PIK3CA mutations in plasma circulating tumor DNA predict survival and treatment outcomes in patients with advanced cancers

Background

Oncogenic mutations in PIK3CA are prevalent in diverse cancers and can be targeted with inhibitors of the phosphoinositide-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway. Analysis of circulating tumor DNA (ctDNA) provides a minimally invasive approach to detect clinically actionable PIK3CA mutations.

Patients and methods

We analyzed PIK3CA hotspot mutation frequency by droplet digital PCR (QX 200; BioRad) using 16 ng of unamplified plasma-derived cell-free DNA from 68 patients with advanced solid tumors (breast cancer, n = 41; colorectal cancer, n = 13; other tumor types, n = 14). Results quantified as variant allele frequencies (VAFs) were compared with previous testing of archival tumor tissue and with patient outcomes.

Results

Of 68 patients, 58 (85%) had PIK3CA mutations in tumor tissue and 43 (74%) PIK3CA mutations in ctDNA with an overall concordance of 72% (49/68, κ = 0.38). In a subset analysis, which excluded samples from 26 patients known not to have disease progression at the time of sample collection, we found an overall concordance of 91% (38/42; κ = 0.74). PIK3CA-mutated ctDNA VAF of ≤8.5% (5% trimmed mean) showed a longer median survival compared with patients with a higher VAF (15.9 versus 9.4 months; 95% confidence interval 6.7-17.1 months; P = 0.014). Longitudinal analysis of ctDNA in 18 patients with serial plasma collections (range 2-22 time points, median 5) showed that those with a decrease in PIK3CA VAF had a longer time to treatment failure (TTF) compared with patients with an increase or no change (10.7 versus 2.6 months; P = 0.048).

Conclusions

Detection of PIK3CA mutations in ctDNA is concordant with testing of archival tumor tissue. Low quantity of PIK3CA-mutant ctDNA is associated with longer survival and a decrease in PIK3CA-mutant ctDNA on therapy is associated with longer TTF.

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Testing for PIK3CA mutations in ctDNA is concordant with testing of tumor tissue.

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High PIK3CA-mutant abundance in ctDNA was associated with shorter survival.

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Increasing PIK3CA-mutant abundance in serial blood samples was associated with shorter TTF.

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Longitudinal monitoring of PIK3CA-mutant ctDNA tracked with cancer clinical course.

Targeted methylation sequencing of plasma cell-free DNA for cancer detection and classification

Background

Targeted methylation sequencing of plasma cell-free DNA (cfDNA) has a potential to expand liquid biopsies to patients with tumors without detectable oncogenic alterations, which can be potentially useful in early diagnosis.

Patients and methods

We developed a comprehensive methylation sequencing assay targeting 9223 CpG sites consistently hypermethylated according to The Cancer Genome Atlas. Next, we carried out a clinical validation of our method using plasma cfDNA samples from 78 patients with advanced colorectal cancer, non-small-cell lung cancer (NSCLC), breast cancer or melanoma and compared results with patients' outcomes.

Results

Median methylation scores in plasma cfDNA samples from patients on therapy were lower than from patients off therapy (4.74 versus 85.29; P = 0.001). Of 68 plasma samples from patients off therapy, methylation scores detected the presence of cancer in 57 (83.8%), and methylation-based signatures accurately classified the underlying cancer type in 45 (78.9%) of these. Methylation scores were most accurate in detecting colorectal cancer (96.3%), followed by breast cancer (91.7%), melanoma (81.8%) and NSCLC (61.1%), and most accurate in classifying the underlying cancer type in colorectal cancer (88.5%), followed by NSCLC (81.8%), breast cancer (72.7%) and melanoma (55.6%). Low methylation scores versus high were associated with longer survival (10.4 versus 4.4 months, P < 0.001) and longer time-to-treatment failure (2.8 versus 1.6 months, P = 0.016).

Conclusions

Comprehensive targeted methylation sequencing of 9223 CpG sites in plasma cfDNA from patients with common advanced cancers detects the presence of cancer and underlying cancer type with high accuracy. Methylation scores in plasma cfDNA correspond with treatment outcomes.

Retreatment with anti-EGFR based therapies in metastatic colorectal cancer: impact of intervening time interval and prior anti-EGFR response

BACKGROUND

This retrospective study aims to investigate the activity of retreatment with anti-EGFR-based therapies in order to explore the concept of clonal evolution by evaluating the impact of prior activity and intervening time interval.

METHODS

Eighty-nine KRAS exon 2-wild-type metastatic colorectal patients were retreated on phase I/II clinical trials containing anti-EGFR therapies after progressing on prior cetuximab or panitumumab. Response on prior anti-EGFR therapy was defined retrospectively per physician-records as response or stable disease ≥6 months. Multivariable statistical methods included a multiple logistic regression model for response, and Cox proportional hazards model for progression-free survival.

