The central role played by the class IA phosphatidylinositol-3-kinase (PI3K) signaling node in human cancer is highlighted in the multiple mechanisms by which these signals become dysregulated. Many ...studies suggest that constitutive PI3K activation in human cancer contributes to drug resistance, including targeted agents and standard cytotoxic therapy. The combination of activation mechanisms and the multiple downstream cascades that emanate from the PI3K node contributes to the difficulty in measuring PI3K activation as a biomarker. Although many agents suppress the pathway in models, the challenge remains to translate this biology into a patient selection strategy (i.e., identify patients with “PI3K activated” tumors) and subsequently link this biomarker definition to drug responses in patients. The various genetic and epigenetic lesions resulting in pathway activation necessitate combined approaches using genetic, genomic, and protein biomarkers to accurately characterize “PI3K activated” tumors. Such a combined approach to pathway status can be assessed using a statistical stratification of patients in a randomized trial into “pathway on” and “pathway off” subsets to compare the treatment effect in each arm. Instead of considering individual biomarkers for their predictive ability, this strategy proposes the use of a collection of biomarkers to identify a specific “pathway on” patient population predicted to have clinical benefit from a pathway inhibitor. Here, we review the current understanding of the mechanisms of PI3K activation in breast cancer and discuss a pathway-based approach using PI3K as a predictive biomarker in clinical development, which is currently in use in a global phase 3 setting.
To characterize folate receptor alpha (FRα) expression in archival and fresh biopsy tumor samples from relapsed ovarian cancer patients.
Patients with ovarian tumors amenable to biopsy were eligible ...to enroll. Eligibility included a minimum requirement of FRα positivity in archival tumor samples (≥25% of cells with ≥2+ staining intensity). Patients received mirvetuximab soravtansine at 6mg/kg once every 3weeks. Core needle biopsies were collected before and after treatment and FRα levels assessed by immunohistochemistry. Descriptive statistics were used to summarize the association between receptor expression and response.
Twenty-seven heavily pre-treated patients were enrolled. Six individuals (22%) did not have evaluable pre-treatment biopsies due to insufficient tumor cells. The concordance of FRα expression in archival and biopsy tissues was 71%, and no major shifts in receptor expression were seen in matched pre- and post-treatment biopsy samples. Adverse events were generally mild (≤grade 2) with keratopathy (48%), fatigue (44%), diarrhea, and blurred vision (each 37%) being the most common treatment-related toxicities. The confirmed objective response rate (ORR) was 22%, including two complete responses and four partial responses. Superior efficacy measures were observed in the subset of patients with the highest FRα levels (ORR, 31%; progression-free survival, 5.4months).
Concordance of FRα expression in biopsy versus archival tumor samples suggests that archival tissue can reliably identify patients with receptor-positive tumors and is appropriate for patient selection in mirvetuximab soravtansine clinical trials. Regardless of the tissue source analyzed, higher FRα expression was associated with greater antitumor activity.
•Folate receptor alpha (FRα) is a rational therapeutic target in ovarian cancer.•FRα expression was compared in paired archival and fresh biopsy tumor tissues.•71% concordance seen between samples obtained from relapsed ovarian patients.•Archival tissue can reliably identify patients with receptor-positive tumors.•Higher FRα expression was associated with greater antitumor activity in this trial.
Mirvetuximab soravtansine-gynx (MIRV), a first-in-class antibody-drug conjugate targeting folate receptor α (FRα), is approved for the treatment of platinum-resistant ovarian cancer in the United ...States.
We conducted a phase 3, global, confirmatory, open-label, randomized, controlled trial to compare the efficacy and safety of MIRV with the investigator's choice of chemotherapy in the treatment of platinum-resistant, high-grade serous ovarian cancer. Participants who had previously received one to three lines of therapy and had high FRα tumor expression (≥75% of cells with ≥2+ staining intensity) were randomly assigned in a 1:1 ratio to receive MIRV (6 mg per kilogram of adjusted ideal body weight every 3 weeks) or chemotherapy (paclitaxel, pegylated liposomal doxorubicin, or topotecan). The primary end point was investigator-assessed progression-free survival; key secondary analytic end points included objective response, overall survival, and participant-reported outcomes.
