Patient-Reported Outcomes in Patients With PIK3CA-Mutated Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Advanced Breast Cancer From SOLAR-1

Next-generation sequencing for guiding matched targeted therapies in people with relapsed or metastatic cancer

BACKGROUND

Matched targeted therapies (MTT) given alone or in combination with systemic anti-cancer therapies have delivered proven survival benefit for many people with newly diagnosed cancer. However, there is little evidence of their effectiveness in the recurrent or late-stage setting. With this uncertainty, alongside the perception that late-stage cancers are too genetically heterogenous or too mutationally diverse to benefit from matched targeted therapies, next-generation sequencing (NGS) of tumours in people with refractory cancer remains a low priority. As a result, next-generation sequencing testing of recurrent or late-stage disease is discouraged. We lack evidence to support the utility of next generation sequencing in guiding matched targeted therapies in this setting.

OBJECTIVES

To evaluate the benefits and harms of matched targeted therapies in people with advanced cancers in randomised controlled trials.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, ClinicalTrials.gov, and the World Health Organisation International Clinical Trials Registry Platform (WHO-ICTRP) search portal up to 30th October 2024. We also screened reference lists of included studies and also the publications that cited these studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that had enroled participants with advanced/refractory solid or haematological cancers who had progressed through at least one line of standard anti-cancer systemic therapy. To be eligible, all participants should have received matched targeted therapy based on next-generation sequencing carried out on their tumour (tumour tissue, blood or bone marrow).

DATA COLLECTION AND ANALYSIS

We systematically searched medical databases (e.g. MEDLINE, Embase) and trial registers for randomised controlled trials (RCTs). Outcomes of interest were progression-free survival (PFS), overall survival (OS), overall response rates (ORR), serious (grade 3 or 4) adverse events (AEs) and quality of life (QOL). We used a random-effects model to pool outcomes across studies and compared predefined subgroups using interaction tests. Grading of Recommendations Assessment, Development and Evaluation (GRADE) assessment of certainty was used to evaluate the quality of evidence.

MAIN RESULTS

We identified a total of 37 studies, out of which 35 studies (including 9819 participants) were included in the meta-analysis. All included studies compared a matched targeted therapy intervention to standard-of-care treatment, non-matched targeted therapies or no treatment (best supportive care): Matched targeted therapy versus standard-of-care treatment Matched targeted therapy (MTT) compared with standard systematic therapy probably reduces the risk of disease progression by 34% (hazard ratio (HR) = 0.66, 95% confidence interval (CI) 0.59 to 0.74; 14 studies, 3848 participants; moderate-certainty evidence). However, MTT might have little to no difference in risk of death (HR = 0.85, 95% CI 0.75 to 0.97; 14 studies, 3848 participants; low-certainty evidence) and may increase overall response rates (low-certainty evidence). There was no clear evidence of a difference in severe (grade 3/4) adverse events between matched targeted therapy and standard-of-care treatment (low-certainty evidence). There was limited evidence of a difference in quality of life between groups (very low-certainty of evidence). Matched targeted therapy in combination with standard-of-care treatment versus standard-of-care treatment alone Matched targeted therapy in combination with standard-of-care treatment compared with standard-of-care treatment alone probably reduces the risk of disease progression by 39% (HR = 0.61, 95% CI 0.53-0.70, 14 studies, 2,637 participants; moderate-certainty evidence) and risk of death by 21% (HR = 0.79, 95% CI 0.70 to 0.89; 11 studies, 2575 participants, moderate-certainty evidence). The combination of MTT and standard-of-care treatment may also increase overall response rates (low-certainty evidence). There was limited evidence of a difference in the incidence of severe adverse events (very low-certainty evidence) and quality of life between the groups (very low-certainty of evidence). Matched targeted therapy versus non-matched targeted therapy Matched targeted therapy compared with non-matched targeted therapy probably reduces the risk of disease progression by 24% (HR = 0.76, 95% CI 0.64 to 0.89; 3 studies, 1568 participants; moderate-certainty evidence) and may reduce the risk of death by 25% (HR = 0.75, 95% CI 0.65 to 0.86, 1307 participants; low-certainty evidence). There was little to no effect on overall response rates between MTT and non-MTT. There was no clear evidence of a difference in overall response rates (low-certainty evidence) and severe adverse events between MTT and non-MTT (low-certainty evidence). None of the studies comparing MTT and non-MTT reported quality of life. Matched targeted therapy versus best supportive care Matched targeted therapy compared with the best supportive care (BSC) i.e. no active treatment probably reduces the risk of disease progression by 63% (HR 0.37, 95% CI 0.28 to 0.50; 4 studies, 858 participants; moderate-certainty evidence). There was no clear evidence of a difference in overall survival between groups (HR = 0.88, 95% CI 0.73 to 1.06, 3 studies, 783 participants; low-certainty evidence). There was no clear evidence of a difference in overall response rates (very low-certainty of evidence) and incidence of severe adverse events (very low-certainty of evidence) between the groups. Quality of life was reported in a single study but did not provide composite scores. Risk of bias The overall risk of bias was judged low for eight studies, unclear for two studies, and the remaining 27 studies were high risk.

AUTHORS' CONCLUSIONS

Matched targeted therapies guided by next-generation sequencing in people with advanced cancer prolongs the time before cancer progresses compared to standard therapies. However, there is limited evidence to suggest that it prolongs overall survival, improves the quality of life or increases adverse events. Importantly, this review supports equitable access to next-generation sequencing technology for all people with advanced cancer and offers them the opportunity to access genotype-matched targeted therapies.

