Complete Remission with Partial Hematological Recovery as a Palliative Endpoint for Treatment of Acute Myeloid Leukemia.

Complete remission with partial hematological recovery (CRh) has been used as an efficacy endpoint in clinical trials of nonmyelosuppressive drugs for acute myeloid leukemia (AML). We conducted a pooled analysis to characterize the clinical outcomes for patients with AML who achieved CRh after treatment with ivosidenib, olutasidenib, enasidenib, or gilteritinib monotherapy in clinical trials used to support marketing applications. The study cohort included 841 adult patients treated at the recommended drug dosage; 64.6% were red blood cell or platelet transfusion dependent at study baseline. Correlations between disease response and outcomes were assessed by logistic regression modeling for categorical variables and by Cox proportional hazards modeling for time-to-event variables. In comparison to patients with no response (NR), those with CRh had a higher proportion with transfusion independence (TI) for at least 56 days (92.3% vs 22.3%, p < 0.0001) or TI for at least 112 days (63.5% vs 8.7%, p < 0.0001), a reduced risk over time for severe infection (HR 0.43, p = 0.0007) or severe bleeding (HR 0.17, p = 0.01), and a longer overall survival (OS) (HR 0.31, p < 0.0001). The effects were consistent across drugs. In comparison to patients with CR, the effect sizes for CRh were similar for TI-56 and for risk over time of infection or bleeding but less for TI-112 and OS. CRh is associated with clinical benefits consistent with clinically meaningful palliative effects for treatment of AML with nonmyelosuppressive drugs, although less robustly than for CR.

FDA Approval Summary: Ciltacabtagene Autoleucel for Relapsed or Refractory Multiple Myeloma.

In February 2022, the U.S. Food and Drug Administration approved ciltacabtagene autoleucel, a chimeric antigen receptor (CAR) T cell therapy targeting the B-cell maturation antigen (BCMA), for adult patients with relapsed/refractory multiple myeloma (RRMM) after ≥4 lines of therapy including an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 monoclonal antibody. Approval was based on overall response rate (ORR), complete response (CR) rate and duration of response (DOR) in 97 adult patients in a single-arm, open-label, multicenter phase 2 trial (CARTITUDE-1 [NCT03548207]). Patients received a single infusion of ciltacabtagene autoleucel, preceded by lymphodepleting chemotherapy. Of the 97 patients evaluable, ORR was 97.9% (95% CI: 92.7, 99.7) with stringent CR rate of 78.4% (95% CI: 68.8, 86.1). After median follow-up of 18 months, median DOR was 21.8 months (95% CI: 21.8, not estimable [NE]) in responders (PR or better) and NE (95% CI: 21.8 months, NE) in patients who achieved stringent CR. Serious adverse reactions occurred in 55% of 97 patients evaluated for safety. Grade 3 or higher cytokine release syndrome and neurologic toxicities occurred in 5% and 11%, respectively, leading to a Risk Evaluation and Mitigation Strategy. Neurologic toxicities included immune effector cell associated neurologic syndrome (ICANS) typically seen with CAR-T products, Parkinsonism, peripheral neuropathy, cranial nerve palsies and Guillain-Barre Syndrome (GBS). One fatal case of hemophagocytic lymphohistiocytosis/macrophage activation syndrome occurred. Prolonged and recurrent grade 3 or 4 cytopenias occurred; a single patient required hematopoietic stem cell rescue.

FDA Approval Summary: Lisocabtagene Maraleucel for Second-Line Treatment of Large B-Cell Lymphoma.

