Background Cyclin‐dependent kinase 4/6 (CDK4/6) inhibitors, including palbociclib, are approved to treat hormone receptor (HR)‐positive/human epidermal growth factor receptor 2 (HER2)‐negative advanced breast cancer (ABC) and are associated with hematologic toxicity. African American women, who are underrepresented in CDK4/6 inhibitor clinical trials, may experience worse neutropenia because of benign ethnic neutropenia. The authors specifically investigated the hematologic safety of palbociclib in African American women with HR‐positive/HER2‐negative ABC. Methods PALINA was a single‐arm, open‐label, investigator‐initiated study of palbociclib (125 mg daily; 21 days on and 7 days off) plus endocrine therapy (ET) in African American women who had HR‐positive/HER2‐negative ABC and a baseline absolute neutrophil count ≥1000/mm3 (ClinicalTrials.gov identifier NCT02692755). The primary outcome was the proportion of patients who completed 12 months of therapy without experiencing febrile neutropenia or treatment discontinuation because of neutropenia. Single nucleotide polymorphism analysis was used to assess Duffy polymorphism status. Results Thirty‐five patients received ≥1 dose of palbociclib plus ET; 19 had a Duffy null polymorphism (cytosine/cytosine). There were no reports of febrile neutropenia or permanent study discontinuation because of neutropenia. Significantly more patients with the Duffy null versus the wild‐type variant had grade 3 and 4 neutropenia (72.2% vs 23.1%; P = .029) and required a palbociclib dose reduction (55.6% vs 7.7%; P = .008). Patients with the Duffy null versus the wild‐type variant had lower overall relative dose intensity (mean ± SD, 81.89% ± 15.87 and 95.67% ± 5.89, respectively; P = .0026) and a lower clinical benefit rate (66.7% and 84.6%, respectively). Conclusions These findings suggest that palbociclib is well tolerated in African American women with HR‐positive/HER2‐negative ABC. Duffy null status may affect the incidence of grade 3 neutropenia, dose intensity, and possibly clinical benefit.

Background: CID occurs in up to 80% of patients with breast cancer who receive trastuzumab (H), pertuzumab (P), and a taxane, with grade 3 experienced by 8-12% of patients. Crofelemer is an extract of the Croton lechleri tree that inhibits luminal chloride efflux, implicated in the HP-related CID. We hypothesized crofelemer would prevent diarrhea in patients with HER2+ breast cancer receiving HP and docetaxel or paclitaxel, with/without carboplatin (THP or TCHP) in the neoadjuvant, adjuvant, or metastatic setting. Clinical trial information: NCT02910219. Methods: Adult patients with HER2+ any stage breast cancer, scheduled to receive at least 3 consecutive cycles of TCHP (docetaxel, carboplatin, trastuzumab and pertuzumab) or THP (trastuzumab and pertuzumab with paclitaxel or docetaxel), normal organ function, PS 0-2, who provided written informed consent were randomized 1:1 to receive crofelemer 125 mg PO 2x/day during cycles 1 and 2 of chemotherapy or no scheduled prophylactic medication. Randomization was stratified according to chemotherapy regimen. The primary endpoint was the incidence of CID of any grade for ≥2 consecutive days assessed by NCI CTCAE v4.0. Provider reported outcomes were collected during clinic visits and prospectively documented in clinical notes. Patient reported outcomes (PRO) were collected from patient diaries. Secondary endpoints were incidence of all grades and grade 3/4 CID by cycle/stratum; time to onset and duration of CID; stool consistency; frequency of break through anti-diarrheal medications use; and FACIT-D total score. Fisher’s exact test was used for comparing binary and categorical variables and summary statistics and Wilcoxon test for ordinal grade variables. The trial was designed to detect a 40% absolute decrease in incidence of CID (from 60% to 20%), two-sided significance level of 0.10. Results: A total of 53 patients were enrolled between 02/21/2017- 08/25/2020 on crofelemer (n=27) or control (n=26) arms. One patient withdrew consent prior to starting protocol procedures and was substituted. Early treatment discontinuation occurred in 7 cases: complications of diarrhea (n=1, control group), chemotherapy regimen changed for other cause than diarrhea (n=4) and non-compliance with trial procedures (n=2). 29 patients had early stage disease treated with TCHP; 23 patients had metastatic disease treated with THP (16 with paclitaxel and 7 with docetaxel). The primary endpoint was not statistically different between the two groups. The incidence of Grade 2 or greater diarrhea was 20.9% vs 26.4% of patients receiving crofelemer or placebo respectively in cycle 1, and 9.5% vs 41.1% in cycle 2 (Table). Results were consistent between provider assessments and patient reported outcomes (PRO). Detailed description of pooled cycle 1-2 data using correlated ordinal model and the additional secondary endpoints will be presented. Conclusions: Although there was no significant difference between crofelemer and control for diarrhea for 2 or more consecutive days in both cycles, there was a clinically meaningful difference between the crofelemer and control groups in maximum within-cycle diarrhea ordinal CTCAE grade diarrhea. These data are supportive for further testing of crofelemer in the ongoing randomized Phase 3 trial OnTARGET (NCT04538625). CycleCTCAE bCrofelemerControlPDiarrhea >= 2 consecutive days a168.069.6NS d265.272.2Maximum diarrhea grade a1Grade 0 c33.321.1NS eGrade 145.852.6Grade 216.721.1Grade 34.25.3Grade 40.00.02Grade 0 c38.117.60.0261 eGrade 152.441.2Grade 29.523.5Grade 30.017.6Grade 40.00.0Maximum diarrhea grade