Predicting Hyperglycemia Among Patients Receiving Alpelisib Plus Fulvestrant for Metastatic Breast Cancer

BACKGROUND

Hyperglycemia is recognized as a common adverse event for patients receiving alpelisib but has been little studied outside of clinical trials. We report the frequency of alpelisib-associated hyperglycemia in a real-world setting and evaluate proposed risk factors.

PATIENTS AND METHODS

We retrospectively identified patients with PIK3CA-mutated, hormone receptor-positive, metastatic breast cancer who initiated treatment with alpelisib plus fulvestrant between August 2019 and December 2021. Ordinal logistic regression evaluated 5 characteristics (diabetes, prediabetes, body mass index [BMI], age, and Asian ancestry) as independent risk factors for ALP-associated hyperglycemia grades 2-4. Risk of error from multiple hypothesis testing was controlled using the false discovery rate method.

RESULTS

The study included n = 92 subjects, all but 1 female, mean age 59.9 (+11.9) years with 50% non-Hispanic White, 15% Hispanic/Latino, 13% Asian, 9% African/Black, and 13% other/unknown. In total 34% of patients had diabetes, 10% had pre-diabetes, and 56% had normoglycemia. Thirty-six percent were obese, 32% were overweight, 25% were normal weight, and 7% were lean. Frequency of grades 1-4 hyperglycemia in current subjects (64.1%) was similar to hyperglycemia reported in the SOLAR-1 trial (63.7%). Our subjects' risk of grades 2-4 hyperglycemia was independently increased by pre-existing diabetes (Odds ratio 3.75, 95% CI, 1.40-10.01), pre-diabetes (6.22, 1.12-34.47), Asian ancestry (7.10, 1.75-28.84), and each unit of BMI above 20 (1.17, 1.07-1.28).

CONCLUSION

While receiving alpelisib, patients of Asian ancestry, as well as patients with pre-existing hyperglycemia and/or BMI above 20, should be closely monitored for hyperglycemia. The mechanism underlying the current association of alpelisib-associated hyperglycemia with Asian ancestry is independent of BMI and merits further study. The high incidence of hyperglycemia resulted in a change in practice to include consultation with a diabetes nurse educator or endocrinologist at the start of alpelisib.

The role of self-perceived age in older adults considering adjuvant chemotherapy

INTRODUCTION

Aging-related concerns can increase the risk of treatment toxicities among older adults considering adjuvant chemotherapy. We previously demonstrated that older adults with cancer who reported feeling older than their chronological age (i.e., self-perceived age) were more likely to have aging-related concerns identified during a geriatric assessment. We explored how decisions about adjuvant chemotherapy vary with or are related to older adults' self-perceived age.

MATERIALS AND METHODS

We conducted a secondary analysis of a multi-phased feasibility pilot using semi-structured interviews that were conducted to explore the patient decision-making process for adjuvant chemotherapy. Interviews incorporated questions about chronological and perceived age as factors for decision-making. Patient eligibility for the study included (1) age ≥ 70 years and older, (2) a diagnosis of breast, colon, or lung cancer and considering adjuvant chemotherapy, and (3) able to read size 18 font in English. Interview data were analyzed using constant comparative method.

RESULTS

Twenty-one patients were enrolled. The mean chronological age was 78 years (range 71-91). The average perceived age of patients was 57 years (range 21-80). Eleven patients chose to receive treatment while ten patients did not. Aging-related themes illustrated that self-perceived age plays an important role when patients make decisions about adjuvant chemotherapy. More specifically, patients who reported their self-perceived age as younger than their chronological age also reported better perceived health status and chose to receive adjuvant chemotherapy.

DISCUSSION

Patients' experiences of aging and self-perceived age may have different implications for decision-making.

Feasibility and Satisfaction of Using NET VITALS Self-assessment Tool Among Patients With Neuroendocrine Tumors

OBJECTIVES

There is a lack of effective patient education regarding diagnosis/treatment of neuroendocrine tumors (NETs), possibly related to their rare incidence.

