Incidence and management of diarrhea in patients with HER2-positive breast cancer treated with pertuzumab

Pyrotinib versus placebo in combination with trastuzumab and docetaxel as first line treatment in patients with HER2 positive metastatic breast cancer (PHILA): randomised, double blind, multicentre, phase 3 trial

OBJECTIVE

To assess the efficacy and safety of pyrotinib (an irreversible pan-HER (human epidermal growth factor receptor) inhibitor), trastuzumab, and docetaxel compared with placebo, trastuzumab, and docetaxel for untreated HER2 positive metastatic breast cancer.

DESIGN

Randomised, double blind, placebo controlled, multicentre, phase 3 trial.

SETTING

40 centres in China between 6 May 2019 and 17 January 2022.

PARTICIPANTS

590 female patients (median age 52 (interquartile range 46-58) years) with untreated HER2 positive metastatic breast cancer.

INTERVENTIONS

Eligible patients were randomised 1:1 to receive either oral pyrotinib (400 mg once daily) or placebo, both combined with intravenous trastuzumab (8 mg/kg in cycle 1 and 6 mg/kg in subsequent cycles) and docetaxel (75 mg/m2) on day 1 of each 21 day cycle. Randomisation was stratified by treatment history of trastuzumab in the (neo)adjuvant setting and hormone receptor status. Patients, investigators, and the sponsor's study team were masked to treatment assignment.

MAIN OUTCOME MEASURES

The primary endpoint was progression-free survival as assessed by the investigator.

RESULTS

Of the 590 randomised patients, 297 received pyrotinib, trastuzumab, and docetaxel treatment (pyrotinib group), and 293 received placebo, trastuzumab, and docetaxel treatment (placebo group). At data cut-off on 25 May 2022, the median follow-up was 15.5 months. The median progression-free survival according to the investigator was significantly longer in the pyrotinib group than in the placebo group (24.3 (95% confidence interval 19.1 to 33.0) months versus 10.4 (9.3 to 12.3) months; hazard ratio 0.41 (95% confidence interval 0.32 to 0.53); one sided P<0.001). Treatment related adverse events of grade 3 or higher were reported in 267 (90%) of the 297 patients in the pyrotinib group and 224 (76%) of the 293 patients in the placebo group. No treatment related deaths occurred in the pyrotinib group, and one (<1%; diabetic hyperosmolar coma) treatment related death occurred in the placebo group. Survival and toxicities are still under assessment with longer follow-up.

CONCLUSIONS

Pyrotinib, trastuzumab, and docetaxel showed superiority by significantly improving progression-free survival compared with placebo, trastuzumab, and docetaxel in patients with untreated HER2 positive metastatic breast cancer. The toxicity was manageable. The findings support this dual anti-HER2 regimen as an alternative first line treatment option in this patient population.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03863223.

A Unique Endoscopic Presentation of Colon Metastases From Primary Invasive Lobular Carcinoma of the Breast

Breast cancer is the leading cause of female malignancy-associated death worldwide. The most common sites of metastases are the lung, liver, brain, and skeleton. A 68-year-old female with invasive lobular carcinoma metastatic to the axial skeleton was found to have new skin and colonic metastases discovered on serial surveillance positron emission tomography-computed tomography scans. The colonic metastases did not present with any gastrointestinal symptoms and did not form exophytic masses, which are typically associated. Instead, her colonic metastases presented as unusual diaphragm-like strictures within the left colon discovered on endoscopy, which is a relatively rare phenomenon. This case raises awareness of and elucidates new manners of presentation of metastatic invasive lobular carcinoma within the colon.

HALT-D: a randomized open-label phase II study of crofelemer for the prevention of chemotherapy-induced diarrhea in patients with HER2-positive breast cancer receiving trastuzumab, pertuzumab, and a taxane

PURPOSE

To assess whether crofelemer would prevent chemotherapy-induced diarrhea (CID) diarrhea in patients with HER2-positive, any-stage breast cancer receiving trastuzumab (H), pertuzumab (P), and a taxane (T; docetaxel or paclitaxel), with/without carboplatin (C; always combined with docetaxel rather than paclitaxel).