The efficacy and safety of PI3K and AKT inhibitors for patients with cancer: A systematic review and network meta-analysis

BACKGROUND

Inhibiting PI3K/AKT pathway activation may hinder the occurrence and progression of cancer. The aim of this study was to evaluate the efficacy and safety of the PI3K/AKT inhibitors and determine the most appropriate inhibitor for different cancer types.

METHODS

Electronic databases up to June 2024 were used to examine the efficacy and safety of PI3K inhibitors (alpelisib, copanlisib, duvelisib, and idelalisib) and AKT inhibitors (capivasertib, ipatasertib and MK-2206) for the treatment of cancer. Data was assessed with a random-effect pairwise and network meta-analysis. Randomized controlled trials and retrospective studies were eligible if they compared PI3K or AKT inhibitors with non-PI3K/AKT controls with no restriction.

RESULTS

The results were based on 34 studies from 34 published articles and 6 online registration trials (6710 patients). According to pairwise meta-analysis, PI3K/AKT inhibitors showed to be highly effective, especially for treating mutant cancers, but had poor safety profiles. According to our network meta-analysis, PI3K/AKT inhibitors, especially the AKT inhibitor capivasertib, are effective for treating solid cancers such as breast cancer (BC). Moreover, PI3K inhibitors, especially idelalisib, were effective for treating hematologic cancers such as chronic lymphocytic leukemia (CLL).

CONCLUSIONS

The PI3K/AKT inhibitors are effective in patients with genetic mutations. For solid cancers such as BC, capivasertib was efficacy and safety. For hematological cancers represented by CLL, idelalisib was efficacy and safety. The above studies can be used when recommending appropriate targeted therapies for patients with different cancer types.

Advances in Trop-2 targeted antibody-drug conjugates for breast cancer: mechanisms, clinical applications, and future directions

Breast cancer remains a leading cause of cancer-related deaths among women worldwide, highlighting the need for novel therapeutic strategies. Trophoblast cell surface antigen 2 (Trop-2), a type I transmembrane glycoprotein highly expressed in various solid tumors including all subtypes of breast cancer, has emerged as a promising target for cancer therapy. This review focuses on recent advancements in Trop-2-targeted antibody-drug conjugates (ADCs) for breast cancer treatment. We comprehensively analyzed the structure and mechanism of action of ADCs, as well as the role of Trop-2 in breast cancer progression and prognosis. Several Trop-2-targeted ADCs, such as Sacituzumab Govitecan (SG) and Datopotamab Deruxtecan (Dato-DXd), have demonstrated significant antitumor activity in clinical trials for both triple-negative breast cancer (TNBC) and hormone receptor-positive/HER2-negative (HR+/HER2-) breast cancer. We systematically reviewed the ongoing clinical studies of these ADCs, highlighting their efficacy and safety profiles. Furthermore, we explored the potential of combining Trop-2-targeted ADCs with other therapeutic modalities, including immunotherapy, targeted therapies, and small molecule inhibitors. Notably, Trop-2-targeted ADCs have shown promise in reprogramming the tumor microenvironment through multiple signaling pathways, potentially enhancing antitumor immunity. This review aims to provide new insights and research directions for the development of innovative breast cancer therapies, offering potential solutions to improve treatment outcomes and quality of life for breast cancer patients.

Capivasertib and fulvestrant for patients with hormone receptor-positive, HER2-negative advanced breast cancer (CAPItello-291): patient-reported outcomes from a phase 3, randomised, double-blind, placebo-controlled trial

BACKGROUND

CAPItello-291 is an ongoing phase 3 trial in which capivasertib-fulvestrant significantly improved progression-free survival versus placebo-fulvestrant in patients with hormone receptor-positive, HER2-negative advanced breast cancer who had relapse or disease progression during or after aromatase inhibitor treatment, in both the overall population and in patients with PIK3CA, AKT1, or PTEN-altered tumours. This study further explored patient-reported health-related quality of life (HRQOL), functioning, symptoms, and symptom tolerability in CAPItello-291.

METHODS

This phase 3, randomised, double-blind, placebo-controlled trial, which was conducted across 193 hospitals and cancer centres in 19 countries, enrolled women with any menopausal status or men, aged ≥18 years (≥20 years in Japan), with hormone receptor-positive, HER2-negative locally advanced or metastatic breast cancer who had relapse or disease progression during or after treatment with an aromatase inhibitor, with or without previous cyclin-dependent kinase (CDK) 4 or 6 inhibitor therapy. Patients had an Eastern Cooperative Oncology Group/WHO performance score of 0 or 1 and could have received up to two previous lines of endocrine therapy and up to one previous line of chemotherapy for advanced disease. Patients were randomly assigned (1:1) using block randomisation (stratified according to the presence or absence of liver metastases, previous use of a CDK4/6 inhibitor [yes vs no], and geographical region) to receive oral capivasertib 400 mg (twice daily for 4 days, followed by 3 days off) plus intramuscular fulvestrant 500 mg (every 14 days for the first three injections, then every 28 days) or placebo with matching fulvestrant dosing. The dual primary endpoint of the trial was investigator-assessed progression-free survival assessed both in the overall population and among patients with PIK3CA, AKT1, or PTEN-altered tumours. The EORTC Quality of Life Questionnaire 30-item core module (QLQ-C30) and breast module (QLQ-BR23), Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE), and Patient Global Impression of Treatment Tolerability (PGI-TT) questionnaires were used to assess patient-reported outcomes. Evaluation of EORTC QLQ-C30 and EORTC QLQ-BR23 were secondary endpoints and evaluation of PRO-CTCAE and PGI-TT were pre-defined exploratory endpoints, and these endpoints are the subject of analysis in this Article. Data were collected at baseline and prespecified timepoints. Patient-reported outcomes were analysed in all randomly assigned patients with an evaluable baseline assessment and at least one evaluable post-baseline assessment. Change from baseline was assessed using mixed model with repeated measures for EORTC QLQ-C30 and summarised for QLQ-BR23. Time to deterioration was described using the Kaplan-Meier method. PGI-TT and PRO-CTCAE responses were summarised at each treatment cycle. Patient-reported outcomes were not prospectively powered for statistical comparison. The trial is registered with ClinicalTrials.gov, NCT04305496.