RESULTS

Retreatment anti-EGFR agents were cetuximab (n = 76) or cetuximab plus erlotinib (n = 13). The median interval time between prior and retreatment regimens was 4.57 months (range: 0.46-58.7). Patients who responded to the prior cetuximab or panitumumab were more likely to obtain clinical benefit to the retreatment compared to the non-responders in both univariate (p = 0.007) and multivariate analyses (OR: 3.38, 95 % CI: 1.27, 9.31, p = 0.019). The clinical benefit rate on retreatment also showed a marginally significant association with interval time between the two anti-EGFR based therapies (p = 0.053). Median progression-free survival on retreatment was increased in prior responders (4.9 months, 95 % CI: 3.6, 6.2) compared to prior non-responders (2.5 months, 95 % CI, 1.58, 3.42) in univariate (p = 0.064) and multivariate analysis (HR: 0.70, 95 % CI: 0.43-1.15, p = 0.156).

CONCLUSION

Our data lends support to the concept of clonal evolution, though the clinical impact appears less robust than previously reported. Further work to determine which patients benefit from retreatment post progression is needed.

Challenges in initiating and conducting personalized cancer therapy trials: perspectives from WINTHER, a Worldwide Innovative Network (WIN) Consortium trial

Advances in 'omics' technology and targeted therapeutic molecules are together driving the incorporation of molecular-based diagnostics into the care of patients with cancer. There is an urgent need to assess the efficacy of therapy determined by molecular matching of patients with particular targeted therapies. WINTHER is a clinical trial that uses cutting edge genomic and transcriptomic assays to guide treatment decisions. Through the lens of this ambitious multinational trial (five countries, six sites) coordinated by the Worldwide Innovative Networking Consortium for personalized cancer therapy, we discovered key challenges in initiation and conduct of a prospective, omically driven study. To date, the time from study concept to activation has varied between 19 months at Gustave Roussy Cancer Campus in France to 30 months at the Segal Cancer Center, McGill University (Canada). It took 3+ years to be able to activate US sites due to national regulatory hurdles. Access to medications proposed by the molecular analysis remains a major challenge, since their availability through active clinical trials is highly variable over time within sites and across the network. Rules regarding the off-label use of drugs, or drugs not yet approved at all in some countries, pose a further challenge, and many biopharmaceutical companies lack a simple internal mechanism to supply the drugs even if they wish to do so. These various obstacles should be addressed to test and then implement precision medicine in cancer.

Phase I study of pazopanib and vorinostat: a therapeutic approach for inhibiting mutant p53-mediated angiogenesis and facilitating mutant p53 degradation

BACKGROUND

We carried out a phase I trial of the vascular endothelial growth factor inhibitor pazopanib and the histone deacetylase inhibitor vorinostat to determine the safety and efficacy. Because these agents are known to target factors activated by TP53 mutation and facilitate mutant p53 degradation, a subgroup analysis may be interesting in patients with TP53 mutant malignancies.

PATIENTS AND METHODS

Patients with advanced solid tumors (n = 78) were enrolled following a 3 + 3 design, with dose expansion for those with responsive tumors. Hotspot TP53 mutations were tested when tumor specimens were available.

RESULTS

Adverse events of ≥grade 3 included thrombocytopenia, neutropenia, fatigue, hypertension, diarrhea and vomiting. Overall, the treatment produced stable disease for at least 6 months or partial response (SD ≥6 months/PR) in 19% of the patients, median progression-free survival (PFS) of 2.2 months, and median overall survival (OS) of 8.9 months. In patients with detected hotspot TP53 mutant advanced solid tumors (n = 11), the treatment led to a 45% rate of SD ≥6 months/PR (1 PR and 3 SD ≥6 months), median PFS of 3.5 months, and median OS of 12.7 months, compared favorably with the results for patients with undetected hotspot TP53 mutations (n = 25): 16% (1 PR and 3 SD ≥6 months, P = 0.096), 2.0 months (P = 0.042), and 7.4 months (P = 0.1), respectively.

CONCLUSION

The recommended phase II dosage was oral pazopanib at 600 mg daily plus oral vorinostat at 300 mg daily. The preliminary evidence supports further evaluation of the combination in cancer patients with mutated TP53, especially in those with metastatic sarcoma or metastatic colorectal cancer.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov, NCT01339871.

The prognostic significance of left ventricular ejection fraction in patients with advanced cancer treated in phase I clinical trials

BACKGROUND

New targeted agents may cause acute cardiac events. The purpose of our study was to investigate the incidence and the prognostic significance of left ventricular ejection fraction (LVEF) in phase I trials.

PATIENTS AND METHODS

Between October 2008 and September 2011, the records of 1166 consecutive patients with advanced cancer treated in the Phase I Clinic who underwent echocardiography were retrospectively reviewed.

