Sarah Gheuens
Analyst · Cantor Fitzgerald
Thanks, Brian. In 2023, our research and development organization made tremendous progress advancing our PK activator development program. Led by mitapivat, the industry's most advanced PK activator, now with over eight years of clinical experience, the consistent and compelling data we have generated to date in PK deficiency, thalassemia and sickle cell disease to continue to de-risk our ongoing development program and highlight the potential for this molecule to transform patient's function and quality of life. We are also enthusiastic about the potential for the rest of our growing pipeline, and we are pleased to note that we remain on track to deliver on our milestones, including, enrolling the first patients in the Phase 2b trial for AG-946 in lower risk MDS, and for the Phase 1 trial for AG-181, the compounds named for our PAH stabilizer for phenylketonuria. Reading our top line data for the Phase 3 ACTIVATE kids-T study in regularly transduced pediatrics patients with TK deficiency, and completing enrollment of the Phase 3 ACTIVATE kids-T study in pediatric patients with TKB. Turning to sickle cell disease, we were pleased to present detailed positive results from the Phase 2 Portion of the Phase 2/3 RISE UP Study mitapivat at ASH in December. The study achieved its primary endpoint of hemoglobin response, and in addition, an improvement in analyzed rates of sickle cell pain crises was observed. And we have been delighted by the enthusiasm of the investigators. We continue to advance enrollment in the Phase 3 portion of this study and remain on track to complete enrollment by the end of this year. While the treatment landscape in sickle cell disease continues to evolve, there remains an urgent and unmet need for convenient novel oral treatment options that address both anemia and sickle cell pain crises. And we believe firmly in mitapivat’s potential to deliver a best-in-class option for patients suffering from this devastating disease. And finally, on thalassemia, I'll take a moment to highlight a few key elements of our program, and the positive top-line Phase 3 data we reported last month in non-transfusion-dependent thalassemia. As a reminder, the Phase 3 program of PYRUKYND in thalassemia, and compacting two Phase 3 randomized placebo-controlled trials, was designed to deliver data across all sub-populations of thalassemia, such as alpha-and beta-thalassemia and populations with different transfusion needs. Both trials enrolled patients with alpha or beta-thalassemia, but enrolled different populations as it relates to transfusion needs. We want to highlight that ENERGIZE is the first clinical program that included patients who were not regularly transfused and alpha-thalassemia patients. As Brian mentioned, there are no FDA-approved treatments for non-transfusion-dependent thalassemia, which represents approximately two-thirds of total thalassemia patients in the U.S. These patients suffer from a poor quality of life, a high rate of serious morbidities, including thrombosis and premature death. We were therefore very pleased to be able to announce positive results from the ENERGIZE study. As a reminder, the ENERGIZE study enrolled a total of 194 patients with either alpha or beta non-transfusion-dependent thalassemia, randomized 2:1 to 100 milligrams mitapivat or placebo twice daily. The speed of enrollment and the actual number of patients enrolled in this study, as well as the high completion and rollover rate, supports the idea that people who are not regularly transfused were motivated to take action and speak to the unmet need for this population. The primary endpoint of this study was hemoglobin response rate, defined as an increase of at least one gram per deciliter in average hemoglobin concentration from week 12 to week 24 compared to baseline. The key secondary endpoints of this study were change from baseline in average FACIT-Fatigue Score and change from baseline in average hemoglobin concentration, also both assessed from week 12 to 24. On the primary endpoints, treatment with mitapivat demonstrated a highly statistically significant result, with 42.3% of patients in the treatment arm achieving a hemoglobin response versus 1.6% of patients in the placebo arm. In line with mitapivat's novel mechanism of action, which focuses on overall red blood cell health, and the data generated with mitapivat across additional disease areas, the beneficial effects of mitapivat in this study extended beyond hemoglobin alone. Specifically, treatment with 100 milligrams mitapivat resulted in statistically significant improvements in both key secondary endpoints, including a change from baseline and average FACIT-Fatigue Score, an important patient-reported measure of how patients feel and function. Importantly, across the primary and secondary endpoints, all pre-specified subgroup analyses favored mitapivat compared to placebo, suggesting that no single subgroup was responsible for driving the results, which supports our plan to file for a broad label covering all thalassemia subtypes. This is therefore the first drug that not only improves hemoglobin but actually makes people with thalassemia feel better, consistent with what we observe in patients with PKD and what we hope to be able to deliver for patients with sickle cell disease as well. Complementing the near-term benefits of thalassemia patients reporting that they had less fatigue and felt better in the near-term, clinicians in the trial and other KOLs appreciate the potential longer-term benefits of reducing markers of hemolysis and the longer-term potential to reduce serious morbidity. We are very much looking forward to presenting the full data set at a medical meeting. Beyond the excitement we have for the ENERGIZE data itself, the readout of the ENERGIZE trial also gives us further confidence towards the readout of ENERGIZE-T. Thalassemia is a hemolytic anemia irrespective of whether a patient is in need of transfusions or not. In addition, the mechanism of action of mitapivat is not dependent on the need for transfusions. We have already demonstrated an improvement in hemolytic anemia in the ENERGIZE trial with a positive change in hemoglobin. We are now waiting to see if the improvement in hemolytic anemia can also be documented via a reduction in transfusions in ENERGIZE-T. As a reminder, the primary endpoint of ENERGIZE-T is transfusion reduction response, defined as a 50% or greater reduction in transfused red blood cell units with a reduction of equal or more than two units of transfused red blood cells in any consecutive 12-week period through week 48 compared to baseline. Like the energized study in non-transfusion-dependent thalassemia, the design of the ENERGIZE-T trial enables us to demonstrate clinical meaningfulness in a variety of ways to see a reduction in transfusion burden, which also includes transfusion metrics in line with that other studies have used. We designed this study incorporating learning from prior studies and agency feedback and believe a dynamic assessment series is important as patients aren't static in their disease. We look forward to the readout of this study by mid-year and plan a single regulatory filing to the FDA and compacting data from both ENERGIZE and ENERGIZE-T by the end of this year, seeking a label that will enable people living with thalassemia access to a convenient and differentiated oral treatment option. Overall, I'm very proud of the tremendous progress made by our R&D organization in 2023 and look forward to continuing this momentum in 2024. With that, I will now turn the call over to Tsveta.