In June 2022, the FDA extended the indication for lisocabtagene maraleucel (liso-cel) to include adults with large B-lymphoma (LBCL) who have refractory disease or relapse within 12 months of first-line chemoimmunotherapy, as well as transplant-ineligible adults with refractory disease or relapse after first-line chemoimmunotherapy. Two clinical trials evaluating a single infusion of liso-cel preceded by lymphodepleting chemotherapy supported the second-line indications. TRANSFORM is a randomized, phase 3, open-label trial comparing liso-cel to standard second-line therapy, including planned autologous hematopoietic stem cell transplantation (HSCT), in 184 transplant-eligible patients. On interim analysis, event-free survival (EFS) by independent review committee (IRC) assessment was statistically significantly improved for the liso-cel arm, with a stratified hazard ratio of 0.34 (95% CI: 0.22, 0.51; p-value <0.0001); the estimated median EFS was 10.1 months in the liso-cel arm versus 2.3 months in the control arm. PILOT is a single-arm phase 2 trial of second-line liso-cel in patients who were transplant-ineligible due to age or comorbidities but had adequate organ function for CAR-T cell therapy. Among 61 patients who received liso-cel (median age, 74 years), the IRC-assessed complete response rate was 54% (95% CI: 41, 67). Among patients achieving complete response, the estimated 1-year rate of continued response was 68% (95% CI: 45, 83). Of the 268 patients combined who received liso-cel as second-line therapy for LBCL, cytokine release syndrome occurred in 45% (Grade 3, 1.3%) and CAR-T cell associated neurologic toxicities occurred in 27% (Grade 3, 7%), warranting a continued risk evaluation and mitigation strategy.

FDA Approval Summary: Pirtobrutinib for Relapsed or Refractory Mantle Cell Lymphoma.

In January 2023, the FDA granted accelerated approval to pirtobrutinib for the treatment of adult patients with relapsed or refractory mantle cell lymphoma (MCL) after at least two lines of systemic therapy, including a Bruton tyrosine kinase (BTK) inhibitor. Approval was based on BRUIN, a single-arm study of pirtobrutinib monotherapy in patients with B-cell malignancies. Efficacy was based on independent review committee-assessed overall response rate (ORR) supported by durability of response in 120 patients with relapsed or refractory MCL who had received a prior BTK inhibitor and received the approved pirtobrutinib dosage of 200 mg once daily. The ORR was 50% [95% confidence interval (CI), 41-59], and the complete response rate was 13% (95% CI, 7-20), with an estimated median duration of response of 8.3 months. The most common nonhematologic adverse reactions were fatigue, musculoskeletal pain, diarrhea, edema, dyspnea, pneumonia, and bruising. Warnings and Precautions in labeling include infection, hemorrhage, cytopenias, atrial arrhythmias, and second primary malignancies. Postmarketing studies were required to evaluate longer-term safety of pirtobrutinib and to verify the clinical benefit of pirtobrutinib. This article summarizes key aspects of the regulatory review, including the indication statement, efficacy and safety considerations, and postmarketing requirements.

FDA Approval Summary: Ivosidenib in Combination with Azacitidine for Treatment of Patients with Newly Diagnosed Acute Myeloid Leukemia with an IDH1 Mutation.

On May 25, 2022, FDA approved a supplemental application for ivosidenib (Tibsovo; Servier) extending the indication in patients with newly diagnosed IDH1-mutated acute myeloid leukemia (AML) in older adults or those with comorbidities to include the combination with azacitidine. The efficacy of ivosidenib in combination with azacitidine was evaluated in Study AG120-C-009, a phase 3, multicenter, double-blind, randomized (1:1), controlled study of ivosidenib or matched placebo in combination with azacitidine in adults with previously untreated AML with an IDH1 mutation who were 75 years or older or had comorbidities that precluded use of intensive induction chemotherapy. Efficacy was established on the basis of improved event-free survival and overall survival on the ivosidenib + azacitidine arm [HR, 0.35; 95% confidence interval (CI), 0.17-0.72; P = 0.0038, and HR, 0.44; 95% CI, 0.27-0.73; P = 0.0010], respectively. Furthermore, the rate and duration of complete remission (CR) were improved with ivosidenib versus placebo [CR 47% versus 15%, two-sided P < 0.0001; median duration of CR not estimable (NE; 95% CI, 13.0-NE) months versus 11.2 (95% CI, 3.2-NE) months. The safety profile of ivosidenib in combination with azacitidine was consistent with that of ivosidenib monotherapy, with important adverse reactions including differentiation syndrome (15%) and QT interval prolongation (20%).