METHODS

Patients scheduled to receive ≥ 3 consecutive TCHP/THP cycles were randomized to crofelemer 125 mg orally twice daily during chemotherapy cycles 1 and 2 or no scheduled prophylactic medication (control). All received standard breakthrough antidiarrheal medication (BTAD) as needed. The primary endpoint was incidence of any-grade CID for ≥ 2 consecutive days. Secondary endpoints were incidence of all-grade and grade 3/4 CID by cycle/stratum; time to onset and duration of CID; stool consistency; use of BTAD; and quality of life (Functional Assessment of Chronic Illness Therapy for Patients With Diarrhea [FACIT-D] score).

RESULTS

Fifty-one patients were randomized to crofelemer (n = 26) or control (n = 25). There was no statistically significant difference between arms for the primary endpoint; however, incidence of grade ≥ 2 CID was reduced with crofelemer vs control (19.2% vs 24.0% in cycle 1; 8.0% vs 39.1%, in cycle 2). Patients receiving crofelemer were 1.8 times more likely to see their diarrhea resolved and had less frequent watery diarrhea.

CONCLUSION

Despite the choice of primary endpoint being insensitive, crofelemer reduced the incidence and severity of CID in patients with HER2-positive breast cancer receiving P-based therapy. These data are supportive of further testing of crofelemer in CID.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT02910219, prospectively registered September 21, 2016.

A Phase I, First-in-Human Study of GSK2849330, an Anti-HER3 Monoclonal Antibody, in HER3-Expressing Solid Tumors

BACKGROUND

GSK2849330, an anti-HER3 monoclonal antibody that blocks HER3/Neuregulin 1 (NRG1) signaling in cancer cells, is engineered for enhanced antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. This phase I, first-in-human, open-label study assessed the safety, pharmacokinetics (PK), pharmacodynamics, and preliminary activity of GSK2849330 in patients with HER3-expressing advanced solid tumors.

PATIENTS AND METHODS

Patients with various tumor types were prospectively selected for HER3 expression by immunohistochemistry; a subset was also screened for NRG1 mRNA expression. In the dose-escalation phase, patients received GSK2849330 1.4-30 mg/kg every 2 weeks, or 3 mg/kg or 30 mg/kg weekly, intravenously (IV). In the dose-expansion phase, patients received 30 mg/kg GSK2849330 IV weekly.

RESULTS

Twenty-nine patients with HER3-expressing cancers, of whom two expressed NRG1, received GSK2849330 (dose escalation: n = 18, dose expansion: n = 11). GSK2849330 was well tolerated. No dose-limiting toxicities were observed. The highest dose, of 30 mg/kg weekly, expected to provide full target engagement, was selected for dose expansion. Treatment-emergent adverse events (AEs) were mostly grade 1 or 2. The most common AEs were diarrhea (66%), fatigue (62%), and decreased appetite (31%). Dose-proportional plasma exposures were achieved, with evidence of HER3 inhibition in paired tissue biopsies. Of 29 patients, only 1 confirmed partial response, lasting 19 months, was noted in a patient with CD74-NRG1-rearranged non-small cell lung cancer (NSCLC).

CONCLUSION

GSK2849330 demonstrated a favorable safety profile, dose-proportional PK, and evidence of target engagement, but limited antitumor activity in HER3-expressing cancers. The exceptional response seen in a patient with CD74-NRG1-rearranged NSCLC suggests further exploration in NRG1-fusion-positive cancers.

IMPLICATIONS FOR PRACTICE

This first-in-human study confirms that GSK2849330 is well tolerated. Importantly, across a variety of HER3-expressing advanced tumors, prospective selection by HER3/NRG1 expression alone was insufficient to identify patients who could benefit from treatment with this antibody-dependent cell-mediated cytotoxicity- and complement-dependent cytotoxicity-enhanced anti-HER3 antibody. The only confirmed durable response achieved was in a patient with CD74-NRG1-rearranged lung cancer. This highlights the potential utility of screening for NRG1 fusions prospectively across tumor types to enrich potential responders to anti-HER3 agents in ongoing trials.