PRO f1Grade 0 c4.08.7NS eGrade 172.039.1Grade 216.043.5Grade 38.08.7Grade 40.00.02Grade 0 c9.10.00.0361 eGrade 181.866.7Grade 24.522.2Grade 34.511.1Grade 40.00.0aProvider assessedbCTCAE: NCI Common Terminology Criteria for Adverse Events v4.0cGrade 0: no diarrheadFisher''s exact testeWilcoxon rank sum testfPRO: Patient reported outcomes Citation Format: Paula R Pohlmann, Deena Graham, Tianmin Wu, Yvonne Ottaviano, Mahsa Mohebtash, Shweta Kurian, Donna McNamara, Filipa Lynce, Robert Warren, Asma Dilawari, Suman Rao, Candace Mainor, Nicole Swanson, Ming Tan, Claudine Isaacs, Sandra M. Swain. Halt-d: A randomized open label phase 2 study of crofelemer for the prevention of chemotherapy induced diarrhea (cid) in patients with breast cancer receiving trastuzumab, pertuzumab, and a taxane [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 P5-18-09.

Introduction: Patients (pts) with high-risk multiple myeloma (HRMM) experience early disease progression post autologous stem cell transplant (ASCT). The median progression free survival (PFS) for HRMM pts undergoing ASCT with lenalidomide (len) maintenance ranges between 27 and 42 months in high risk pts and 22 months in ultra-high risk, defined by two or more adverse cytogenetic abnormalities such as: gain(1q), t(4;14), t(14;16),t(14;20), or del(17p)( Chakraborty et al, Leukemia,2018 and Jackson et al, Lancet, 2018). Elotuzumab, a humanized IgG kappa monoclonal antibody against SLAM-F7 (CS-1), is approved in combination with len and dexamethasone (ERd) in pts with relapsed MM (Dimopoulus et al, BJH, 2017). It directly activates natural killer (NK) cells and mediates myeloma cell death by antibody-dependent cell mediated cytoxicity. We hypothesized that administration of ERd as post-ASCT consolidation will enhance an immune-competent phenotype, by restoring NK cells and effector T-cell populations at a time of maximal disease de-bulking, and will ultimately improve outcomes among pts with HRMM. Methods: Thirty-one HRMM patients who achieved stable disease or better were treated beginning at 30-90 days post ASCT with ERd (29/31 pts) or elotuzumab/pomalidomide )/dex (EPd) (2/31 pts) between September 2016 and February 2019. With institutional review board approval, electronic medical records were reviewed for baseline characteristics, treatment history, adverse events (AE) while on therapy as defined by common terminology criteria for adverse events (CTCAE), and survival outcomes. Treatment with ERd or EPd was administered for 4 consecutive 28-day cycles per standard dosing regimens with a tapering or discontinuation of corticosteroids per investigator discretion with cycles 3 and 4. HRMM was defined by any of the following: ISS or Revised-ISS stage 3, CD-138 selected FISH with del 17p, 1q21 gain, t(4;14), t(14;16), and t(14;20), cytogenetics with 13q del or complex karyotype, and/or high-risk gene expression profile score. Ultra-HR pts were defined by having both del 13q and 1q21 gain by FISH based on recent unpublished COMPASS data. Minimal residual disease (MRD) was evaluated upon achievement of very good partial remission or complete remission using 10-color multiparametric flow cytometry. PFS was measured using the log-rank test. Response criteria was defined per International Myeloma Working Group criteria. Results: Baseline characteristics of all 31 patients are shown in Table 1. Thirty-four percent were ISS-3, 71% (22/31 pts) had high-risk FISH, of which 19% were ultra-high risk (6/22 pts). Seven pts (22.6%) underwent tandem-ASCT pre-consolidation. Of the 8 pts who had GEP testing, 2 (25%) were high risk. Best response to treatment by cycle is depicted in Table 2. Consolidative ERd/EPd deepened response compared to post-ASCT with 71.4% vs 19.4% achieving stringent complete remission (sCR). Post-consolidation, 19.3% vs 12.9%, pre-consolidation, achieved MRD negativity. With a median follow-up of 24.8 months, median PFS was 31.4 months (Figure 1). There was no significant association between median PFS and variables such as tandem ASCT and ultra-HR using multivariate cox regression. Although all pts experienced at least one AE while on therapy, only 1 patient (3.22%) experienced a grade 3 AE. Hematologic AEs included: anemia (48%), neutropenia (45%), and thrombocytopenia (52%), while the most common non-hematologic AEs included: fatigue (32%), malaise (23%), and back pain (19%). One patient experienced a serious AE (SAE) which was PCP pneumonia requiring hospitalization, resulting in early discontinuation from therapy. There was no treatment-related mortality. Conclusion: ERd or EPd as 4 months of fixed duration consolidation therapy post-ASCT resulted in a median PFS of 31.4 months amongst pts with HRMM, similar to or perhaps surpassing historical reports of HRMM pts receiving lenalidomide maintenance until progression. This therapy may offer comparable, if not superior, outcomes while having the advantage of allowing for significant time without therapy and perhaps improving quality of life and financial toxicity. This study is limited due to its retrospective nature. Larger prospective studies evaluating fixed duration ERd/EPd in HRMM patients post ASCT should be conducted. Disclosures Rowley: Allergan: Equity Ownership; Fate Therapeutics: Consultancy. Goldberg:COTA: Equity Ownership; Bristol-Myers Squibb: Consultancy; Cancer Outcomes Tracking and Analysis (COTA) Inc.: Equity Ownership. Siegel:Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bristol-Myers Squibb Company: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Biran:Bristol Meyers Squibb: Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Merck: Research Funding.