FINDINGS

Between June 2, 2020, and Oct 13, 2021, 901 patients were enrolled, of whom 708 patients were randomly assigned to receive capivasertib-fulvestrant (n=355) or placebo-fulvestrant (n=353). The median age of the patients was 59 years (IQR 51-67) in the capivasertib-fulvestrant group and 58 years (IQR 49-66) in the placebo-fulvestrant group. At data cutoff (Aug 15, 2022), the median duration of follow-up for progression-free survival in censored patients was 13·0 months (IQR 9·1-16·7) for capivasertib-fulvestrant and 12·7 months (IQR 2·0-16·4) for placebo-fulvestrant in the overall population. EORTC QLQ-C30 global health status/quality of life (GHS/QOL) scores were maintained from baseline and were similar between treatment groups throughout the study period (difference in mean change from baseline of -2·5 [95% CI -4·5 to -0·6] with capivasertib-fulvestrant vs -5·6 [-7·9 to -3·4] with placebo-fulvestrant; treatment difference 3·1 [95% CI 0·2 to 6·0]). Median time to deterioration in EORTC QLQ-C30 GHS/QOL was 24·9 months (95% CI 13·8 to not reached) in the capivasertib-fulvestrant group and 12·0 months (10·2 to 15·7) in the placebo-fulvestrant group (hazard ratio [HR] 0·70, 95% CI 0·53 to 0·92). Time to deterioration HRs for all EORTC QLQ-C30 and QLQ-BR23 subscale scores showed little difference between the treatment groups, except for diarrhoea, which was worse in the capivasertib-fulvestrant group than in the placebo-fulvestrant group (HR 2·75, 95% CI 2·01-3·81). In PRO-CTCAE symptom assessment, the proportion of patients reporting loose and watery stools "frequently" or "almost constantly" was 29% higher at cycle 1, day 15 in the capivasertib-fulvestrant group than in the placebo-fulvestrant group, decreasing at subsequent cycles. Other PRO-CTCAE-reported symptoms (rash, mouth or throat sores, itchy skin, and numbness or tingling in hands or feet) were absent or mild in most patients in both groups throughout treatment. According to the PGI-TT, most patients in both groups reported "not at all" or "a little bit" of bother from treatment side-effects.

INTERPRETATION

Patient-reported outcomes from CAPItello-291 demonstrated that capivasertib-fulvestrant delayed time to deterioration of GHS/QOL and maintained other dimensions of HRQOL (except symptoms of diarrhoea) similarly to fulvestrant. With the clinical efficacy and manageable safety profile, these exploratory results further support the positive benefit-risk profile of capivasertib-fulvestrant in this population.

FUNDING

AstraZeneca.

Activity and safety of enobosarm, a novel, oral, selective androgen receptor modulator, in androgen receptor-positive, oestrogen receptor-positive, and HER2-negative advanced breast cancer (Study G200802): a randomised, open-label, multicentre, multinational, parallel design, phase 2 trial

BACKGROUND

The androgen receptor is a tumour suppressor in oestrogen receptor-positive breast cancer. The activity and safety of enobosarm, an oral selective androgen receptor modulator, was evaluated in women with oestrogen receptor (ER)-positive, HER2-negative, and androgen receptor (AR)-positive disease.

METHODS

Women who were postmenopausal (aged ≥18 years) with previously treated ER-positive, HER2-negative, locally advanced or metastatic breast cancer with an Eastern Cooperative Oncology Group performance status of 0-2 were enrolled in a randomised, open-label, multicentre, multinational, parallel design, phase 2 trial done at 35 cancer treatment centres in nine countries. Participants were stratified on the setting of immediately preceding endocrine therapy and the presence of bone-only metastasis and randomly assigned (1:1) to 9 mg or 18 mg oral enobosarm daily using an interactive web response system. The primary endpoint was clinical benefit rate at 24 weeks in those with centrally confirmed AR-positive disease (ie, the evaluable population). This trial is registered with ClinicalTrials.gov (NCT02463032).

FINDINGS

Between Sept 10, 2015, and Nov 28, 2017, 136 (79%) of 172 patients deemed eligible were randomly assigned to 9 mg (n=72) or 18 mg (n=64) oral enobosarm daily. Of these 136 patients, 102 (75%) patients formed the evaluable population (9 mg, n=50; 18 mg, n=52). The median age was 60·5 years (IQR 52·3-69·3) in the 9 mg group and 62·5 years (54·0-69·3) in the 18 mg group. The median follow-up was 7·5 months (IQR 2·9-14·1). At 24 weeks, 16 (32%, 95% CI 20-47) of 50 in the 9 mg group and 15 (29%, 17-43) of 52 in the 18 mg group had clinical benefit. Six (8%) of 75 patients who received 9 mg and ten (16%) of 61 patients who received 18 mg had grade 3 or grade 4 drug-related adverse events, most frequently increased hepatic transaminases (three [4%] of 75 in the 9 mg group and two [3%] of 61 in the 18 mg group), hypercalcaemia (two [3%] and two [3%]), and fatigue (one [1%] and two [3%]). Four deaths (one in the 9 mg group and three in the 18 mg group) were deemed unrelated to the study drug.

