A phase 1 study of weekly everolimus (RAD001) in combination with docetaxel in patients with metastatic breast cancer

Is more better? An analysis of toxicity and response outcomes from dose-finding clinical trials in cancer

BACKGROUND

The overwhelming majority of dose-escalation clinical trials use methods that seek a maximum tolerable dose, including rule-based methods like the 3+3, and model-based methods like CRM and EWOC. These methods assume that the incidences of efficacy and toxicity always increase as dose is increased. This assumption is widely accepted with cytotoxic therapies. In recent decades, however, the search for novel cancer treatments has broadened, increasingly focusing on inhibitors and antibodies. The rationale that higher doses are always associated with superior efficacy is less clear for these types of therapies.

METHODS

We extracted dose-level efficacy and toxicity outcomes from 115 manuscripts reporting dose-finding clinical trials in cancer between 2008 and 2014. We analysed the outcomes from each manuscript using flexible non-linear regression models to investigate the evidence supporting the monotonic efficacy and toxicity assumptions.

RESULTS

We found that the monotonic toxicity assumption was well-supported across most treatment classes and disease areas. In contrast, we found very little evidence supporting the monotonic efficacy assumption.

CONCLUSIONS

Our conclusion is that dose-escalation trials routinely use methods whose assumptions are violated by the outcomes observed. As a consequence, dose-finding trials risk recommending unjustifiably high doses that may be harmful to patients. We recommend that trialists consider experimental designs that allow toxicity and efficacy outcomes to jointly determine the doses given to patients and recommended for further study.

Targeted Therapy to β3 Integrin Reduces Chemoresistance in Breast Cancer Bone Metastases

Breast cancer bone metastases are common and incurable. Tumoral integrin β3 (β3) expression is induced through interaction with the bone microenvironment. Although β3 is known to promote bone colonization, its functional role during therapy of established bone metastases is not known. We found increased numbers of β3+ tumor cells in murine bone metastases after docetaxel chemotherapy. β3+ tumor cells were present in 97% of post-neoadjuvant chemotherapy triple-negative breast cancer patient samples (n = 38). High tumoral β3 expression was associated with worse outcomes in both pre- and postchemotherapy triple-negative breast cancer groups. Genetic deletion of tumoral β3 had minimal effect in vitro, but significantly enhanced in vivo docetaxel activity, particularly in the bone. Rescue experiments confirmed that this effect required intact β3 signaling. Ultrastructural, transcriptomic, and functional analyses revealed an alternative metabolic response to chemotherapy in β3-expressing cells characterized by enhanced oxygen consumption, reactive oxygen species generation, and protein production. We identified mTORC1 as a candidate for therapeutic targeting of this β3-mediated, chemotherapy-induced metabolic response. mTORC1 inhibition in combination with docetaxel synergistically attenuated murine bone metastases. Furthermore, micelle nanoparticle delivery of mTORC1 inhibitor to cells expressing activated αvβ3 integrins enhanced docetaxel efficacy in bone metastases. Taken together, we show that β3 integrin induction by the bone microenvironment promotes resistance to chemotherapy through an altered metabolic response that can be defused by combination with αvβ3-targeted mTORC1 inhibitor nanotherapy. Our work demonstrates the importance of the metastatic microenvironment when designing treatments and presents new, bone-specific strategies for enhancing chemotherapeutic efficacy.

Neutropenia and docetaxel exposure in metastatic castration-resistant prostate cancer patients: A meta-analysis and evaluation of a clinical cohort