A total of 453 participants underwent randomization; 227 were assigned to the MIRV group and 226 to the chemotherapy group. The median progression-free survival was 5.62 months (95% confidence interval CI, 4.34 to 5.95) with MIRV and 3.98 months (95% CI, 2.86 to 4.47) with chemotherapy (P<0.001). An objective response occurred in 42.3% of the participants in the MIRV group and in 15.9% of those in the chemotherapy group (odds ratio, 3.81; 95% CI, 2.44 to 5.94; P<0.001). Overall survival was significantly longer with MIRV than with chemotherapy (median, 16.46 months vs. 12.75 months; hazard ratio for death, 0.67; 95% CI, 0.50 to 0.89; P = 0.005). During the treatment period, fewer adverse events of grade 3 or higher occurred with MIRV than with chemotherapy (41.7% vs. 54.1%), as did serious adverse events of any grade (23.9% vs. 32.9%) and events leading to discontinuation (9.2% vs. 15.9%).
Among participants with platinum-resistant, FRα-positive ovarian cancer, treatment with MIRV showed a significant benefit over chemotherapy with respect to progression-free and overall survival and objective response. (Funded by ImmunoGen; MIRASOL ClinicalTrials.gov number, NCT04209855.).
Aims
Mirvetuximab soravtansine is a first‐in‐class antibody–drug conjugate recently approved for the treatment of folate receptor‐α positive ovarian cancer. The aim of this study was to develop a ...population pharmacokinetic model to describe the concentration–time profiles of mirvetuximab soravtansine, the payload (DM4) and a metabolite (S‐methyl‐DM4).
Methods
Mirvetuximab soravtansine was administered intravenously from 0.15 to 7 mg/kg to 543 patients with predominantly platinum‐resistant ovarian cancer in 3 clinical studies, and the plasma drug concentrations were analysed using a nonlinear mixed‐effects modelling approach. Stepwise covariate modelling was performed to identify covariates.
Results
We developed a semi‐mechanistic population pharmacokinetic model that included linear and nonlinear routes for the elimination of mirvetuximab soravtansine and a target compartment for the formation and disposition of the payload and metabolite in tumour cells. The clearance and volume of the central compartment were 0.0153 L/h and 2.63 L for mirvetuximab soravtansine, 8.83 L/h and 3.67 L for DM4, and 2.04 L/h and 6.3 L for S‐methyl‐DM4, respectively. Body weight, serum albumin and age were identified as statistically significant covariates. Exposures in patients with renal or hepatic impairment and who used concomitant cytochrome P450 (CYP) 3A4 inhibitors were estimated.
Conclusion
There is no need for dose adjustment due to covariate effects for mirvetuximab soravtansine administered at the recommended dose of 6 mg/kg based on adjusted ideal body weight. Dose adjustment is not required for patients with mild or moderate renal impairment, mild hepatic impairment, or when concomitant weak and moderate CYP3A4 inhibitors are used.
Abstract Purpose A phase II study of temsirolimus was conducted in children and adolescents with high-grade glioma, neuroblastoma or rhabdomyosarcoma. Patients and methods Temsirolimus 75 mg/m2 was ...administered once weekly until disease progression or intolerance. Using the Simon 2-stage design, further enrolment in each disease cohort required ⩾2 objective responses within the first 12 weeks for the first 12 evaluable patients (those who received ⩾3 temsirolimus doses). Results Fifty-two heavily pretreated patients with relapsed (12%) or refractory (88%) disease, median age 8 years (range 1–21 years), were enroled and treated. One patient with neuroblastoma achieved confirmed partial response within the first 12 weeks; thus, none of the 3 cohorts met the criterion for continued enrolment. Disease stabilisation at week 12 was observed in 7 of 17 patients (41%) with high-grade glioma (5 diffuse pontine gliomas, 1 glioblastoma multiforme and 1 anaplastic astrocytoma), 6 of 19 (32%) with neuroblastoma and 1 of 16 (6%) with rhabdomyosarcoma (partial response confirmed at week 18). In the three cohorts, median duration of stable disease or better was 128, 663 and 75 d, respectively. The most common treatment-related adverse events were thrombocytopaenia, hyperlipidaemia and aesthenia. Pharmacokinetic findings were similar to those observed in adults. Conclusions Temsirolimus administered weekly at the dose of 75 mg/m2 did not meet the primary objective efficacy threshold in children with high-grade glioma, neuroblastoma or rhabdomyosarcoma; however, meaningful prolonged stable disease merits further evaluation in combination therapy.