Combination of Pertuzumab and Trastuzumab in the Treatment of HER2-Positive Early Breast Cancer: A Review of the Emerging Clinical Data

Human epidermal growth factor receptor type 2 (HER2) is a relevant and effective target in breast cancer. The development of monoclonal antibodies against HER2 has revolutionized the treatment of HER2-positive breast cancer. The humanized monoclonal antibody, trastuzumab, was the first in its class to be widely adopted. It was initially studied in the metastatic setting and then in the treatment of early-stage disease, demonstrating significant improvement in overall survival in both settings. The addition of pertuzumab further improved upon results achieved with trastuzumab and chemotherapy, specifically extending overall survival in patients with metastatic disease, lessening the risk of recurrence when used in the adjuvant setting, and improving pathologic complete response rate when utilized in the neoadjuvant setting. In this article, we review the studies that support the use of HER2-directed monoclonal antibodies in early-stage breast cancer both in the adjuvant and neoadjuvant settings and focus on the success of dual HER2-targeted therapy achieved with the combination of trastuzumab and pertuzumab. A newer way to administer these agents, specifically the subcutaneous formulation of pertuzumab and trastuzumab with recombinant human hyaluronidase, will also be discussed.

Association between pertuzumab-associated diarrhoea and rash and survival outcomes in patients with HER2-positive metastatic breast cancer: Exploratory analysis from the CLEOPATRA trial

BACKGROUND

Skin rash and diarrhoea are known side-effects of pertuzumab. Studies with other anti-HER2 agents suggested that adverse events correlate with patient outcomes. In this exploratory cohort of patients with metastatic HER2-positive breast cancer included in the CLEOPATRA trial we evaluated the value of rash and diarrhoea as prognostic markers and as predictors of pertuzumab benefit.

METHODS

This is a retrospective analysis of the multicenter, prospective, randomised CLEOPATRA trial. We defined two analytic cohorts: cohort 1 (C1) included patients from treatment initiation, and cohort 2 (C2) included patients after discontinuation of docetaxel. A landmark analysis was introduced to deal with immortal-time bias. Study endpoints were progression-free survival (PFS) and overall survival (OS). Univariable and multivariable Cox proportional hazards models were used.

RESULTS

Of the 808 patients and after application of the landmark analysis, C1 and C2 included 777 and 518 patients, respectively. In C1, rash occurred in 271 patients (34.9%) and diarrhoea in 470 (60.5%). Rash was prognostic for PFS and OS (C1: adjusted hazard ratio [aHR] = 0.66 [95% CI = 0.48-0.91], p = 0.010]; C2: aHR 0.52 [95% CI = 0.30-0.89], p = 0.018) in both cohorts, while diarrhoea was only prognostic for PFS in cohort 2 (aHR = 0.65 [95% CI = 0.46-0.91], p = 0.011). Rash and diarrhoea were not predictive of pertuzumab benefit (in terms of PFS/OS) in the two cohorts.

CONCLUSIONS

In patients treated with pertuzumab, trastuzumab, and docetaxel, rash is prognostic whenever it occurs during treatment, while diarrhoea only has prognostic value when occurring after docetaxel discontinuation. However, neither rash nor diarrhoea predict pertuzumab benefit.

Neoadjuvant docetaxel with or without carboplatin plus dual HER2 blockade for HER2-positive breast cancer: a retrospective multi-center Chinese study

Background

This study aimed to compare the real-world efficacy and safety of the TCbHP regimen (docetaxel, carboplatin, trastuzumab and pertuzumab) and the THP regimen (docetaxel, trastuzumab and pertuzumab) as neoadjuvant therapy for Chinese patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer.

Methods

We compared efficacy and safety outcomes from 72 Chinese patients with HER2-positive breast cancer who underwent neoadjuvant dual HER2 blockade plus TCb or T chemotherapy and surgery between March 2019 and June 2020.

