The role of serum thymidine kinase 1 activity in neoadjuvant-treated HER2-positive breast cancer: biomarker analysis from the Swedish phase II randomized PREDIX HER2 trial

BACKGROUND

Thymidine kinase 1 (TK1) plays a pivotal role in DNA synthesis and cellular proliferation. TK1 has been studied as a prognostic marker and as an early indicator of treatment response in human epidermal growth factor 2 (HER2)-negative early and metastatic breast cancer (BC). However, the prognostic and predictive value of serial TK1 activity in HER2-positive BC remains unknown.

METHODS

In the PREDIX HER2 trial, 197 HER2-positive BC patients were randomized to neoadjuvant trastuzumab, pertuzumab, and docetaxel (DPH) or trastuzumab emtansine (T-DM1), followed by surgery and adjuvant epirubicin and cyclophosphamide. Serum samples were prospectively collected from all participants at multiple timepoints: at baseline, after cycle 1, 2, 4, and 6, at end of adjuvant therapy, annually for a total period of 5 years and/or at the time of recurrence. The associations of sTK1 activity with baseline characteristics, pathologic complete response (pCR), event-free survival (EFS), and disease-free survival (DFS) were evaluated.

RESULTS

No association was detected between baseline sTK1 levels and all the baseline clinicopathologic characteristics. An increase of TK1 activity from baseline to cycle 2 was seen in all cases. sTK1 level at baseline, after 2 and 4 cycles was not associated with pCR status. After a median follow-up of 58 months, 23 patients had EFS events. There was no significant effect between baseline or cycle 2 sTK1 activity and time to event. A non-significant trend was noted among patents with residual disease (non-pCR) and high sTK1 activity at the end of treatment visit, indicating a potentially worse long-term prognosis.

CONCLUSION

sTK1 activity increased following neoadjuvant therapy for HER2-positive BC but was not associated with patient outcomes or treatment benefit. However, the post-surgery prognostic value in patients that have not attained pCR warrants further investigation.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02568839. Registered on 6 October 2015.

Serum thymidine kinase 1 and its kinetics in HER2-positive breast cancer: Results from the Swedish phase II PREDIX HER2 trial

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Background: Thymidine kinase 1 (TK1) plays a pivotal role in DNA synthesis and cellular proliferation. TK1 has been studied as a prognostic marker and as an early indicator of treatment response in HER2-negative early and metastatic breast cancer (BC). Here we present the first report of TK1 in HER2-postitive BC. Methods: In the PREDIX HER2 trial, 202 patients with HER2-positive BC were randomized to 6 cycles of neoadjuvant trastuzumab, pertuzumab and docetaxel or trastuzumab emtansine every three weeks followed by surgery and adjuvant epirubicin and cyclophosphamide. Serum was prospectively collected from all participants at multiple timepoints: At baseline, after cycles 2, 4 and 6, at end of adjuvant therapy and then annually for 5 years and in case of recurrence. TK1 activity was measured by DiviTum assay (Biovica, Sweden), blinded to treatment allocation, patient characteristics and outcome. TK1 activity was correlated with baseline characteristics, pathologic complete response (pCR) and event-free survival (EFS). Results: Baseline TK1 activity as categorical variable was not associated with tumor size or hormone receptor expression. An increase of TK1 activity was seen in the majority of cases after treatment (mean TK1 at baseline = 111.7, after cycle 2 = 1257.0, after cycle 4 = 1157.0, after cycle 6 = 1178.0). Neither baseline TK1, on-treatment TK1 nor its change from baseline to cycle 2 were significantly associated with pCR in multivariable logistic regression analysis (Table). Baseline TK1 activity was not predictive for differential benefit to the study treatments ( pinteraction = 0.19). After a median follow-up of 52.5 months, 21 patients had EFS events. There was no significant correlation between baseline TK1 activity and EFS in multivariable Cox regression analysis. Conclusions: Serum TK1 activity in HER2-positive BC increased following treatment with neoadjuvant therapy but was not correlated to pCR rates or EFS. [Table: see text]

Neoadjuvant Trastuzumab, Pertuzumab, and Docetaxel vs Trastuzumab Emtansine in Patients With ERBB2-Positive Breast Cancer: A Phase 2 Randomized Clinical Trial

Importance

Trastuzumab emtansine (T-DM1) is presently approved for treatment of advanced breast cancer and after incomplete response to neoadjuvant therapy, but the potential of T-DM1 as monotherapy is so far unknown.

