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Journal of Clinical Oncology

Journal of Clinical Oncology RSS feed - Early Release
Journal of Clinical Oncology










Purpose

Treatment decisions in clinical oncology are guided by results from phase III randomized clinical trials (RCTs). The results of subgroup analyses may be potentially important in individualizing patient care. We investigated the appropriateness of the use and interpretation of subgroup analyses in oncology RCTs on the basis of the CONSORT statement requirements.

Methods

Phase III RCTs published between January 1, 2011, and December 31, 2013, were reviewed to identify eligible studies of solid tumor treatments. Information related to the subgroup analyses included prespecification, number, subgroup factors, interaction test use, and claim of subgroup difference.

Results

A total of 221 publications reporting data on 184,500 patients were analyzed. One hundred eighty-eight (85%) RCTs were reported with subgroup analyses. Of those, 146 (78%) trials were reported with at least six subgroups. For the majority of trials with subgroup analyses (173; 92%), the actual number of subgroup analyses conducted cannot be determined. Only 59 (31%) RCTs were reported with fully prespecified subgroups and only 64 (34%) trials were reported with interaction tests. In addition, 102 (54%) RCTs were reported with claims of subgroup differences. Of those, only 18 claims of RCTs (18%) were based on significant interaction test results.

Conclusion

The reporting of subgroup analyses in contemporary oncology RCTs is neither uniform nor complete; it requires improvement to ensure consistency and to provide critical information for guiding patient care. Major problems include testing of a large number of subgroups, subgroups without prespecifications, and inadequate use of interaction tests.


Purpose

Programmed death 1 is an immune checkpoint that suppresses antitumor immunity. Nivolumab, a fully human immunoglobulin G4 programmed death 1 immune checkpoint inhibitor antibody, was active and generally well tolerated in patients with advanced solid tumors treated in a phase I trial with expansion cohorts. We report overall survival (OS), response durability, and long-term safety in patients with non–small-cell lung cancer (NSCLC) receiving nivolumab in this trial.

Patients and Methods

Patients (N = 129) with heavily pretreated advanced NSCLC received nivolumab 1, 3, or 10 mg/kg intravenously once every 2 weeks in 8-week cycles for up to 96 weeks. Tumor burden was assessed by RECIST (version 1.0) after each cycle.

Results

Median OS across doses was 9.9 months; 1-, 2-, and 3-year OS rates were 42%, 24%, and 18%, respectively, across doses and 56%, 42%, and 27%, respectively, at the 3-mg/kg dose (n = 37) chosen for further clinical development. Among 22 patients (17%) with objective responses, estimated median response duration was 17.0 months. An additional six patients (5%) had unconventional immune-pattern responses. Response rates were similar in squamous and nonsquamous NSCLC. Eighteen responding patients discontinued nivolumab for reasons other than progressive disease; nine (50%) of those had responses lasting > 9 months after their last dose. Grade 3 to 4 treatment-related adverse events occurred in 14% of patients. Three treatment-related deaths (2% of patients) occurred, each associated with pneumonitis.

Conclusion

Nivolumab monotherapy produced durable responses and encouraging survival rates in patients with heavily pretreated NSCLC. Randomized clinical trials with nivolumab in advanced NSCLC are ongoing.


Purpose

Neurotoxic effects of brain irradiation include cognitive impairment in 50% to 90% of patients. Prior studies have suggested that donepezil, a neurotransmitter modulator, may improve cognitive function.

Patients and Methods

A total of 198 adult brain tumor survivors ≥ 6 months after partial- or whole-brain irradiation were randomly assigned to receive a single daily dose (5 mg for 6 weeks, 10 mg for 18 weeks) of donepezil or placebo. A cognitive test battery assessing memory, attention, language, visuomotor, verbal fluency, and executive functions was administered before random assignment and at 12 and 24 weeks. A cognitive composite score (primary outcome) and individual cognitive domains were evaluated.