INTERPRETATION

Enobosarm has anti-tumour activity in patients with ER-positive, HER2-negative advanced breast cancer, showing that AR activation can result in clinical benefit, supporting further clinical investigation of selective AR activation strategies for the treatment of AR-positive, ER-positive, HER2-negative advanced breast cancer.

FUNDING

GTx.

Therapeutic evolution in HR+/HER2- breast cancer: from targeted therapy to endocrine therapy

Breast cancer, a complex and varied disease, has four distinct subtypes based on estrogen receptor and human epidermal growth factor receptor 2 (HER2) levels, among which a significant subtype known as HR+/HER2-breast cancer that has spurred numerous research. The prevalence of breast cancer and breast cancer-related death are the most serious threats to women's health worldwide. Current progress in treatment strategies for HR+/HER2-breast cancer encompasses targeted therapy, endocrine therapy, genomic immunotherapy, and supplementing traditional methods like surgical resection and radiotherapy. This review article summarizes the current epidemiology of HR+/HER2-breast cancer, introduces the classification of HR+/HER2-breast cancer and the commonly used treatment methods. The mechanisms of action of various drugs, including targeted therapy drugs and endocrine hormone therapy drugs, and their potential synergistic effects are deeply discussed. In addition, clinical trials of these drugs that have been completed or are still in progress are included.

Genetic Testing Enhances the Precision Diagnosis and Treatment of Breast Cancer

The contemporary comprehension of breast cancer has progressed to the molecular level. As a heterogeneous malignancy, conventional pathological diagnosis and histological classification could no longer meet the needs of precisely managing breast cancer. Genetic testing based on gene expression profiles and gene mutations has emerged and substantially contributed to the precise diagnosis and treatment of breast cancer. Multigene assays (MGAs) are explored for early-stage breast cancer patients, aiding the selection of adjuvant therapy and predicting prognosis. For metastatic breast cancer patients, testing specific genes indicates potentially effective antitumor agents. In this review, genetic testing in early-stage and metastatic breast cancer is summarized, as well as the advantages and challenges of genetic testing in breast cancer.

Surrogate endpoints for HTA decisions of breast cancer drugs: utility and pitfalls

PURPOSE OF REVIEW

Health technology assessment (HTA) of cancer drugs is important to identify whether drugs should be publicly funded. With increasing use of surrogate end points in clinical trials including breast cancer, a review of literature was done to synthesize evidence for validation of these surrogate end points and their potential role in HTA decisions pertaining to breast cancer.

FINDINGS

Disease free survival (DFS) in human epidermal receptor 2 (HER2) positive early breast cancer remains the only validated surrogate end point. Other surrogate end points like pathological complete response (pCR) and event free survival (EFS) in early breast cancer (EBC) and objective response rate (ORR) and progression free survival (PFS) in advanced disease have not been validated for overall survival (OS). Moreover, surrogate end points for quality of life (QOL) have not been established and drugs that improve PFS can have detrimental effect on QOL. End points like pCR have excellent prognostic utility in individual patients but have weak correlation with survival at trial level.

SUMMARY

Most surrogate end points used in breast cancer do not predict OS or QOL which makes it challenging to use them for decisions regarding public funding of cancer drugs. These findings are relevant to HTA agencies prior to making drug reimbursement decisions.

Comparison of robotic versus laparoscopic versus open distal gastrectomy for locally advanced gastric cancer: a prospective trial-based economic evaluation

IMPORTANCE

It is largely unclear whether robotic distal gastrectomy (RDG) is cost-effective for locally advanced gastric cancer (LAGC).

OBJECTIVE

To evaluate the cost-effectiveness of RDG, laparoscopic distal gastrectomy (LDG), and open distal gastrectomy (ODG) for patients with LAGC.

DESIGN, SETTING, AND PARTICIPANTS

Inverse probability of treatment weighting (IPTW) was used to balance baseline characteristics. A decision-analytic model was constructed to evaluate the cost-effectiveness of RDG, LDG, and ODG.

EXPOSURES

RDG, LDG, and ODG.

MAIN OUTCOMES AND MEASURES

Incremental cost-effectiveness ratio (ICER) and quality-adjusted life year (QALY).

RESULTS

This pooled analysis of two randomized controlled trials included 449 patients: 117, 254, and 78 patients in the RDG, LDG, and ODG groups, respectively. After IPTW, RDG demonstrated its priority in terms of less blood loss, postoperative length, and complication rate (all P < 0.05). RDG also showed higher QOL with more cost, representing an ICER of $85,739.73 per QALY and $42,189.53 per QALY compared to LDG and ODG, respectively. In probabilistic sensitivity analysis, RDG achieved the best cost-effectiveness for patients with LAGC only when the willingness-to-pay threshold was > $85,739.73 per QALY, which significantly exceeded 3 times Chinese per capita GDP. Furthermore, one of the most important factors was the indirect costs of robotic surgery in terms of the cost-effectiveness of RDG compared to that of LDG or ODG.

CONCLUSIONS AND RELEVANCE

Although improved short-term outcomes and QOL were seen in patients underwent RDG, the economic burden should be considered in the clinical decision-making regarding robotic surgery use for patients with LAGC. Our findings may vary in different health care settings and affordability. Trial registration CLASS-01 trial (ClinicalTrials.gov, CT01609309) and FUGES-011 trial (ClinicalTrials.gov, NCT03313700).

