Attempts to optimize radiotherapy and chemotherapy efficacy with the use of targeted agents in rectal and prostate cancers : from animal models to early phase I/II clinical trials

Molecular-targeted agents are potent tumor inhibitors that target specific molecular pathways during carcinogenesis. They possess radio- and/or chemosensitizing properties which lead to many attempts to clinically combine these drugs with conventional radiotherapy and chemotherapy. Radiotherapy and chemotherapy play a central role in the management of prostate and rectal cancers. In locally advanced rectal cancer, chemoradiotherapy followed by curative surgery significantly reduces the risk of loco-regional relapse. Yet, disease-free survival and overall survival of patients are not improved. Previously, the addition of Epidermal Growth Factor Receptor-targeting drugs to chemoradiotherapy in rectal cancer resulted only in limited efficacy. The results showed an inferior rate of complete pathologic response compared to chemoradiation alone. It is therefore necessary to optimize the integration of EGFR-targeting drugs to preoperative chemoradiation in order to improve the long-term clinical outcome of patients with locally advanced rectal cancer. In prostate cancer, patient’s prognosis declines dramatically at the onset of metastasis. Metastatic prostate cancer initially responds to androgen deprivation therapy but would eventually progress to a state of castration-resistant disease for which therapeutic options become limited. Encouraging data from clinical trials using angiogenesis-targeting agents have motivated researchers to further evaluate whether the blockade of this biological pathway would add benefits to chemotherapy in metastatic castration-resistant prostate cancer.(MED - Sciences médicales) -- UCL, 201

Phase I study of sorafenib in combination with docetaxel and prednisone in chemo-naïve patients with metastatic castration-resistant prostate cancer

PURPOSE: We performed a dose-escalation study to investigate the safety of sorafenib in combination with docetaxel and prednisone in chemo-naïve patients with metastatic castration-resistant prostate cancer (mCRPC). METHODS: Six patients were included per dose level. Following docetaxel infusion on day 1 (75 mg/m(2)/q3 weeks), sorafenib was administered at 200 mg BID on days 2-19 (dose level 1), at 200 mg BID on days 1-21 (dose level 2), at 400 mg BID on days 2-19 (dose level 3), at 400 mg BID on days 1-21 (dose level 4). Maximal tolerated dose (MTD) was exceeded if ≥2 patients experienced dose-limiting toxicities (DLT) during cycle 1. The recommended phase 2 dose for sorafenib was defined as one dose level below MTD. If MTD was not reached, the highest feasible dose would be selected to treat an expanded cohort to confirm safety. RESULTS: Two DLTs were observed during sorafenib dose-escalation consisting of grade 4 febrile neutropenia (dose level 2) and grade 3 hand-foot syndrome (HFS) (dose level 3). Our pharmacokinetic results showed an increased exposure to docetaxel across all dose levels during sorafenib comedication. The main grade ≥3 toxicities were neutropenia (35 %), HFS (27 %), and febrile neutropenia (19 %). The prostate-specific antigen (PSA) response rate was 74 %. Median overall survival was 25.2 months. CONCLUSION: Three-weekly docetaxel and prednisone could be combined with sorafenib at 400 mg BID on days 1-21 without reaching MTD. However, we observed a pharmacokinetic interaction between sorafenib and docetaxel, associated with significant toxicities, raising concerns about the safety of this combination in mCRPC

Phase Ib study of duligotuzumab (MEHD7945A) plus cisplatin/5-fluorouracil or carboplatin/paclitaxel for first-line treatment of recurrent/metastatic squamous cell carcinoma of the head and neck

This open-label, multicenter, phase Ib study assessed the safety and preliminary activity of duligotuzumab, a dual-action antibody that blocks ligand binding to human epidermal growth factor receptor 3 (HER3) and epidermal growth factor receptor, in combination with chemotherapy, in the first-line treatment of patients with recurrent/metastatic squamous cell cancer of the head and neck.status: publishe

Phase II trial of preoperative radiotherapy (RT) and panitumumab (PAN) in KRAS wild type (wt) rectal cancer (RC).

Background: The addition of anti Epidermal Growth Factor Receptor (EGFR) monoclonal antibodies (mabs) to preoperative chemoradiation in RC has produced low pathological complete response (pCR) rate. The postulated reasons for the poor outcome are: lack of patient selection, suboptimal treatment sequencing, and potential negative interaction between anti EGFR mabs and chemotherapy (CT) when used concurrently as radiosensitizers. Given these issues, we conducted a phase II trial of PAN in combination with preoperative RT in Kras wt RC. Methods: We studied several treatment sequences in murine models of Kras wt human colorectal cancer. Next, we used our preclinical results to design the treatment schedule of the phase II trial. PAN (6mg/kg/q2w) was combined with RT (45 Gy) to treat T3-4, Kras wt RC. Surgery was done 6-8 weeks after the end of RT. The primary endpoint, the pCR rate on surgical specimen, was assessed centrally (Simon: H0=5%, H1=17%, α=0.05, β=0.2). Results: In our murine models, the addition of anti EGFR mabs to RT significantly improved response when anti EGFR mabs were started during RT and extended after the end of RT (p50% pathological tumour regression (grade 3 Dworak) and 12 (70%) showed >2mm of tumour-free circumferential resection margin. Conclusions: Preclinical data confirm the need of optimal treatment sequencing to potentiate synergism between anti EGFR mabs and RT. However, the pCR rate in our phase II trial remains low despite adequate patient selection and optimized study design. Thus, we do not recommend the concurrent use of anti EGFR mabs and RT in the neoadjuvant treatment of RC

Panitumumab as a radiosensitizing agent in KRAS wild-type locally advanced rectal cancer

Our goal was to optimize the radiosensitizing potential of anti-epidermal growth factor receptor (EGFR) monoclonal antibodies, when given concomitantly with preoperative radiotherapy in KRAS wild-type locally advanced rectal cancer (LARC). Based on pre-clinical studies conducted by our group, we designed a phase II trial in which panitumumab (6 mg/kg/q2 weeks) was combined with preoperative radiotherapy (45 Gy in 25 fractions) to treat cT3-4/N + KRAS wild-type LARC. The primary endpoint was complete pathologic response (pCR) (H0 = 5 %, H1 = 17 %, α = 0.05, β = 0.2). From 19 enrolled patients, 17 (89 %) were evaluable for pathology assessment. Although no pCR was observed, seven patients (41 %) had grade 3 Dworak pathological tumor regression. The regimen was safe and was associated with 95 % of sphincter-preservation rate. No NRAS, BRAF, or PI3KCA mutation was found in this study, but one patient (5 %) showed loss of PTEN expression. The quantification of plasma EGFR ligands during treatment showed significant upregulation of plasma TGF-α and EGF following panitumumab administration (p < 0.05). At surgery, patients with important pathological regression (grade 3 Dworak) had higher plasma TGF-α (p = 0.03) but lower plasma EGF (p = 0.003) compared to those with grade 0-2 Dworak. Our study suggests that concomitant panitumumab and preoperative radiotherapy in KRAS wild-type LARC is feasible and results in some tumor regression. However, pCR rate remained modest. Given that the primary endpoint of our study was not reached, we remain unable to recommend the use of panitumumab as a radiosensitizer in KRAS wild-type LARC outside a research setting