METHODS

In this cross-sectional survey study, NET patients attending the 2019 Annual Los Angeles NET Education Conference were approached to complete NET VITALS, a self-assessment tool gauging patients' perception/awareness of their NET diagnosis/treatment, and a satisfaction survey. Feasibility of NET VITALS, patient satisfaction with NET VITALS, and patients' perception/awareness of their NET diagnosis/treatment were evaluated.

RESULTS

This analysis included 68 patients (median age, 63 years; 47.1% gastrointestinal NETs; 88.2% metastatic disease). Participation was 88.3% (68/77), with a median of 85.7% of items completed (range, 61.9%-100.0%). More than 30% of the patients answered "Don't know/Not familiar"/left blank questions related to tumor characteristics, years of symptoms, and liver-directed therapies. In addition, 69.5% of the patients did not feel sufficient information about NETs was provided at diagnosis. Overall, 67.8% of the patients felt that NET VITALS provides topics to discuss with providers and 76.3% would recommend NET VITALS to others.

CONCLUSIONS

NET VITALS is a feasible and acceptable self-assessment tool to potentially help patients improve communication about their NET diagnosis/treatment with their physician. Further studies will examine NET VITALS' generalizability and discuss its incorporation into clinical care.

Abstract P4-11-12: Integrating the patient and partner distress and perceptions about prognosis in women with metastatic breast cancer guides the medical oncology consultation

Methods: Women with metastatic breast cancer and their partners completed couples’ tailored biopsychosocial screening and alignment in perception of prognosis immediately before consultation with a Medical Oncologist. In addition, couples were offered a standardized couples’ session before the medical consultation, individual couples’ counseling, and a strengths-based group intervention. As a component of biopsychosocial screening, each patient and her partner were asked individually their understanding of prognosis. They were asked their perception of likelihood of cure with supporting text and percentages provided: 76-100%; 51-75%; 26-50%, or 0-25%. Results: To date 254 women were considered eligible for this program. Complete data for both partners is available on 205. All the patients had metastatic breast cancer prior to their Medical Oncology appointment. The average age of the patient was 54 years (Range 25-84) and 55 years (Range 26-84) for the partner. In the perception of prognosis, 48.7% of patients and their partner were aligned and 51.3% were misaligned. The patient was more likely to have considered their prognosis worse in 59% and the partner 41%. The most commonly endorsed distress items for the patient were: Worry about the future 61%; Side effects of treatment 60%; Fatigue 59%; How my family will cope 58%; and Sleeping 49%. Distress for the partner included: Feeling anxious or fearful 49%; Wanting to best help my partner 37% and Sleeping 37%. Both the patient and partner sought assistance with Understanding treatment options 73.6%; Feeling anxious or fearful 62.5%, Worry about the future 57.3% Fatigue 56.3%, and Pain 56.3%- Partner practical distress was significantly higher for those couples who were not in alignment, p<.05. Conclusions: It is possible to openly ask patients and their partners about prognosis. In women with metastatic breast cancer, lack of alignment with understanding prognosis was common with the patient being more likely to have realistic expectations than their partner. A better understanding of the patient/partner’s expectations about treatment outcome has the potential to guide the Medical Oncologist to individualize communications including discussion about goals of care.

Citation Format: Joanne Mortimer, James Waisman, Yuan, Sayeh Lavasani, Daphne Stewart, Mina Sedrak, Niki Patel, Courtney Bitz, Karen Clark, Marianne Razavi, Matthew J Loscalzo. Integrating the patient and partner distress and perceptions about prognosis in women with metastatic breast cancer guides the medical oncology consultation [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-11-12.