The incidence of neutropenia in metastatic castration‐resistant prostate cancer (mCRPC) patients treated with docetaxel has been reported to be lower compared to patients with other solid tumors treated with a similar dose. It is suggested that this is due to increased clearance of docetaxel in mCRPC patients, resulting in decreased exposure. The aims of this study were to (1) determine if exposure in mCRPC patients is lower vs patients with other solid tumors by conducting a meta‐analysis, (2) evaluate the incidence of neutropenia in patients with mCRPC vs other solid tumors in a clinical cohort, and (3) discuss potential clinical consequences. A meta‐analysis was conducted of studies which reported areas under the plasma concentration‐time curves (AUCs) of docetaxel and variability. In addition, grade 3/4 neutropenia was evaluated using logistic regression in a cohort of patients treated with docetaxel. The meta‐analysis included 36 cohorts from 26 trials (n = 1150 patients), and showed that patients with mCRPC had a significantly lower mean AUC vs patients with other solid tumors (fold change [95% confidence interval (CI)]: 1.8 [1.5‐2.2]), with corresponding AUCs of 1.82 and 3.30 mg∙h/L, respectively. Logistic regression, including 812 patient, demonstrated that patients with mCRPC had a 2.2‐fold lower odds of developing grade 3/4 neutropenia compared to patients with other solid tumors (odds ratio [95%CI]: 0.46 [0.31‐0.90]). These findings indicate that mCRPC patients have a lower risk of experiencing severe neutropenia, possibly attributable to lower systemic exposure to docetaxel.

Safety and Efficacy of Docetaxel, Bevacizumab, and Everolimus for Castration-resistant Prostate Cancer (CRPC)

BACKGROUND

Previous data suggests that co-targeting mammalian target of rapamycin and angiogenic pathways may potentiate effects of cytotoxic chemotherapy. We studied combining mammalian target of rapamycin and vascular endothelial growth factor inhibition with docetaxel in castrate-resistant prostate cancer (CRPC).

METHODS

Eligible patients had progressive, metastatic, chemotherapy-naive CRPC. Docetaxel and bevacizumab were given intravenously day 1 with everolimus orally daily on a 21-day cycle across 3 dose levels (75:15:2.5, 75:15:5, and 65:15:5; docetaxel mg/m2, mg/kg bevacizumab, and mg everolimus, respectively). Maintenance therapy with bevacizumab/everolimus without docetaxel was allowed after ≥ 6 cycles.

RESULTS

Forty-three subjects were treated across all dose levels. Maximal tolerated doses for the combined therapies observed in the phase 1B portion of the trial were: docetaxel 75 mg/m2, bevacizumab 15 mg/kg, and everolimus 2.5 mg. Maximal prostate-specific antigen decline ≥ 30% and ≥ 50% was achieved in 33 (79%) and 31 (74%) of patients, respectively. Best response by modified Response Evaluation Criteria In Solid Tumors criteria in 25 subjects with measurable disease at baseline included complete or partial response in 20 (80%) patients. The median progression-free and overall survival were 8.9 months (95% confidence interval, 7.4-10.6 months) and 21.9 months (95% confidence interval, 18.4-30.3 months), respectively. Hematologic toxicities were the most common treatment-related grade ≥ 3 adverse events including: febrile neutropenia (12; 28%), lymphopenia (12; 28%), leukocytes (10; 23%), neutrophils (9; 21%), and hemoglobin (2; 5%). Nonhematologic grade ≥ 3 adverse events included: hypertension (8; 19%), fatigue (3; 7%), pneumonia (3; 7%), and mucositis (4; 5%). There was 1 treatment-related death owing to neutropenic fever and pneumonia in a patient treated at dose level 3 despite dose modifications and prophylactic growth factor support.

CONCLUSIONS

Docetaxel, bevacizumab, and everolimus can be safely administered in CRPC and demonstrate a significant level of anticancer activity, meeting the predetermined response criteria. However, any potential benefit of combined therapy must be balanced against increased risk for toxicities. Our results do not support the hypothesis that this combination of agents improves upon the results obtained with docetaxel monotherapy in an unselected population of chemotherapy-naive patients with CRPC.

Phase I Trial of Everolimus and Capecitabine in Metastatic HER2- Breast Cancer

BACKGROUND

The mammalian target of rapamycin (mTOR) pathway is a driver of breast tumorigenesis. The mTOR inhibitor everolimus reverses antihormonal therapy resistance and is an approved therapy for metastatic breast cancer. A synergistic effect with fluoropyrimidine has been suggested. The present study evaluated the safety and tolerability of an all-oral combination of everolimus and capecitabine for metastatic breast cancer (MBC).