Pan-Asian adapted ESMO Clinical Practice Guidelines for the diagnosis, staging and treatment of patients with metastatic breast cancer

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, staging and treatment of patients with metastatic breast cancer (MBC) was published in 2021. A special, hybrid guidelines meeting was convened by ESMO and the Korean Society of Medical Oncology (KSMO) in collaboration with nine other Asian national oncology societies in May 2022 in order to adapt the ESMO 2021 guidelines to take into account the differences associated with the treatment of MBC in Asia. These guidelines represent the consensus opinions reached by a panel of Asian experts in the treatment of patients with MBC representing the oncological societies of China (CSCO), India (ISMPO), Indonesia (ISHMO), Japan (JSMO), Korea (KSMO), Malaysia (MOS), the Philippines (PSMO), Singapore (SSO), Taiwan (TOS) and Thailand (TSCO). The voting was based on the best available scientific evidence and was independent of drug access or practice restrictions in the different Asian countries. The latter were discussed when appropriate. The aim of these guidelines is to provide guidance for the harmonisation of the management of patients with MBC across the different regions of Asia, drawing from data provided by global and Asian trials whilst at the same time integrating the differences in genetics, demographics and scientific evidence, together with restricted access to certain therapeutic strategies.

Clinicopathological features and prognosis of breast cancer combined with symptomatic bone marrow metastases: A 10-year, single-center, real-world study of 67 cases

PURPOSE

Bone marrow metastasis (BMM) is uncommon in breast cancer (BC), and early diagnosis is challenging. BMM lacks definitive treatment options and poses a great threat to the survival of patients. Herein, we investigated the clinical features, prognosis, and factors affecting the prognosis of BC patients with symptomatic BMM to help improve the understanding of this disease and provide effective diagnostic and treatment strategies.

METHODS

Clinical data of 67 patients with BC and BMM were retrospectively analyzed for clinical characteristics, treatment, and prognosis of BMM. Univariate and multivariate analyses were performed to determine factors affecting overall survival following BMM (BMMOS).

RESULTS

Among patients with BMM, 86.6% were diagnosed after bone metastasis (BM), while 13.4% were diagnosed simultaneously with BM. A total of 73.1%, 13.4%, and 13.4% of the patients had hormone receptor-positive/human epidermal growth factor 2-negative (HR+/HER2-) tumors, HER2+ tumors, and triple-negative tumors, respectively. The most common symptoms of BMM were the coexistence of anemia and thrombocytopenia (26.9%), anemia (19.4%), and pancytopenia (17.9%). The median BMMOS was 7.6 months (95% CI, 3.9-11.3). Univariate and multivariate analyses showed that BMMOS was associated with platelet count <75 × 109 /L at the time of BMM diagnosis. The BMMOS of patients who underwent endocrine therapy, combined chemotherapy, and mono-chemotherapy after BMM was 15.7, 9.7, and 8.6 months, respectively, whereas that of untreated patients was 2.9 months, and the difference among the results was statistically significant (χ2  = 20.102, p < 0.0001). Changes in patient hemogram and/or body temperature during treatment were consistent with the overall effect of the disease (p < 0.0001).

CONCLUSION

BMM should be considered in BC patients with BM, an unexplained reduction in hemogram parameters, especially anemia and thrombocytopenia, and/or fever without chills. Active, effective, individualized treatment strategies can prolong BMMOS.

How I treat endocrine-dependent metastatic breast cancer

Estrogen receptor-positive (ER+)/HER2-negative (HER2-), the so-called luminal-type breast cancer, is the most frequent subset, accounting for around 70% of all breast cancer cases. Endocrine therapy (ET) combined with cyclin-dependent kinases (CDK) 4/6 inhibitors is the standard first option in the management of advanced luminal breast cancer independently of disease extension. Classically, patients undergo multiple lines of ET ± targeted treatments until endocrine resistance occurs and palliative chemotherapy is proposed. Understanding endocrine resistance mechanisms and development of novel ET options is one of the main challenges in current clinical research. Another area of utmost interest is the improvement of post-endocrine therapeutic approaches. Among others, the development of antibody-drug conjugates (ADCs) is very promising, and some of these drugs will probably soon become a part of the therapeutic arsenal against this incurable disease. This review paper provides an overview of currently available treatment options in ER+/HER2- metastatic breast cancer and extensively discusses new approaches in late clinical development.

Filling the Gap after CDK4/6 Inhibitors: Novel Endocrine and Biologic Treatment Options for Metastatic Hormone Receptor Positive Breast Cancer

The rise of cyclin-dependent kinase (CDK)4/6 inhibitors has rapidly reshaped treatment algorithms for hormone receptor (HR)-positive metastatic breast cancer, with endocrine treatment (ET) plus a CDK4/6-inhibitor currently representing the standard of care in the first line setting. However, treatment selection for those patients experiencing progression while on ET + CDK4/6-inhibitors remains challenging due to the suboptimal activity or significant toxicities of the currently available options. There is also a paucity of data regarding the efficacy of older regimens, such as everolimus + exemestane, post-CDK4/6 inhibition. In this setting of high unmet need, several clinical trials of novel drugs have recently reported encouraging results: the addition of the AKT-inhibitor capivasertib to fulvestrant demonstrated a significant improvement in progression-free survival (PFS); the oral selective estrogen receptor degrader (SERD) elacestrant prolonged PFS compared to traditional ET in a phase 3 trial, particularly among patients with detectable ESR1 mutations; finally, PARP inhibitors are available treatment options for patients with pathogenic BRCA1/2 germline mutations. Overall, a plethora of novel endocrine and biologic treatment options are finally filling the gap between first-line ET and later line chemotherapy. In this review article, we recapitulate the activity of these novel treatment options and their potential role in future treatment algorithms.