Abstract P4-11-13: Prevalence of treatment-related symptoms in patients with breast cancer undergoing (neo)adjuvant endocrine therapy with or without chemotherapy for early stage breast cancer

Prevalence of treatment-related symptoms in patients with breast cancer undergoing (neo)adjuvant endocrine therapy with or without chemotherapy for early stage breast cancer. Background: Survivorship care plans require identification of post-treatment problems.Methods: After completion of (neo) adjuvant therapy and immediately prior to a survivorship visit which included a treatment summary and care planning, patients completed an automated tablet-based series of 25 biopsychosocial questions (Survivorship-SupportScreen). Problems were identified and rated on a Likert scale of 1-5. This analysis addresses the differences in patient reported symptoms in women treated with endocrine therapy (ET) alone compared to those receiving chemotherapy and ET (CT+ET). Results: 204 women with a mean age of 57.5 years at screening time (Range 27-90) completed the Survivorship-SupportScreen within a median of 0.9 years of initial diagnosis. The 113 patients receiving CT+ET were younger than the 91 treated with ET alone (Mean 54.83 versus 60.89, with p<0.001) with no significant difference in time from first diagnosis to screening.

Prevalence of problems was similar for both groups, except for neuropathy (p<0.001). By Logistic regression models neuropathy was 2.5 times more likely in patients treated with chemotherapy. Patients ≥ 50 years treated with CT+ET reported more hot flashes and lack of regular exercise: OR=2.18, p=0.024, and OR=2.04, p=0.033. Conclusions: We have demonstrated the feasibility of screening patient as they transition from active treatment to survivorship. Except for neuropathy, all patients receiving CT+ET had similar problems compared with those on ET alone. Women ≥ 50 years who received CT+ET, were more likely to report hot flashes and lack of regular exercise. Despite the fact that most of these women are likely cured of their cancer, the negative lingering sequelae of problem-related distress were reported by all patients.

CT+ETET alonepFatigue81/110 (73.64%)65/88 (73.86%)0.971Worry about recurrence77/113 (68.14%)60/91 (65.93%)0.739Sleeping70/112 (62.5%)51/91 (56.04%)0.351Not being physically active67/110 (60.9%)50/89 (56.18%)0.500Neuropathy64/113 (56.64%)29/91 (31.87%)<0.001Pain62/112 (55.36%)43/90 (47.78%)0.284Hot flashes61/113 (53.98%)52/91 (57.14%)0.652Thinking clearly53/111 (47.75%)38/89 (42.7%)0.476Vaginal dryness47/113 (41.59%)31/91 (34.07%)0.271Gained weight45/113 (39.82%)34/91 (37.36%)0.720

Citation Format: Joanne Mortimer, Sharla Moore, Niki Patel, Mina Sedrak, Daphne Stewart, Yuan Yuan, James Waisman, Brittany Bradford, Matthew Loscalzo, Karen Clark, Marianne Razavi. Prevalence of treatment-related symptoms in patients with breast cancer undergoing (neo)adjuvant endocrine therapy with or without chemotherapy for early stage breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-11-13.

NCCN Guidelines® Insights: Older Adult Oncology, Version 1.2021

The NCCN Guidelines for Older Adult Oncology address specific issues related to the management of cancer in older adults, including screening and comprehensive geriatric assessment (CGA), assessing the risks and benefits of treatment, preventing or decreasing complications from therapy, and managing patients deemed to be at high risk for treatment-related toxicity. CGA is a multidisciplinary, in-depth evaluation that assesses the objective health of the older adult while evaluating multiple domains, which may affect cancer prognosis and treatment choices. These NCCN Guidelines Insights focus on recent updates to the NCCN Guidelines providing specific practical framework for the use of CGA when evaluating older adults with cancer.

Phase I/II trial of palbociclib, pembrolizumab and letrozole in patients with hormone receptor-positive metastatic breast cancer

BACKGROUND

CDK4/6 inhibitors modulate immune response in breast cancer. This phase I/II trial was designed to test the safety and efficacy of palbociclib, pembrolizumab and letrozole in women with hormone receptor positive (HR⁺) human epidermal growth factor receptor 2 negative (HER2^-) metastatic breast cancer (MBC).

PATIENTS AND METHODS

Women with stage IV HR⁺ HER2^- MBC were enrolled and treated with palbociclib, pembrolizumab and letrozole. Primary end-points were safety, tolerability and efficacy.