Highlights of FDA Oncology Approvals in 2023: Bispecific T-cell Engagers, Pediatric Indications, and Inclusive Drug Development.

SUMMARY: Cancer drug development remained robust in 2023. Highlights of U.S. drug approvals this year include new immunotherapies and targeted drug development in adult and pediatric patients as well as patients with rare diseases.

FDA Approval Summary: Axicabtagene Ciloleucel for Second-Line Treatment of Large B-Cell Lymphoma.

In April 2022, the FDA approved axicabtagene ciloleucel (axi-cel) for adults with large B-cell lymphoma (LBCL) that is refractory to first-line chemoimmunotherapy or that relapses within 12 months of first-line chemoimmunotherapy. Approval was based on ZUMA-7, a randomized (1:1), open-label trial in 359 patients with primary refractory LBCL (74%) or early relapse who were transplant candidates. The study compared a single course of axi-cel to standard therapy, consisting of chemoimmunotherapy followed by high-dose therapy and autologous hematopoietic stem cell transplantation (HSCT) in responding patients. Overall, 94% of the experimental arm received chimeric antigen receptor (CAR) T-cell product, and 35% of the control arm received on-protocol HSCT. The primary endpoint was event-free survival, which was significantly longer in the axi-cel arm with an HR of 0.40 (95% confidence interval, 0.31-0.51; P value < 0.0001) and estimated median of 8.3 months, versus 2.0 months with standard therapy. Among 168 recipients of axi-cel, cytokine release syndrome occurred in 92% (Grade ≥ 3, 7%), neurologic toxicity in 74% (Grade ≥ 3, 25%), prolonged cytopenias in 33%, and fatal adverse reactions in 1.8%. This is the first FDA approval of a CAR T-cell therapy for LBCL in the second-line setting and reflects a potential paradigm shift.

Association between antibiotics and adverse oncological outcomes in patients receiving targeted or immune-based therapy for hepatocellular carcinoma.

Background & Aims: Immune checkpoint inhibitors (ICIs) alone or in combination with other ICIs or vascular endothelial growth factor pathway inhibitors are therapeutic options in unresectable/metastatic hepatocellular carcinoma (HCC). Whether antibiotic (ATB) exposure affects outcome remains unclear. Methods: This study retrospectively analysed an FDA database including 4,098 patients receiving ICI (n = 842) either as monotherapy (n = 258) or in combination (n = 584), tyrosine kinase inhibitor (TKI) (n = 1,968), vascular endothelial growth factor pathway inhibitors (n = 480), or placebo (n = 808) as part of nine international clinical trials. Exposure to ATB within 30 days before or after treatment initiation was correlated with overall survival (OS) and progression-free survival (PFS) across therapeutic modality before and after inverse probability of treatment weighting (IPTW). Results: Of 4,098 patients with unresectable/metastatic HCC, of which 39% were of hepatitis B aetiology and 21% were of hepatitis C aetiology, 83% were males with a median age of 64 years (range 18-88), a European Collaborative Oncology Group performance status of 0 (60%), and Child-Pugh A class (98%). Overall, ATB exposure (n = 620, 15%) was associated with shorter median PFS (3.6 months in ATB-exposed vs. 4.2 months; hazard ratio [HR] 1.29; 95% CI 1.22, 1.36) and OS (8.7 months in ATB-exposed vs. 10.6 months; HR 1.36; 95% CI 1.29, 1.43). In IPTW analyses, ATB was associated with shorter PFS in patients treated with ICI (HR 1.52; 95% CI 1.34, 1.73), TKI (HR 1.29; 95% CI 1.19, 1.39), and placebo (HR 1.23; 95% CI 1.11, 1.37). Similar results were observed in IPTW analyses of OS in patients treated with ICI (HR 1.22; 95% CI 1.08, 1.38), TKI (HR 1.40; 95% CI 1.30, 1.52), and placebo (HR 1.40; 95% CI 1.25, 1.57). Conclusions: Unlike other malignancies where the detrimental effect of ATB may be more prominent in ICI recipients, ATB is associated with worse outcomes in this study across different therapies for HCC including placebo. Whether ATB is causally linked to worse outcomes through disruption of the gut-liver axis remains to be demonstrated in translational studies. Impact and Implications: A growing body of evidence suggests the host microbiome, frequently altered by antibiotic treatment, as an important outcome predictor in the context of immune checkpoint inhibitor therapy. In this study, we analysed the effects of early antibiotic exposure on outcomes in almost 4,100 patients with hepatocellular carcinoma treated within nine multicentre clinical trials. Interestingly, early exposure to antibiotic treatment was associated with worse outcomes not only in patients treated with immune checkpoint inhibitors but also in those treated with tyrosine kinase inhibitors and placebo. This is in contrast to data published in other malignancies, where the detrimental effect of antibiotic treatment may be more prominent in immune checkpoint inhibitor recipients, highlighting the uniqueness of hepatocellular carcinoma given the complex interplay between cirrhosis, cancer, risk of infection, and the pleiotropic effect of molecular therapies for this disease.