RESULTS

Most of the patients were White (78%), and the most common tumor types were colorectal cancer and melanoma. Of 1166 patients, 177 (15.2%) patients had an LVEF of <50%. No difference in overall survival (OS) between patients with LVEF ≥ 50% and patients with LVEF < 50% was seen (median OS 7.4 versus 7.0 months, P = 0.84). Patients with LVEF ≤ 35% had shorter survival compared with those with LVEF between 35% and 50% (median 4.2 versus 8.0 months; P = 0.005). In multivariate analysis of patients with LVEF < 50%, independent factors predicting longer survival were LVEF > 35%, ≤2 prior systemic therapies, ≤2 metastatic sites, and normal lactate dehydrogenase and albumin levels.

CONCLUSION

Echocardiography would improve patient selection for enrollment in phase I clinical trials. These data suggest that it is safe to treat patients with LVEF between 35% and 50%.

First-in-human study of pbi-05204, an oleander-derived inhibitor of akt, fgf-2, nf-κΒ and p70s6k, in patients with advanced solid tumors

BACKGROUND

PBI-05204, a Nerium oleander extract (NOE) containing the cardiac glycoside oleandrin, inhibits the α-3 subunit of Na-K ATPase, as well as FGF-2 export, Akt and p70S6K, hence attenuating mTOR activity. This first-in-human study determined the safety, pharmacokinetics (PK) and pharmacodynamics (PD) of PBI-05204 in patients with advanced cancer. Methods Forty-six patients received PBI-05204 by mouth for 21 of 28 days (3 + 3 trial design). Dose was escalated 100% using an accelerated titration design until grade 2 toxicity was observed. Plasma PK and mTOR effector (p70S6K and pS6) protein expressions were evaluated. Results Dose-limiting toxicities (grade 3 proteinuria, fatigue) were observed at dose level 8 (0.3383 mg/kg/day). Common possible drug-related adverse were fatigue (26 patients, 56.5%), nausea (19 patients, 41.3%) and diarrhea (15 patients, 32.6 %). Electrocardiogram monitoring revealed grade 1 atrioventricular block (N = 10 patients) and grade 2 supraventricular tachycardia (N = 1). The MTD was DL7 (0.2255 mg/kg) where no toxicity of grade ≥ 3 was observed in seven patients treated. Seven patients (15%) had stable disease > 4 months. Mean peak oleandrin concentrations up to 2 ng/mL were achieved, with area under the curves 6.6 to 25.5 μg/L*hr and a half-life range of 5-13 h. There was an average 10% and 35% reduction in the phosphorylation of Akt and pS6 in PBMC samples in 36 and 32 patients, respectively, tested between predose and 21 days of treatment. Conclusions PBI-05204 was well tolerated in heavily pretreated patients with advanced solid tumors. The recommended Phase II dose is 0.2255 mg/kg/day.

Abstract P1-08-18: PIK/AKT/MTOR pathway activation in triple negative breast cancer and outcomes with matched therapy in phase I clinical trials: Response in both patients with and without direct molecular alterations

Introduction

The PI3K/AKT/MTOR pathway is a known driver in triple negative breast cancers (TNBC). We analyzed patients with TNBC seen in our Phase I clinic including molecular subtyping and correlation with response to therapies targeting the PI3K/AKT/mTOR pathway.

Methods

Patients with advanced TNBC [negative (&lt;1%) expression for estrogen and progesterone receptors and negative Her 2 (&lt;/ = 1+ by IHC or non-amplified by FISH)] whose tumors had undergone molecular profiling (including PIK3CA/PTEN mutation analysis and/or PTEN immunohistochemistry (IHC)). We evaluated sequential patients seen in the Phase I clinic at M.D. Anderson Cancer Center treated on at least one Phase I clinical trial and correlated molecular status with clinical outcomes on therapy. Molecular profiling methods including hotspot analysis, next generation sequencing and IHC.

Results

Forty-four patients (median age 56, range 27-81; all female; white race76%) with a median of 2 (0-7) prior therapies (40% received ≥3 prior systemic therapies) and 2 metastatic sites (range, 1-6) were included. Histology: invasive ductal carcinoma 29 (66%), metaplastic 12 (27%), other 3 (7%). Nine out of 42 patients tested (19%) had a PIK3CA mutation and, 11 out of 33 patients tested (33%) demonstrated PTEN loss on IHC and 2 patients had PTEN mutations. Altogether, 21 out of 44 patients had at least one alteration in the PI3K/AKT/mTOR pathway. Sixteen of these 21 patients received “matched” therapy consisting of at least one agent targeting the PI3K/AKT/mTOR pathway. Four out of 16 patients (25%) with at least one molecular alteration, treated with one or more regimens containing at least one agent targeting the PI3K/AKT/mTOR pathway (“matched” therapy), demonstrated clinical benefit: complete response (CR) (N = 1)/partial response (PR) (N = 1)/stable disease ≥ 6 months (SD) (N = 2). Similarly, three out of 12 patients (25%) who did not demonstrate a direct molecular alteration in the PI3K/AKT/mTOR pathway and who were treated with PI3K-directed therapy, had either CR (N = 1)/PR (N = 1)/SD ≥ 6 months (N = 1). Twenty-eight patients received PI3K/AKT/mTOR pathway directed therapy yielding CR (N = 2), PR (N = 3) and CR/PR/ SD ≥ 6 months (N = 1) while those who received other therapies had CR (N = 0), PR (N = 1) and CR/PR/SD&gt;6mo (N = 3)and a median TTF of 3.1 (2.1-4.8) vs. 1.8 (1.4-2.5) months (p = 0.23).