Results

Of this mostly middle-age, married, non-Hispanic white sample, 66% had primary brain tumors, 27% had brain metastases, and 8% underwent prophylactic cranial irradiation. After 24 weeks of treatment, the composite scores did not differ significantly between groups (P = .48); however, significant differences favoring donepezil were observed for memory (recognition, P = .027; discrimination, P = .007) and motor speed and dexterity (P = .016). Significant interactions between pretreatment cognitive function and treatment were found for cognitive composite (P = .01), immediate recall (P = .05), delayed recall (P = .004), attention (P = .01), visuomotor skills (P = .02), and motor speed and dexterity (P < .001), with the benefits of donepezil greater for those who were more cognitively impaired before study treatment.

Conclusion

Treatment with donepezil did not significantly improve the overall composite score, but it did result in modest improvements in several cognitive functions, especially among patients with greater pretreatment impairments.


Purpose

We examined the impact of different epidermal growth factor receptor (EGFR) mutations and clinical characteristics on progression-free survival (PFS) in patients with advanced EGFR-mutated non–small-cell lung cancer treated with EGFR tyrosine kinase inhibitors (TKIs) as first-line therapy.

Patients and Methods

This meta-analysis included randomized trials comparing EGFR TKIs with chemotherapy. We calculated hazard ratios (HRs) and 95% CIs for PFS for the trial population and prespecified subgroups and calculated pooled estimates of treatment efficacy using the fixed-effects inverse-variance-weighted method. All statistical tests were two sided.

Results

In seven eligible trials (1,649 patients), EGFR TKIs, compared with chemotherapy, significantly prolonged PFS overall (HR, 0.37; 95% CI, 0.32 to 0.42) and in all subgroups. For tumors with exon 19 deletions, the benefit was 50% greater (HR, 0.24; 95% CI, 0.20 to 0.29) than for tumors with exon 21 L858R substitution (HR, 0.48; 95% CI, 0.39 to 0.58; Pinteraction < .001). Never-smokers had a 36% greater benefit (HR, 0.32; 95% CI, 0.27 to 0.37) than current or former smokers (HR, 0.50; 95% CI, 0.40 to 0.63; Pinteraction < .001). Women had a 27% greater benefit (HR, 0.33; 95% CI, 0.28 to 0.38) than men (HR, 0.45; 95% CI, 0.36 to 0.55; treatment-sex interaction P = .02). Performance status, age, ethnicity, and tumor histology did not significantly predict additional benefit from EGFR TKIs.

Conclusion

Although EGFR TKIs significantly prolonged PFS overall and in all subgroups, compared with chemotherapy, greater benefits were observed in those with exon 19 deletions, never-smokers, and women. These findings should enhance drug development and economic analyses, as well as the design and interpretation of clinical trials.


Purpose

Quitting smoking provides important health benefits to patients with cancer. A cancer diagnosis may motivate quitting—potentially providing a teachable moment in which oncologists can encourage and assist patients to quit—but little is known about whether a recent cancer diagnosis (including diagnosis of a cancer that is less strongly linked to smoking) is associated with increased quitting.

Methods

Cancer Prevention Study-II Nutrition Cohort participants reported smoking status at enrollment in 1992 to 1993 and approximately biennially through 2009. Quit rates of smokers diagnosed with cancer during 2- and 4-year intervals were compared with those of smokers not diagnosed with cancer (12,182 and 12,538 smokers in 2- and 4-year analyses, respectively). Cancers likely to cause physical limitations or symptoms that could influence smoking (cancers of the lung, head and neck, esophagus, or any metastatic cancer) were excluded. Logistic regressions calculated quit rates controlling for age, sex, survey year, cardiovascular disease, and chronic obstructive pulmonary disease.

Results

The 2-year quit rate was higher among the 772 smokers who were diagnosed with cancer (31.3%; 95% CI, 28.0% to 34.5%) than among smokers not diagnosed with cancer (19.5%; 95% CI, 19.0% to 19.9%). A similar difference was observed for 4-year quit rates (43.0% v 33.8%). Results were similar by cancer site and stage.

