Long-term efficacy and safety of addition of carboplatin with or without veliparib to standard neoadjuvant chemotherapy in triple-negative breast cancer: 4-year follow-up data from BrighTNess, a randomized phase 3 trial

BACKGROUND

Primary analyses of the phase 3 BrighTNess trial showed addition of carboplatin with/without veliparib to neoadjuvant chemotherapy significantly improved pathological complete response (pCR) rates with manageable acute toxicity in patients with triple-negative breast cancer (TNBC). Here, we report 4.5-year follow-up data from the trial.

DESIGN

Women with untreated stage II-III TNBC were randomized (2:1:1) to paclitaxel (weekly for 12 doses) plus either: (a) carboplatin (every 3 weeks for four cycles) plus veliparib (twice daily); (b) carboplatin plus veliparib placebo; or (c) carboplatin placebo plus veliparib placebo. All patients then received doxorubicin and cyclophosphamide (AC) every 2‒3 weeks for four cycles. The primary endpoint was pCR. Secondary endpoints included event-free survival (EFS), overall survival (OS), and safety. Since the co-primary endpoint of increased pCR with carboplatin plus veliparib with paclitaxel versus carboplatin with paclitaxel was not met, secondary analyses are descriptive.

RESULTS

Of 634 patients, 316 were randomized to carboplatin plus veliparib with paclitaxel, 160 to carboplatin with paclitaxel, and 158 to paclitaxel. With median follow-up of 4.5 years, the hazard ratio [HR] for EFS for carboplatin plus veliparib with paclitaxel versus paclitaxel was 0.63 (95% confidence interval [CI] 0.43‒0.92, P=0.02), but 1.12 (95% CI 0.72‒1.72, P=0.62) for carboplatin plus veliparib with paclitaxel versus carboplatin with paclitaxel. In post hoc analysis, HR for EFS was 0.57 (95% CI 0.36‒0.91, P=0.02) for carboplatin with paclitaxel versus paclitaxel. OS did not differ significantly between treatment arms, nor did rates of myelodysplastic syndromes, acute myeloid leukemia, or other secondary malignancies.

CONCLUSION

Improvement in pCR with addition of carboplatin was associated with long-term EFS benefit with a manageable safety profile, and without increasing the risk of second malignancies, while adding veliparib did not impact EFS. These findings support the addition of carboplatin to weekly paclitaxel followed by AC neoadjuvant chemotherapy for early stage TNBC.

Neoadjuvant weekly paclitaxel and carboplatin with trastuzumab and pertuzumab in HER2-positive breast cancer: a Brown University Oncology Research Group (BrUOG) study

PURPOSE

In HER2-positive breast cancer (HER2+ BC), neoadjuvant chemotherapy (NACT) with dual HER2-targeted therapy achieves high pathologic complete response (pCR) rates. Anthracycline-free NACT regimens avoid toxicities associated with anthracyclines, but every 3-week TCHP also has substantial side effects. We hypothesized that a weekly regimen might have equivalent efficacy with less toxicity; we also investigated whether poorly responding patients would benefit from switching to AC.

METHODS

Patients with clinical stage II-III HER2+ BC received weekly paclitaxel 80 mg/m² and carboplatin AUC2 with every 3-week trastuzumab and pertuzumab (wPCbTP), with the option of splitting the pertuzumab loading dose. After 12 weeks, responding patients continued wPCbTP for another 6 weeks, while non-responders switched to AC. Dose modifications and post-op therapy were at investigator discretion.

RESULTS

In 30 evaluable patients, the pCR rate was 77% (95% CI 58-90%); 12/14 (86%) in ER-negative and 11/16 (69%) in ER-positive. Only two patients transitioned to AC for non-response, of which one achieved pCR. There were no episodes of febrile neutropenia or grade ≥ 3 peripheral neuropathy, though several patients who continued wPCbTP stopped before week 18. Split-dose pertuzumab was associated with less grade ≥ 2 diarrhea (40%) than the standard loading dose (60%).

CONCLUSION

pCR rates with our regimen were as high as reported with TCHP with fewer grade ≥ 3 toxicities, though diarrhea remains a concern. Too few patients had a suboptimal response to adequately test switching to AC. The wPCbTP regimen should be considered an alternative to TCHP as neoadjuvant therapy for HER2+ BC.