Conclusions

A significant percentage of patients with TNBC demonstrate a direct alteration in the PI3K/AKT/mTOR pathway. Our data shows that PI3K-directed therapies benefit both those patients with and without direct molecular alterations in this pathway. Further molecular testing results will be presented. This data suggests that there may be additional molecular alterations that activate PI3K/AKT/mTOR in patients with TNBC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-18.

Melanoma patients in a phase I clinic: molecular aberrations, targeted therapy and outcomes

BACKGROUND

The purpose of the study was to assess the outcome of patients with advanced melanoma treated with matched molecularly targeted therapy.

PATIENTS AND METHODS

We reviewed 160 consecutive patients with metastatic melanoma treated in the phase I program (N = 35 protocols). Treatment was considered to be 'matched' (N = 84) if at least one drug in the regimen was known to inhibit the functional activity of at least one of the patient's mutations.

RESULTS

Of 160 patients, 134 (83.7%) had adequate tissue for molecular analysis; 69% (110 of 160) had ≥1 mutation: 61.2% (82 of 134), BRAF; 20.7% (23 of 111), NRAS; 2.6% (2 of 77), KIT; 2.3% (1 of 44), KRAS; 20% (1 of 5), GNAQ; 11.1% (1 of 9), P53 and 2.6% (1 of 39), coexisting mutations in BRAF and PIK3CA. Eighty-four patients (52.4%) were treated with matched-targeted agents, most of whom had BRAF mutations (N = 74). Twenty-six percent of patients (41 of 160) achieved a complete or partial remission (CR/PR) [40% (34 of 84)) on a matched phase I protocol versus 9.2% (7 of 76) for those on a non-matched study (P ≤ 0.0001)]. The median progression-free survival (PFS) (95% CI) was longer for patients treated on a matched phase I trial than on their prior first standard treatment [5.27 (4.10, 6.44) versus 3.10 (1.92, 4.28) months, P = 0.023], but not on non-matched phase I treatment. Multivariable analysis showed that matched therapy was an independent predictor of higher CR/PR rates, prolonged PFS and survival.

CONCLUSIONS

For melanoma patients, especially those with BRAF mutations, administering molecularly matched agents can be associated with better outcomes, including longer PFS compared with their first-line systemic therapy.

Aberrations in the epidermal growth factor receptor gene in 958 patients with diverse advanced tumors: implications for therapy

BACKGROUND

Epidermal growth factor receptor (EGFR) mutations are associated with the response to EGFR inhibitors in patients with non-small-cell lung cancer (NSCLC). We sought to investigate EGFR aberrations in patients with diverse advanced cancers.

PATIENTS AND METHODS

Patients referred to the phase I clinic were evaluated for the presence of EGFR mutations and response to therapy.

RESULTS

EGFR aberrations were detected in 34 of 958 patients (3.5%). Though EGFR mutations were most frequent in NSCLC (21 of 131, 16%), they were also present in a variety of other solid tumors (13 of 827 patients, 1.6%) including adrenocortical (1/10 patients), skin (1/24), breast (1/55), carcinoid (1/8), cholangiocarcinoma (1/20), head and neck (1/61), ovarian (1/84), parathyroid (1/1), salivary gland (1/20), renal (1/17), sarcoma (2/38), and thymic carcinomas (1/7). Of the 13 EGFR aberration-positive non-NSCLC patients (median number of prior systemic therapies = 3), 6 had treatment with an EGFR inhibitor. Two patients (diagnosis = parathyroid tumor and basal cell carcinoma) achieved stable disease (SD), lasting 6 and 7 months, respectively.

CONCLUSION

We found EGFR aberrations in 1.6% of a large group of patients with diverse tumors other than NSCLC, and treatment with an EGFR inhibitor could be associated with prolonged SD.

Abstract P5-20-09: Tumor mutational analysis and therapy outcomes for patients (pts) with metastatic/unresectable locally advanced myoepithelial/metaplastic breast cancer treated with PI3K targeted therapy

Background: Metaplastic breast cancers are considered a chemorefractory subset of triple negative breast cancers. Molecular profiling has demonstrated that metaplastic tumors are enriched for epithelial-to-mesenchymal transition (EMT), frequently express myoepithelial differentiation, make up a component of the ‘claudin-low’ subtype, and harbor relatively high rates of mutations/activation of the PI3kinase pathway (Hennessy, Cancer Research, 2009; Prat, Breast Cancer Res, 2010).

Methods: Data from pts with myoepithelial/metaplastic breast cancer treated within the Center for Targeted Therapy using regimens with known inhibitors of the PI3K pathway were evaluated to determine response to therapy. Mutational analyses were performed in archived tumor samples when available.