Objective

To assess pathologic complete response (pCR) to standard neoadjuvant therapy of combination docetaxel, trastuzumab, and pertuzumab (DTP) vs T-DM1 monotherapy in patients with ERBB2 (formerly HER2)-positive breast cancer.

Design, Setting, and Participants

This randomized phase 2 trial, conducted at 9 sites in Sweden, enrolled 202 patients between December 1, 2014, and October 31, 2018. Participants were 18 years or older, with ERBB2-positive tumors larger than 20 mm and/or verified lymph node metastases. Analysis was performed on an intention-to-treat basis.

Interventions

Patients were randomized to receive 6 cycles of DTP (standard group) or T-DM1 (investigational group). Crossover was recommended at lack of response or occurrence of intolerable toxic effects. Assessment with fluorine 18-labeled fluorodeoxyglucose (18F-FDG) positron emission tomography combined with computed tomography (PET-CT) was performed at baseline and after 2 and 6 treatment cycles.

Main Outcome and Measures

Pathologic complete response, defined as ypT0 or Tis ypN0. Secondary end points were clinical and radiologic objective response; event-free survival, invasive disease-free survival, distant disease-free survival, and overall survival; safety; health-related quality of life (HRQoL); functional and biological tumor characteristics; and frequency of breast-conserving surgery.

Results

Overall, 202 patients were randomized; 197 (99 women in the standard group [median age, 51 years (range, 26-73 years)] and 98 women in the investigational group [median age, 53 years (range, 28-74 years)]) were evaluable for the primary end point. Pathologic complete response was achieved in 45 patients in the standard group (45.5%; 95% CI 35.4%-55.8%) and 43 patients in the investigational group (43.9%; 95% CI 33.9%-54.3%). The difference was not statistically significant (P = .82). In a subgroup analysis, the pCR rate was higher in hormone receptor-negative tumors than in hormone receptor-positive tumors in both treatment groups (45 of 72 [62.5%] vs 45 of 125 [36.0%]). Three patients in the T-DM1 group experienced progression during therapy. In an exploratory analysis, tumor-infiltrating lymphocytes at 10% or more (median) estimated pCR significantly (odds ratio, 2.76; 95% CI, 1.42-5.36; P = .003). Response evaluation with 18F-FDG PET-CT revealed a relative decrease of maximum standardized uptake value by more than 31.3% (median) was associated with pCR (odds ratio, 6.67, 95% CI, 2.38-20.00; P < .001).

Conclusions and Relevance

In this study, treatment with standard neoadjuvant combination DTP was equal to T-DM1.

Trial Registrations

ClinicalTrials.gov Identifier: NCT02568839; EudraCT number: 2014-000808-10.

Docetaxel, trastuzumab, pertuzumab versus trastuzumab emtansine as neoadjuvant treatment of HER2-positive breast cancer: Results from the Swedish PREDIX HER2 trial identifying a new potential de-escalation standard?

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Background: Neoadjuvant therapy produces high rates of pathological complete response (pCR) and is the standard of care in HER2 positive breast cancer; however, the optimal treatment regimen remains to be established. Methods: In this randomized phase II study patients ≥18 years with HER2 positive breast cancer > 20mm or verified lymph node metastases were randomized to 6 courses of docetaxel, trastuzumab and pertuzumab (DTP, group A) or trastuzumab emtansine (T-DM1, group B), q 21 days. The protocol allowed switch to the competing treatment upon lack of response or drug-related severe toxicity. Patients received postoperative epirubicin+cyclophosphamide, trastuzumab for a total of one year and endocrine therapy. Accrual was completed in October 2018 after randomization of 202 patients, data on pCR were available for 190 at the time for this abstract submission. Median age, 52 years (26-74), menopausal status, histological type and grade were well balanced between the treatment groups. 62.6% of the tumors were hormone receptor (HR) positive. Results: Primary endpoint was pathological objective response. 190 patients completed the protocol-specified preoperative treatment. pCR was achieved in 45.3% of patients, 46.4% in patients treated with DTP and 44.1% with T-DM1 (chi-sq., p = 0.75). In HR-positive tumors, pCR was obtained in 35.3% of patients, 35.9% in group A vs. 34.6% in group B (p = 0.87); in HR-negative tumors, the overall pCR rate was 62.0%, 66.7% in group A vs. 57.9% in group B (p = 0.45). Severe (grade 3/4) toxicity was reported at 68 occasions related to DTP, compared with 16 related to T-DM1, 26 vs. 3 caused by febrile neutropenia. Significantly better quality of life was reported by patients treated with T-DM1. Conclusions: Our data on TDM-1 demonstrates similar efficacy and less toxicity, in particular for patients with HER2 and HR positive cancers, being a potential new standard for neoadjuvant therapy. Clinical trial information: NCT02568839.