TRAIL REGISTRATION

ClinicalTrials.gov identifier: NCT02789657.

Abstract PD3-04: Analysis of ERBB2 (HER2) amplification by ctDNA in a phase Ib dose-escalation trial evaluating trastuzumab emtansine (T-DM1) with neratinib in women with metastatic disease with initially diagnosed HER2+ breast cancer: NSABP FB-10

Background:

In this phase Ib study, the activity of T-DM1 plus N was assessed in patients (pt) previously treated with trastuzumab, pertuzumab, and a taxane (H+P+T). Several mechanisms of resistance have been hypothesized in pts progressing following H+P+T, including acquired alterations in the ERBB (HER) family proteins, reactivation of bypass or parallel pathways, or selective elimination of HER2-overexpressing clones. Loss of HER2 amp has been shown to occur in 25-35% of pts with residual tumor after neoadjuvant therapy or in metastatic disease after initial therapy with chemotherapy and HER2-targeted agents. Data on concordance of HER2 status between tissue and blood is limited. In 7 pts with cfDNA HER2 amp, concomitant tissue was concordant in all 7 pairs and response to anti-HER2 therapy occurred in 6. In our study we have retrospectively analyzed cfDNA in blood samples obtained at study entry.

Methods:

Eligible pts had prior H+P+T as neoadjuvant therapy, or 1st-line metastatic disease, measurable disease, ECOG PS ≤2, and adequate hematologic, renal, and liver function. Pts with stable brain metastases were eligible. Treatment consisted of T-DM1 3.6 mg/kg iv q3wk and N 120, 160, 200, or 240 mg/d using a 3+3 dose-escalation design. HER2+ was determined at initial diagnosis; tissue confirmation at study entry (after H+P+T progression) was not required. Blood was collected in for pharmacokinetic analyses of N peak and trough, and for cfDNA using the Guardant360 assay, which is a 73-gene next-generation cfDNA-sequencing panel that detects SNVs, indels, CNAs, and fusions, utilizing Digital Sequencing and custom bioinformatics methods for error correction. The cut-off for HER2 amp was a copy number of ≥2.0 established by Guardant based on training-set data.

Results:

There were 27 H+P+T-resistant pts enrolled and all pts had a blood sample analyzed for HER2 amp. Eighteen pts were evaluable for efficacy at 6 wks and 11 pts at 12 wks. Dose-limiting toxicity occurred in 6 pts during cycle 1, 1 pt was withdrawn for non-compliance, and 2 pts were withdrawn for disease complications. The recommended phase II dose of N was determined to be 160 mg/d. Responses were seen at all dose-levels of N. Pharmacokinetic analyses did not show a clear relationship with either peak or trough and dose-level. Ten pts showed HER2 amp in blood and 17 were non-amp. Of 18 pts evaluable after 2 cycles (6 wks), 12 pts had an objective response (7 amp; 5 non-amp) and 5 had progressive disease (1 amp; 4 non-amp). At 12 wks, there were 3 CRs and 8 PRs (7 amp; 4 non-amp). All CRs were in amp pts and lasted 364, 510, and 859+ days.

Conclusions:

HER2 amp as determined by cfDNA was found in 10 of 27 pts. The deeper and more prolonged (>12 wk) responses occurred in 7 of 10 amp HER2 pts v 4 of 17 non-amp HER2 pts (p=0.04). In our ongoing phase II study of this regimen concomitant tissue and blood will be analyzed to better understand potential benefit or lack of benefit, with continued use of anti-HER2 therapy after progression on anti-HER2 therapies.

Support: Puma Biotechnology, Inc.

Citation Format: Abraham J, Puhalla SL, Sikov WM, Montero AJ, Salkeni MA, Razaq WA, Beumer JH, Kiesel BF, Buyse ME, Adamson LM, Srinivasan A, Pogue-Geile KL, Allegra CJ, Nagy RJ, Jacobs SA. Analysis of ERBB2 (HER2) amplification by ctDNA in a phase Ib dose-escalation trial evaluating trastuzumab emtansine (T-DM1) with neratinib in women with metastatic disease with initially diagnosed HER2+ breast cancer: NSABP FB-10 [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD3-04.