PATIENTS AND METHODS

MBC patients naive to capecitabine and mTOR inhibitors who had received ≤ 3 previous chemotherapy regimens in the metastatic setting were eligible for the present study. The patients were scheduled to receive capecitabine 825 mg/m² twice daily for 14 days in a 21-day cycle, combined with everolimus in 5 separate dose cohorts: 2.5 mg every other day, 2.5 mg daily, 5 mg daily, 7.5 mg daily, and 10 mg daily. A 3+3 design was used. The maximum tolerated dose was based on the dose-limiting toxicity of everolimus plus capecitabine.

RESULTS

A total of 18 patients were enrolled in the present trial. The median age was 58 years. Most had received previous anthracycline (83%) and taxane (94%) therapy. The maximum tolerated dose was everolimus 7.5 mg daily and capecitabine 825 mg/m². The incidence of grade 3 events was low and mainly hematologic in nature. One incident each of grade 4 neutropenia, thrombocytopenia, hyperglycemia, and mucositis occurred. No grade 5 events occurred. The clinical benefit rate was 50%. The median progression-free survival was 196 days, and the median overall survival was 569 days.

CONCLUSION

The all-oral regimen of everolimus with capecitabine is active and well tolerated, with encouraging results for progression-free survival, overall survival, and clinical benefit rate in patients with MBC.

Dose-finding designs for trials of molecularly targeted agents and immunotherapies

Recently, there has been a surge of early phase trials of molecularly targeted agents (MTAs) and immunotherapies. These new therapies have different toxicity profiles compared to cytotoxic therapies. MTAs can benefit from new trial designs that allow inclusion of low-grade toxicities, late-onset toxicities, addition of an efficacy endpoint, and flexibility in the specification of a target toxicity probability. To study the degree of adoption of these methods, we conducted a Web of Science search of articles published between 2008 and 2014 that describe phase 1 oncology trials. Trials were categorized based on the dose-finding design used and the type of drug studied. Out of 1,712 dose-finding trials that met our criteria, 1,591 (92.9%) utilized a rule-based design, and 92 (5.4%; range 2.3% in 2009 to 9.7% in 2014) utilized a model-based or novel design. Over half of the trials tested an MTA or immunotherapy. Among the MTA and immunotherapy trials, 5.8% used model-based methods, compared to 3.9% and 8.3% of the chemotherapy or radiotherapy trials, respectively. While the percentage of trials using novel dose-finding designs has tripled since 2007, the adoption of these designs continues to remain low.

Role of genetic variation in docetaxel-induced neutropenia and pharmacokinetics

Docetaxel is used for treatment of several solid malignancies. In this study, we aimed for predicting docetaxel clearance and docetaxel-induced neutropenia by developing several genetic models. Therefore, pharmacokinetic data and absolute neutrophil counts (ANCs) of 213 docetaxel-treated cancer patients were collected. Next, patients were genotyped for 1936 single nucleotide polymorphisms (SNPs) in 225 genes using the drug-metabolizing enzymes and transporters platform and thereafter split into two cohorts. The combination of SNPs that best predicted severe neutropenia or low clearance was selected in one cohort and validated in the other. Patients with severe neutropenia had lower docetaxel clearance than patients with ANCs in the normal range (P=0.01). Severe neutropenia was predicted with 70% sensitivity. True low clearance (1 s.d.<mean clearance) was identified in 80% of cases. These models however did not reach statistical significance. To improve the predictive value of these models, the addition of non-genetic influencing factors is needed.

Inter-patient variability in docetaxel pharmacokinetics: A review

Docetaxel is a frequently used chemotherapeutic agent in the treatment of solid cancers. Because of the large inter-individual variability (IIV) in the pharmacokinetics (PK) of docetaxel, it is challenging to determine the optimal dose in individual patients in order to achieve optimal efficacy and acceptable toxicity. Despite the established correlation between systemic docetaxel exposure and efficacy, the precise factors influencing docetaxel PK are not yet completely understood. This review article highlights currently known factors that influence docetaxel PK, and focusses on those that are clinically relevant. For example, liver impairment should be taken into account when calculating docetaxel dosages as this may decrease docetaxel clearance. In addition, drug-drug interactions may be of distinct clinical importance when using docetaxel. Particularly, drugs strongly inhibiting CYP3A4 such as ketoconazole should not be concurrently administered without dose modification, as they may decrease the clearance of docetaxel. Gender, castration status, and menopausal status might be of importance as potential factors influencing docetaxel PK. The role of pharmacogenetics in predicting docetaxel PK is still limited, since no polymorphisms of clinical importance have yet been established.