Results: 23 pts have been treated using 6 different therapy regimens and one pt was treated on two separate clinical trials for a total of 24 analyzable outcomes. Patients were treated with liposomal doxorubicin, bevacizumab and the mTOR inhibitor, temsirolimus (DAT, n=17); liposomal doxorubicin and temsirolimus (DT, n=1); paclitaxel, bevacizumab and temsirolimus (TAT, n=3); paclitaxel and temsirolimus (TT, n=1), paclitaxel in combination with an experimental PI3K inhibitor (TEx, n=1), or temsirolimus alone (tem, n=1). Response was measured every two cycles using RECIST criteria. Most pts had received prior chemotherapy, median of 2 prior regimens (range 0–7). Three patients were not evaluated for response, one who died of pneumonia during cycle 2 (DAT) and two who have not yet completed 2 cycles of therapy (DAT, TEx). Response rate (CR+PR) was 35% (CR = 2, PR=4, SD≥6 months=2, SD&lt;6 months=2, PD/death=7) with the anthracycline based regimens, DAT and DT; whereas, stable disease was the best response seen thus far with the paclitaxel based regimens or temsirolimus alone: TAT (SD&lt;6months=2, PD=1), TT (SD&lt;6months=1), tem (SD&lt;6months=1). 8 of 9 tumors tested (89%) were found to have mutations that would lead to activation of the PI3K pathway: PIK3CA=5 (62%), PTEN=2 (25%) and NF2=1(13%). The two patients with CR from DAT had mutations in NF2 and PIK3CA, respectively. Both patients remain in CR (2+ years and 1+ year respectively) after discontinuing protocol therapy, and both continue maintenance everolimus.

Conclusion: Activating mutations in the PI3K pathway are common in metaplastic breast cancers, a tumor subtype that shares molecular features with claudin-low and mesenchymal/mesenchymal-stem cell like triple negative breast cancers. DAT has demonstrated activity in myoepithelial/metaplastic breast cancer including two durable CRs to therapy. This regimen should be explored in larger, randomized trials to test superiority to chemotherapy alone.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-20-09.

Electrocardiograms (ECGs) in phase I anticancer drug development: the MD Anderson Cancer Center experience with 8518 ECGs

BACKGROUND

Cardiac sequelae from oncologic drugs are important in early cancer drug development. Prolongation of the corrected QT interval (QTc) by noncardiac drugs is the most common cause of drug development delays, nonapprovals and postmarketing withdrawals by the US Food and Drug Administration.

PATIENTS AND METHODS

We analyzed 8518 electrocardiograms (ECGs) in 525 consecutive cancer patients enrolled in 22 industry-sponsored phase I clinical trials, starting 1 January 2006.

RESULTS

Seventy-four patients [14%, 95% confidence interval (CI) 11% to 17%] with normal QTc at baseline had QTc intervals above upper limit of normal after treatment initiation; 33 (6%, 95% CI 4% to 9%) had prolonged QTc intervals at baseline, and only one (3%, 95% CI 0% to 16%) worsened after dosing. Seven of 33 patients (21%, 95% CI 9% to 39%) with prolonged baseline QTc had normalization of QTc intervals after dosing. All QTc prolongations were clinically insignificant; study drugs were continued uneventfully. Two of 525 patients (0.4%, 95% CI 0% to 1%) experienced cardiac serious adverse events (myocardial infarction possibly related to drug and unstable atrial flutter related to metastatic disease). Both cardiac events were detected by clinical assessment, not surveillance ECGs.

CONCLUSION

Frequent ECG monitoring provided no clinically significant information in 525 patients in early phase trials.

Risk of serious toxicity in 1181 patients treated in phase I clinical trials of predominantly targeted anticancer drugs: the M. D. Anderson Cancer Center experience

BACKGROUND

This study assessed toxicity in advanced cancer patients treated in a phase I clinic that focuses on targeted agents.

PATIENTS AND METHODS

An analysis of database records of 1181 consecutive patients with advanced cancer who were treated in the phase I program starting 1 January 2006 was carried out.

RESULTS

All patients were treated on at least 1 of the 82 phase I clinical trials. Overall, 56 trials (68.3%) had only targeted agents, 13 (15.9%) only cytotoxics, and 13 (15.9%) targeted and cytotoxic agents. Rates of grade 3 and 4 toxicity that were at least possibly drug related were 7.1% and 3.2%, respectively, and 5 of the 1181 patients (0.4%) died from toxicity that was at least possibly drug related. The most common grade 3 or more toxic effects were neutropenia, thrombocytopenia, anemia, dehydration, infection, altered mental status, bleeding, vomiting, nausea, and diarrhea. Eastern Cooperative Oncology Group (ECOG) performance status greater than zero and use of a cytotoxic agent were selected as independent factors associated with serious toxicity.