Abstract PD1-03: Multivariate analysis of subtype and gene expression signatures predictive of pathologic complete response (pCR) in triple-negative breast cancer (TNBC): CALGB 40603 (Alliance)

Support: U10CA180821, U10CA180882

Background: The addition of either carboplatin (Cb) or bevacizumab (Bev) to standard neoadjuvant chemotherapy (NACT) increases pCR rates in TNBC overall and in the dominant subset of basal-like cancers (Sikov et al, JCO 2015; Sikov et al, SABCS 2014). Multigene expression signatures more accurately reflect tumor biology for response prediction and prognosis than individual gene expression. We evaluated the ability of multivariate analysis of gene expression signatures to create predictive models for achievement of pCR in TNBC.

Methods: RNA sequencing was successful on 389 pretreatment samples from patients with available pCR data, and used to assign PAM50 subtype and calculate gene signatures scores for 489 published expression signatures. Elastic net, a penalized regression model for high dimensional variable selection, was used to select features associated with pCR in all TNBC and in the basal-like subset. Models were derived in a training set (2/3 of samples) and validated in a separate test set (1/3). A separate model was derived using 196 TNBC samples from patients treated only on the standard NACT +/- Cb arms for application to external TNBC neoadjuvant data sets not treated with Bev.

Results: Consistent with our prior partial data set, 343 (88%) of the cancers were classified basal-like, in whom the in breast pCR rate was 54%; the remainder were classified normal-like (n=32) or HER2-enriched (n=14) with a non-basal pCR rate of 56%. Elastic Net analysis in all TNBC generated a model of 23 signatures and treatment assignment with 68% sensitivity and 64% specificity. The area under the curve was 0.64 (p-value=0.0019). Nineteen modules, including immune cell signatures (Th1, NK, IgG), immunoglobulin variable region expression, addition of Cb and Bev and expression of genes at regions 15q25, 17p11.2-13.3, and 8p22 were positively associated with response. The latter two regions are associated with aggressive breast cancer, and while not part of the 17p13 signature, this region contains TP53, a gene important in TNBC. Six modules were associated with resistance, including luminal progenitor, TGFB, NOTCH, FOS/JUN, 8p amplicon, and eosinophil signatures. When limited to basal-like samples, a model including 32 modules and addition of Cb and Bev was generated, with 62.3% sensitivity and 59.1% specificity. Seventeen features were selected in both models. Omitting Bev-treated patients, a model using just the gene expression signatures was developed. The predictive value of this model will be assessed using an external cohort of TNBC patients treated with neoadjuvant docetaxel and Cb (NCT01560663) and results presented.

Conclusions: Multivariate analysis of gene expression signatures derived from pretreatment samples enabled the construction of models to predict achievement of pCR in TNBC. These models performed well on our test set, and will be assessed for their predictive ability in other TNBC data sets. If validated by future analyses, this could help us identify patients likely to achieve pCR with standard NACT and may benefit from the addition of agents such as Cb or Bev.

ClinicalTrials.gov Identifier: NCT00861705.

Citation Format: Hoadley KA, Hyslop T, Fan C, Berry DA, Hahn O, Tolaney SM, Sikov WM, Perou CM, Carey LA. Multivariate analysis of subtype and gene expression signatures predictive of pathologic complete response (pCR) in triple-negative breast cancer (TNBC): CALGB 40603 (Alliance) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr PD1-03.

SWOG S0800 (NCI CDR0000636131): addition of bevacizumab to neoadjuvant nab-paclitaxel with dose-dense doxorubicin and cyclophosphamide improves pathologic complete response (pCR) rates in inflammatory or locally advanced breast cancer