SU2C phase Ib study of paclitaxel and MK-2206 in advanced solid tumors and metastatic breast cancer

BACKGROUND

There is preclinical synergism between taxanes and MK-2206. We aim to determine the maximum tolerated dose, safety, and activity of combining MK-2206 and paclitaxel in metastatic cancer.

METHODS

Patients received weekly doses of paclitaxel at 80mg/m2 on day 1, followed by MK-2206 orally on day 2 escalated at 90mg, 135mg, and 200mg. Treatment continued until progression, excessive toxicity, or patient request. Blood and tissue were collected for pharmacokinetic and pharmacodynamics markers. A cycle consisted of three weeks of therapy. Dose-limiting toxicity (DLT) was defined as unacceptable toxicity during the first cycle. All statistical tests were two-sided.

RESULTS

Twenty-two patients were treated, nine in dose escalation and 13 in dose expansion. Median age was 55 years. Median number of cycles was four. Dose escalation was completed with no DLT. CTCAE Grade 3 or higher adverse events were fatigue (n = 2), rash (n = 2), hyperglycemia (n = 1), and neutropenia (n = 7). Four patients in the expansion phase required MK-2206 dose reduction. Phase II recommended dose was established as paclitaxel 80mg/m2 weekly on day 1, and MK-2206 135mg weekly on day 2. Paclitaxel systemic exposure was similar in the presence or absence of MK-2206. Plasma MK-2206 concentrations were similar to data from previous phase I monotherapy. There was a statistically significant decrease in expression of pAKT S473 (P = .01) and pAKT T308 (P = .002) after therapy. PI3K/AKT/mTOR downregulation in tumor tissues and circulating markers did not correlate with tumor response or clinical benefit. There were five objective responses, and nine patients had stable disease.

CONCLUSION

MK-2206 was well tolerated with paclitaxel. Preliminary antitumor activity was documented.

Parallel phase Ib studies of two schedules of buparlisib (BKM120) plus carboplatin and paclitaxel (q21 days or q28 days) for patients with advanced solid tumors

PURPOSE

Phosphatidylinositol-3-kinase I (PI3K) inhibition sensitizes a wide range of cancer cell lines to platinum/taxane-based chemotherapy. This phase I study combines buparlisib, a pan-class 1A PI3K inhibitor, with two schedules of carboplatin and paclitaxel for patients with advanced solid tumors (ClinicalTrials.gov, NCT01297452).

METHODS

There were two regimens: Group 1 received carboplatin AUC 5 and paclitaxel 175 mg/m(2), on day 1 of a 21-day cycle with pegfilgrastim support; Group 2 received carboplatin AUC 5 (day 1) and paclitaxel 80 mg/m(2) (days 1, 8, and 15) on a 28-day cycle without growth factor support. In both groups, three dose levels of buparlisib were explored: 50, 80, and 100 mg/day. Primary endpoint was to identify recommended phase II doses of buparlisib in both groups.

RESULTS

Thirty subjects enrolled, 16 in Group 1 and 14 in Group 2. The DLTs were elevated alkaline phosphatase (n = 1) and uncomplicated neutropenia (n = 2). The median numbers of cycles were 5 (Group 1) and 6 (Group 2). The MTDs for buparlisib were 100 mg/day in Group 1 and 80 mg/day in Group 2. Among 25 patients with measurable disease, the confirmed objective response rate was 20% (one complete response, four partial responses). Among three patients with known loss of PTEN expression, all derived clinical benefit from treatment.

CONCLUSION

The addition of buparlisib to carboplatin + paclitaxel was well tolerated, and preliminary activity was notable against tumors with loss of PTEN expression.