RESULTS

Between November 2016 and July 2020, 23 patients were enrolled with 20 evaluable for response, including 4 patients in cohort 1 and 16 patients in cohort 2. Cohort 1 median age was 48 years (33-70) and cohort 2 median age was 55 (37-75). Cohort 1 closed early due to limited accrual. Grade III-IV adverse events were neutropenia (83%), leucopaenia (65%), thrombocytopenia (17%) and elevated liver enzymes (17%). In cohort 1, 50% achieved a partial response (PR) and 50% had stable disease (SD). In cohort 2, 31% achieved complete response (CR), 25% had PR and 31% had SD by Response Evaluation Criteria in Solid Tumours version 1.1. Median progression-free survival was 25.2 months (95% confidence interval [CI] 5.3, not reached) and median overall survival was 36.9 months (95% CI 36.9, not reached) in cohort 2 with a median follow-up of 24.8 months (95% CI 17.1, not reached). A correlative immune biomarker analysis was published separately.

CONCLUSION

The combination of palbociclib, pembrolizumab and letrozole is well tolerated, and a complete response rate of 31% was identified in HR⁺ MBC patients who received this combination as front-line therapy. Confirmatory trials are required to better understand the immune-priming effects of CDK4/6 inhibitors.

Abstract OT-24-01: Phase I study combining ipatasertib with chemotherapy and atezolizumab in patients with metastatic triple negative breast cancer

Background: The PI3K-ATK pathway is one of the most common cancer drivers in breast cancer, and the AKT inhibitor ipatasertib (ipat) has shown great efficacy in patients (pts) with metastatic triple negative breast cancer (mTNBC). The current phase I trial is designed to test the safety and efficacy of the following ipat combinations: ipat + carboplatin (C) + paclitaxel (T); ipat + C; ipat + capecitabine (cape) + atezolizumab (atezo). Trial Design: This is a Phase I open-label study for pts with mTNBC. Eligible pts receive one of three regimens: A) weekly carbo AUC 2 plus taxol 80 mg/m2 days 1, 8, 15 and daily ipat 300 mg every 28 days; B) weekly carbo AUC 2, days 1, 8, 15 and daily ipat 400 mg every 28 days; C) cape 750 mg bid 1 week on 1 week off, ipat 300 mg daily and atezo 840 mg iv days 1, 15 every 28 days. Eligibility Criteria: Eligible patients must have histologically confirmed mTNBC (ER/PR ≤ 10%, HER2- per ASCO/CAP); RECIST 1.1 measurable disease; 0-2 lines of chemotherapy prior for mTNBC; AEs recovered to ≤ Gr 2 per CTCAE 5.0; adequate bone marrow, hepatic and renal function. Prior exposure to AKT targeted therapy is excluded.Specific Aims: Primary objectives are to evaluate the safety and tolerability of the combinations and determine the recommended Phase II dose (RP2D) of the combinations. Secondary objectives are to evaluate response rate, clinical benefit rate, progression free survival, and overall survival. Statistical Design: For the safety-lead in, a “3 at risk design” will be utilized to assess toxicity for the combination therapy. The DLT period is 1-cycle (28 days). Each participant will remain on the dosing level according to the escalation dose level they were enrolled in, and intra-dose level escalations will not be allowed, even if the MTD is defined at a higher dose level. Rules for escalation are as follows: if escalating from Level 1, two dose levels will be open, Level 2A, and Level 2B. Only if both 2A and 2B result in a decision to escalate will dose level 3 for this triplet be open. When both 2A and 2B are both open, slots will be given to the arm with the most open slots (starting with 2A if there are ties). When a maximum tolerable dose level has been defined by the dose escalation portion of the study, and the recommended phase 2 dose (RP2D not to exceed the MTD) has been selected, additional patients will be accrued to confirm the tolerability of the regimen. For Arm C, at least 12 patients will be treated at the RP2D to confirm tolerability. Additional patients can be accrued if the total number of patients accrued does not exceed 21 patients (e.g. if the RP2D is dose level 1, with 2A and 2B not well-tolerated based on 3 patients on each 2A and 2B, the total at RP2D could be 15). If one agent is discontinued due to toxicity, then the participant may continue to receive the remaining single agent or doublet agent therapy on protocol. With 12 patients, any specific severe toxicity with 20% incidence will be observed with 93% probability.