SWOG S0800, a randomized open-label Phase II clinical trial, compared the combination of weekly nab-paclitaxel and bevacizumab followed by dose-dense doxorubicin and cyclophosphamide (AC) with nab-paclitaxel followed or preceded by AC as neoadjuvant treatment for HER2-negative locally advanced breast cancer (LABC) or inflammatory breast cancer (IBC). Patients were randomly allocated (2:1:1) to three neoadjuvant chemotherapy arms: (1) nab-paclitaxel with concurrent bevacizumab followed by AC; (2) nab-paclitaxel followed by AC; or (3) AC followed by nab-paclitaxel. The primary endpoint was pathologic complete response (pCR) with stratification by disease type (non-IBC LABC vs. IBC) and hormone receptor status (positive vs. negative). Overall survival (OS), event-free survival (EFS), and toxicity were secondary endpoints. Analyses were intent-to-treat comparing bevacizumab to the combined control arms. A total of 215 patients were accrued including 11 % with IBC and 32 % with triple-negative breast cancer (TNBC). The addition of bevacizumab significantly increased the pCR rate overall (36 vs. 21 %; p = 0.019) and in TNBC (59 vs. 29 %; p = 0.014), but not in hormone receptor-positive disease (24 vs. 18 %; p = 0.41). Sequence of administration of nab-paclitaxel and AC did not affect the pCR rate. While no significant differences in OS or EFS were seen, a trend favored the addition of bevacizumab for EFS (p = 0.06) in TNBC. Overall, Grade 3-4 adverse events did not differ substantially by treatment arm. The addition of bevacizumab to nab-paclitaxel prior to dose-dense AC neoadjuvant chemotherapy significantly improved the pCR rate compared to chemotherapy alone in patients with triple-negative LABC/IBC and was accompanied by a trend for improved EFS. This suggests reconsideration of the role of bevacizumab in high-risk triple-negative locally advanced breast cancer.

Evaluation of ER/PR and HER2 status by RNA sequencing in tissue core biopsies from preoperative clinical trial specimens

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Background: Next-generation sequencing for measuring RNA (RNASeq) offer increased sensitivity, dynamic range and provide unbiased detection of all transcripts. To evaluate the clinical utility of such methods, we sequenced entire transcriptomes from fresh-frozen biopsies in a cohort of 120 patients enrolled on a preoperative therapy trial receiving carboplatin, nab paclitaxel and either bevacizumab (HER2-) or trastuzumab (HER2+).

Methods: Total RNA was extracted and amplified from frozen breast core biopsies and libraries constructed using TruSeq (Illumina). Sequencing was performed on the Illumina GAII platform. 75bp reads were mapped using Tophat and transcript abundance in FPKM units (Fragments per kilo-base of mRNA per million reads) calculated using Cufflinks. CLIA approved assays were performed for ER, PR, HER2 (IHC+/- FISH) on patient tumors. Four tumors from each subtype (ER +ve/HER2 -ve; HER2 +ve; ER/HER2 -ve) were analyzed for correlation with clinical status. PAM50 classification will be provided for verification of molecular subtypes.

Results: RNA-Seq library construction/sequencing were successful in 12/12 samples with 50-90% reads mapped. ER +ve tumors ranged in FPKM values from 1.76-22.67 and ER -ve tumors ranged from 0.00-0.79. i.e. ER RNASeq measurements can separate clinical ER status. HER2 +ve tumors ranged in FPKM values from 2.62-21.71 and HER2 -ve tumors from 0.21-1.79. Of note, 7/8 HER2 -ve tumors ranged from 0.21-0.87 with one ‘outlier’ at 1.79±0.3. This outlier was HER2 IHC 2+, FISH ratio 1.1 with 45% of tumor cells with polysomy chromosome 17. Correspondence of ER/PR and HER2 status with molecular subtyping by PAM50 analysis will be presented.

Conclusions: RNASeq has potential to provide in depth analysis of the breast cancer transcriptome and a single analysis test for standard markers. In addition, RNASeq may uncover unexpected expression patterns in conventionally-defined HER2 -ve tumors. If reproducible in larger datasets, this technology may provide both standard and novel information previously unavailable to oncologists and their patients.

Splenosis presenting as occult gastrointestinal bleeding

A 48-year-old man presented with recurrent gastrointestinal bleeding and anemia. Routine endoscopic evaluation was nondiagnostic. Angiography demonstrated multiple apparent arteriovenous malformations. Exploratory laparotomy revealed numerous splenic implants along the small and large bowels, some of which had apparently eroded through the bowel mucosa and bled. Excision of these penetrating lesions prevented further bleeding. An incidentally noted renal cell cancer was also resected. The patient's splenosis was the result of childhood trauma that caused splenic rupture and precipitated splenectomy. Splenosis develops frequently following traumatic splenic rupture. Experimental evidence suggests that the presence of an intact spleen suppresses the growth and development of splenic implants. Following splenectomy, splenules may replace some of the "housekeeping" and immunologic functions of the spleen, but even patients with documented splenosis should be considered functionally hyposplenic. While in most cases splenules cause no symptoms, splenosis must be considered in the differential diagnosis of previously splenectomized patients who present with unexplained masses or occult bleeding.