Conclusion

A diagnosis of cancer, even a cancer not strongly related to smoking and with a relatively good prognosis, may be associated with increased quitting that is sustained well after diagnosis. Results support the hypothesis that a cancer diagnosis presents a teachable moment that can be capitalized on to promote cessation.


Purpose

To evaluate preferences for and experiences with genetic testing in a diverse cohort of patients with breast cancer identified through population-based registries, with attention to differences by race/ethnicity.

Methods

We surveyed women diagnosed with nonmetastatic breast cancer from 2005 to 2007, as reported to the SEER registries of metropolitan Los Angeles and Detroit, about experiences with hereditary risk evaluation. Multivariable models evaluated correlates of a strong desire for genetic testing, unmet need for discussion with a health care professional, and receipt of testing.

Results

Among 1,536 patients who completed the survey, 35% expressed strong desire for genetic testing, 28% reported discussing testing with a health care professional, and 19% reported test receipt. Strong desire for testing was more common in younger women, Latinas, and those with family history. Minority patients were significantly more likely to have unmet need for discussion (failure to discuss genetic testing with a health professional when they had a strong desire for testing): odds ratios of 1.68, 2.44, and 7.39 for blacks, English-speaking Latinas, and Spanish-speaking Latinas compared with whites, respectively. Worry in the long-term survivorship period was higher among those with unmet need for discussion (48.7% v 24.9%; P <.001). Patients who received genetic testing were younger, less likely to be black, and more likely to have a family cancer history.

Conclusion

Many patients, especially minorities, express a strong desire for genetic testing and may benefit from discussion to clarify risks. Clinicians should discuss genetic risk even with patients they perceive to be at low risk, as this may reduce worry.


Purpose

The phase III North American Intergroup E2496 Trial (Combination Chemotherapy With or Without Radiation Therapy in Treating Patients With Hodgkin's Lymphoma) compared doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) with mechlorethamine, doxorubicin, vincristine, bleomycin, vinblastine, etoposide, and prednisone (Stanford V). We report results of a planned subgroup analysis in patients with stage I or II bulky mediastinal Hodgkin lymphoma (HL).

Patients and Methods

Patients were randomly assigned to six to eight cycles of ABVD every 28 days or Stanford V once per week for 12 weeks. Two to 3 weeks after completion of chemotherapy, all patients received 36 Gy of modified involved field radiotherapy (IFRT) to the mediastinum, hila, and supraclavicular regions. Patients on the Stanford V arm received IFRT to additional sites ≥ 5 cm at diagnosis. Primary end points were failure-free survival (FFS) and overall survival (OS).

Results

Of 794 eligible patients, 264 had stage I or II bulky disease, 135 received ABVD, and 129 received Stanford V. Patient characteristics were matched. The overall response rate was 83% with ABVD and 88% with Stanford V. At a median follow-up of 6.5 years, the study excluded a difference of more than 21% in 5-year FFS and more than 16% in 5-year OS between ABVD and Stanford V (5-year FFS: 85% v 79%; HR, 0.68; 95% CI, 0.37 to 1.25; P = .22; 5-year OS: 96% v 92%; HR, 0.49; 95% CI, 0.16 to 1.47; P = .19). In-field relapses occurred in < 10% of the patients in each arm.

Conclusion

For patients with stage I or II bulky mediastinal HL, no substantial statistically significant differences were detected between the two regimens, although power was limited. To the best of our knowledge, this is the first prospective trial reporting outcomes specific to this subgroup, and it sets a benchmark for comparison of ongoing and future studies.


Purpose

Evidence supporting the clinical utility of predictive biomarkers of anthracycline activity is weak, with a recent meta-analysis failing to provide strong evidence for either HER2 or TOP2A. Having previously shown that duplication of chromosome 17 pericentromeric alpha satellite as measured with a centromere enumeration probe (CEP17) predicted sensitivity to anthracyclines, we report here an individual patient–level pooled analysis of data from five trials comparing anthracycline-based chemotherapy with CMF (cyclophosphamide, methotrexate, and fluorouracil) as adjuvant chemotherapy for early breast cancer.