CONCLUSION

Phase I trials of primarily targeted agents showed low rates of toxicity, with 10.3% of patients experiencing grade 3 or 4 toxicity and a 0.4% rate of death, at least possibly drug related.

PD09-01: Target-Based Therapeutic Matching in Early-Phase Clinical Trials in Patients with Advanced Breast Cancer and PIK3CA Mutations

Background: Therapeutic matching based on underlying molecular abnormalities showed promising results in early-phase clinical trials. PIK3CA mutations may predict response to therapies with PI3K/AKT/mTOR inhibitors.

Methods: Tumors from patients with breast cancer referred to the Clinical Center for Targeted Therapy (Phase I Program) were analyzed for PIK3CA mutations. Patients with PIK3CA mutations were treated, whenever feasible, with agents targeting the PI3K/AKT/mTOR pathway.

Results: Of 54 patients analyzed, 15 (28%) had PIK3CA mutations. PIK3CA mutations were found in 5/9 (56%) metaplastic, 3/8 (38%) HER2−positive, 7/29 (24%) hormone receptor-positive, and 0/8 (0%) triple negative (excluding metaplastic) breast cancers (P=0.07). Of the 15 patients with PIK3CA mutations, 12 (80%) were treated in clinical trials containing a PI3K/AKT/mTOR pathway inhibitor (median age, 54; median number of prior therapies, 3). Of these 12 patients, 3 (25%, 95% CI 0.09−0.53) had stable disease for more than 6 months (SD≥6 months; n=1) or a partial response (PR; n=2). Breast cancer patients without PIK3CA mutations treated on the same protocols had a rate of SD≥6 months/PR of 8% (1/12; 95% CI 0.01−0.35, p=0.6). Of the 4 patients with a H1047R mutation treated with agents targeting the PI3K/AKT/mTOR pathway, 3 (75%) had SD≥6 months (n=1) or a PR (n=2) compared to 0 of 8 patients (0%) with other PIK3CA mutations (P=0.045). Patients with H1047R mutations had a median progression-free survival (PFS) of 8.5 months compared to 2 months in patients with other PIK3CA mutations (p=0.13).

Conclusion: Heavily pretreated patients with PIK3CA-mutant advanced breast cancer had a SD≥6 months/PR rate of 25% on protocols incorporating PI3K/AKT/mTOR. Patients with mutation H1047R had significantly longer SD≥6 months/PR rate compared to those with other PIK3CA mutations. Our observations suggest that screening for PIK3CA mutations is warranted in larger numbers of patients with advanced breast cancer when treatment with PI3K/AKT/mTOR pathway inhibitors is planned.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD09-01.

Ofatumumab in the treatment of chronic lymphocytic leukemia

Ofatumumab is a type I fully human monoclonal antibody (IgG1) that binds to a unique epitope on the human CD20 molecule expressed on the surface of B cells. It binds specifically to both the small and large extracellular loops of the CD20 molecule. A phase I-II study demonstrated that ofatumumab was well tolerated and resulted in objective responses. In a phase II study of ofatumumab in fludarabine- and alemtuzumab-refractory chronic lymphocytic leukemia (CLL) or fludarabine-refractory CLL with bulky (> 5 cm) lymphadenopathy, the response rates were 58% and 47%, respectively. This study led to accelerated approval of ofatumumab by the U.S. Food and Drug Administration for the treatment of CLL refractory to fludarabine and alemtuzumab. In a phase II study of ofatumumab with fludarabine and cyclophosphamide in untreated CLL, patients were randomized to ofatumumab 500 mg (group A) or 1000 mg (group B) (initial dose, 300 mg, both groups), combined with fludarabine and cyclophosphamide. The higher ofatumumab dose resulted in a higher complete response (CR) rate (50%), compared to the lower-dose ofatumumab group (CR, 32%) (overall response rates, 77% and 73%, respectively). A phase III study of ofatumumab combined with fludarabine and cyclophosphamide versus fludarabine and cyclophosphamide in relapsed CLL are ongoing, as well as several clinical trials of ofatumumab. Ofatumumab has significant antileukemic activity and ongoing clinical trials will determine the role of ofatumumab in CLL.

Clinical outcomes of patients with breast cancer in a phase I clinic: The M. D. Anderson Cancer Center experience