Citation Format: Yuan Yuan, Susan E. Yost, Jin Sun Lee, Paul H. Frankel, Christopher Ruel, Mireya Murga, Aileen Tang, Norma Martinez, James Waisman, Niki Patel, Mina Sedrak, Daphne Stewart, Sayeh Lavasani, Joanne Mortimer. Phase I study combining ipatasertib with chemotherapy and atezolizumab in patients with metastatic triple negative breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr OT-24-01.

A Phase II Clinical Trial of Pembrolizumab and Enobosarm in Patients with Androgen Receptor-Positive Metastatic Triple-Negative Breast Cancer

LESSONS LEARNED

The combination of enobosarm and pembrolizumab was well tolerated and showed a modest clinical benefit rate of 25% at 16 weeks. Future trials investigating androgen receptor-targeted therapy in combination with immune checkpoint inhibitors are warranted.

BACKGROUND

Luminal androgen receptor is a distinct molecular subtype of triple-negative breast cancer (TNBC) defined by overexpression of androgen receptor (AR). AR-targeted therapy has shown modest activity in AR-positive (AR+) TNBC. Enobosarm (GTx-024) is a nonsteroidal selective androgen receptor modulator (SARM) that demonstrates preclinical and clinical activity in AR+ breast cancer. The current study was designed to explore the safety and efficacy of the combination of enobosarm and pembrolizumab in patients with AR+ metastatic TNBC (mTNBC).

METHODS

This study was an open-label phase II study for AR+ (≥10%, 1+ by immunohistochemistry [IHC]) mTNBC. Eligible patients received pembrolizumab 200 mg intravenous (IV) every 3 weeks and enobosarm 18 mg oral daily. The primary objective was to evaluate the safety of enobosarm plus pembrolizumab and determine the response rate. Peripheral blood, tumor biopsies, and stool samples were collected for correlative analysis.

RESULTS

The trial was stopped early because of the withdrawal of GTx-024 drug supply. Eighteen patients were enrolled, and 16 were evaluable for responses. Median age was 64 (range 36-81) years. The combination was well tolerated, with only a few grade 3 adverse events: one dry skin, one diarrhea, and one musculoskeletal ache. The responses were 1 of 16 (6%) complete response (CR), 1 of 16 (6%) partial response (PR), 2 of 16 (13%) stable disease (SD), and 12 of 16 (75%) progressive disease (PD). Response rate (RR) was 2 of 16 (13%). Clinical benefit rate (CBR) at 16 weeks was 4 of 16 (25%). Median follow-up was 24.9 months (95% confidence interval [CI], 17.5-30.9). Progression-free survival (PFS) was 2.6 months (95% CI, 1.9-3.1) and overall survival (OS) was 25.5 months (95% CI, 10.4-not reached [NR]).

CONCLUSION

The combination of enobosarm and pembrolizumab was well tolerated, with a modest clinical benefit rate of 25% at 16 weeks in heavily pretreated AR+ TNBC without preselected programmed death ligand-1 (PD-L1). Future clinical trials combining AR-targeted therapy with immune checkpoint inhibitor (ICI) for AR+ TNBC warrant investigation.

The Effects of Time to Treatment Initiation for Patients With Non-small-cell Lung Cancer in the United States

BACKGROUND

The purpose of this study was to determine the effects of time from diagnosis to treatment (TTI) on survival in patients with nonmetastatic non-small-cell lung cancer (NSCLC).

MATERIALS AND METHODS

The National Cancer Database was queried for patients with stages 1 to 3 NSCLC between 2004 and 2013. Patients with missing survival status/time, unknown TTI, or receipt of palliative therapy were excluded. Multivariable Cox proportional hazards modeling, logistic regression, and recursive partitioning analysis were performed to determine associated variables and survival outcomes.