Phase II multicentered study of low-dose everolimus plus cisplatin and weekly 24-hour infusion of high-dose 5-fluorouracil and leucovorin as first-line treatment for patients with advanced gastric cancer

OBJECTIVE

This phase II trial investigates the efficacy and safety of low-dose everolimus in combination with cisplatin-fluorouracil chemotherapy in patients with advanced gastric cancer.

METHODS

Eligible patients with chemotherapy-naïve advanced gastric cancer received low-dose everolimus (10 mg p.o. on days 1, 8 and 15) plus cisplatin and a weekly 24-hour infusion of high-dose 5-fluorouracil and leucovorin (HDFL) chemotherapy (cisplatin 35 mg/m(2) intravenous infusion for 24 h on days 1 and 8, 5-fluorouracil 2,000 mg/m(2) and leucovorin 300 mg/m(2) intravenous infusion for 24 h on days 1, 8 and 15) every 28 days. The primary endpoint was objective response rate (ORR) according to the Response Evaluation Criteria in Solid Tumors version 1.0.

RESULTS

Forty patients (19 men; 21 women; median age, 54.1 years; range, 33.7-73.3 years) received a median of 6 (range, 1-30; 95% CI, 4.9-8.0) cycles of study treatment. The ORR was 52.5% (21 confirmed partial response). The median progression-free survival and overall survival were 6.9 (95% CI, 4.9-8.4) and 10.5 (95% CI, 8.6-12.3) months, respectively. Most adverse events were mild.

CONCLUSION

Adding low-dose everolimus to cisplatin-HDFL chemotherapy failed to increase the ORR as in a preplanned statistical assumption but may prolong progression-free survival in treatment-naïve advanced gastric cancer patients.

Pneumonitis and pulmonary fibrosis associated with breast cancer treatments

To review the available published data regarding the incidence, mechanisms of pathogenesis, clinical presentations and management of pneumonitis caused by anti-cancer treatments (radiotherapy (RT) and systemic agents) that are included in the guidelines of the treatment of breast cancer (BC) and address the issues on the current grading classification of pneumonitis. A literature search was performed between July and October 2013 using PubMed for papers published from January 1989 to October 2013. Any clinical trial, case report, case series, meta-analysis or systematic review that reported on pulmonary toxicity of any BC therapeutic modality was included (only papers published in English). Most of anticancer treatments currently used in the management of BC may induce some degree of pneumonitis that is estimated to have an incidence of 1-3 %. There is an obvious distinction between chemotherapy- and targeted treatment-related lung toxicity. Moreover, the current classification of pneumonitis needs to be modified as there is a clear diversity in grade 2. As pneumonitis is relatively common and reported as side effect of new anticancer agents, physicians need to be aware of the clinical and radiological manifestations of drug- and RT-induced toxicities in patients with BC. A key recommendation is the subdivision of grade 2 cases to two subgroups. We provide an algorithm, along with real life cases as managed in the breast Unit of Royal Marsden Hospital, with the aim to guide physicians in managing all possible eventualities that may come across in clinical practise.

The emergence of targeted drugs in breast cancer to prevent resistance to endocrine treatment and chemotherapy

INTRODUCTION

Deregulated signaling pathways are associated with resistance to chemotherapy and endocrine treatment, providing a rationale for the implementation of novel targeted therapies in breast cancer therapy. Key molecules targeted therapeutically in ongoing clinical breast cancer trials are phosphoinositide 3-kinase-Akt-mammalian target of rapamycin (mTOR), Src, insulin-like growth factor 1 receptor, heat shock protein-90, histone deacetylases, cyclin-dependent kinases (CDKs), Notch and human epidermal growth factor receptors (HERs).

AREAS COVERED

This review provides an overview of novel targeted agents currently explored in clinical breast cancer trials and registered in ClinicalTrials.gov. The main focus will be on their ability to prevent or reverse endocrine resistance and chemoresistance in breast cancer.