Eligibility criteria and enrollment of a diverse racial and ethnic population in multiple myeloma clinical trials.

The narrow eligibility criteria may contribute to the underrepresentation of racial and ethnic subgroups in cancer clinical trials. We conducted a retrospective pooled analysis of multicenter global clinical trials submitted to the US Food and Drug Administration between 2006 and 2019 to support the approval of the use of multiple myeloma (MM) therapies that analyze the rates and reasons for trial ineligibility based on race and ethnicity in MM clinical trials. Race and ethnicity were coded per Office of Management and Budget standards. Patients flagged as having screen failures were identified as ineligible. Ineligibility rates were calculated as the percentage of patients who were ineligible compared with the screened population within the respective racial and ethnic subgroups. Trial eligibility criteria were grouped into specific categories to analyze the reasons for trial ineligibility. Black patients (24%) and other (23%) race subgroups had higher ineligibility rates than White patients (17%). The Asian race had the lowest ineligibility rate (12%) among all racial subgroups. Failure to meet the hematologic laboratory criteria (19%) and treatment-related criteria (17%) were the most common reasons for ineligibility among Black patients and were more common in Black patients than in other races. Failure to meet disease-related criteria was the most common reason for ineligibility among White (28%) and Asian (29%) participants. Our analysis indicates that specific eligibility criteria may contribute to enrollment disparities for racial and ethnic subgroups in MM clinical trials. However, the small number of screened patients in the underrepresented racial and ethnic subgroups limits definitive conclusions.

FDA Oncology Center of Excellence Crowdsourcing Initiative: Outreach to the Scientific Community to Identify Research Questions for Pooled Analyses of Oncology Clinical Trial Data.

The FDA Oncology Center of Excellence recently launched a crowdsourcing pilot to request ideas from the scientific community for research questions that FDA could address with pooled analyses of clinical trial data submitted to the agency for regulatory purposes. This effort builds on FDA's track record of publishing pooled analyses to explore scientific questions that cannot be addressed in a single trial due to limited sample size. The research crowdsourcing pilot tested a new approach for obtaining external input on regulatory science activities, because FDA is generally unable to share patient-level data outside of the agency due to federal disclosure laws and regulations protecting different types of data submitted in regulatory applications. We received 29 submissions over the 28-day crowdsourcing campaign, including one research idea that we are exploring for possible follow-up. Based on our experience with this pilot, we learned that crowdsourcing is a promising new approach to gather external input and feedback. We identified opportunities to build understanding in the external oncology community about the types of data typically included in regulatory applications and expand the dissemination of published FDA pooled analyses to help inform future drug development and clinical practice.

FDA Analysis of Ineligibility for Acute Myeloid Leukemia Clinical Trials by Race and Ethnicity.

