Maintenance Treatment Of Patients Research Articles

Deaddicta® for maintenance treatment of Opioid-dependence: A six-month follow-up.

Opioid dependence, is one of the world's most critical health problems. Deaddicta is a herbal product considered an effective treatment for opioid addiction. Deaddicta's efficacy in the maintenance treatment of patients with opioid use disorder has recently been demonstrated through a double-blind randomized controlled trial (RCT). This study aimed to evaluate the permanence of Deaddicta's efficacy six months after the end of the maintenance treatment for opioid dependence. This study was performed following the previous RCT on the maintenance treatment of opioid addicts. Out of 41 participants who completed the study for three months in the previous research, 15 from the intervention group (Deaddicta capsules, 1500 mg/day) returned for follow-up. They all previously fulfilled the DSM-IV criteria for addiction, were aged 18 to 65, and had discontinued Deaddicta for six months. The outcome measures included addiction severity, depression and anxiety levels, and craving score. The scores of each parameter were compared in three phases: before intervention; after three months of intervention; and six months after the end of the study. Depression, anxiety, and craving scores decreased six months after the end of the previous study. This decrease was significant in the craving score (P = 0.011). No significant increase was observed in the frequency of use. The regression analysis showed a negative relationship between craving and the progression of phases. The Deaddicta product may have desirable and effective properties in decreasing temptation and, as a result, the maintenance treatment of opioid dependence.

Cost-effectiveness of olaparib plus bevacizumab versus bevacizumab monotherapy in the maintenance of patients with homologous recombination deficiency-positive advanced ovarian cancer after response to first-line platinum-based chemotherapy

ObjectiveThe PAOLA-1 trial confirmed that adding olaparib to bevacizumab significantly increased clinical benefit following response to platinum-based chemotherapy in homologous recombination deficiency-positive ovarian cancer. The objective of this analysis was...

Real-world data on niraparib maintenance treatment in patients with non-gBRCA mutated platinum-sensitive recurrent ovarian cancer

ObjectivesThe aim of this study was to provide real-world efficacy and safety data on niraparib maintenance treatment in patients with non-germline (gBRCA)1/2 mutated platinum-sensitive recurrent ovarian cancer.MethodsThis retrospective multi-center cohort...

Rituximab as a maintenance treatment in patients with pemphigus vulgaris: When is the right time for discontinuation?

Rituximab as a maintenance treatment in patients with pemphigus vulgaris: When is the right time for discontinuation?

523P Camrelizumab plus apatinib as maintenance treatment in patients with extensive-stage small cell lung cancer who were responding or stable after standard first-line chemotherapy (CAMERA): Results from a single-arm, phase II trial

523P Camrelizumab plus apatinib as maintenance treatment in patients with extensive-stage small cell lung cancer who were responding or stable after standard first-line chemotherapy (CAMERA): Results from a single-arm, phase II trial

Economic impact of olaparib on maintenance treatment of patients with BRCA-mutation positive, platinum-sensitive relapsing high-grade serous epithelial ovarian cancer in Spain

ObjectiveTo estimate the economic impact of the introduction of olapa- rib in the Spanish National Health System as maintenance monotherapy in patients with BRCA-mutation positive high-grade serous ovarian cancer. Method: A budget impact model was developed from the Spanish NHS perspective and a time horizon of 5 years for four treatment lines. The model included prevalent and incident patients estimated according to Spanish epidemiological data. Patients moved between treatment lines according to the progression-free survival and overall survival curves obtained from the respective clinical trials. Only direct costs (€2017) were considered: pharmacological, administration, adverse effects and genetic tests. The robustness of the model was verified by a univariate sensitivity analysis. ResultsThe use of olaparib meant that, after 5 years, 6% fewer patients progressed to later lines compared to scenario without olaparib, remaining longer in the second line and delaying the initiation of subsequent lines. The total estimated budgetary impact ranged between € 1.6 and € 5.4 million (1-5 years). The economic impact associated to the introduction of olaparib is partially offset by the lower cost of chemotherapy, related adverse events, and palliative care in patients with olaparib than in patients without it. ConclusionsOlaparib as maintenance treatment in patients with BR- CA-mutation positive high-grade serous ovarian cancer increases progression-free survival and delays the use of subsequent chemotherapy, with an budgetary impact for the Spanish National Health System of 5.4 million euros after 5 years.