Patients and Methods

Fluorescent in situ hybridization for CEP17, HER2, and TOP2A was performed in three laboratories on samples from 3,846 of 4,864 eligible patients from five trials evaluating anthracycline-containing chemotherapy versus CMF. Methodologic differences did not affect HER2-to-CEP17 ratios but necessitated different definitions for CEP17 duplication: > 1.86 observed copies per cell for BR9601, NEAT, Belgian, and DBCG89D trials and > 2.25 for the MA.5 trial.

Results

Fluorescent in situ hybridization data were available in 89.3% (HER2), 83.9% (CEP17), and 80.6% (TOP2A) of 3,846 patient cases with available tissue. Both CEP17and TOP2A treatment-by-marker interactions remained significant in adjusted analyses for recurrence-free and overall survival, whereas HER2 did not. A combined CEP17 and TOP2A–adjusted model predicted anthracycline benefit across all five trials for both recurrence-free (hazard ratio, 0.64; 95% CI, 0.51 to 0.82; P = .001) and overall survival (hazard ratio, 0.66; 95% CI, 0.51 to 0.85; P = .005).

Conclusion

This prospectively planned individual-patient pooled analysis of patient cases from five adjuvant trials confirms that patients whose tumors harbor either CEP17 duplication or TOP2A aberrations, but not HER2 amplification, benefit from adjuvant anthracycline chemotherapy.










Purpose

AUY922 is an HSP90 inhibitor that causes degradation of HSP chaperones and their client proteins, including epidermal growth factor receptor. We conducted a phase I/II trial to evaluate AUY922 and erlotinib for patients with EGFR-mutant lung cancer and disease progression during erlotinib treatment.

Patients and Methods

All patients had developed acquired resistance after treatment with erlotinib and underwent repeat tumor biopsies before study entry to assess for EGFR T790M. In phase I, 18 patients were treated with AUY922 intravenously once per week and erlotinib once per day in 28-day cycles using a 3 + 3 dose-escalation design. In phase II, 19 additional patients were treated at the maximum-tolerated dose. The primary end point of the phase II trial was complete plus partial response rate.

Results

In phase I (n = 18), three patients were treated in each cohort, except the highest-dose cohort (AUY922 70 mg and erlotinib 150 mg), which expanded to six patients because of a dose-limiting toxicity (ie, junctional cardiac rhythm). Common drug-related adverse events were diarrhea, skin rash, hyperglycemia, and night blindness. All patients treated at maximum-tolerated dose (n = 25) were evaluable for response. The partial response rate was 16% (four of 25 patients; 95% CI, 5% to 36%) and was independent of tumor T790M status.

Conclusion

Partial responses were observed, but the duration of treatment with AUY922 and erlotinib was limited by toxicities, especially night blindness. This phase II study of AUY922 and erlotinib did not meet its primary end point.



Purpose

Autologous stem-cell transplantation (ASCT) has shown to provide curative benefit in patients with relapsed lymphoma and multiple myeloma (MM), often requiring hematopoietic support until marrow engraftment. Because of Jehovah's Witnesses' (JW) refusal of blood products, treatment challenges arise. This study represents 125 JWs with lymphoma (n = 55), MM (n = 68), or amyloidosis (n = 2), treated with high-dose chemotherapy (HDC) and ASCT without transfusions.

Patients and Methods

Priming with intravenous iron and erythropoietin occurred to increase hemoglobin (Hb) pretransplantation. Cytokine mobilization of stem-cells was used. Delay to HDC was done to allow Hb and platelets to approach 11 g/dL and 100 x 103/μL, respectively. Patients with MM received a standard dose of melphalan 200 mg/m2, with dose reduction for severe kidney dysfunction. Patients with lymphoma received carmustine 300 mg/m2, cyclophosphamide 1,500 mg/m2 on days 2 through 5 (total 6 g/m2), and etoposide 700 mg/m2 per day on days 2 through 4 (total 2,100 mg/m2). Post-transplantation, a combination of granulocyte colony-stimulating factor, erythropoietin, aminocaproic acid, and phytonadione was administered.