Purpose
Exploratory subgroup analyses from the phase 3 global advanced renal cell carcinoma (ARCC) trial were conducted to assess the influence of tumor histology on outcome of patients treated with ...temsirolimus (Torisel™) or interferon-α (IFN).
Patients and methods
Patients with ARCC including clear cell and other types such as papillary and chromophobe histologies received either IFN (3 million units MU subcutaneously three times weekly, escalating to 18 MU) or temsirolimus (25 mg intravenously weekly).
Results
Approximately 80% of patients had clear cell and 20% of patients had other histologies, the majority of which were papillary. Patients with clear cell and other RCC histologies, treated with temsirolimus, demonstrated comparable median overall and progression-free survival. In contrast, patients with other RCC histologies, treated with IFN, demonstrated shorter median overall and progression-free survival than patients with clear cell RCC. Hazard ratios for death for treatment with temsirolimus versus IFN were less than 1 for patients regardless of tumor histology. For patients treated with temsirolimus, 59% with clear cell and 68% with other RCC histologies experienced tumor reductions. For patients treated with IFN, 35% with clear cell and 14% with other RCC histologies had tumor reductions. However, temsirolimus did not appear to improve the objective response rate compared to IFN. Temsirolimus resulted in a superior clinical benefit rate compared with IFN, regardless of tumor histology.
Conclusion
Temsirolimus appears to be efficacious in patients with clear cell and non-clear cell histologies and can, therefore, be used for the treatment of all types of RCC.
Clinical trials have validated the importance of mammalian target of rapamycin (mTOR) as a therapeutic target in patients with advanced renal cell carcinoma (RCC). The TORC1 complex controls ...translation of key proteins involved in cell proliferation and regulates the expression and stability of hypoxia-inducible factor (HIF)-1alpha. Temsirolimus, the first mTOR inhibitor approved for treatment of advanced RCC, has demonstrated significantly longer overall survival (hazard ratio for death, 0.73; 95% confidence interval, 0.58-0.92, P = .008) and progression-free survival (P <.001) compared with interferon alfa (IFN) for patients with poor prognostic features. Median progression-free survival durations were 3.8 and 1.9 months, respectively, for patients treated with temsirolimus or IFN, and median overall survivals were 10.9 and 7.3 months, respectively. Exploratory analyses indicate that temsirolimus benefits those patients with metastatic RCC and multiple adverse prognostic factors regardless of tumor histology or nephrectomy status. Most adverse events that occur in patients receiving temsirolimus can be managed medically (eg, hyperglycemia, hyperlipidemia) or addressed by supportive measures (eg, stomatitis, rash). Although development of symptomatic pneumonitis is rare, monitoring is recommended. Temsirolimus is now considered an important first-line treatment option for patients with advanced RCC and multiple factors predictive of short survival. Current trials are investigating the use of temsirolimus in sequence or in combination with other targeted agents to further improve outcomes.
Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy in adult women. The most easily identifiable riskfactor is a strong family history of either ovarian or breast cancer; that ...may indicate the presence of an inherited germ-line mutation in either BRCA-1 or BRCA-2. Common symptoms, such as abdominal bloating and early satiety, indicate more advanced disease, involving the upper abdomen and present in approximately 70% of patients at the time of diagnosis. Physical examination often reveals the presence of a pelvic mass, which is best evaluated by transvaginal ultrasound (TVU) for confirmation. Exploratory laparotomy is required for histologic confirmation, staging and tumor debulking and should be performed by a surgeon trained in these aspects of ovarian cancer management. Patients with early-stage disease, limited to the ovary or pelvis (stages I and II, respectively), have survival in the 80-95% range, whereas the survival of patients with disease involving the upper abdomen or beyond (stages III and IV, respectively) is 10-30%. Because of the propensity of EOC to spread beyond the confines of the ovary, the majority of patients will require postoperative chemotherapy in an attempt to eradicate residual disease. For selected patients with early-stage disease, confined to the ovary, such as those with well-differentiated, completely encapsulated tumors (e.g., stage IA, grade 1), no further treatment is necessary in view of excellent survival after surgery alone. For patients with higher-risk early-stage disease (e.g., those with pelvic extension, capsular rupture or involvement, positive washings, ascites or high-grade lesions) and for patients with advanced-stage disease (stages III and IV), postoperative combination chemotherapy with a taxane and platinum combination is the standard of care. Such treatment is capable of inducing responses in > 70% of patients with residual EOC and is also capable of prolonging both disease-free and overall survival. Unfortunately, despite an initial response to chemotherapy in the majority of patients, relapse is afrequent problem and is often detected by a rise in the serum tumor marker CA-125 in the absence of symptoms or signs of disease by physical examination or radiographic studies. In such cases, a hormonal maneuver is oftentimes considered in order to avoid the toxic effects of chemotherapy when the patient is asymptomatic and the goal of treatment is largely palliation, although eventually the development of clinical progression mandates the institution of second-line chemotherapy. If the treatment-free interval is > 6 months from the completion of first-line treatment, rechallenge with platinum-based chemotherapy is a reasonable first step. For those patients who develop resistance to second-line platinum or who have difficulty tolerating this agent, multiple other options are available for relapse management, including liposomal doxorubicin, topotecan, gemcitabine and etoposide per os. Eventually the disease becomes resistant to multiple chemotherapy agents, and reorienting management toward supportive care and pain control is necessary. Ongoing efforts to identify more effective multiagent first-line regimens, to develop more effective strategies for early detection and to incorporate agents with novel mechanisms of action, such as antiangiogenesis compounds, hold promise.
Temsirolimus, an inhibitor of mammalian target of rapamycin (mTOR), has anti-tumor activity in patients with relapsed or refractory mantle cell lymphoma (MCL) and other mature lymphoid neoplasms. ...mTOR is an intracellular kinase that controls the mRNA translation of many proteins (eg, cyclin D1) that can act as oncogenes and contribute to lymphomagenesis. Characterized by overexpression of cyclin D1, MCL was identified as a disease that might be susceptible to mTOR inhibition. When single-agent temsirolimus was explored in two phase II studies for treatment of patients with relapsed or refractory MCL, it demonstrated anti-tumor activity, with overall response rates of 38% and 41%. Subsequently, a three-arm, randomized phase III trial was conducted to compare two dosing regimens of temsirolimus with investigator's choice of therapy for heavily pretreated patients with relapsed or refractory MCL (N = 162; randomized 1:1:1). Once-weekly intravenous temsirolimus 175 mg for 3 weeks followed by 75 mg once weekly (175/75) significantly improved progression-free survival (hazard ratio = 0.44; P = .0009) versus investigator's choice therapy. Median progression-free survival durations were 4.8 and 1.9 months, respectively. The objective response rates were 22% in the 175/75 group and 2% in the investigator's choice group (P = .0019). For patients receiving temsirolimus, the most frequent grade 3 or 4 adverse events were thrombocytopenia, anemia, neutropenia, and asthenia. The results of this trial established a recommended clinical dose for temsirolimus monotherapy in patients with relapsed or refractory MCL and validated the importance of mTOR in the pathogenesis of advanced MCL. Objective responses also have been reported for other mature B-cell neoplasms (eg, diffuse large B-cell lymphoma or follicular lymphoma) in the phase II setting. Temsirolimus as monotherapy or in combination with other active agents warrants further investigation for treatment of MCL and other non-Hodgkin lymphomas.
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