Results

All 72 patients were women (32-76 years old) and the overall pathological complete response (pCR) rate was 70.8% (51/72). The pCR rates were 76.1% (35/46) for the TCbHP regimen and 61.5% (16/26) for the THP regimen (P=0.28). Univariate analyses revealed that pCR was associated with clinical T classification (P=0.024), AJCC stage (P=0.042), estrogen receptor (ER) status (P=0.002), progesterone receptor (PR) status (P=0.035), Ki-67 index (P<0.001), and immunohistochemical HER2 status (P<0.001). Multivariate analyses revealed that pCR was independently predicted by ER status (OR: 0.227, 95% CI: 0.053-0.852; P=0.032) and immunohistochemical HER2 status (OR: 43.673, 95% CI: 6.801-875.86; P<0.001). The common adverse events for both regimens included neutropenia, anemia, thrombocytopenia, nausea, and diarrhea. Relative to the THP group, the TCbHP group had higher frequencies of grade 3-4 thrombocytopenia (17% vs. 0%, P=0.044) and grade 3-4 diarrhea (15% vs. 0%, P=0.044). Both regimens had very good cardiac safety.

Conclusions

These results suggest that both TCbHP and THP regimens may be useful neoadjuvant treatments for high-risk early or locally advanced HER2-positive breast cancer. Both regimens had generally good safety outcomes, although clinicians should be aware of the risks of grade 3-4 thrombocytopenia and diarrhea during TCbHP treatment. Elderly patients who require neoadjuvant therapy may benefit from 6 cycles of THP treatment, based on its good efficacy and mild adverse events.

Phase II Feasibility and Biomarker Study of Neoadjuvant Trastuzumab and Pertuzumab With Chemoradiotherapy for Resectable Human Epidermal Growth Factor Receptor 2-Positive Esophageal Adenocarcinoma: TRAP Study

PURPOSE

Approximately 15% to 43% of esophageal adenocarcinomas (EACs) are human epidermal growth factor receptor 2 (HER2) positive. Because dual-agent HER2 blockade demonstrated a survival benefit in breast cancer, we conducted a phase II feasibility study of trastuzumab and pertuzumab added to neoadjuvant chemoradiotherapy (nCRT) in patients with EAC.

PATIENTS AND METHODS

Patients with resectable HER2-positive EAC received standard nCRT with carboplatin and paclitaxel and 41.4 Gy of radiotherapy, with 4 mg/kg of trastuzumab on day 1, 2 mg/kg per week during weeks 2 to 6, and 6 mg/kg per week during weeks 7, 10, and 13 and 840 mg of pertuzumab every 3 weeks. The primary end point was feasibility, defined as ≥ 80% completion of treatment with both trastuzumab and pertuzumab. An exploratory comparison of survival with a propensity score-matched cohort receiving standard nCRT was performed, as were exploratory pharmacokinetic and biomarker analyses.

RESULTS

Of the 40 enrolled patients (78% men; median age, 63 years), 33 (83%) completed treatment with trastuzumab and pertuzumab. No unexpected safety events were observed. R0 resection was achieved in all patients undergoing surgery, with pathologic complete response in 13 patients (34%). Three-year progression-free and overall survival (OS) were 57% and 71%, respectively (median follow-up, 32.1 months). Compared with the propensity score-matched cohort, a significantly longer OS was observed with HER2 blockade (hazard ratio, 0.58; 95% CI, 0.34 to 0.97). Results of pharmacokinetic analysis and activity on [¹⁸F]fluorodeoxyglucose positron emission tomography scans did not correlate with survival or pathologic response. Patients with HER2 3+ overexpression or growth factor receptor-bound protein 7 (Grb7) -positive tumors at baseline demonstrated significantly better survival (P = .007) or treatment response (P = .016), respectively.

CONCLUSION

Addition of trastuzumab and pertuzumab to nCRT in patients with HER2-positive EAC is feasible and demonstrates potentially promising activity compared with historical controls. HER2 3+ overexpression and Grb7 positivity are potentially predictive for survival and treatment response, respectively.