Health-related quality of life in the Swedish PREDIX HER2 trial, evaluating docetaxel, trastuzumab, pertuzumab versus trastuzumab emtansine as neoadjuvant treatment of HER2-positive breast cancer

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Background: Neoadjuvant therapy combining docetaxel, trastuzumab and pertuzumab (DTP) was compared to trastuzumab emtansine (T-DM1) in the randomized phase 2 PREDIX HER2 trial. Patients, ≥18 years with HER2 positive breast cancer, ≥20mm or with verified lymph node metastases, were randomized to six courses of DTP (Standard arm) or T-DM1 (Experimental arm). Primary endpoint was pathological objective response to primary medical therapy at post-treatment surgery. Health related quality of life (HRQoL) was a secondary outcome, and is of specific interest as there was no difference between the randomization groups regarding the main endpoint (results presented in a separate abstract sent to ASCO 2019, Bergh et al.). Methods: Of 202 randomized patients, 190 are available for evaluation at this point. HRQoL was measured, using EORTC QLQ-C30 + EORTC QLQ-BR23, at baseline before randomization and after six courses. Results: No differences between the randomization arms were found at baseline. Results after six courses, based on 163 patients (86%) and adjusted to baseline values, revealed statistical significant differences (p≤0.01), favoring the experimental T-DM1 arm on 7 out of 15 of the EORTC QLQ-C30 variables (Physical functioning, Role functioning, Social functioning, Global quality of Life, Fatigue, Dyspnea, and Diarrhea). For the breast cancer specific questionnaire (EORTC-BR23), the experimental arm scored statistically significantly better on 5 out of 7 subscales (Body image, Sexual functioning, Sexual enjoyment, Systemic therapy side effects and Upset by hair loss). All of the statistical significant differences were of moderate or large clinical significance (≥10 scale scores). No differences between the randomization arms were found for the remaining HRQoL variables. Conclusions: The experimental arm reported better HRQoL than the control arm after six courses. Trastuzumab emtansine may be a useful treatment alternative due to better HRQoL and lower toxicity. Clinical trial information: NCT02568839.

Concentrations of polychlorinated biphenyls in blood and the risk for testicular cancer

An increasing incidence of testicular cancer has been reported from several western countries during the last decades. According to current hypothesis testicular cancer is initiated during the foetal period and exposure to endocrine disruptors such as some persistent organic pollutants has been of concern. We have previously reported the results for concentrations of polychlorinated biphenyls (PCBs), p,p'-dichlorodiphenyl-dichloroethylene (pp'-DDE), hexachlorobenzene (HCB) and chlordanes in 58 cases with testicular cancer, 61 age-matched controls and 44 case mothers and 45 control mothers. In that report, significant increase of odds ratio (OR) was found for sum of PCBs, HCB, trans- and cis-nonachlordane in case mothers. These data have now been further analysed for 37 congeners of PCBs. No significant differences were found among cases and controls. However, case mothers had significantly increased concentrations of a number of PCB congeners. A priori decided grouping of PCBs yielded for oestrogenic PCBs OR = 2.4, 95% confidence interval (CI) = 0.95-6.0, enzyme-inducing PCBsOR = 2.6, 95% CI = 1.03-6.5 and toxic equivalents (TEQ) yielded OR = 3.3, 95% CI = 1.3-8.4. These data further elucidate the role of foetal exposure to different PCB congeners in the aetiology of testicular cancer.

Increasing incidence rates of childhood malignant diseases in Sweden during the period 1960–1998

We analysed the trends in incidence rates of childhood cancer in Sweden. All cases of malignant diseases and benign brain tumours in children, 0-14 years old, reported to the Swedish Cancer Registry 1960 to 1998 were included, n=9298. Cases were classified according to the International Classification of Childhood Cancer. Average annual change in incidence rate was calculated to +1.01%, (95% confidence interval CI=0.80, 1.22). An increase in incidence rate per year was found for leukaemia, +0.85% (95% CI=0.42, 1.28), lymphomas +1.87% (95% CI=1.17, 2.58), CNS (central nervous system) tumours +1.45% (95% CI=1.02, 1.88), sympathetic nervous system tumours +1.61% (95% CI=0.79, 2.44), hepatic tumours +2.62% (95% CI=2.02, 3.21), and germ cell and gonadal tumours +1.21% (95% CI=0.23, 2.19). Of the CNS tumours, significant changes were seen for low-grade glioma/astrocytoma +2.10% (95% CI=1.41, 2.80), benign brain tumours +3.77% (95% CI=2.47, 5.10), and PNET/medulloblastoma +1.96% (95% CI=0.48, 3.46). Changes in diagnostic criteria and better diagnostic tools may have contributed to these results.