Genetic Heterogeneity and Tissue-specific Patterns of Tumors with Multiple PIK3CA Mutations

PURPOSE

To comprehensively characterize tissue-specific and molecular subclasses of multiple PIK3CA (multi-PIK3CA) mutations and assess their impact on potential therapeutic outcomes.

EXPERIMENTAL DESIGN

We profiled a pan-cancer cohort comprised of 352,392 samples across 66 tumor types using a targeted hybrid capture-based next-generation sequencing panel covering at least 324 cancer-related genes. Molecularly defined subgroups, allelic configuration, clonality, and mutational signatures were identified and tested for association with PI3K inhibitor therapeutic response.

RESULTS

Multi-PIK3CA mutations are found in 11% of all PIK3CA-mutant tumors, including 9% of low tumor mutational burden (TMB) PIK3CA-mutant tumors, and are enriched in breast and gynecologic cancers. Multi-PIK3CA mutations are frequently clonal and in cis on the same allele and occur at characteristic positions across tumor types. These mutations tend to be mutually exclusive of mutations in other driver genes, and of genes in the PI3K pathway. Among PIK3CA-mutant tumors with a high TMB, 18% are multi-PIK3CA mutant and often harbor an apolipoprotein B mRNA-editing enzyme, catalytic polypeptide (APOBEC) mutational signature. Despite large differences in specific allele combinations comprising multi-PIK3CA mutant tumors, especially across cancer types, patients with different classes of multi-PIK3CA mutant estrogen receptor-positive, HER2-negative breast cancers respond similarly to PI3K inhibition.

CONCLUSIONS

Our pan-tumor study provides biological insights into the genetic heterogeneity and tissue specificities of multi-PIK3CA mutations, with potential clinical utility to guide PI3K inhibition strategies.

Biology and Targetability of the Extended Spectrum of PIK3CA Mutations Detected in Breast Carcinoma

PURPOSE

Alpelisib is a PI3K alpha (PI3Kα)-selective inhibitor approved for the treatment of hormone receptor-positive/HER2-negative (HR+/HER2-) PIK3CA-mutated advanced breast cancer (ABC) based on the SOLAR-1 trial, which defined 11 substitutions in exons 7, 9, and 20 in PIK3CA (SOLAR1m). We report alpelisib effectiveness for ABC harboring SOLAR1m, as well as other pathogenic PIK3CA mutations (OTHERm) using comprehensive genomic profiling (CGP).

EXPERIMENTAL DESIGN

A total of 33,977 tissue and 1,587 liquid biopsies were analyzed using hybrid capture-based CGP covering the entire coding sequence of PIK3CA. Clinical characteristics and treatment history were available for 10,750 patients with ABC in the deidentified Flatiron Health-Foundation Medicine clinico-genomic database (FH-FMI CGDB).

RESULTS

PIK3CAm were detected in 11,767/33,977 (35%) of tissue biopsies, including 2,300 (7%) samples with OTHERm and no SOLAR1m. Liquid biopsy had 77% sensitivity detecting PIK3CAm, increasing to 95% with circulating tumor DNA fraction ≥2%. In patients with HR+/HER2- ABC and PIK3CAm receiving alpelisib/fulvestrant (ALP+FUL; n = 182) or fulvestrant alone (FUL; n = 119), median real-world progression-free survival (rwPFS) was 5.9 months on ALP+FUL [95% confidence interval (CI): 5.1-7.4] versus 3.1 months on FUL (95% CI: 2.7-3.7; P < 0.0001). In patients with OTHERm, median rwPFS was 4.0 months on ALP+FUL (95% CI: 2.8-10.1) versus 2.5 months on FUL (95% CI: 2.2-3.7; P = 0.0054).

CONCLUSIONS

CGP detects diverse PIK3CAm in a greater number of patients with ABC than PCR hotspot testing; 20% of patients with PIK3CAm do not have SOLAR1m. These patients may derive benefit from alpelisib. See related commentary by Tau and Miller, p. 989.

Phosphoinositide 3-Kinase (PI3K) Inhibitors and Breast Cancer: An Overview of Current Achievements

The phosphatidylinositol 3-kinase (PI3K) pathway is one of the most altered pathways in human cancers, and it plays a central role in cellular growth, survival, metabolism, and cellular mobility, making it a particularly interesting therapeutic target. Recently, pan-inhibitors and then selective p110α subunit inhibitors of PI3K were developed. Breast cancer is the most frequent cancer in women and, despite therapeutic progress in recent years, advanced breast cancers remain incurable and early breast cancers are at risk of relapse. Breast cancer is divided in three molecular subtypes, each with its own molecular biology. However, PI3K mutations are found in all breast cancer subtypes in three main "hotspots". In this review, we report the results of the most recent and main ongoing studies evaluating pan-PI3K inhibitors and selective PI3K inhibitors in each breast cancer subtype. In addition, we discuss the future of their development, the various potential mechanisms of resistance to these inhibitors and the ways to circumvent them.