OA02.05 Dendritic Cell Immunotherapy Versus Best Supportive Care as Maintenance Treatment in Patients with Pleural Mesothelioma

OA02.05 Dendritic Cell Immunotherapy Versus Best Supportive Care as Maintenance Treatment in Patients with Pleural Mesothelioma

On-demand Versus Continuous Maintenance Treatment With a Proton Pump Inhibitor for Mild Gastroesophageal Reflux Disease: A Prospective Randomized Multicenter Study.

It remains unclear which maintenance treatment modality is most appropriate for mild gastroesophageal reflux disease (GERD). We aimed to compare on-demand treatment with continuous treatment using a proton pump inhibitor (PPI) in the maintenance treatment for patients with non-erosive GERD or mild erosive esophagitis. Patients whose GERD symptoms improved after 4 weeks of standard dose PPI treatment were prospectively enrolled at 25 hospitals. Subsequently, the enrolled patients were randomly assigned to either an on-demand or a continuous maintenance treatment group, and followed in an 8-week interval for up to 24 weeks. A total of 304 patients were randomized to maintenance treatment (continuous, n = 151 vs on-demand, n = 153). The primary outcome, the overall proportion of unwillingness to continue the assigned maintenance treatment modality, failed to confirm the non-inferiority of on-demand treatment (45.9%) compared to continuous treatment (36.1%). Compared with the on-demand group, the GERD symptom and health-related quality of life scores significantly more improved and the overall satisfaction score was significantly higher in the continuous treatment group, particularly at week 8 and week 16 of maintenance treatment. Work impairment scores were not different in the 2 groups, but the prescription cost was less in the on-demand group. Serum gastrin levels significantly elevated in the continuous treatment group, but not in the on-demand group. Continuous treatment seems to be more appropriate for the initial maintenance treatment of non-erosive GERD or mild erosive esophagitis than on-demand treatment. Stepping down to on-demand treatment needs to be considered after a sufficient period of continuous treatment.

Case-control matching-guided exposure-efficacy relationship for avelumab in patients with urothelial carcinoma.

Exposure-response (E-R) analyses are an integral component of understanding the benefit/risk profile of novel oncology therapeutics. These analyses are typically conducted using data from the treatment arm to characterize the relationship between drug exposure (low vs. high) and efficacy or safety outcomes. For example, outcomes of patients with lower exposure in the treatment arm (e.g., Q1) might be compared to outcomes of those with higher drug exposure (Q2, Q3, and Q4). Outcomes from the lowest exposure quartile may be also compared to the control arm to evaluate whether the Q1 subgroup derived clinical benefit. However, the sample size and the distribution of patient baseline characteristics and disease risk factors are not balanced in such a comparison (Q1 vs. control), which may bias the analysis and causal interpretation of clinical benefit in the Q1 subgroup. Herein, we report the use of case-control matching to account for this bias and better understand the E-R relationship for avelumab in urothelial carcinoma, a PD-L1 inhibitor approved for the treatment of several cancers. Data from JAVELIN-100 was utilized which is a phase III study of avelumab in first-line maintenance treatment in patients with urothelial carcinoma; this clinical study demonstrated superiority of avelumab versus best-supportive care leading to approval in the United States, Europe, and other countries. A post hoc case-control matching method was implemented to compare the efficacy outcome between Q1 avelumab subgroup and matched patients extracted from the control arm with similar baseline characteristics, which showed a clinically relevant difference in overall survival in favor of the Q1 avelumab subgroup. This analysis demonstrates the importance of accounting for imbalance in important baseline covariates when comparing efficacy outcomes between subgroups within the treatment arm versus the control arm.