Increased concentrations of polychlorinated biphenyls, hexachlorobenzene, and chlordanes in mothers of men with testicular cancer

An increasing incidence of testicular cancer has been reported from several countries in the Western world during the last decades. According to current hypothesis, testicular cancer is initiated during the fetal period, and exposure to endocrine disruptors, i.e., xenoestrogens, has been of concern. In this investigation we studied the concentrations of the sum of 38 polychlorinated biphenyls (PCBs), p,p'-dichlorodiphenyl-dichloroethylene, hexachlorobenzene (HCB), and chlordanes, in 61 cases with testicular cancer and 58 age-matched controls. Furthermore, case and control mothers were also asked to participate, and 44 case mothers and 45 control mothers agreed. They were of similar age. In cases only the concentration on lipid basis of cis-nonachlordane was significantly increased, whereas case mothers showed significantly increased concentrations of the sum of PCBs, HCB, trans- and cis-nonachlordane, and the sum of chlordanes. Among case mothers the sum of PCBs yielded an odds ratio (OR) of 3.8; 95% confidence interval (CI), 1.4-10 was calculated using the median concentration for the control mothers as cutoff value. For HCB, OR = 4.4 (95% CI, 1.7-12); for trans-nonachlordane, OR = 4.1 (95% CI, 1.5-11); for cis-nonachlordane, OR = 3.1 (95% CI, 1.2-7.8); and for sum of chlordanes, OR = 1.9 (95% CI, 0.7-5.0). No consistent different risk pattern was found for seminoma or nonseminoma testicular cancer.

Breast-feeding duration and the risk of malignant diseases in childhood in Sweden

OBJECTIVE

To evaluate childhood cancer in relation to duration of breast-feeding.

SETTING

Sweden. Records from Child Healthcare Centres were scrutinised regarding information on breast-feeding and other health-related items.

SUBJECTS

All children aged 0-14 y with a malignant disease (benign brain tumours included) during the time period 1988-91 (n = 962) were identified from the Swedish Cancer Register. An equal number of controls matched for sex and age were selected from the Swedish Birth Register.

RESULTS

Information was obtained for 835 cases and 860 controls. Overall, duration of breast-feeding did not influence the risk for a malignant disease in this age group. However, breast-feeding > or = 1 month increased the risk for non-Hodgkin's lymphoma (NHL) yielding an odds ratio (OR) 5.5 with 95% confidence interval (CI) 1.2-25. Breast-feeding 1 -< 6 months gave OR 5.1, CI 1.1-24 and > 6 months gave OR 7.0, CI 1.3-37 with a significant trend (P = 0.04). Adjustment for maternal and birth-related co-variates gave similar results. For other malignancies no significant changes of the risk were obtained.

CONCLUSIONS

Overall, no association between duration of breast-feeding and childhood malignancies was found except for a significantly increased risk for NHL, but this was based on low numbers of cases and needs to be confirmed in other investigations.

Levels of cadmium, zinc and copper in renal cell carcinoma and normal kidney

Levels (microgram/g dry weight) of cadmium (Cd), zinc (Zn) and copper (Cu) were determined in kidneys with renal cell carcinoma from 20 male and 11 female patients. Autopsied kidneys from nine males and eight females who had died of nonmalignant diseases were used as controls. The mean levels in cortex of Cd was in cases 103.2 and in controls 79.9 (not significantly different). For non-smoking cases, mean level of Cd in cortex was somewhat lower than in the controls. No significant differences were found between cases and controls for Cd levels in the medulla. Zn in cortex was significantly lower in the cases aged > or = 69 years (mean 182.0) than in the corresponding controls (mean 237.6). Zn in medulla was significantly lower in all cases (mean 103.5) than in controls (mean 162.2). The mean level of Cu in the medulla in cases was 10.7 and in controls 13.0 (P = 0.05). No differences were found for Cu levels in cortex.