Results

There were two major and 15 minor bleeding complications, none occurring at platelets less than 5.0 x 103/μL, with six (4.8%) treatment-related mortalities. The median decrease in Hb was 5.0 g/dL, with median Hb nadir of 7.0 g/dL. The median number of days with platelet count less than 10 x 103/μL was 3, with median platelet nadir of 5.0 x 103/μL. Cardiac complications occurred in 40 patients (32%).

Conclusion

ASCT can safely be performed without transfusion support. A platelet transfusion trigger of ≤ 5 x 103/μL may be appropriate in select patients. Pharmacotherapy and cardiac monitoring are effective in the management of cardiac complications.













Purpose

Cixutumumab, formerly IMC-A12, is a recombinant human monoclonal immunoglobulin G1 antibody that targets insulin-like growth factor I receptor (IGF-IR). Cixutumumab was synergistic with castration in a hormone-sensitive prostate cancer xenograft model.

Patients and Methods

Patients with new metastatic prostate cancer were randomly assigned within 30 days of initiating androgen deprivation (AD) to cixutumumab added to a luteinizing hormone–releasing hormone agonist with bicalutamide versus AD alone. With 180 patients and one-sided alpha of 0.10, there would be 90% power to detect an absolute 20% difference in undetectable prostate-specific antigen (PSA; ≤ 0.2 ng/mL) rate at 28 weeks (relative risk, 1.44); this end point was previously strongly correlated with survival. Secondary end points included the proportion of patients with PSA > 4.0 ng/mL, safety and tolerability, circulating tumor cell (CTC) levels, and seven plasma IGF-IR biomarkers. Fisher's exact test was used for the primary end point, and extended Mantel-Haenszel 2 test was used for three PSA response categories.

Results

The trial accrued 210 eligible patients (105 randomly assigned to each arm). Patient characteristics were similar in both arms. Undetectable PSA rate was 42 (40.0%) of 105 for cixutumumab plus AD and 34 (32.3%) of 105 for AD alone (relative risk, 1.24; one-sided P = .16). Lower baseline CTCs (0 v 1 to 4 v ≥ 5/7.5 mL whole blood) were associated with higher rate of PSA response (three categories; P = .036) in 39 evaluable patients. IGF-IR biomarkers were not correlated with PSA outcome, and cixutumumab did not significantly change these biomarker levels.

Conclusion

Cixutumumab plus AD did not significantly increase the undetectable PSA rate in men with new metastatic hormone-sensitive prostate cancer. CTCs at baseline may carry prognostic value.



Purpose

This study was undertaken to determine the magnitude of pulmonary dysfunction in childhood cancer survivors when compared with healthy controls and the extent (and predictors) of decline over time.

Patients and Methods

Survivors underwent baseline (t1) pulmonary function tests, followed by a second comprehensive evaluation (t2) after a median of 5 years (range, 1.0 to 10.3 years). Survivors were also compared with age- and sex-matched healthy controls at t2.

Results

Median age at cancer diagnosis was 16.5 years (range, 0.2 to 21.9 years), and time from diagnosis to t2 was 17.1 years (range, 6.3 to 40.1 years). Compared with odds for healthy controls, the odds of restrictive defects were increased 6.5-fold (odds ratio [OR], 6.5; 95% CI, 1.5 to 28.4; P < .01), and the odds of diffusion abnormalities were increased 5.2-fold (OR, 5.2; 95% CI, 1.8 to 15.5; P < .01). Among survivors, age younger than 16 years at diagnosis (OR, 3.0; 95% CI, 1.2 to 7.8; P = .02) and exposure to more than 20 Gy chest radiation (OR, 5.6; 95% CI, 1.5 to 21.0; P = .02, referent, no chest radiation) were associated with restrictive defects. Female sex (OR, 3.9; 95% CI, 1.7 to 9.5; P < .01) and chest radiation dose (referent: no chest radiation; ≤ 20 Gy: OR, 6.4; 95% CI, 1.7 to 24.4; P < .01; > 20 Gy: OR, 11.3; 95% CI, 2.6 to 49.5; P < .01) were associated with diffusion abnormalities. Among survivors with normal pulmonary function tests at t1, females and survivors treated with more than 20 Gy chest radiation demonstrated decline in diffusion function over time.