LBA36 Efficacy and safety of senaparib as maintenance treatment in patients with newly diagnosed advanced ovarian cancer (FLAMES study): A randomized, double-blind, placebo-controlled, phase III trial

LBA36 Efficacy and safety of senaparib as maintenance treatment in patients with newly diagnosed advanced ovarian cancer (FLAMES study): A randomized, double-blind, placebo-controlled, phase III trial

P-196 - Chlormethine gel as maintenance treatment for patients with mycosis fungoides

P-196 - Chlormethine gel as maintenance treatment for patients with mycosis fungoides

Controlled Hookworm Infection for Medication-free Maintenance in Patients with Ulcerative Colitis: A Pilot, Double-blind, Randomized Control Trial.

Human hookworm has been proposed as a treatment for ulcerative colitis (UC). This pilot study assessed the feasibility of a full-scale randomized control trial examining hookworm to maintain clinical remission in patients with UC. Twenty patients with UC in disease remission (Simple Clinical Colitis Activity Index [SCCAI] ≤4 and fecal calprotectin (fCal) <100 ug/g) and only on 5-aminosalicylate received 30 hookworm larvae or placebo. Participants stopped 5-aminosalicylate after 12 weeks. Participants were monitored for up to 52 weeks and exited the study if they had a UC flare (SCCAI ≥5 and fCal ≥200 µg/g). The primary outcome was difference in rates of clinical remission at week 52. Differences were assessed for quality of life (QoL) and feasibility aspects including recruitment, safety, effectiveness of blinding, and viability of the hookworm infection. At 52 weeks, 4 of 10 (40%) participants in the hookworm group and 5 of 10 (50%) participants in the placebo group had maintained clinical remission (odds ratio, 0.67; 95% CI, 0.11-3.92). Median time to flare in the hookworm group was 231 days (interquartile range [IQR], 98-365) and 259 days for placebo (IQR, 132-365). Blinding was quite successful in the placebo group (Bang's blinding index 0.22; 95% CI, -0.21 to 1) but less successful in the hookworm group (0.70; 95% CI, 0.37-1.0). Almost all participants in the hookworm group had detectable eggs in their faeces (90%; 95% CI, 0.60-0.98), and all participants in this group developed eosinophilia (peak eosinophilia 4.35 × 10^9/L; IQR, 2.80-6.68). Adverse events experienced were generally mild, and there was no significant difference in QoL. A full-scale randomized control trial examining hookworm therapy as a maintenance treatment in patients with UC appears feasible.

Aripiprazole once monthly as a maintenance treatment for patients with schizophrenia and alcohol/substance use disorder: an observational, real-world study

PurposeThis paper aims to investigate the role of aripiprazole once monthly as a maintenance treatment in a sample of patients with schizophrenia comorbid with alcohol and substance use disorder (AUD/SUD).Design/methodology/approachA sample of 24 Italian adult patients has been recruited and treated with aripiprazole once monthly after clinical stabilization with oral aripiprazole during May 2021 and June 2022. Clinical evaluations have been performed at the baseline (T0) and after 12 (T1) and 24 (T2) weeks.FindingsDuring the study period, an improvement of both the clinical condition and general health from baseline was observed, as well as a reduction of craving for alcohol/substances. However, from T0, the number of patients who continued with this study decreased at T1 (n = 8) and then at T2 (n = 4). No serious adverse events were reported, including changes in weight, lipid/glucose metabolism, electrocardiogram and extra-pyramidal side effects.Originality/valueAlthough limited by the high number of drop outs, this observational real-world study provided insights into the use of aripiprazole once monthly among a sample of patients with schizophrenia and comorbid SUD/AUD. Further studies of longer duration and on a larger sample are needed.

Understanding differences in the rates of BRCA/HRD testing and treatment in 1st line maintenance in patients with ovarian cancer treated by gynecologic oncologists compared to other providers: A quality initiative by Integra Connect (IC) PrecisionQ.

