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679 FT-4202, an Allosteric Activator of Pyruvate Kinase-R, Demonstrates Proof of Mechanism and Proof of Concept after a Single Dose and after Multiple Daily Doses in a Phase 1 Study of Patients with Sickle Cell Disease

Program: Oral and Poster Abstracts
Type: Oral
Session: 114. Hemoglobinopathies, Excluding Thalassemia—Clinical:Novel Treatments for Sickle Cell Disease
Hematology Disease Topics & Pathways:
sickle cell disease, Adult, Diseases, Non-Biological, Therapies, Hemoglobinopathies, Young Adult, Study Population, Clinically relevant
Monday, December 7, 2020: 2:00 PM

R. Clark Brown, MD, PhD1, Kimberly Cruz, MD, MS2*, Theodosia A. Kalfa, MD, PhD3, Frans A. Kuypers, PhD4*, Santosh L. Saraf, MD5, Jeremie H. Estepp, MD6, Luke R. Smart, MD3, Punam Malik, MD7, Mark Lerman, MD8*, Renae Mayer, MD9*, Maria D. Ribadeneira, PhD10*, Sanjeev Forsyth, MS10*, Patricia Schroeder, PhD10*, Eric Wu, PhD10*, Patrick Kelly, MD10 and Marilyn J. Telen, MD11

1Department of Pediatrics, Aflac Cancer & Blood Disorders Center of Children’s Healthcare of Atlanta and the Department of Pediatrics, Emory University, Atlanta, GA
2Advanced Pharma, Miami, FL
3Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
4Children's Hospital Oakland Research Institute, Oakland, CA
5Department of Medicine, University of Illinois at Chicago, Chicago, IL
6Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN
7Cincinnati Children's Hospital Medical Center, Cincinnati, OH
8Atlanta Center for Medical Research, Atlanta, GA
9Lynn Institute, Tulsa, OK
10Forma Therapeutics, Inc., Watertown, MA
11Duke Univ. Med. Ctr., Durham, NC

INTRODUCTION: The hallmark of sickle cell disease (SCD) is hemoglobin S (HbS) polymerization upon deoxygenation, resulting in red blood cell (RBC) sickling, oxidative damage, membrane damage, hemolysis, cell adhesion, and vaso-occlusion. Exacerbating the pathogenesis of SCD, the HbS RBC has [1] increased (↑) 2,3-DPG with decreased (↓) O2 affinity (↑ P50) and [2] ↓ RBC ATP. FT-4202, a small molecule allosteric activator of erythrocyte pyruvate kinase (PKR), increases PKR activity resulting in ↓ 2,3-DPG levels and ↑ ATP levels in RBCs. In healthy volunteer (HV) studies (Kalfa et al. Blood 2019), FT-4202 was well tolerated, demonstrating physiologic responses (↓ 2,3-DPG and ↑ ATP) with biologic effects including ↑ O2 affinity, ↓ reticulocytes (P<.001) and ↑ Hb (ns). Based on the safety and pharmacokinetic/pharmacodynamic (PK/PD) profile in HV studies, FT-4202 is being evaluated in patients (pts) with SCD, first in a single dose (SD) cohort and then in multiple-dose (MD) cohorts (14-day and 12-week) [NCT03815695].

METHODS: In the SD and 14-day MD cohorts, pts with SCD were randomized 3:1 to FT-4202 or placebo. Safety assessments included treatment-emergent adverse events (TEAEs), vital signs, ECGs and laboratory parameters. PK/PD blood sampling was performed for up to 72h after the last dose and at the end-of-study visit; PD parameters included 2,3-DPG, ATP, P50, RBC deformability with controlled deoxygenation and reoxygenation (Lorrca® oxygenscan) and varying osmolality (Lorrca® osmoscan). To maintain study blind, pt identifiers were removed when needed.