Conclusion

Childhood cancer survivors exposed to pulmonary-toxic therapy are significantly more likely to have restrictive and diffusion defects when compared with healthy controls. Diffusion capacity declines with time after exposure to pulmonary-toxic therapy, particularly among females and survivors treated with high-dose chest radiation. These individuals could benefit from subsequent monitoring.


Purpose

Allogeneic stem-cell transplantation (SCT) induces long-term remission in a fraction of patients with high-risk chronic lymphocytic leukemia (CLL) or Richter's transformation (RT). Our purpose was to determine the outcomes of patients whose disease progressed after allogeneic SCT.

Patients and Methods

We retrospectively analyzed the outcomes of 72 patients (52 with CLL and 20 with RT) who underwent allogeneic SCT between 1998 and 2011 and had documented progression after transplantation. Twenty-two (31%) never had a response, and 50 (69%) had a response but experienced relapse after a median of 7 months (range, 2 to 85 months). Forty-eight patients who were receiving or were candidates to receive post-SCT cell-based therapies were not included in this analysis.

Results

The median age at time of transplantation was 58 years (range, 30 to 72 years). Sixty-two patients (86%) received more than two treatment regimens and 37 (51%) received more than three treatment regimens before SCT. Sixty-six patients (92%) had active disease at the time of transplantation. The 2- and 5-year survival rates were 67% and 38% (patients with CLL) and 36% and 0% (patients with RT). The patients who developed acute or chronic graft-versus-host disease had a longer overall survival (OS; P = .05). In a multivariable analysis, RT or low hemoglobin at the time of SCT predicted shorter OS. Chronic graft-versus-host disease and an initial response to SCT predicted longer OS.

Conclusion

Patients with CLL in whom allogeneic SCT fails may have a response to and benefit from salvage therapies, and their prognosis is relatively good.



Purpose

The identification of patients with metastatic triple-negative breast cancer (mTNBC) who are expected to benefit from platinum-based chemotherapy is of interest. We conducted a single-arm phase II clinical trial of single-agent platinum for mTNBC with biomarker correlates.

Patients and Methods

Patients with mTNBC received first- or second-line cisplatin (75 mg/m2) or carboplatin (area under the concentration-time curve 6) by physician's choice once every 3 weeks. Coprimary end points were objective response rate (RR) and response prediction by p63/p73 gene expression. Secondary and exploratory end points included toxicity assessment, RR in cisplatin versus carboplatin, and RR in molecularly defined subgroups, including BRCA1/2 mutation carriers.

Results

Patients (N = 86; 69 as first-line therapy) received cisplatin (n = 43) or carboplatin (n = 43). RR was 25.6% (95% CI, 16.8% to 36%) and was numerically higher with cisplatin (32.6%) than with carboplatin (18.7%). RR was 54.5% in patients with germline BRCA1/2 mutations (n = 11). In patients without BRCA1/2 mutations (n = 66), exploratory analyses showed that a BRCA-like genomic instability signature (n = 32) discriminated responding and nonresponding tumors (mean homologous recombination deficiency–loss of heterozygosity/homologous recombination deficiency–large-scale state transitions [HRD-LOH/HRD-LST] scores were 12.68 and 5.11, respectively), whereas predefined analysis by p63/p73 expression status (n = 61), p53 and PIK3CA mutation status (n = 53), or PAM50 gene expression subtype (n = 55) did not. Five of the six long-term responders alive at a median of 4.5 years lacked germline BRCA1/2 mutations, and two of them had increased tumor HRD-LOH/HRD-LST scores.

Conclusion

Platinum agents are active in mTNBC, especially in patients with germline BRCA1/2 mutations. A measure of tumor DNA repair function may identify patients without mutations who could benefit from platinum therapy agents. Prospective controlled confirmatory trials are warranted.