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Background: Patients with metastatic breast cancer refractory to standard therapy are eligible for phase I trials. We assessed prognostic factors and clinical outcomes for patients with breast cancer in a phase I clinic focused on targeted agents. Methods: We reviewed the medical records of sequential patients with metastatic breast cancer who presented to our phase I clinic from September 2004 to May 2008. We assessed the relationship between overall survival and patients’ demographic and clinical characteristics using both univariate and multivariate (Cox proportional hazard model) analyses. Results: Ninety-two patients were identified with median age of 53 years (range 28 to 83 years). The median number of prior therapies was 5 (range 1 to 16). The median follow-up of surviving patients is 7.4 months. The median overall survival is 6.7 (95% CI: 5.2, 9.7) months. In univariate analysis, factors predicting shorter survival were elevated Ca-125 (p = 0.001) (Ca27.29 was not significant), albumin < 3.5 g/dL (p = 0.002), worsening ECOG performance status (p = 0.004), absolute neutrophil count < 7.3 x 109/L (p = 0.004), ≥ 10 prior treatment regimens (p = 0.008), ≥ 5 prior chemotherapy-only regimens (p = 0.008), body mass index (BMI) < 25 (p = 0.018), and elevated platelet counts (p = 0.007). In multivariate analysis, independent factors predicting shorter survival were ≥10 prior treatments (vs. <10 prior treatments) (HR = 3.27; 95% CI 1.37, 7.81; p = 0.0077), ECOG performance status 2–3 (vs. 0–1) (HR = 2.92; 95% CI 1.28, 6.66; p = 0.01), and albumin < 3.5 g/dL (vs. > 3.5g/dL) (hazard ratio [HR] = 2.88; 95% CI; 1.41, 5.89; p = 0.004). Of 78 patients treated on a first phase I trial, 14 (18%) demonstrated stable disease (SD), with a median duration of 18 weeks (range 10–25). Of those 19 patients treated on a second phase I trial, 6 (32%) had SD with a median duration of 12 weeks (range 8–17). Two of 4 (50%) patients treated on a third phase I trial had SD with a median duration of 20 weeks (range 16–24). Conclusions: Patients with metastatic breast cancer referred for our phase I studies had a median survival of 6.6 months. In this preliminary analysis, independent factors predicting shorter survival were ≥ 10 prior treatments, worsening ECOG performance status and low albumin levels.

No significant financial relationships to disclose.

The combination of oxaliplatin, fludarabine (FLU), cytarabine (Ara-c), and rituximab (R) (OFAR) in patients with Richter’s Transformation and FLU-refractory CLL

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Background: Patients with (FLU-ref) CLL and Richter’s transformation (RT) have a very poor prognosis. Oxaliplatin (OX), a platinum analog with a 1,2-diaminocyclohexamine carrier ligand, has a different activity and side effect profile from cisplatin. OX covalently binds DNA, inducing DNA intra- and inter-strand cross-links. FLU and Ara-c act synergistically to inhibit excision-repair of DNA cross-links, thereby providing the rationale for combining OX, FLU, Ara-c, and R (OFAR). Methods: The phase I portion of a phase I/II study of the OFAR regimen had increasing doses of OX. The OFAR regimen consists of OX 17.5, 20, or 25mg/m2, d1–4; fludarabine 30mg/m2, d2,3; Ara-c 1gm/m2, d2,3; and rituximab 375mg/m2, d3. Courses were given every 4 wks; patients received Neulasta 6mg each course and prophylaxis for tumor lysis, DNA virus’, and PCP. Results: 19 patients enrolled in phase I; 1 received no treatment, 8 had RT, and 10 had FLU-ref CLL. Patients received OX 17.5mg/m2 (3), 20mg/m2 (8), or 25mg/m2 (7). Patients receiving at least 1 course were evaluable for toxicity and could receive up to 6 courses. There were no dose-limiting toxicities, defined as any ≥ G3, non-hematologic, treatment-related toxicity. The major toxicity was hematologic and appeared OX-dose dependent. Neutropenia (G3–4) was experienced by 1/3, 6/8, and 7/7 patients treated at 17.5, 20, and 25mg/m2 OX levels, respectively. Thrombocytopenia (G3–4) was experienced by 2/3, 8/8, and 7/7 of patients treated at 17.5, 20, and 25mg/m2m OX levels, respectively. There were no treatment-related deaths. Five patients continue treatment on the phase I portion, and results will be evaluable, with 3 responders, including 2 complete, in the 7 evaluable patients with RT. Among the 10 FLU-ref patients, there are 5 PRs; treatment continues for 3 of them. Pharmacodynamic analyses demonstrate enhanced killing by OX in the presence of FLU and Ara-c. Conclusions: The OFAR regimen is safe and active for treating patients with RT and FLU-ref CLL. This trial continues to accrue patients to confirm efficacy.

No significant financial relationships to disclose.

Hodgkin's disease in patients infected with human immunodeficiency virus: frequency, presentation and clinical outcome