Splenosis presenting as occult gastrointestinal bleeding

A 48-year-old man presented with recurrent gastrointestinal bleeding and anemia. Routine endoscopic evaluation was nondiagnostic. Angiography demonstrated multiple apparent arteriovenous malformations. Exploratory laparotomy revealed numerous splenic implants along the small and large bowels, some of which had apparently eroded through the bowel mucosa and bled. Excision of these penetrating lesions prevented further bleeding. An incidentally noted renal cell cancer was also resected. The patient's splenosis was the result of childhood trauma that caused splenic rupture and precipitated splenectomy. Splenosis develops frequently following traumatic splenic rupture. Experimental evidence suggests that the presence of an intact spleen suppresses the growth and development of splenic implants. Following splenectomy, splenules may replace some of the "housekeeping" and immunologic functions of the spleen, but even patients with documented splenosis should be considered functionally hyposplenic. While in most cases splenules cause no symptoms, splenosis must be considered in the differential diagnosis of previously splenectomized patients who present with unexplained masses or occult bleeding.

Locally advanced breast cancer

Over the past 20 years, the prognosis for women diagnosed with locally advanced breast cancer (LABC; clinical stages IIB through IIIB) has improved significantly with recognition of the efficacy of multimodal therapy for reducing both local and distant recurrences, even in patients with inflammatory breast cancer (IBC). Most patients will respond to induction, or neoadjuvant, chemotherapy (NAC) with an anthracycline-based regimen, enabling many patients with large but operable tumors to undergo breast-conserving surgery (BCS) and enabling resection in most patients with inoperable disease. However, only a small percentage of patients achieve a pathologic complete response (CR) with this approach. Long-term disease-free survival (DFS) and overall survival (OS) correlate with the extent of residual disease in the breast and axillary nodes following NAC. The addition of paclitaxel or docetaxel, either in combination with an anthracycline or as a separate regimen administered before or after anthracycline-based therapy, increases clinical and pathologic response rates and may improve DFS. With the possible exception of patients with IBC, BCS does not compromise outcome. Partial mastectomy should be accompanied by standard nodal dissection in patients with clinically or radiographically positive axillae; in patients with negative axillae, sentinel lymph node (SLN) sampling, with subsequent axillary dissection reserved for patients with involved nodes, may reduce postoperative morbidity. Patients who received only anthracycline-based NAC who are found to have significant residual disease in the breast or involved axillary nodes at surgery should receive adjuvant chemotherapy with paclitaxel. Postoperative radiation to the residual breast or chest wall and regional nodal areas reduces locoregional recurrences, but its impact on OS remains controversial. Adjuvant hormonal therapy with tamoxifen improves DFS and OS in patients with hormone receptor (HR)-positive tumors, and ovarian ablation should be considered in premenopausal patients with HR-positive tumors and multiple involved nodes or stage IIIB disease. Neoadjuvant hormonal therapy with either tamoxifen or an aromatase inhibitor may benefit frail or elderly patients with HR-positive tumors for whom chemotherapy is not an option. No advantage has been demonstrated for high-dose chemotherapy requiring hematopoietic stem-cell support as either NAC or adjuvant therapy in LABC. Newer treatment approaches, including trastuzumab (Herceptin, Genentech, Inc., South San Francisco, CA), in patients with Her-2-overexpressing tumors or other biologic agents, do not have a proven role in the management of LABC at this time.

Multicentric warfarin-induced skin necrosis complicating heparin-induced thrombocytopenia

Two patients developed catastrophic multicentric skin necrosis while receiving warfarin to treat venous thromboembolism complicated by immune-mediated heparin-induced thrombocytopenia (HIT). Patient 1 developed skin necrosis involving the breasts, thighs, and face, as well as venous limb gangrene and bilateral hemorrhagic necrosis of the adrenal glands, resulting in death. The second patient developed bilateral mammary necrosis necessitating mastectomies, as well as skin necrosis involving the thigh. Neither patient had an identifiable hypercoagulable syndrome, other than HIT. HIT may represent a risk factor for the development of multicentric warfarin-induced skin necrosis (WISN).