5576 Background: The role of PARPi in the treatment of advanced ovarian cancer (aOC) has expanded in recent years. In this context, South Carolina Oncology Associates (SCOA) partnered with Integra Connect (IC) on a quality initiative (QI) to evaluate the rate of BRCA and HRD testing in newly diagnosed OC patients and the use of maintenance therapy in the 1st line (1L) setting in aOC. Patients with aOC at SCOA are typically managed by gynecologic oncologists. Methods: Using the IC Precision Q real-world database of over 1 million cancer patients across 275 sites of care, we assessed newly diagnosed OC patients evaluated via medical chart curation from 1/1/2020 to 6/30/2022 for BRCA and HRD testing at SCOA (N = 81) and other oncology practices (N = 1,045). We also studied the use of maintenance therapy in patients with stage II-IV OC who completed platinum-based chemotherapy from 1/1/2020 to 6/30/2022 at SCOA (N = 75) and other oncology practices (N =899). SCOA was compared to other oncology practices in terms of provider specialty treating the patient, rates of HRD and BRCA testing, and use of 1L maintenance treatment in patients with or without BRCA or HRD mutations. Descriptive analyses were used. Proportions were compared using a two tailed two sample z-test. Results: Among newly diagnosed patients at SCOA, 95% of patients with OC were primarily managed by a gynecologic oncologist compared to 5% at other practices. The rate of BRCA testing at SCOA was 81% (66 of 81) compared to 75% (788 of 1045) and HRD testing was 60% (49 of 81) compared to 39% (403 of 1045) at other oncology practices in the IC database. The difference in HRD testing was significant (p &lt; 0.01). The use of 1L maintenance regardless of biomarker status was 64% (48 of 75) at SCOA compared to 50% (449 of 899) at other practices. The difference in 1L maintenance use was significant (p&lt;0.05). PARPi were used at SCOA for maintenance therapy in 82% (38 of 46) of patients compared to 74% (314 of 427) at other practices. The use of maintenance in BRCA or HRD positive patients was 84% (21 of 25) at SCOA compared to 75% (151 of 201) for other practices. Conclusions: In this real-world study, treatment by gynecologic oncologists was associated with higher rates of BRCA and HRD testing and higher use of 1L maintenance treatment in patients with aOC compared to other practices. These findings underscore the importance of gynecologic oncologists in the management of aOC to ensure optimal testing and adherence to treatment guidelines.

Once-Daily Crisaborole Ointment, 2%, as a Long-Term Maintenance Treatment in Patients Aged ≥ 3 Months with Mild-to-Moderate Atopic Dermatitis: A 52-Week Clinical Study.

Topical treatments for atopic dermatitis (AD) used reactively often fail to achieve lasting disease control; many of these therapies are associated with safety concerns that limit long-term use. Crisaborole ointment, 2%, is a nonsteroidal phosphodiesterase 4 inhibitor for the treatment of mild-to-moderate AD that has potential as a long-term maintenance therapy. The aim was to evaluate the long-term efficacy and safety of crisaborole once daily (QD) compared to vehicle QD as a maintenance therapy to reduce the incidence of flares in patients with AD who previously responded to crisaborole twice daily (BID). CrisADe CONTROL was a randomized, double-blind, vehicle-controlled, 52-week, phase III study of patients aged ≥3 months with mild-to-moderate AD involving ≥5% treatable body surface area. Eligible patients received crisaborole BID during an open-label run-in period of up to 8 weeks. Responders were randomly assigned in the double-blind maintenance period to receive either crisaborole QD or vehicle QD. Responders were defined as patients who achieved Investigator's Static Global Assessment (ISGA) success (ISGA score of 0 [clear] or 1 [almost clear] with a ≥ 2-grade improvement) and ≥ 50% improvement in Eczema Area and Severity Index total score (EASI-50) from baseline. Patients who experienced a flare (ISGA score ≥2) during the double-blind maintenance period switched to crisaborole BID for up to 12 weeks. During this period, patients were assessed every 4 weeks; if the flare resolved (ISGA score ≤ 1), patients resumed their assigned treatment. The primary endpoint was flare-free maintenance until onset of the first flare. Key secondary endpoints were number of flare-free days, number of flares, and maintenance of pruritus response until onset of the first flare. The incidence of treatment-emergent adverse events was also analyzed. Overall, 497 patients entered the open-label run-in period with crisaborole BID, of which 270 patients were randomized into the 52-week double-blind maintenance period of the study. Of the 270 patients, 135 were randomly assigned to the crisaborole QD group and 135 were randomly assigned to the vehicle QD group. Median time of flare-free maintenance was longer for patients who received crisaborole versus vehicle (111 vs 30 days, respectively; p = 0.0034). The mean number of flare-free days was higher for patients who received crisaborole versus vehicle (234.0 vs 199.4 days, respectively; p = 0.0346). The mean number of flares was lower for patients who received crisaborole versus vehicle (0.95 vs 1.36, respectively; p = 0.0042). No clear trend was observed in maintenance of pruritus response between crisaborole- and vehicle-treated patients. Crisaborole was well tolerated, with no new or unexpected safety findings when used as maintenance treatment. Crisaborole QD was effective and well tolerated for long-term maintenance treatment and flare reduction in adult and pediatric patients with mild-to-moderate AD. ClinicalTrials.gov, NCT04040192, 31 July 2019.