BACKGROUND: Patients of certain racial and ethnic groups have been underrepresented in clinical trials for treatment of malignancy. One potential barrier to participation is entry requirements that lead to patients in various racial and ethnic groups not meeting eligibility criteria for studies (ie, "screen failure"). The objective of this study was to analyze the rates and reasons for trial ineligibility by race and ethnicity in trials of acute myeloid leukemia (AML) submitted to the U.S. Food and Drug Administration (FDA) between 2016 and 2019. MATERIALS AND METHODS: Multicenter, global clinical trials submitted to the FDA to support AML drugs and biologics. We examined the rate of ineligibility among participants screened for studies of AML therapies submitted to the FDA from 2016 to 2019. Data were extracted from 13 trials used in approval evaluations, including race, screen status, and reason for ineligibility. RESULTS: Overall, patients in historically underrepresented racial and ethnic groups were less likely to meet entry criteria for studies compared to White patients, with 26.7% of White patients, 29.4% of Black patients, and 35.9% of Asian patients not meeting entry criteria. Lack of relevant disease mutation was the reason for ineligibility more frequently among Black and Asian patients. The findings were limited by the small number of underrepresented patients screened for participation. CONCLUSION: Our results suggest that entry requirements for studies may put underrepresented patients at a disadvantage, leading to less eligible patients and thus lower participation in clinical trials.

Minimal Residual Disease Data in Hematologic Malignancy Drug Applications and Labeling: An FDA Perspective.

Minimal residual disease (MRD) is increasingly used as a prognostic biomarker, a measure of clinical efficacy, and a guide for treatment decisions in various hematologic malignancies. We sought to characterize MRD data in registrational trials in hematologic malignancies submitted to the U.S. Food and Drug Administration (FDA) with the ultimate goal of expanding the utility of MRD data in future drug applications. We descriptively analyzed MRD data collected in registrational trials, including the type of MRD endpoint, assay, disease compartment(s) assessed, and the acceptance of MRD data in the U.S. prescribing information (USPI). Of 196 drug applications submitted between January 2014 and February 2021, 55 (28%) included MRD data. Of the 55 applications, MRD data was proposed by the Applicant for inclusion in the USPI in 41 (75%) applications but was included in only 24 (59%). Despite an increasing number of applications that proposed to include MRD data in the USPI, the acceptance rate decreased over time. Although MRD data have the potential to expedite drug development, our analysis identified challenges and specific areas for improvement, including assay validation, standardization of collection methods to optimize performance, and considerations in trial design and statistical methodology.

Considerations for Drug Development in Myelodysplastic Syndromes.

Myelodysplastic syndromes (MDS) have historically been challenging diseases for drug development due to their biology, preclinical modeling, and the affected patient population. In April 2022, the FDA convened a panel of regulators and academic experts in MDS to discuss approaches to improve MDS drug development. The panel reviewed challenges in MDS clinical trial design and endpoints and outlined considerations for future trial design in MDS to facilitate drug development to meaningfully meet patient needs. Challenges for defining clinical benefit in patients with MDS include cumbersome response criteria, standardized transfusion thresholds, and application and validation of patient reported outcome instruments. Clinical trials should reflect the biology of disease evolution, the advanced age of patients with MDS, and how patients are treated in real-world settings to maximize the likelihood of identifying active drugs. In patients with lower-risk disease, response criteria for anemic patients should be based on baseline transfusion dependency, improvement in symptoms, and quality of life. For higher-risk patients with MDS, trials should include guidance to prevent dose reductions or delays that could limit efficacy, specify minimal durations of treatment (in the absence of toxicity or progression), and have endpoints focused on overall survival and durable responses. MDS trials should be designed from the outset to allow the practicable application of new therapies in this high-needs population, with drugs that can be administered and tolerated in community settings, and with endpoints that meaningfully improve patients' lives over existing therapies.

Project Confirm: Accelerated Drug Approvals for Chronic Myeloid Leukemia.

The FDA has an accelerated approval program for drugs that have been identified as promising treatments for serious conditions when the available data suggest that the benefits outweigh the foreseeable risks. All of the currently available treatment options for chronic myeloid leukemia (CML) initially went through the accelerated approval program. Here, a group of academic CML experts, patient panelists, and members from the FDA convened to discuss the utility of the accelerated approval program as it pertains to CML, and the utility of this program in future drug development in this disease. The results of that discussion are summarized here.