Spontaneous venous thrombosis in a young patient with combined factor V Leiden and lupus anticoagulant

We describe a case of a 28-year-old man who developed an extensive spontaneous deep venous thrombosis. Testing revealed heterozygotic factor V Leiden mutation, and the presence of both lupus anticoagulant (LA) and elevated IgM anticardiolipin antibody (ACA). Several family members were found to be heterozygous for factor V Leiden. A paternal aunt had the factor V Leiden mutation, an elevated plasma homocysteine and a borderline increased IgG ACA level. No other family member had a history of a venous thrombotic event. This case illustrates that evaluation of young patients who present with venous thrombosis should be performed for both hereditary and acquired thrombophilic defects. The family studies suggest that the presence of a lupus anticoagulant may be more clinically significant than elevated ACA in risk assessment. Although screening family members when the proband carries factor V Leiden is controversial, psychological reassurance of those who test negative and simple advice on occupations or social habits (e.g., smoking) for those who test positive may be important benefits.

Weekly high-dose paclitaxel in metastatic and locally advanced breast cancer: a preliminary report

The optimal dose and schedule for paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in the treatment of patients with advanced breast cancer are not known. Based on our phase I study in non-small cell lung cancer, in which the dose intensity of paclitaxel was successfully escalated by using a weekly schedule, we initiated a phase II study of weekly paclitaxel in previously untreated patients with metastatic breast cancer (MBC) and locally advanced breast cancer (LABC). Treatment consists of weekly paclitaxel 175 mg/m2 intravenously over 3 hours for 6 weeks, followed by a 2-week break. Doses are modified for neutropenia (absolute neutrophil count < 1,500/microL), bilirubin levels greater than 1.5 times normal, or greater than grade 1 neuropathy. Patients with MBC continue treatment until disease progression. Patients with LABC receive one to two cycles before proceeding to surgery if resectable. Thus far, 15 patients, eight with MBC and seven with LABC, are assessable for response and/or toxicity. Most patients have required dose modification, with median delivery of 75% (cycle 1) and 50% (cycle 2) of the planned dose of paclitaxel. Neutropenia has been the most common cause of dose reductions, although only one patient required treatment for neutropenic fever. Six patients have developed grade 2/3 peripheral sensory neuropathy, but with dose reductions many have continued treatment with stable or improving neurologic symptoms. Objective responses have been seen in 12 of 14 assessable patients, including six with MBC (one complete response, five partial responses) and six with LABC (two complete responses, four partial responses), for an overall response rate of 86% (95% confidence interval, 66% to 96%). All responding LABC patients have been rendered free from disease at surgery. These preliminary results are very encouraging. Accrual to the study continues.

Weekly paclitaxel as a radiation sensitizer for locally advanced gastric and pancreatic cancers: the Brown University Oncology Group experience

Many patients with cancer of the stomach or pancreas have locally advanced, unresectable disease at diagnosis or will develop an early local or regional recurrence despite potentially curative surgery. Effective local treatment could increase the proportion of patients able to undergo surgery and decrease locoregional recurrences, which should improve overall survival. External beam radiation (RT) by itself has little effect. Standard treatment, such as RT with concurrent administration of 5-fluorouracil-based chemotherapy as a radiation sensitizer, has, at best, a modest impact on locoregional recurrences and survival. The use of a more effective radiosensitizer might improve the efficacy of local treatment. Paclitaxel synchronizes cells at G2M, the phase of the cell cycle during which cells are most sensitive to the effects of ionizing radiation, and has been demonstrated to sensitize a variety of human cell lines to the effects of RT. In patients with locally advanced non-small cell lung cancer (NSCLC), the Brown University Oncology Group (BrUOG) has demonstrated a high response rate to low-dose weekly paclitaxel with concurrent RT. In addition, we demonstrated that the response to paclitaxel/RT was not affected by mutations in the p53 tumor suppressor gene. This suggested that paclitaxel/RT would be a rational treatment approach for other malignancies with a high frequency of p53 mutations, such as gastric and pancreatic cancers. We have completed a phase I study of weekly paclitaxel and concurrent radiation for locally advanced gastric and pancreatic cancers. The maximum tolerated dose of paclitaxel was 50mg/m2/week for six weeks with 50 Gray (Gy) abdominal radiation. The dose limiting toxicities were abdominal pain, nausea and anorexia. Preliminary response data from ongoing phase II studies suggest that preoperative paclitaxel/RT has substantial activity in patients with locally advanced gastric and pancreatic cancers, though whether this will translate into improved disease-free and overall survival in these patients is not known.