients <75 years in good PS. TMA availability, BRAF mutation and KRAS mutation were all independent prognostic factors for survival. The observed 21% BRAF mutation incidence is higher than the previously and repeatedly reported incidence of 5-12% in mCRC. Screening for BRAF mutations before selection of treatment is relevant for many patients, especially outside clinical trials. A BRAF mutation only partly explained the very poor prognosis of many mCRC patients. Survival in unselected metastatic colorectal cancer patients is extremely variable and subgroups have an extremely short survival compared to trial patients. Patients without available TMA had worse prognostic factors and shorter survival, which questions the total generalizability of present TMA studies and implies that we lack information on the biologically worst mCRC cases. Lack of available tissue is an important underexposed issue which introduces sample bias, and this should be recognized more clearly when conclusions are made from translational mCRC studies.