Pertuzumab in the treatment of HER2-positive breast cancer: an evidence-based review of its safety, efficacy, and place in therapy

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer is a distinct subset of breast cancer that results from overexpression of HER2 protein. Pertuzumab-a recombinant humanized monoclonal antibody that binds to the extracellular dimerization domain II of HER2-was recently approved for adjuvant therapy and neoadjuvant therapy of HER2-positive early breast cancer. As pertuzumab and trastuzumab bind to different domains of the extracellular dimerization domain of HER2, a combination therapy of pertuzumab and trastuzumab is beneficial for the treatment of metastatic cancer, advanced local cancer, or early cancer by dual HER2 blockage. Many clinical trials have been performed using pertuzumab for breast cancer patients; these include the CLEOPATRA trial for palliative therapy, the APHINITY trial for adjuvant therapy, and the NeoSphere and the TRYPHAENA trials for neoadjuvant therapy. These trials revealed pertuzumab to be a safe and effective drug regardless of the patient age and hormone receptor status. Notably, pertuzumab use was associated with severe cardiac toxicity in some cases; however, the risk of pertuzumab-induced cardiac dysfunction was low. The most common adverse effect associated with pertuzumab-use was diarrhea, but most cases were not severe. Several different chemotherapeutic agents have been investigated to determine optimal chemotherapeutic combinations for dual HER2 blockage. Some exploratory analyses indicate that pertuzumab treatment offered little benefit to patients with node-negative and small primary tumors; pertuzumab treatment was also found not be cost-effective. Further research will reveal the appropriate usage of pertuzumab for treating a subset of eligible patients.

Pertuzumab-associated diarrhea in HER2/neu-positive breast cancer patients: A comparison of trials to actual practice

BACKGROUND

Although landmark trials in the metastatic (CLEOPATRA) and neo-adjuvant (NeoSphere; TRYPHAENA) settings identified all-grade diarrhea as a pertuzumab-associated adverse event, it was not classified as dose-limiting. In actual practice, diarrhea is often a reason for treatment modifications.

OBJECTIVES

To compare the risk of pertuzumab-associated diarrhea in actual practice to the risks in randomized controlled trials.

METHODS

We conducted a retrospective cohort study of HER2/neu-positive breast cancer patients who received a pertuzumab-containing regimen between January 2012 and August 2015. We calculated the risk of diarrhea with 95% confidence limits (CLs), and then used two-sample t-tests to compare the risk between trials and actual practice.

RESULTS

A total of 27 patients in the study cohort received a pertuzumab-containing treatment regimen for HER2/neu-positive breast cancer. The overall risk of all-grade and severe diarrhea in actual practice was 70% (95% CLs 55-90%) and 37% (95% CLs 20-66%), respectively. No severe diarrhea was observed in the metastatic setting, and the risk of all-grade diarrhea (44%, 95% CLs 21-92%) was similar to the CLEOPATRA study (67%). The risk of all-grade diarrhea in the neo-adjuvant setting was 83% (95% CLs 68-100%), compared to 46% in the NeoSphere trial (p = 0.03). The risk of severe diarrhea (Grade 3-4) in the neo-adjuvant setting was 47% (95% CLs 27-80%) versus 6% in the NeoSphere (p < 0.0001) and 12% in the TRYPHAENA (p < 0.01) trials.

CONCLUSIONS

The risk of all-grade and severe diarrhea associated with neoadjuvant pertuzumab use for HER2/neu-positive breast cancer was greater in actual practice than in trials.

Incidence and Management of Diarrhea With Adjuvant Pertuzumab and Trastuzumab in Patients With Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer

BACKGROUND

The APHINITY (BIG 4-11) study showed that pertuzumab significantly improved the rates of invasive disease-free survival among patients with human epidermal growth factor receptor 2 (HER2)-positive, operable breast cancer when added to adjuvant trastuzumab and chemotherapy. Because diarrhea was a common adverse event that could compromise treatment administration, we evaluated the incidence and management of diarrhea in the APHINITY study.

PATIENTS AND METHODS

The APHINITY trial is a prospective, randomized, multicenter, multinational, double-blind, placebo-controlled trial. The eligible patients were randomly assigned to receive standard adjuvant chemotherapy and 1 year of trastuzumab combined with pertuzumab or placebo. The diarrhea incidence, severity (National Cancer Institute common terminology criteria for adverse events, version 4.0), onset, and management were analyzed.