EXPERT OPINION

HER2 targeted agents have extended survival substantially, both in the adjuvant and metastatic setting, pointing to a crucial dependency on this pathway in HER2-amplified breast cancer, including drug resistance reversal. While data on mTOR inhibitors are encouraging and preliminary results on CDK4/6 and Src inhibitors exciting, so far other targeted agents have been of limited benefit when added in concert with conventional therapies. Future clinical trials should systematically explore biomarkers and defects in functional gene cascades to identify relevant biological mechanisms to be targeted therapeutically in breast cancer.

Everolimus: a new hope for patients with breast cancer

BACKGROUND

Breast cancer cells can develop resistance to standard hormonal treatment and chemotherapy with the activation of the mTOR pathway; this is supported by results of preclinical and clinical studies. In clinical trials, the addition of everolimus to hormonal treatment or anti-HER2 treatment improved the outcomes of breast cancer patients. The aim of this review is to discuss the efficacy and safety data of everolimus in all categories of breast cancer in recent published studies.

SCOPE

Everolimus showed positive results in clinical studies. A literature search was made from PubMed, ASCO and San Antonio Breast Cancer Symposium Meeting abstracts by using the following search key words: 'everolimus', 'RAD001', 'mTOR inhibitor', 'breast cancer' 'endocrine therapy resistance' and 'HER-2 targeted therapies'. The last search was on June 10, 2013. The most important limitation of our review is that most of the data on everolimus rely on phase I and II trials.

FINDINGS

Preclinical studies showed that mTOR activation can be the responsible mechanism in all subgroups of breast cancer. Results of both the TAMRAD and BOLERO-2 studies have showed that mTOR inhibition in combination with endocrine therapy can be a new treatment strategy for MBC patients who are resistant to aromatase inhibitors. In the BOLERO-2 study, time to deterioration in health-related quality of life was also significantly higher in the everolimus and exemestane arm compared to the exemestane plus placebo arm. The recently completed BOLERO-3 study showed that mTOR inhibition in combination with trastuzumab plus vinorelbine treatment significantly improved PFS compared to trastuzumab plus vinorelbine alone in trastuzumab-resistant MBC patients.

CONCLUSION

Recent trials have shown that everolimus has produced promising anti-tumor activity in combination with trastuzumab in HER2-positive metastatic breast cancer and in combination with exemestane in patients with hormone-receptor-positive metastatic breast cancer who had recurrence or progression while receiving a nonsteroidal aromatase inhibitor. Results of ongoing studies with everolimus show evidence that using everolimus in earlier stages of the disease, namely in the adjuvant and neoadjuvant settings, could be benefical.

Everolimus: side effect profile and management of toxicities in breast cancer

Everolimus is an orally available inhibitor of the mammalian target of rapamycin (mTOR), which has been approved in combination with exemestane for hormone receptor-positive (HR) breast cancer after failure of treatment with non-steroidal aromatase inhibitors. Everolimus is generally very well tolerated with most common side effects including stomatitis, rash, fatigue, hyperglycemia, hyperlipidemia, and myelosuppression. Most of these side effects are mild and resolve with dose interruptions or dose reductions. Symptomatic non-infectious pneumonitis is a relatively uncommon class effect of mTOR inhibitors, which can be life threatening. Given the efficacy of everolimus in HR-positive metastatic breast cancer, it is crucial for physicians to recognize toxicities related to everolimus and start timely interventions. This review will focus on the adverse events reported with everolimus in breast cancer trials and will provide practical guidelines for the management of these adverse events.

A phase 1 study of everolimus plus docetaxel plus cisplatin as induction chemotherapy for patients with locally and/or regionally advanced head and neck cancer

BACKGROUND

Activation of the phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway is common in head and neck cancers, and it has been demonstrated that inhibition of mTOR complex 1 sensitizes cell lines to platinum and taxane chemotherapy. The authors conducted a phase 1 study to evaluate the addition of oral everolimus to cisplatin and docetaxel as induction chemotherapy for head and neck cancer.