RESULTS

Altogether, 1,393,232 patients met inclusion criteria. The median follow-up was 36 months. The median TTI increased between 2004 and 2013 from 35 to 39 days (P < .001). On multivariable Cox proportional hazards modeling, TTI groups 31 to 60 days, 61 to 90 days, and > 90 days were independently related to poorer overall survival (OS) compared with TTI 1 to 30 days (hazard ratio, 1.04, 1.10, and 1.14; 95% confidence interval [CI], 1.02-1.06, 1.07-1.12, and 1.11-1.17, respectively; P < .001 for all). Recursive partitioning analysis revealed that TTI of ≤ 45 days was the most optimal threshold for survival (P < .001); patients with TTI ≤ 45 days had a median OS of 70.2 months (95% CI, 69.3-71.1 months) versus 61.5 months (95% CI, 60.5-62.4) (P < .001). There were significant disparities by age, race, ethnicity, and income for delayed (> 45 days) TTI (P < .001 for all). Subgroup analysis revealed that stage 1 and 2 patients with TTI > 45 days had a higher risk of mortality compared with TTI ≤ 45 days (hazard ratio, 1.15 and 1.05; 95% CI, 1.12-1.17 and 1.01-1.09, respectively) (P < .001).

CONCLUSIONS

Increased TTI is independently associated with poorer survival in non-metastatic NSCLC. TTI ≤ 45 days is a clinically targetable time frame associated with improved outcomes and ought to be considered for patients with lung cancer undergoing definitive therapy.

Abstract P5-06-26: Gut microbiome profiling of patients with metastatic breast cancer undergoing immune checkpoint inhibitor therapy

Background: Collection of fecal samples is non-invasive, and DNA sequencing of microorganisms can provide a profile of the gut microbiome which may be an indicator of general health and disease, including inflammation, digestive inefficiencies, and the presence of pathogens. The gut microbiome has been associated with response to immune checkpoint inhibitors (ICI) in patients with solid tumors. We aim to study the association of gut microbiome and response to therapy in patients with metastatic breast cancer (BC) undergoing ICI therapies.

Methods: 50 fecal samples from two ICI clinical trials (NCT02971761, N=22; NCT02778685, N=28) were collected at baseline, on treatment and at the end of treatment. DNA was extracted, and 16S rRNA gene libraries were generated targeting the variable region 4 (V4) region of the bacterial and archaeal rRNA gene. Libraries were sequenced on the Illumina MiSeq and sequence reads were analyzed using QIIME2.

Results: A total of 22 dominant taxa (present ≥5% in any one sample) were identified in samples from 12 triple negative BC patients treated with pembrolizumab + GTx-024 (Enobosarm) and 17 dominant taxa were identified taxa 10 ER+ BC patients treated with pembrolizumab, letrozole, and palbociclib. As is true for most microbiome studies, inter-subject variation was much greater than intra-subject variation. However, in some patients there was a significant change in the composition of the microbial communities over time. In the first study, two patients had partial response (PR) to treatment and both had relatively “healthy” gut microbiota dominated by Bacteroides, Faecalibacterium prausnitzii, and other short chain fatty acid producers like Ruminococcus bromii or Roseburia faecis. Most of the patients who progressed had dysbiotic gut microbiomes and four had very high (≥20%) relative abundance of Prevotella copri, an organism associated with inflammation. In the second study, four patients had PR, and as before, these patients had “healthy” gut signatures dominated by Bacteroides and short chain fatty acid-producing Firmicutes. In one of these patients, a high level of Prevotella stercorea (57%)at baseline was replaced by Bacteroides and Lachnospira as treatment proceeded. Three additional patients had very high levels of P. copri (≥34%); one resolved during treatment, the others did not. Shannon’s diversity index was used to measure abundance and evenness in the fecal communities. Several samples in both studies had very low diversity at baseline. In most cases, the diversity increased following treatment.

Conclusion: Most patients who progressed on ICI had dysbiotic gut microbiomes present at baseline and later time points, such as a high relative abundance of Prevotella (implicated in inflammatory processes); this often resolved during therapy. Our observations provide promise for future use of the gut microbiome as a predictor of response to immunotherapy for BC and the potential for modulating the gut microbiome to improve responses in patients with dysbiosis.