Progression-free survival and safety at 3.5 years of follow-up: results from the randomised phase 3 PRIMA/ENGOT-OV26/GOG-3012 trial of niraparib maintenance treatment in patients with newly diagnosed ovarian cancer

PurposeTo report updated long-term efficacy and safety from the double-blind, placebo-controlled, phase 3 PRIMA/ENGOT-OV26/GOG-3012 study (NCT02655016). MethodsPatients with newly diagnosed advanced ovarian cancer with complete or partial response (CR or PR) to first-line platinum-based chemotherapy received niraparib or placebo once daily (2:1 ratio). Stratification factors were best response to first-line chemotherapy regimen (CR/PR), receipt of neoadjuvant chemotherapy (yes/no), and homologous recombination deficiency (HRD) status (deficient [HRd]/proficient [HRp] or not determined). Updated (ad hoc) progression-free survival (PFS) data (as of November 17, 2021) by investigator assessment (INV) are reported. ResultsIn 733 randomised patients (niraparib, 487; placebo, 246), median PFS follow-up was 3.5years. Median INV-PFS was 24.5 versus 11.2months (hazard ratio, 0.52; 95% confidence interval [CI], 0.40–0.68) in the HRd population and 13.8 versus 8.2months (hazard ratio, 0.66; 95% CI, 0.56–0.79) in the overall population for niraparib and placebo, respectively. In the HRp population, median INV-PFS was 8.4 versus 5.4months (hazard ratio, 0.65; 95% CI, 0.49–0.87), respectively. Results were concordant with the primary analysis. Niraparib-treated patients were more likely to be free of progression or death at 4years than placebo-treated patients (HRd, 38% versus 17%; overall, 24% versus 14%). The most common grade ≥ 3 treatment-emergent adverse events in niraparib patients were thrombocytopenia (39.7%), anaemia (31.6%), and neutropenia (21.3%). Myelodysplastic syndromes/acute myeloid leukaemia incidence rate (1.2%) was the same for niraparib- and placebo-treated patients. Overall survival remained immature. ConclusionsNiraparib maintained clinically significant improvements in PFS with 3.5years of follow-up in patients with newly diagnosed advanced ovarian cancer at high risk of progression irrespective of HRD status. No new safety signals were identified.

Randomised clinical trial: 3-year interim analysis results of the VISION trial to evaluate the long-term safety of vonoprazan as maintenance treatment in patients with erosive oesophagitis

BackgroundVISION is a randomised, phase 4, open-label, parallel-group, multicentre study conducted in 33 centres in Japan. The aim of this study was to assess the long-term safety of vonoprazan for maintenance treatment of healed erosive oesophagitis versus lansoprazole.MethodsPatients with endoscopically diagnosed erosive oesophagitis were randomised 2:1 to once-daily vonoprazan 20 mg or lansoprazole 30 mg, for a 4- to 8-week healing phase. Patients with endoscopically confirmed healing entered a 260-week maintenance phase with a once-daily starting dose of vonoprazan 10 mg or lansoprazole 15 mg. Primary endpoint was change in gastric mucosal histopathology.ResultsOf 208 patients (vonoprazan, n = 139; lansoprazole, n = 69) entering the healing phase, 202 entered the maintenance phase (vonoprazan, n = 135; lansoprazole, n = 67). At 3 years, 109 vonoprazan-treated and 58 lansoprazole-treated patients remained on treatment. Histopathological evaluation of gastric mucosa showed that hyperplasia of parietal, foveolar and G cells was more common with vonoprazan than lansoprazole at week 156 of the maintenance phase. There was no marked increase in the occurrence of parietal, foveolar and G cell hyperplasia among patients in the vonoprazan group from week 48 to week 156. Histopathological evaluation of the gastric mucosa also showed no neoplastic changes in either group. No new safety issues were identified.ConclusionsIn this interim analysis of VISION, no new safety concerns were identified in Japanese patients with healed erosive oesophagitis receiving vonoprazan or lansoprazole as maintenance treatment for 3 years. (CT.gov identifier: NCT02679508; JapicCTI-163153; Japan Registry of Clinical Trials: jRCTs031180040).