Use of Single-Arm Trials for US Food and Drug Administration Drug Approval in Oncology, 2002-2021.

Importance: Single-arm trials have allowed for transformative therapies to be made available to patients expeditiously. However, using single-arm trials to support drug approval presents several challenges that must be carefully considered. Observations: Between January 1, 2002, and December 31, 2021, the US Food and Drug Administration granted 176 new malignant hematology and oncology indications based on single-arm trials, including 116 accelerated approvals (AAs) and 60 traditional approvals. Overall, 87 approvals (49%) were for new molecular entities or original biologics and 89 (51%) were supplemental indications. Response rate (RR) was the most common end point used to support approval in these single-arm trials (173 of 176 [98%]). Of the 116 AAs based on single-arm trials, 45 (38%) fulfilled their postmarketing requirement to verify clinical benefit, 61 (52%) are pending verification of benefit, and 10 (9%) were withdrawn from the market as of December 31, 2021. Most (56 of 61 [92%]) AAs based on single-arm trials pending verification of benefit occurred during the previous 5 years and have ongoing confirmatory trials as of December 2021. Conclusions and Relevance: Single-arm trials have been a common development strategy to support regulatory approval as early-stage expansion cohorts with promising durable RRs have become more prevalent. In the appropriate context, single-arm trials using durable RRs can allow patients expedited access to novel therapies and will continue to serve a role in advancing drug development in oncology. However, single-arm trials have a smaller noncomparative safety data set, inability to use time-to-event end points, and other limitations that require careful consideration within the context of the disease and available therapies. The randomized clinical trial remains the preferred approach in clinical investigation.

FDA Approval Summary: Ripretinib for Advanced Gastrointestinal Stromal Tumor.

On May 15, 2020, the FDA approved ripretinib for adult patients with advanced gastrointestinal stromal tumor who have received prior treatment with three or more kinase inhibitors, including imatinib. The approval was based on results from INVICTUS (NCT03353753), an international, multi-center, double-blind, placebo-controlled trial. Patients were randomly allocated (2:1) to receive either ripretinib 150 mg once daily (n = 85) or matching placebo (n = 44). The trial demonstrated a statistically significant improvement in progression-free survival (PFS) as assessed by modified RECIST v1.1 by blinded independent central review for patients randomized to ripretinib, with a median PFS of 6.3 months [95% confidence interval (CI): 4.6-6.9] compared with 1.0 month (95% CI: 0.9-1.7) for placebo [HR: 0.15 (95% CI: 0.09-0.25); P < 0.0001, stratified log-rank test]. There was no statistically significant difference in objective response rate in the ripretinib arm, 9% (95% CI: 4.2-18) compared with placebo 0% [(95% CI: 0-8); P = 0.0504, Fisher exact test]. The median overall survival (OS) in the ripretinib arm was 15.1 months (95% CI: 12.3-15.1) compared with 6.6 months (95% CI: 4.1-11.6) in the placebo arm. A formal statistical comparison of OS was not made due to the prespecified hierarchical analysis plan. The most common (≥20%) adverse events with ripretinib, in order of decreasing frequency, were alopecia, fatigue, nausea, abdominal pain, constipation, myalgia, diarrhea, decreased appetite, palmar-plantar erythrodysesthesia, and vomiting. Other important risks of ripretinib include new primary cutaneous malignancies, hypertension, and cardiac dysfunction.

FDA Approval Summary: Pemigatinib for Previously Treated, Unresectable Locally Advanced or Metastatic Cholangiocarcinoma with FGFR2 Fusion or Other Rearrangement.