Background: Immune-related adverse events (irAEs) associated with immune checkpoint inhibitors (ICIs) are often managed via immunosuppressive agents (ISAs); however, their impact on ICI efficacy is not well studied. The impact of the use of ISAs on ICI efficacy in patients with advanced melanoma was therefore investigated.Methods: This is a real-world, multicenter, retrospective cohort study of patients with advanced melanoma who received ICIs (n = 370). Overall survival (OS) and time to treatment failure (TTF) from the time of ICI initiation were compared among patients in subgroups of interest by unadjusted and 12-week landmark sensitivityadjusted analyses. The association of irAEs and their management with OS and TTF were evaluated using univariate and multivariable Cox proportional hazards regression models.Results: Overall, irAEs of any grade and of grade ≥3 occurred in 57% and 23% of patients, respectively. Thirty-seven percent of patients received steroids, and 3% received other ISAs. Median OS was longest among patients receiving both (not reached [NR]), shorter among those receiving only systemic steroids (SSs) (84.2 months; 95% CI, 40.2 months to NR), and shortest among those who did not experience irAEs (10.3 months; 95% CI, 6-20.1 months) (p < .001). Longer OS was significantly associated with the occurrence of irAEs and the use of SSs with or without ISAs upon multivariable-adjusted analysis (p < .001). Similar results were

Background: Immune-related adverse events (irAEs) often require treatment with high-dose systemic steroids (SS) and other immunosuppressive agents (ISAs). NCCN Guidelines recommend prophylactic antibiotics for Pneumocystis jirovecii pneumonia (PJP) for patients receiving prolonged SS/ISAs. However, there is a paucity of evidence regarding the incidence of opportunistic infections (OIs) and non-OIs and the role of prophylactic antibiotics in patients on SS/ISAs for irAEs. Methods: A retrospective analysis was conducted of patients treated using immune checkpoint inhibitor (ICI) therapy at 5 MedStar Health hospitals from January 2011 to April 2018. OIs were defined per the Infectious Diseases Society of America guidelines for the prevention and treatment of OIs in patients with HIV. The study cohort included patients who received ≥20 mg daily of a prednisone equivalent for ≥4 weeks to manage irAEs. Results: The study cohort identified 112 (15%) of 758 total patients treated using ICIs. Baseline characteristics included the following: median age was 64 years, 74% (n=82) of patients were White, 89% (n=100) had an ECOG performance status ≤1, 61% (n=68) had melanoma, 19% (n=21) had non–small cell lung cancer, 45% (n=50) were treated using an anti–PD-(L)1 ICI, and 33% (n=37) were treated using an anti–PD-1/anti–CTLA-4 combination. The median starting SS dose was 100 mg of a prednisone equivalent, and 25% of patients required additional ISAs, with infliximab (n=15) and mycophenolate mofetil (n=9) being the most common. We found that 20% (n=22) of patients developed any infection, including 7% (n=8) with OIs (oral candidiasis [n=4], nondisseminated varicella zoster infection [n=2], PJP [n=1], and Listeria monocytogenes endophthalmitis [n=1]) and 13% (n=14) with non-OIs (most common: Clostridium difficile and pneumonia [n=5 each]). PJP prophylaxis with sulfamethoxazole/trimethoprim was given to 13% (n=14) patients, of whom 43% (n=6) developed OIs/non-OIs. Conclusions: Our study highlights the fundamental issues for patients on ICI therapy who require SS/ISAs for irAEs: the degree of immunosuppression and the relative risk of OI. We noted a low incidence of OIs overall and breakthrough infections despite PJP prophylaxis. We question whether PJP prophylaxis is efficacious or necessary. Prospective trials are required to answer these questions.