RESULTS: As of 17-July-2020, the SD (700 mg FT-4202) cohort is complete and the 1st MD cohort (MD-1, 300 mg once daily) is enrolling. Unblinded data from the SD and blinded data from the MD-1, 3 pt safety lead-in (randomized 2:1) are summarized. No serious adverse events (SAEs) or TEAEs leading to pt withdrawal were reported. In the SD cohort, 7 pts (2 males, 5 females, all HbSS) received 700 mg FT-4202 (n=5) or placebo (n=2). Six transient Grade 1 TEAEs occurred in 4 of 7 (57%) pts, including 3 TEAEs (arthralgia, headache, palpitations) in 2 of 5 (40%) pts receiving FT-4202 and 3 TEAEs (back pain, myalgia, pruritis) in 2 of 2 (100%) pts receiving placebo. RBC ATP concentrations increased by 30% and RBC 2,3-DPG concentrations decreased by 26% 24h after FT-4202. Increased O2 affinity (↓P50) with a decreased point of sickling (PoS) and improved HbS RBC deformability were observed in all FT-4202-treated pts. Improved HbS RBC membrane function was also demonstrated with a shift of the osmoscan results towards normal. Improved hematologic parameters, including ~0.9 g/dL Hb increase compared with placebo, were also observed 24h after a single dose of FT-4202. In 3 pts with SCD (3 females, all HbSS) who thus far completed MD-1, 14 days of 300 mg FT-4202 or placebo daily was well tolerated, with 1 pt reporting transient, unrelated Grade 2 TEAEs of nausea/vomiting at the end of the 14-day dosing period. Laboratory changes relative to pretreatment for each pt are shown in Table 1. In 2 of 3 SCD MD-1 pts treated with FT-4202/placebo (currently blinded), Hb increased by > 1 g/dL, % reticulocytes decreased, and markers of hemolysis were improved after 14 days of treatment (compared to pre-treatment levels). Hematologic parameters returned to pre-treatment levels 4 to 7 days post-treatment (data not shown) without clinical AEs. Functional studies in the 2 pts with increased Hb showed improved RBC deformability (↓ PoS) and improved RBC membrane function while on study treatment relative to pre-treatment and/or post-treatment.

CONCLUSION: FT-4202 has a favorable safety profile in pts with SCD receiving a single dose or up to 14 days of dosing. A single dose of FT-4202 led to decreased 2,3-DPG and increased ATP, resulting in increased O2 affinity, decreased PoS, improved RBC deformability, and improved RBC membrane function. Initial blinded results of daily dosing with 300 mg FT-4202/placebo over 14 days show improvement in both hematologic and hemolytic parameters in 2 of 3 pts with SCD, along with improved RBC functional studies, suggesting the pharmacodynamic consequences of PKR activation may be of clinical benefit in SCD. Multiple-dose cohorts are ongoing to further evaluate the safety, PK/PD, and biological activity of FT-4202 following daily administration in pts with SCD; updated data will be presented.

Disclosures: Brown: Imara, Inc.: Consultancy, Research Funding; Forma Therapeutics, Inc,: Research Funding; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis, Inc.: Consultancy, Research Funding. Kalfa: Agios Pharmaceuticals, Inc: Consultancy, Research Funding; Forma Therapeutics, Inc: Research Funding. Kuypers: Forma Therapeutics, Inc.: Research Funding. Saraf: Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Boards, Speakers Bureau; Novartis, Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees; Pfizer, Global Blood Therapeutics, Novartis: Research Funding. Estepp: Global Blood Therapeutics, Forma Therapeutics, Pfizer, Eli Lilly and Co: Research Funding; Daiichi Sankyo, Esperion, Global Blood Therapeutics: Consultancy; ASH, NHLBI: Research Funding. Malik: Aruvant Sciences, CSL Behring: Patents & Royalties; Aruvant Sciences, Forma Therapeutics, Inc.: Consultancy. Ribadeneira: Forma Therapeutics, Inc.: Current Employment. Forsyth: Forma Therapeutics, Inc.: Current Employment. Schroeder: Forma Therapeutics, Inc.: Current Employment. Wu: Forma Therapeutics, Inc.: Current Employment. Kelly: Forma Therapeutics, Inc.: Current Employment. Telen: Forma Therapeutics: Research Funding; GlycoMimetics Inc.: Consultancy; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Behring: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees.

*signifies non-member of ASH