Purpose

This study was designed to assess efficacy, safety, and predictors of response to iniparib in combination with gemcitabine and carboplatin in early-stage triple-negative and BRCA1/2 mutation–associated breast cancer.

Patients and Methods

This single-arm phase II study enrolled patients with stage I to IIIA (T ≥ 1 cm) estrogen receptor–negative (≤ 5%), progesterone receptor–negative (≤ 5%), and human epidermal growth factor receptor 2–negative or BRCA1/2 mutation–associated breast cancer. Neoadjuvant gemcitabine (1,000 mg/m2 intravenously [IV] on days 1 and 8), carboplatin (area under curve of 2 IV on days 1 and 8), and iniparib (5.6 mg/kg IV on days 1, 4, 8, and 11) were administered every 21 days for four cycles, until the protocol was amended to six cycles. The primary end point was pathologic complete response (no invasive carcinoma in breast or axilla). All patients underwent comprehensive BRCA1/2 genotyping, and homologous recombination deficiency was assessed by loss of heterozygosity (HRD-LOH) in pretreatment core breast biopsies.

Results

Among 80 patients, median age was 48 years; 19 patients (24%) had germline BRCA1 or BRCA2 mutations; clinical stage was I (13%), IIA (36%), IIB (36%), and IIIA (15%). Overall pathologic complete response rate in the intent-to-treat population (n = 80) was 36% (90% CI, 27 to 46). Mean HRD-LOH scores were higher in responders compared with nonresponders (P = .02) and remained significant when BRCA1/2 germline mutations carriers were excluded (P = .021).

Conclusion

Preoperative combination of gemcitabine, carboplatin, and iniparib is active in the treatment of early-stage triple-negative and BRCA1/2 mutation–associated breast cancer. The HRD-LOH assay was able to identify patients with sporadic triple-negative breast cancer lacking a BRCA1/2 mutation, but with an elevated HRD-LOH score, who achieved a favorable pathologic response. Confirmatory controlled trials are warranted.


Purpose

Glycoprotein NMB (gpNMB), a negative prognostic marker, is overexpressed in multiple tumor types. Glembatumumab vedotin is a gpNMB-specific monoclonal antibody conjugated to the potent cytotoxin monomethyl auristatin E. This phase II study investigated the activity of glembatumumab vedotin in advanced breast cancer by gpNMB expression.

Patients and Methods

Patients (n = 124) with refractory breast cancer that expressed gpNMB in ≥ 5% of epithelial or stromal cells by central immunohistochemistry were stratified by gpNMB expression (tumor, low stromal intensity, high stromal intensity) and were randomly assigned 2:1 to glembatumumab vedotin (n = 83) or investigator's choice (IC) chemotherapy (n = 41). The study was powered to detect overall objective response rate (ORR) in the glembatumumab vedotin arm between 10% (null) and 22.5% (alternative hypothesis) with preplanned investigation of activity by gpNMB distribution and/or intensity (Stratum 1 to Stratum 3).

Results

Glembatumumab vedotin was well tolerated as compared with IC chemotherapy (less hematologic toxicity; more rash, pruritus, neuropathy, and alopecia). ORR was 6% (five of 83) for glembatumumab vedotin versus 7% (three of 41) for IC, without significant intertreatment differences for predefined strata. Secondary end point revealed ORR of 12% (10 of 83) versus 12% (five of 41) overall, and 30% (seven of 23) versus 9% (one of 11) for gpNMB overexpression (≥ 25% of tumor cells). Unplanned analysis showed ORR of 18% (five of 28) versus 0% (0 of 11) in patients with triple-negative breast cancer (TNBC), and 40% (four of 10) versus 0% (zero of six) in gpNMB-overexpressing TNBC.

Conclusion

Glembatumumab vedotin is well tolerated in heavily pretreated patients with breast cancer. Although the primary end point in advanced gpNMB-expressing breast cancer was not met for all enrolled patients (median tumor gpNMB expression, 5%), activity may be enhanced in patients with gpNMB-overexpressing tumors and/or TNBC. A pivotal phase II trial (METRIC [Metastatic Triple-Negative Breast Cancer]) is underway.