RESULTS

A total of 4805 patients were randomized. Diarrhea of any grade was the most common adverse event and occurred in 71% of patients in the pertuzumab arm versus 45% in the placebo arm. Diarrhea grade 3 to 4 was observed in 10% and 4% in the pertuzumab and placebo arms, respectively. The greatest incidence of diarrhea was reported during the concomitant administration of HER2-targeted therapy and taxane (61% vs. 34% of patients experienced an event with pertuzumab vs. placebo, respectively). A marked decrease was observed on chemotherapy cessation. Antidiarrheal agents were commonly used, and diarrhea rarely caused treatment dose modifications or discontinuation.

CONCLUSION

Diarrhea was a common adverse event in the APHINITY study. Most episodes were low grade and were generally manageable with common antidiarrheal agents. The incidence of diarrhea was greater with the combination of a taxane and HER2-targeted treatment and decreased once chemotherapy was stopped.

Patterns of occurrence and implications of neratinib-associated diarrhea in patients with HER2-positive breast cancer: analyses from the randomized phase III ExteNET trial

Background

We characterized patterns of occurrence and the impact of neratinib-associated diarrhea in the absence of protocol-directed antidiarrheal prophylaxis or a formal diarrhea management plan using data from Extended Adjuvant Treatment of Breast Cancer with Neratinib (ExteNET).

Methods

ExteNET is a multicenter, double-blind, placebo-controlled, randomized phase III trial involving community-based and academic institutions in 40 countries. Women with HER2-positive early-stage breast cancer with prior standard primary therapy and trastuzumab-based (neo)adjuvant therapy were randomized to neratinib 240 mg/day or placebo for 12 months. Safety, a secondary outcome, was assessed using the National Cancer Institute Common Terminology Criteria version 3.0. Health-related quality of life by diarrhea grade was assessed using Functional Assessment of Cancer Therapy-Breast (FACT-B).

Results

Two thousand eight hundred sixteen women (1408 per group) were safety-evaluable. Grade 3 and 4 diarrhea occurred in 561 (39.8%) and 1 (0.1%) patients with neratinib versus 23 (1.6%) and 0 patients with placebo, respectively. In the neratinib group, 28.6% of patients had grade 3 events during month 1 decreasing to ≤ 6% after month 3. The median cumulative duration of grade 3/4 diarrhea with neratinib was 5 days (interquartile range, 2–9). Serious diarrheal events (n = 22, 1.6%) and diarrheal events requiring hospitalization (n = 20, 1.4%) were rare with neratinib. Changes in FACT-B total score by diarrhea grade in the neratinib group did not meet the threshold for clinically important differences.

Conclusions

In the absence of antidiarrheal prophylaxis, neratinib-related diarrhea is short-lived and not associated with complications or long-term sequelae. This suggests that targeted preventive management with antidiarrheal prophylaxis early during neratinib treatment is appropriate.

Trial registration

ClinicalTrials.gov NCT00878709. Registered 9 April 2009.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1112-5) contains supplementary material, which is available to authorized users.

Development of a Subcutaneous Fixed-Dose Combination of Pertuzumab and Trastuzumab: Results From the Phase Ib Dose-Finding Study

Adding pertuzumab to trastuzumab (both monoclonal antibodies targeting human epidermal growth factor receptor 2 [HER2]) has proven survival benefits when combined with chemotherapy for patients with HER2-positive breast cancer. The combination of pertuzumab and trastuzumab together in 1 vial for subcutaneous (SC) administration is being developed as a ready-to-use formulation to reduce the treatment burden on patients while improving healthcare efficiency. An open-label, 2-part, phase Ib dose-finding study (NCT02738970) was undertaken in healthy male volunteers (part 1) and female patients with HER2-postive early breast cancer who had completed standard (neo)adjuvant treatment (part 2). This study aimed to identify an SC pertuzumab dose given with recombinant human hyaluronidase that results in comparable exposure to that of the intravenous (IV) pertuzumab dose, based on pertuzumab serum trough concentration and area under the serum concentration-time curve. Pharmacokinetics (PK), safety, and tolerability of a single dose of SC pertuzumab given alone or in a fixed-dose combination (comixed or coformulated) with trastuzumab were also assessed. A maintenance dose of 600 mg for SC pertuzumab resulted in an equivalent exposure to that of IV pertuzumab, and no new safety signals were identified for SC pertuzumab or trastuzumab. A loading dose of 1200 mg for SC pertuzumab was selected based on approximate dose proportionality. The PK and safety results support further development of a fixed-dose coformulation combination of pertuzumab and trastuzumab for SC administration, which will be investigated in an upcoming phase III trial in patients with HER2-positive early breast cancer.