Analysis of adverse events and quality of life in high-grade serous ovarian cancer patients with Olaparib maintenance therapy: A single-center study in China.

Olaparib showed good efficacy and tolerability in the maintenance treatment of patients with initial therapy or high-grade serous recurrent ovarian cancer patients. This study aimed to analyze adverse events (AEs) of patients taking Olaparib and the quality of life (QoL) with Olaparib in 1 center of China. The study included 98 patients who received Olaparib and 210 patients without Olaparib from July 2018 to October 2021 for high-grade serous ovarian cancer in the Gynecology Oncology Department of Jiangsu Provincial Hospital. Information of clinicopathologic characteristics was collected from medical records. Then, we used the QLQ-C30 and Quality of Life Ovarian Cancer 28 Questionnaire (QLQ-OV28) to determine the QoL of 98 patients with and 210 patients without Olaparib. Among all 98 patients with Olaparib, 66 patients in first-line and 32 patients in more than second-line treatment. Regarding the best objective response with Olaparib maintenance in 78 patients with partial remission from most recent chemotherapy, 3 (3.84%) patients showed complete response (CR) and 6 (7.69%) showed as partial response (PR), whereas stable disease was observed in 42 patients (53.84%) and 27 patients (34.6%) showed as progression disease. AEs of Grade 3 and more were: anemia in 16 patients (16.32%), neutropenia in 20 patients (20.40%), thrombocytopenia in 4 patients (4.08%), and headache in 4 patients (4.08%). Dose reduction and drug discontinuation accounted for 73.40% and 20.40%, respectively. Olaparib as maintenance therapy increased QoL on all functioning domains and several symptom domains. Consistent with previous clinical trials, Olaparib maintenance therapy was proved safe and effective. Most patients may experience Grade 1 and 2 AEs. Olaparib maintenance therapy can increase QoL in several domains.

Switching from intravenous to subcutaneous vedolizumab maintenance treatment in patients with inflammatory bowel disease followed by therapeutic drug monitoring

Objective Vedolizumab (VDZ) for subcutaneous (SC) administration has recently become available. We aimed to assess feasibility, safety and clinical outcome when switching from intravenous (IV) to SC VDZ maintenance treatment in a real world cohort of patients with inflammatory bowel disease (IBD) followed by therapeutic drug monitoring (TDM). Methods Eligible IBD patients were switched from IV to SC treatment and assessed six months prior to switch, at baseline and six, twelve and twenty-six weeks after switch. Primary outcome was proportion of patients on SC treatment after 26 weeks. Secondary outcomes included adverse events (AEs), clinical disease activity, biochemical markers, treatment interval, serum-VDZ (s-VDZ), preferred route of administration and health-related quality of life. Results In total, 108 patients were switched. After 26 weeks, 100 patients (92.6%) were still on SC treatment and median s-VDZ was 47.6 mg/L (IQR 41.3 − 54.6). The most frequent AE was injection site reaction (ISR), reported by 20 patients (18.5%). There were no clinically significant changes in disease activity, biochemical markers and quality of life. The proportion of patients preferring SC administration increased from 28.0% before switch to 59.4% after 26 weeks (p < 0.001). Conclusions Nine out of ten patients still received SC treatment after 26 weeks. No change in disease activity occurred, and levels of serum VDZ increased. Although almost one fifth of patients experienced ISRs, a higher proportion favored SC administration at 26 weeks. This study demonstrates that SC maintenance treatment is a safe and feasible alternative to IV treatment.

