Jared Gollob
Analyst · various risks, uncertainties and other factors, including those set forth in Kymera's most recent filings with the SEC and any other future filings that the Company may make with the SEC. You are cautioned not to place any undue reliance on these forward-looking statements and Kymera disclaims any obligation to update such statements. I will now hand the call over to Nello Mainolfi, Founder and CEO
Thanks, Nello. Starting with our oncology programs, we are pleased to report that the three disclosed oncology programs STAT3, IRAKIMid and MDM2 are all tracking as expected. First, I will discuss our STAT3 program. KT-333, as mentioned, is our lead STAT3 degrader. As brief background, STAT3 is a transcriptional regulator that has been linked to numerous cancers and other inflammatory and autoimmune diseases, and it is a target that has long been considered undruggable. Our focus here is on developing selective STAT3 degraders for the treatment of hematological malignancies and solid tumors, as well as autoimmune and fibrotic diseases. We believe our STAT3 degraders have the potential to provide a transformative solution to address multiple STAT3 dependent pathologies. In terms of a clinical update, recall that we received IND clearance from FDA in 4Q '21. The first clinical site was activated in 1Q '22, and the trial is actively recruiting patients. As a reminder, KT-333 is being evaluated in adult patients with relapse refractory liquid and solid tumors, including aggressive lymphomas. Dose escalation is expected to proceed throughout 2022 and we look forward to presenting the first patient data, including preliminary safety and proof-of-mechanism clinical data, in the second half of 2022. Moving now to IRAKIMid, KT-413 is a novel heterobifunctional degrader that targets degradation of both IRAK4 and the IMiD substrates, Ikaros and Aiolos, with a single small molecule. KT-413 was designed to address both, the IL-1R, TLR and the Type 1 interferon pathways synergistically to broaden activity against MYD88 mutant B-cell malignancies. KT-413 is on a similar time line in STAT3 having received IND clearance from FDA late last year. The first clinical site was activated in 1Q '22 and patient recruitment is underway. As a reminder, the Phase I trial for KT-413 is focused on adult patients with relapsed refractory B-cell lymphomas, including MYD88 mutant diffused large B cell lymphoma or DLBCL. Our plans remain to present KT-413's first patient data, including preliminary safety and proof-of-mechanism clinical data, in the second half of 2022. Before concluding with an update on our IRAK4 program, I wanted to touch briefly on MDM2, a program we announced for the first time at our R&D day late last year. As we have shared, we are very excited about the potential of this program. MDM2 is the crucial regulator of the most common tumor suppressor p53, which remains intact or wild type in more than 50% of cancers. Based on preclinical data, we believe our highly potent MDM2 degrader KT-253 has the ability, unlike small molecule inhibitors, to suppress the MDM2 feedback loop and thus the potential to rapidly induce apoptosis even with brief exposures. We believe KT-253 has the potential to be effective in a wide range of hematological malignancies and solid tumors with functioning p53. Just a few weeks ago, we shared preclinical data at AACR highlighting the biological superiority of MDM2 degradation over inhibition. Specifically, we presented preclinical data for KT-253 that demonstrated extremely potent in-vitro cell killing and in-vivo antitumor activity with intermittent dosing that is superior to data reported for existing small molecule inhibitors and indicates the potential for improved efficacy and safety with degradation versus inhibition. You can find that poster along with all other publications in the scientific resources section of our website. As planned, KT-253 is currently in IND enabling activities to support an IND filing in the second half of 2022. Finally, I will cover our IRAK4 program and our lead candidate, KT-474. As previously disclosed, late last year, we completed dose escalation in the single ascending dose and multiple ascending dose portions of our Phase I clinical trial, where we enrolled over 100 healthy adult volunteers. As reported, initial data demonstrated near complete IRAK4 knockdown in PBMC and skin, as well as robust ex-vivo inhibition of multiple disease-relevant cytokines with a favorable safety profile. Specifically in the multiple ascending dose portion of the trial where subjects received 14 daily doses and we explored a range of doses from 25 mg to 200 mg, robust IRAK4 degradation was seen across all dose levels with up to 98% reduction in PBMC at steady state between day seven and 14, plateauing after 100 mg. In skin, IRAK4 levels were also reduced to near the lower limit of detection by day 14 at the top dose, but had not yet reached steady state, suggesting that continued dosing beyond 14 days would likely result in further declines in IRAK4 levels at daily doses of 50 mg to 200 mg. Finally, ex-vivo cytokine induction by TLR agonists showed greater than 50% inhibition of most cytokines and maximum inhibition of 85% in the 100 mg dose group. This robust inhibition was seen in conjunction with greater than 90% IRAK4 knockdown in monocytes. With that previously disclosed data as context, I will now comment on our plans for 2022, including a few recent developments. We have selected the dose equivalent of 100 mg in the fed state to take into Part C, the patient portion of the Phase I trial. Based on our clinical experience to date, we believe that the 100 mg dose is the level at which we have maximized the pharmacology of KT-474, and which will drive robust IRAK4 degradation leading to TLR INR pathway inhibition in multiple different disease-relevant cell types that can impact inflammation and result in disease-modifying clinical activity. Having observed in SAD, an increase in exposure with KT-474 in the fed state versus fasted, we are enrolling an additional SAD cohort to determine the 100 mg dose equivalent in the fed state. Once we have those results, we will then proceed to the patient cohort portion of the trial. In respect to the patient cohort, we have made a modification to the study design. Specifically, we will be extending the dosing duration from 14 days to 28 days. This decision was made in conjunction with our partner, Sanofi, and we recently aligned with FDA on this protocol modification. Many of you have asked about our ability to track clinical endpoints in this portion of the trial, which we had not planned to do with just 14 days of dosing. A witness change to 28 days of dosing and 14 days of follow up, we have now added several exploratory clinical endpoints, including the eczema area and severity index, or EASI for atopic dermatitis, total abscess and inflammatory nodule count for hidradenitis suppurativa as well as additional measures of symptoms and physician or investigator global assessments for both diseases. We plan to share the results of the patient cohort in the second half of this year, as previously guided. Finally, prior to selecting the dose for the patient cohort, we undertook a comprehensive analysis of all safety data from the SAD and MAD portions of Phase I, which recently included unblinded results. Consistent with what we have previously disclosed, the unblinded safety analysis showed KT-474 to be safe and well tolerated with no serious adverse events and no treatment discontinuations. A full analysis of 24-hour Holter ECGs, as well as safety ECGs that were part of the Phase I study, did not show any arrhythmias or other ECG adverse events. We did identify a modest non-adverse, non-dose dependent, 10 msec to 20 msec prolongation of QTc relative to baseline only after multi dosing in the MAD portion of the trial. This modest effect plateaued by day seven and completely reversed after day 14, following the completion of dosing. Importantly, the QTc interval itself remained less than 450 msec and, therefore, the QTc prolongation did not qualify as a grade 1 adverse event. FDA was informed of the full safety data set, including the comprehensive QTc analysis, and did not object to the proposed dose selection, as well as the protocol adjustments to Part C that include 28 days of dosing, both to enable evaluation of exploratory clinical endpoints and to extend safety monitoring. Our broader clinical plans, aside from this adjustment to the patient cohort, remain unchanged and we are excited to advance KT-474 through further clinical development. Before Nello concludes the call with some closing remarks, I will hand the call to Bruce Jacobs, our Chief Financial Officer, who will share some brief comments on our financial results for the first quarter. Bruce?