Phase I trial of afatinib and 3-weekly trastuzumab with optimal anti-diarrheal management in patients with HER2-positive metastatic cancer

Background

Trastuzumab is the mainstay of therapy for patients with HER2-positive breast and gastric cancer but resistance frequently occurs. Afatinib, an irreversible oral ErbB family blocker, shows clinical activity in trastuzumab-refractory HER2-positive metastatic breast cancer.

Materials and methods

This phase I study used a modified 3 + 3 dose escalation design to determine the maximum tolerated dose (MTD) of oral once-daily afatinib in combination with 3-weekly intravenous trastuzumab (8 mg/kg week 1; 6 mg/kg 3-weekly thereafter) for patients with confirmed advanced or metastatic HER2-positive cancer.

Results

Of the 13 patients treated, 6 received daily afatinib 20 mg and 7 received 30 mg. One patient who received afatinib 30 mg developed a tumor lysis syndrome and was not evaluable for dose-limiting toxicity (DLT). Two of the six remaining patients receiving afatinib 30 mg and 1 of the 6 patients receiving afatinib 20 mg experienced DLTs (all CTCAE ≥ grade 2 diarrhea despite optimal management) in the first treatment cycle. The most common drug-related adverse events were diarrhea (n = 13, 100%), asthenia (n = 8, 61.5%), rash (n = 7, 53.8%) and paronychia (n = 5, 38.5%). No pharmacokinetic interaction was observed. One patient (7.7%) had an objective response (20 mg afatinib cohort). Nine patients (69.2%) experienced clinical benefit.

Conclusions

Despite optimal management of diarrhea including treatment of grade I symptoms, it was not possible to treat the patients above a dose of 20 mg of afatinib daily in combination with 3-weekly trastuzumab. The MTD of afatinib in combination with the recommended 3-weekly dose of trastuzumab was 20 mg daily.

Efficacy of neoadjuvant pertuzumab in addition to chemotherapy and trastuzumab in routine clinical treatment of patients with primary breast cancer: a multicentric analysis

PURPOSE

Neoadjuvant combination treatment with chemotherapy (CTX), trastuzumab (TZM), and pertuzumab (PTZ) has been shown to result in higher pathological complete response rates (pCR) in comparison with treatment with chemotherapy and trastuzumab (CTX/TZM). This analysis was aimed at real-world validation of these results from prospective randomized trials.

METHODS

In a retrospective analysis conducted in the PRAEGNANT network, patients were eligible for inclusion if they had either received neoadjuvant therapy with CTX/TZM or chemotherapy, trastuzumab, and pertuzumab (CTX/TZM/PTZ) and subsequently underwent surgery for their primary breast cancer. The effect of the two neoadjuvant regimens on pCR in addition to commonly applicable predictors of pCR was analyzed in 300 patients from three study sites, using logistic regression analyses with treatment arm, age, clinical tumor stage, grading, and hormone receptor status as predictors.

RESULTS

pCR with complete disappearance of all tumor cells was seen in 30.2% (n = 58) of patients treated with CTX/TZM and in 52.8% (n = 57) of those treated with CTX/TZM/PTZ. CTX/TZM/PTZ was positively associated with pCR (adjusted odds ratio 2.44; 95% CI 1.49-4.02). Mastectomy rates were not influenced by the therapy.