Abstract P3-02-04: Phase II study of Pembrolizumab Maintenance treatment in patients with HER2-negative inflammatory breast cancer (IBC) and triple-negative breast cancer (TNBC) after response to chemotherapy

Abstract Accumulating physical and hematologic toxicities make the indefinite use of chemotherapy unfeasible for many patients with metastatic/recurrent HER2– IBC or TNBC. Whether maintenance immunotherapy has a role in the treatment of these patients is unclear. We conducted a single-arm phase II trial of pembrolizumab monotherapy in patients with metastatic/recurrent HER2– IBC or TNBC (regardless of their PD-L1 expression status) and report here the clinical data from this trial. Methods: Eligible patients were enrolled between 2015 and 2022 and had had a CR, a PR, or SD after a minimum of 3 cycles of chemotherapy for metastatic/recurrent disease. PD-L1 expression status was not used to determine eligibility. Patients received 200 mg of pembrolizumab every 3 weeks (q3w) until disease progression, intolerable toxicity, or 2 years. In late 2021, the study was amended to allow patients who had received ≥8 cycles of q3w therapy to transition to q6w dosing (400 mg), based on the FDA’s approval of both dosing regimens across all indications. The primary endpoint was the 4-month disease control rate (DCR); exploratory endpoints included safety and correlative biomarkers from tissue and blood to ascertain associations between clinical response and PD-L1 expression, T-cell clonality, and immune profiling. Results: Of 43 patients (median age, 54 years; range, 34-77 years), 11 had IBC (10 with triple-negative IBC and 1 with ER+ HER2– IBC), and 32 had TNBC. The 4-month DCR was 58.1% (95% CI: 43.4%-72.9%). During a median follow-up of 11.4 months, 25 patients died. The entire cohort’s median OS and PFS times were 26.0 months (95% CI: 11.0-33.5 months) and 4.8 months (95% CI: 3.0-7.1 months), respectively. The median OS times of the IBC and TNBC groups did not differ significantly, nor did those of the CR, PR, and SD groups. The median PFS times of the IBC group (2.2 months) and TNBC group (4.8 months) did not differ significantly (p = .12), but those of the CR, PR, and SD groups did (not reached, 10.3 months, and 3.4 months, respectively; p = .01). Among the 37 patients who are off study treatment, most patients (84%; n=31/37) discontinued treatment owing to disease progression rather than toxicities (n=2), and the toxicities overall were consistent with the known profile of single-agent anti-PD1. Five patients had grade 3 events; there were no grade 4 or 5 events. Three patients had irreversible endocrinopathies (thyroiditis and adrenal insufficiency) requiring hormone replacement, but only 1 patient discontinued pembrolizumab because of these events. One patient discontinued treatment because of optic neuritis requiring steroids. Four patients completed 2 years of treatment without disease progression. Conclusions: Pembrolizumab maintenance therapy achieves acceptable disease control after induction chemotherapy. The PFS in this trial compares favorably to the expected durations of response to later lines of therapy. The toxicity profile of pembrolizumab compares favorably with those of chemotherapy and ADCs, which may provide a rationale for the use of ICIs in this setting. However, whether pembrolizumab maintenance therapy is helpful in TNBC patients who have received concurrent pembrolizumab with neoadjuvant chemotherapy is unknown, as these patients were excluded from the trial. Acknowledgements: This trial was supported by Merck. Citation Format: Toshiaki Iwase, Angela Alexander, Vivian Chiv, Megumi Kai, Kumiko Kida, Charla Parker, Angela N. Marx, Evan Cohen, Hui Gao, James Reuben, Xiaoping Wang, Savitri Krishnamurthy, Diane Liu, Yu Shen, David Ramirez, Debu Tripathy, Daniel Booser, Clinton Yam, Vicente Valero, Bora Lim, Naoto T. Ueno, Jie S. Willey. Phase II study of Pembrolizumab Maintenance treatment in patients with HER2-negative inflammatory breast cancer (IBC) and triple-negative breast cancer (TNBC) after response to chemotherapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-02-04.