Overexpressed Cyclin D1 and CDK4 proteins are responsible for the resistance to CDK4/6 inhibitor in breast cancer that can be reversed by PI3K/mTOR inhibitors

CDK4/6 inhibitors are the standard treatment in advanced HR+/HER2- breast cancer patients. Nevertheless, the resistance to CDK4/6 inhibitors is inevitable and the strategies to overcome resistance are of great interest. Here, we show that the palbociclib-resistant breast cancer cells expressed significantly higher levels of Cyclin D1 and CDK4 proteins because of upregulated protein synthesis. Silencing Cyclin D1 or CDK4 led to cell cycle arrest while silencing Cyclin E1 or CDK2 restored the sensitivity to palbociclib. Furthermore, PI3K/mTOR pathway was hyper-activated in palbociclib-resistant cells, leading to more phosphorylated 4E-BP1 and higher levels of Cyclin D1 and CDK4 translation. Targeting PI3K/mTOR pathway with a specific PI3Kα inhibitor (BYL719) or an mTOR inhibitor (everolimus) reduced the protein levels of Cyclin D1 and CDK4, and restored the sensitivity to palbociclib. The tumor samples expressed significantly higher levels of Cyclin D1, CDK4, p-AKT and p-4E-BP1 after progression on palbociclib treatment. In conclusion, our findings suggest that overexpressed Cyclin D1 and CDK4 proteins lead to the resistance to CDK4/6 inhibitor and PI3K/mTOR inhibitors are able to restore the sensitivity to CDK4/6 inhibitors, which provides the biomarker and rationale for the combinational use of CDK4/6 inhibitors and PI3K/mTOR inhibitors after CDK4/6 inhibitor resistance in breast cancer.

Real world outcomes with alpelisib in metastatic hormone receptor-positive breast cancer patients: A single institution experience

Background

It is critically important to study the real-world data of FDA-approved medications to understand the response rates and toxicities observed in the real-world population not represented in the clinical trials.

Methods

We reviewed charts of patients diagnosed with metastatic, hormone receptor-positive, human epidermal growth factor receptor 2 negative, PIK3CA-mutated breast cancer treated with alpelisib from May 2019 to January 2022. Clinical characteristics and treatment outcomes were collected. The association of clinical characteristics with responses and adverse events (AEs) was evaluated using the logistic regression model.

Results

27 patients were included. Median age at alpelisib initiation 67 years (range: 44, 77 years). Majority of patients had excellent performance status at time of alpelisib initiation. Most patients had chronic comorbidities, notably; 2 patients had controlled type 2 diabetes mellitus at time of alpelisib initiation. Majority had a median of three lines of therapy (range: 1, 7) before alpelisib. Clinical responses were determined using RECIST v1.1. 3/27 (11.11%) patients discontinued therapy before response assessment due to grade 3 AEs. Overall response rate was 12.5% (3/24), with all partial responses (PR). The median duration of response was 5.77 months (range: 5.54, 8.98). 14/27 (51.9%) of patients required dose interruption/reduction. Overall, 23/27 (85.19%) patients discontinued alpelisib of which 11 (47.83%) discontinued alpelisib due to AEs. Median duration of treatment was 2 months in patients who had grade 3 AEs (range: <1.00, 8.30) and 6.28 (1.15, 10.43) in those who did not. Any grade AEs were reported in 24/27 (88.9%) patients, namely, hyperglycemia 16/27 (59.3%), nausea 11/27 (40.7%), diarrhea 10/27 (37.0%), fatigue 7/27 (25.9%) and rash 6/27 (22.2%). Grade 3 AEs were reported in 13/27 patients (50%), namely, hyperglycemia in 7/27 (53.8%) patients followed by skin rash 4/27 (30.8%), GI side effects 3/27 (23.1%). Those with progressive disease as best response to alpelisib, had more non-metabolic comorbidities, higher number of liver metastases, PIK3CA E545K mutations, and shorter duration on therapy compared to those with PR and stable disease.

Conclusion

Patients should be counseled about the toxicity and modest benefit observed with alpelisib in real-world clinical practice when used in later lines of therapy.

At a crossroads: how to translate the roles of PI3K in oncogenic and metabolic signalling into improvements in cancer therapy

Numerous agents targeting various phosphatidylinositol 3-kinase (PI3K) pathway components, including PI3K, AKT and mTOR, have been tested in oncology clinical trials, resulting in regulatory approvals for the treatment of selected patients with breast cancer, certain other solid tumours or particular haematological malignancies. However, given the prominence of PI3K signalling in cancer and the crucial role of this pathway in linking cancer growth with metabolism, these clinical results could arguably be improved upon. In this Review, we discuss past and present efforts to overcome the somewhat limited clinical efficacy of PI3Kα pathway inhibitors, including optimization of inhibitor specificity, patient selection and biomarkers across cancer types, with a focus on breast cancer, as well as identification and abrogation of signalling-related and metabolic mechanisms of resistance, and interventions to improve management of prohibitive adverse events. We highlight the advantages and limitations of laboratory-based model systems used to study the PI3K pathway, and propose technologies and experimental inquiries to guide the future clinical deployment of PI3K pathway inhibitors in the treatment of cancer.

Biomarkers for Systemic Therapy in Metastatic Breast Cancer: ASCO Guideline Update

PURPOSE

To update the ASCO biomarkers to guide systemic therapy for metastatic breast cancer (MBC) guideline.

METHODS

An Expert Panel conducted a systematic review to identify randomized clinical trials and prospective-retrospective studies from January 2015 to January 2022.

RESULTS

The search identified 19 studies informing the evidence base.