CONCLUSIONS

The results of clinical trials were confirmed in this dataset of patients who were treated outside of clinical trials in everyday routine work. pCR rates can be improved by 20% with pertuzumab in routine clinical use.

Phase Ib study evaluating safety and clinical activity of the anti-HER3 antibody lumretuzumab combined with the anti-HER2 antibody pertuzumab and paclitaxel in HER3-positive, HER2-low metastatic breast cancer

Purpose To investigate the safety and clinical activity of comprehensive human epidermal growth factor receptor (HER) family receptor inhibition using lumretuzumab (anti-HER3) and pertuzumab (anti-HER2) in combination with paclitaxel in patients with metastatic breast cancer (MBC). Methods This phase Ib study enrolled 35 MBC patients (first line or higher) with HER3-positive and HER2-low (immunohistochemistry 1+ to 2+ and in-situ hybridization negative) tumors. Patients received lumretuzumab (1000 mg in Cohort 1; 500 mg in Cohorts 2 and 3) plus pertuzumab (840 mg loading dose [LD] followed by 420 mg in Cohorts 1 and 2; 420 mg without LD in Cohort 3) every 3 weeks, plus paclitaxel (80 mg/m2 weekly in all cohorts). Patients in Cohort 3 received prophylactic loperamide treatment. Results Diarrhea grade 3 was a dose-limiting toxicity of Cohort 1 defining the maximum tolerated dose of lumretuzumab when given in combination with pertuzumab and paclitaxel at 500 mg every three weeks. Grade 3 diarrhea decreased from 50% (Cohort 2) to 30.8% (Cohort 3) with prophylactic loperamide administration and omission of the pertuzumab LD, nonetheless, all patients still experienced diarrhea. In first-line MBC patients, the objective response rate in Cohorts 2 and 3 was 55% and 38.5%, respectively. No relationship between HER2 and HER3 expression or somatic mutations and clinical response was observed. Conclusions Combination treatment with lumretuzumab, pertuzumab and paclitaxel was associated with a high incidence of diarrhea. Despite the efforts to alter dosing, the therapeutic window remained too narrow to warrant further clinical development.

TRIAL REGISTRATION

on ClinicalTrials.gov with the identifier NCT01918254 first registered on 3rd July 2013.

Development and clinical application of anti-HER2 monoclonal and bispecific antibodies for cancer treatment

HER2-targeted immunotherapy consists of monoclonal antibodies (e.g. trastuzumab, pertuzumab), bispecific antibodies (e.g. MM-111, ertumaxomab) and activated T cells armed with anti-HER2 bispecific antibody (HER2Bi-aATC). Trastuzumab is a classic drug for the treatment of HER2 positive metastatic breast cancer. The combined application of pertuzumab, trastuzumab and paclitaxel has been suggested as a standard therapy for HER2 positive advanced breast cancer. The resistance to anti-HER2 antibody has resulted in disease progression. HER2-directed bispecific antibody may be a promising therapeutic approach for these patients. Ertumaxomab enhanced the interaction of immune effector cells and tumor cells. MM-111 simultaneously binds to HER2 and HER3 and blocks downstream signaling. Besides, HER2Bi-aATC is also an alternative therapeutic approach for HER2 positive cancers. In this review, we summarized the recent advancement of HER2-targeted monoclonal antibodies (trastuzumab, pertuzumab and T-DM1) and bispecific antibodies (MM-111, ertumaxomab and HER2Bi-aATC), especially focus on clinical trial results.

Rifaximin for Pertuzumab-Related GI Toxicities

Pertuzumab is a monoclonal antibody against HER2. Diarrhea and abdominal pain are common adverse events of pertuzumab-based therapy, occurring in almost 70% of patients. The incidence of gastrointestinal toxicities intensifies when pertuzumab is given in combination with chemotherapy. Rifaximin, a non-absorbable oral antibiotic, may provide symptomatic relief in patients with refractory gastrointestinal toxicities from pertuzumab-based therapy beyond standard routine antidiarrheal medications. We present a case of HER2-related therapy-induced diarrhea and abdominal pain managed successfully with Rifaximin.