On April 17, 2020, the FDA granted accelerated approval to pemigatinib (PEMAZYRE, Incyte Corporation) for the treatment of adults with previously treated, unresectable locally advanced or metastatic cholangiocarcinoma with an FGFR2 fusion or other rearrangement as detected by an FDA-approved test. Approval was based on FIGHT-202 (NCT02924376), a multicenter open-label single-arm trial. Efficacy was based on 107 patients with locally advanced unresectable or metastatic cholangiocarcinoma whose disease had progressed on or after at least one prior therapy and had an FGFR2 gene fusion or rearrangement. Patients received pemigatinib, 13.5 mg orally, once daily for 14 consecutive days, followed by 7 days off therapy. Safety was based on a total of 466 patients, 146 of whom had cholangiocarcinoma and received the recommended dose. Efficacy endpoints were overall response rate (ORR) and duration of response (DOR) determined by an independent review committee using RECIST 1.1. ORR was 36% (95% confidence interval: 27-45). Median DOR was 9.1 months. The most common adverse reactions were hyperphosphatemia, alopecia, diarrhea, nail toxicity, fatigue, dysgeusia, nausea, constipation, stomatitis, dry eye, dry mouth, decreased appetite, vomiting, arthralgia, abdominal pain, hypophosphatemia, back pain, and dry skin. Ocular toxicity and hyperphosphatemia are important risks of pemigatinib. The recommended dosage is 13.5 mg orally once daily for 14 consecutive days followed by 7 days off therapy in 21-day cycles. FDA also approved the FoundationOne CDX (Foundation Medicine, Inc.) as a companion diagnostic for patient selection.

Improving Dose-Optimization Processes Used in Oncology Drug Development to Minimize Toxicity and Maximize Benefit to Patients.

This review highlights strategies to integrate dose optimization into premarketing drug development and discusses the underlying statistical principles. Poor dose optimization can have negative consequences for patients, most commonly because of toxicity, including poor quality of life, reduced effectiveness because of inability of patients to stay on current therapy or receive subsequent therapy because of toxicities, and difficulty in developing combination regimens. We reviewed US Food and Drug Administration initial approvals (2019-2021) of small molecules and antibody-drug conjugates for oncologic indications to determine the proportion with a recommended dosage at the maximum tolerated dose or the maximal administered dose, to characterize the use of randomized evaluations of multiple dosages in dose selection, to describe the frequency of dose modifications at the recommended dosage, and to identify case examples that highlight key principles for premarket dose optimization during drug development. Herein, we highlight major principles for dose optimization and review examples of recent US Food and Drug Administration approvals that illustrate how investigation of dose- and exposure-response relationships and use of randomized dose trials can support dose optimization. Although there has been some progress, dose optimization through randomized dose evaluation in oncology trials is not routinely conducted. Dose optimization is essential to ensure that patients receive therapies which maximize efficacy while minimizing toxicity.

FDA Approval Summary: Belantamab Mafodotin for Patients with Relapsed or Refractory Multiple Myeloma.

On August 5, 2020, the FDA granted accelerated approval to belantamab mafodotin-blmf (BLENREP; GlaxoSmithKline) for the treatment of adult patients with relapsed or refractory multiple myeloma who have received at least four prior therapies including an anti-CD38 monoclonal antibody, a proteasome inhibitor, and an immunomodulatory agent. Substantial evidence of effectiveness was obtained from the phase II, multicenter DREAMM-2 trial. Patients received belantamab mafodotin 2.5 or 3.4 mg/kg intravenously once every 3 weeks until disease progression or unacceptable toxicity. The trial demonstrated an overall response rate of 31% in the 2.5 mg/kg cohort and 34% in the 3.4 mg/kg cohort. Keratopathy was the most frequent adverse event, occurring in 71% and 77% of patients, respectively. Other ocular toxicities included changes in visual acuity, blurred vision, and dry eye. The U.S. prescribing information for belantamab mafodotin includes a boxed warning for ocular toxicity, and belantamab mafodotin is available only through a restricted program under a Risk Evaluation and Mitigation Strategy. This article summarizes the data and the FDA review process supporting accelerated approval of belantamab mafodotin 2.5 mg/kg intravenously once every 3 weeks. This approval may be contingent upon verification and description of clinical benefit in confirmatory trial(s).