We report the frequency, presenting characteristics, progression-free survival, event-free survival, overall survival and AIDS-free survival of patients with previously untreated Hodgkin's disease (HD) in the setting of infection by human immunodeficiency virus (HIV). To accomplish this we retrospectively reviewed all untreated patients presenting to the University of Texas M.D. Anderson Cancer Center between July 1985 and August 1999 with HD and HIV infection. All available records were reviewed to determine presentation, clinical characteristics, treatment outcome, progression-free survival and overall survival. We identified 887 patients with HD and 3,500 with Non-Hodgkin's Lymphoma (NHL). The ratio of NHL to HD in HIV-negative versus HIV-positive patients was 3.9 versus 6.9, respectively. There were 14 HIV-positive patients with HD and 97 with NHL. The median age of the HIV-positive HD patients was 33 years, and 13 were male. Three patients had Acquired Immune Deficiency syndrome (AIDS) at the time of HD diagnosis, and seven had B-symptoms. Ann Arbor stage was I in one, II in three, III in four and IV in six patients. Mixed cellularity histology was seen in eight, bone marrow involvement in five and extranodal disease in seven patients. Four patients had elevated serum lactate dehydrogenase, three low serum albumin, and nine elevated serum beta2-microglobulin, The median CD4 count was 160/microl. Eleven patients received ABVD or equivalent regimens, followed by radiotherapy in five. One patient was treated with COPP and radiotherapy, one with NOVP and radiotherapy and one only with radiotherapy. All patients received some antiretroviral therapy, but it was variable over the years. With a median follow-up of 64 months for survivors, the projected 5-year progression-free survival was 64%, event-free survival 45%, overall survival 54% and AIDS-free survival 45%. Six patients died of complications arising from HIV infection, including one patient who had preexisting AIDS at HD presentation. Two patients died of HD, without developing other conditions diagnostic of AIDS. We conclude that in our referral patient population HIV infection is associated with preferential development of NHL rather than HD, which appears curable with standard treatment regimens. Since HIV-related deaths exceed those caused by HD, future investigation should focus on integration of chemotherapy and highly active antiretroviral therapy.

Liposomal vincristine in relapsed non-Hodgkin's lymphomas: early results of an ongoing phase II trial

OBJECTIVE

Vincristine is an active agent in lymphomas, but is often neurotoxic, and the resulting dose reductions have been associated with lower remission and survival rates in Hodgkin's disease. Liposomal vincristine (Onco-TCS) has prolonged half-life, reaches higher concentration in tumors and lymph nodes than in nerves, and administered at full doses appears to be less neurotoxic, and more active then free vincristine in mice bearing L-1210 and P-388 leukemias. We therefore explored its activity in relapsed non-Hodgkin's lymphomas (NHL) and acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Eligible patients had histologically proven relapse, age > or = 16 years, normal renal function, neutrophils > 500/microliter, platelets > 50,000/microliter, and no HIV infection, central nervous system disease, or serious neuropathy. Patients were treated with 2.0 mg/m2 of liposomal vincristine i.v. over 60 minutes q 14 days. Responders received up to 12 injections.

RESULTS

Of the 51 registered patients, 35 are currently evaluable for response. Median age was 62 years (range 19-86), and 21 were male. The median number of prior regimens was 3 (range 1-10) and had included vincristine in all patients, of whom 51% were refractory to their last regimen. Serum LDH was high in 46%, and beta 2-microglobulin > 3.0 mg/l in 63% of patients. Of the 155 administered injections, 138 (89%) were at the 2.0 mg/m2 level. The median injected dose was 3.8 mg (range 2.6-4.8 mg), and median number of injections was 4 (range 1-12). Responses were seen in 14 of 34 (41%) patients with NHL (95% confidence intervals (95% CI) 25%-59%). Response rates were 10% for indolent, 71% for transformed, and 47% for aggressive NHL, but the 95% confidence intervals overlapped. Median progression-free survival was 5.5 months for responders. Grade 3-4 motor or sensory neuropathy was seen in 11, and caused termination of therapy in five patients. All five had prior neuropathy, two had previously received paclitaxel, one platinum, and two paclitaxel and platinum. Fever was detected in three patients, but there were no toxic deaths.

CONCLUSIONS

Liposomal vincristine is active and well tolerated in this heavily pretreated population with relapsed NHL, but can be neurotoxic in a fraction of patients heavily exposed to prior neurotoxic agents. These data, if confirmed, would suggest a potential role for liposomal vincristine in the combination therapy of previously untreated patients with NHL.

Severe aplastic anaemia relapsing during a pregnancy; spontaneous remission following termination

The case of a 29-year-old woman with aplastic anaemia in remission who relapsed during pregnancy is reported here. Following successful Caesarean delivery, spontaneous remission was obtained and the patient remains well thereafter. Pathogenetic and therapeutic aspects of this rare complication of pregnancy are discussed.

Detection of "PNH red cell" populations in hematological disorders using the Sephacryl Gel Test micro typing system

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal disorder characterised by an unusual sensitivity of abnormal red cell population(s) to complement lysis, due to a complete or incomplete defect of various surface molecules, including CD55 and CD59. PNH has been associated with various hematological disorders. Using a newly introduced method, the Sephacryl gel test microtyping system, we investigated the presence of CD55 or CD59 defective red cell populations in several hematological disorders. It was also found that a large proportion of such patients possess CD55 deficient populations, while a smaller but still significant proportion possess CD59 deficient populations. Defective red cell populations were detected in normal subjects as well. These findings need further investigation. Nevertheless the Sephacryl Gel Test microtyping system although non specific, seems to be useful in screening for the PNH and/or "PNH-like" red cell defect in several hematological disorders.