Citation Format: Yuan Yuan, Sarah Highlander, Susan E Yost, Kim Robinson, Simran Padam, Aileen Tang, Norma Martinez, John Gillece, Lauren Reining, Mina Sedrak, Joanne Mortimer, James Waisman. Gut microbiome profiling of patients with metastatic breast cancer undergoing immune checkpoint inhibitor therapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-06-26.

Abstract P3-11-04: A phase II study of pembrolizumab, letrozole and palbociclib in patients with metastatic estrogen receptor positive breast cancer

Background: The combination of CDK4/6 inhibitor and aromatase inhibitor is the current standard of care therapy for patients with estrogen receptor positive (ER+) metastatic breast cancer (MBC). Single agent immune check point inhibitor (ICI) pembrolizumab has a response rate of 12% in selected patients (PD-L1+), and preclinical studies demonstrated immune-modulatory effect of CDK4/6 inhibitors. The combination of CDK 4/6 inhibitors and ICI might turn “immune-cold” breast cancer tumors into “immune-hot” tumors. This study was designed to evaluate the safety and efficacy of adding pembrolizumab to letrozole and palbociclib in patients with ER+ MBC.

Methods: This is an open-label single arm study enrolling patients with biopsy proven ER+ MBC with measurable disease by RECIST1.1, ECOG performance status 0-1. Patient received letrozole (2.5mg po daily), palbociclib (125mg po daily 3 weeks on, 1 week off), and pembrolizumab (200mg iv q3wks). Two cohorts were included: cohort 1 for patients who were previously on letrozole and palbociclib for &gt; 6 months and had pembrolizumab added on C1D1, and cohort 2 for patients who had all 3 drugs started on C1D1. Premenopausal patients received ovarian suppression prior to C1D1. The primary objective was to determine the safety and tolerability of the combination. The secondary objectives were RR, PFS, and OS. For both cohorts, a three-at-risk design (modified rolling design) was used for safety-lead to ensure the triplet was well-tolerated. This design permitted only 3 patients to be a risk for DLT at any one time during the “safety lead-in” and permitted continuing accrual if ≤1 DLT occurred in the first 6 patients. Secondary consideration was response (cohort 2 only), with an a priori requirement of at least 9 responses to warrant further evaluation. Baseline tumor specimen, peripheral blood plasma, and PBMCs were collected for immune correlative analysis.

Results: A total of 20 patients were accrued to this trial (4 in cohort 1, 16 in cohort 2), with 19 eligible for response assessment because one patient was determined to be TNBC upon repeat of biopsy. Median age was 49 years, with 40% Hispanic, and 60% non-Hispanic. There were 2 DLTs (1 biopsy site infection and delay in treatment that was possibly related to treatment in cohort 1, and 1 pneumonitis in cohort 2). 9/20 patients (45%) had dose delay and 9/20 patients (45%) had dose reduction, with the most common cause being neutropenia. Gr 4 AEs included neutropenia (n=4), WBC (n=3), LFT (n=1), and bowel perforation (n=1). Grade 3 AEs included neutropenia (n=11), WBC (n=9), LFT (n=3), PLT (n=2), and pneumonitis, pruritus, anemia, biopsy site infection (n=1 each). Other immune-related toxicities of Grade 2 included: hypothyroidism, colitis, LFTs, and dermatitis (n≤2 each). Responses were CR 1/19 (5.3%), PR 8/19 (42.1%), SD 6/19 (31.6%) and PD 4/19 (21.1%). Median follow up was 13.7 (95% CI 6.4-16.9) months and median PFS was not reached. No association of baseline tumor PD-L1 (22C3) and clinical response were observed (data available on 13 patients). PBMC flow from the first 9 patients (5 PR, 4 SD) showed lower percentage of naïve CD8+ T cells (CD8+CD45RA+ CD27+), and higher level of non-naïve KLRG1+CD8+ T cell (CD8+CD45RA− CD27− KLRG1+) were associated with clinical response (p&lt;0.05).