METHODS

In this single-institution phase 1 study, 3 doses of daily everolimus were explored: 5 mg daily, 7.5 mg daily (administered as 5 mg daily alternating with 10 mg daily), and 10 mg daily of each 21-day cycle. Cisplatin and docetaxel doses were fixed (both were 75 mg/m(2) on day 1 of 21-day cycle) at each dose level with pegfilgrastim support. A standard 3 + 3 dose-escalation plan was used. After induction, patients were removed from protocol.

RESULTS

Eighteen patients were enrolled (15 men, 3 women), and their median Karnofsky performance status was 90. The most common toxicities were hyperglycemia, low hemoglobin, fatigue, and thrombocytopenia. Dose-limiting toxicities (DLTs) were neutropenic fever (1 event at dose level 2, 2 events at dose level 3), and all patients recovered fully from these DLTs. The maximum tolerated dose was exceeded at dose level 3. The progression-free survival rate at 1 year was 87.5% (95% confidence interval, 56.8%-96.7%); and, at 2 years, it was 76.6% (95% confidence interval, 41.2%-92.3%). Activating PI3K catalytic subunit α (PIK3CA) gene mutations were identified in 2 human papillomavirus-associated oropharyngeal cancers.

CONCLUSIONS

The phase 2 recommended dose was 7.5 mg daily for everolimus plus cisplatin and docetaxel (both at 75 mg/m(2) on day 1 of a 21-day cycle) given with pegfilgrastim support.

mTOR inhibitors in breast cancer: a systematic review

PI3K/AKT/mTOR pathway is a crucial mediator of tumor progression. As the PI3K/Akt pathway is heavily deregulated in breast cancer, the application of mTOR inhibitors in breast cancer patients seems warranted. This is the first systematic review according to PRISMA guidelines to synthesize all available data of mTOR inhibitors in all subcategories of breast cancer. The search strategy retrieved 16 studies evaluating everolimus (1492 patients), seven studies examining temsirolimus (1245 patients), one study evaluating sirolimus (400 patients) and two studies evaluating MKC-1 (60 patients). The Breast Cancer Trials of Oral Everolimus-2 (BOLERO-2) study has marked a turning point in the evaluation of everolimus in the treatment of estrogen receptor positive breast cancer. Given the positive results, everolimus has entered NCCN 2012 guidelines, and its approval of its combination with exemestane by FDA and EMA is imminent. In addition, the promising antitumor activity and long-term disease control further suggest that mTOR inhibition with everolimus may provide an avenue for achieving long-lasting benefit from trastuzumab-based therapy in HER2-positive patients. Regarding temsirolimus, it seems that the agent may play, in the future, a role in the treatment of metastatic breast cancer; importantly, however, there is an unmet need to find its optimal target subpopulation.

A phase I study of temsirolimus plus carboplatin plus paclitaxel for patients with recurrent or metastatic (R/M) head and neck squamous cell cancer (HNSCC)

PURPOSE

The mammalian target of rapamycin complex 1 (mTORC1) is aberrantly activated in many head and neck squamous cell carcinomas (HNSCCs). This phase I study combines the mTORC1 inhibitor temsirolimus with carboplatin and paclitaxel.

METHODS

This was a single institution phase I study for patients with R/M HNSCC with a standard 3 + 3 design. Three doses of temsirolimus were planned: 15, 20, and 25 mg. Due to excessive toxicity with the original study regimen, the protocol was amended to carboplatin AUC 1.5, paclitaxel 80 mg/m(2), and temsirolimus (according to dose escalation plan), all on days 1 and 8 of a 21-day cycle.

RESULTS

18 patients (14 male, 4 female) enrolled, with median age 56 years (range 33-78). The most common toxicities were anemia, leukopenia, thrombocytopenia, and hyperglycemia. Among all patients treated, the confirmed objective partial response (cPR) rate was 22 %. DLT was not exceeded among 6 patients treated at dose level 3 of the revised protocol, and 4 of 6 subjects treated at this dose level had cPRs.

CONCLUSION

The phase II recommended regimen is temsirolimus 25 mg, carboplatin AUC 1.5, and paclitaxel 80 mg/m(2), all on days 1 and 8 of a 21-day cycle. A phase II study of this regimen in R/M HNSCC is ongoing.