RECOMMENDATIONS

Candidates for a regimen with a phosphatidylinositol 3-kinase inhibitor and hormonal therapy should undergo testing for PIK3CA mutations using next-generation sequencing of tumor tissue or circulating tumor DNA (ctDNA) in plasma to determine eligibility for alpelisib plus fulvestrant. If no mutation is found in ctDNA, testing in tumor tissue, if available, should be used. Patients who are candidates for poly (ADP-ribose) polymerase (PARP) inhibitor therapy should undergo testing for germline BRCA1 and BRCA2 pathogenic or likely pathogenic mutations to determine eligibility for a PARP inhibitor. There is insufficient evidence for or against testing for a germline PALB2 pathogenic variant to determine eligibility for PARP inhibitor therapy in the metastatic setting. Candidates for immune checkpoint inhibitor therapy should undergo testing for expression of programmed cell death ligand-1 in the tumor and immune cells to determine eligibility for treatment with pembrolizumab plus chemotherapy. Candidates for an immune checkpoint inhibitor should also undergo testing for deficient mismatch repair/microsatellite instability-high to determine eligibility for dostarlimab-gxly or pembrolizumab, as well as testing for tumor mutational burden. Clinicians may test for NTRK fusions to determine eligibility for TRK inhibitors. There are insufficient data to recommend routine testing of tumors for ESR1 mutations, for homologous recombination deficiency, or for TROP2 expression to guide MBC therapy selection. There are insufficient data to recommend routine use of ctDNA or circulating tumor cells to monitor response to therapy among patients with MBC.Additional information can be found at www.asco.org/breast-cancer-guidelines.

Targeted Therapy in HR+ HER2- Metastatic Breast Cancer: Current Clinical Trials and Their Implications for CDK4/6 Inhibitor Therapy and beyond Treatment Options

A metastatic state of breast cancer (MBC) affects hundreds of thousands of women worldwide. In hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) MBC, cyclin-dependent kinase (CDK)4/6 inhibitors can improve the progression-free survival (PFS), as well as the overall survival (OS), in selected patients and have been established as first- and second-line therapies. However, as MBC remains uncurable, resistance to CDK4/6 inhibitors occurs and requires alternative treatment approaches. Data on targeted therapy continue to mature, and the number of publications has been constantly rising. This review provides a summary and update on the clinical relevance, patient selection, ongoing trials of CDK4/6 inhibitors, and further targeted therapy options. It focuses on clinical aspects and practicability, as well as adverse events and patient-reported outcomes.

Endocrine Treatment for Breast Cancer Patients Revisited-History, Standard of Care, and Possibilities of Improvement

PURPOSE OF REVIEW

Due to the findings of current studies and the approval of novel substances for the therapy of hormone-receptor-positive breast cancer patients, the established standards of endocrine treatment are changing. The purpose of this review is to give an overview of the history of endocrine treatment, to clarify its role in the present standard of care, and to discuss the possibilities of improvement.

RECENT FINDINGS

Tamoxifen, aromatase inhibitors, and fulvestrant are the main drugs that have been used for decades in the therapy of hormone-receptor-positive breast cancer patients. However, since a relevant number of women suffer at some point from disease recurrence or progression, several novel substances are being investigated to overcome resistance mechanisms by interfering with certain signaling pathways, such as the PI3K/AKT/mTOR or the CDK4/6 pathways. mTOR and CDK4/6 inhibitors were the first drugs approved for this purpose and many more are in development.

SUMMARY

Endocrine treatment is one of the best tolerable cancer therapies available. Continuous investigation serves to improve patients' outcomes and modernize the current standard of care. Considering the resistance mechanisms and substances analyzed against these, endocrine treatment of hormone-receptor-positive breast cancer is on the brink of a new era.

Endocrine Treatment and Targeted Therapy for Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Metastatic Breast Cancer: ASCO Guideline Update

PURPOSE

To update recommendations of the ASCO systemic therapy for hormone receptor (HR)-positive metastatic breast cancer (MBC) guideline.

METHODS

An Expert Panel conducted a systematic review to identify new, potentially practice-changing data.

RESULTS

Fifty-one articles met eligibility criteria and form the evidentiary basis for the recommendations.

RECOMMENDATIONS

Alpelisib in combination with endocrine therapy (ET) should be offered to postmenopausal patients, and to male patients, with HR-positive, human epidermal growth factor receptor 2 (HER2)-negative, PIK3CA-mutated, ABC, or MBC following prior endocrine therapy with or without a cyclin-dependent kinase (CDK) 4/6 inhibitor. Clinicians should use next-generation sequencing in tumor tissue or cell-free DNA in plasma to detect PIK3CA mutations. If no mutation is found in cell-free DNA, testing in tumor tissue, if available, should be used as this will detect a small number of additional patients with PIK3CA mutations. There are insufficient data at present to recommend routine testing for ESR1 mutations to guide therapy for HR-positive, HER2-negative MBC. For BRCA1 or BRCA2 mutation carriers with metastatic HER2-negative breast cancer, olaparib or talazoparib should be offered in the 1st-line through 3rd-line setting. A nonsteroidal aromatase inhibitor (AI) and a CDK4/6 inhibitor should be offered to postmenopausal women with treatment-naïve HR-positive MBC. Fulvestrant and a CDK4/6 inhibitor should be offered to patients with progressive disease during treatment with AIs (or who develop a recurrence within 1 year of adjuvant AI therapy) with or without one line of prior chemotherapy for metastatic disease, or as first-line therapy. Treatment should be limited to those without prior exposure to CDK4/6 inhibitors in the metastatic setting.Additional information can be found at www.asco.org/breast-cancer-guidelines.