Conclusion: The combination of letrozole, palbociclib, and pembrolizumab is well tolerated in patients with ER+ MBC.

Citation Format: Yuan Yuan, Susan E Yost, Jin Sun Lee, Colt Egelston, Paul H Frankel, Christopher Ruel, Simran Padam, Aileen Tang, Norma Martinez, Jana Portnow, Christina Yeon, Cary Presant, Swapnil Rajurkar, Mina Sedrak, Niki Patel, Peter Lee, Joanne Mortimer. A phase II study of pembrolizumab, letrozole and palbociclib in patients with metastatic estrogen receptor positive breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-11-04.

Abstract OT1-05-02: A phase II clinical trial of the combination of pembrolizumab and selective androgen receptor modulator GTx-024 in patients with advanced androgen receptor positive triple negative breast cancer

Background: Androgen receptor (AR) targeted therapy and immunotherapy represent one of the most promising strategies for metastatic triple negative breast cancer (mTNBC), which accounts for 15-20% of all breast cancers. As a nonsteroidal selective androgen receptor modulator (SARM), GTx-024 demonstrated preclinical activity in AR+ TNBC PDX model. Pembrolizumab is a highly selective humanized monoclonal antibody of the programmed cell death 1 receptor (PD-1). The complementary modes of action and low potential for overlapping toxicity make the combination promising in patients with AR+ mTNBC.

Trial Design: This is an open-label Phase 2 study for AR+ mTNBC. Eligible participants receive pembrolizumab 200mg IV every 3 weeks in combination with GTx-024 18mg po daily.

Eligibility Criteria: Eligible patients must have AR+ (&gt;10%, 1+ by IHC) TNBC; failed up to 2 lines of therapy in metastatic setting; and have measurable disease per RECIST1.1. Patients are excluded if they have had prior checkpoint inhibitors or AR targeted agents. Patients with current or prior use of testosterone, testosterone-like agents, androgenic compounds, or anti-androgens (including systemic steroids and immunosuppressive medications)are excluded, as well as current or prior history of noninfectious pneumonitis requiring systemic steroid therapy.

Specific Aims: The primary objective is to evaluate the safety/tolerability of GTx-024 and pembrolizumab and determine the response rate (CR or PR via RECIST 1.1) in patients with advanced AR+ TNBC. We will use clinical benefit rate (CBR), duration of response (DOR), PFS, and OS to test the efficacy of this novel drug combination.

Statistical Design: A Simon's MiniMax two-stage Phase 2 design will be utilized. Based on the previously reported response rate associated with single agent pembrolizumab (19%), we consider a response rate of 19% for the combination as discouraging, and a 39% response rate as encouraging. As a result, we will initially accrue 15 patients (including 6 patients from safety lead-in treated at the tolerable dose). If 2 or fewer patients respond, we will stop accrual for futility. Otherwise, the study will accrue an additional 14 patients for a total of 29 patients. With 29 patients, if only 8 or fewer respond (≤27.6%), the study will be considered discouraging unless secondary evidence of clinical benefit is substantial. With more than 8 patients responding out of the 29 patients, the combination would be considered promising. This design has 85% power to declare a true response rate of 39% as promising (power), and a 10% probability of declaring a true 19% response rate as encouraging (type I error). The probability of early termination if the true response rate is 19% is 44%.

Target Accrual: 29

Study Contact: Yuan Yuan MD PhD, City of Hope Comprehensive Cancer Center; Duarte, CA 91030; Email: yuyuan@coh.org

Citation Format: Yuan Y, Frankel P, Synold T, Lee P, Yost S, Martinez N, Tang A, Mendez B, Schmolze D, Apple S, Hurria A, Waisman J, Somlo G, Tank N, Sedrak M, Mortimer J. A phase II clinical trial of the combination of pembrolizumab and selective androgen receptor modulator GTx-024 in patients with advanced androgen receptor positive triple negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT1-05-02.

Abstract P1-08-04: Not presented

This abstract was not presented at the symposium.