Chia Tai Tianqing opens China Phase 2 of JAK2 drug TQ05105 in myelofibrosis
The 51-patient trial begins recruiting after a prior JAK2 program combination was terminated, testing whether TQ05105 alone can hit a 35% spleen-volume reduction bar in intermediate/high-risk myelofibrosis.
Executive Summary
- A China-based Phase 2 study of TQ05105 in intermediate/high-risk myelofibrosis has opened enrollment, targeting a spleen-volume response bar that the drug has not yet cleared as a monotherapy in a registered trial.
- The sponsor's attempt to pair TQ05105 with a second investigational compound in the same disease was terminated, leaving this monotherapy study as the active vehicle for testing the drug's clinical activity.
- Enrollment held at its planned target and the protocol shows no amendment churn, indicating the study start is proceeding on its registered design rather than showing signs of operational strain.
- No trial identified in the myelofibrosis field shares TQ05105's target, so the study's read on this specific mechanism will stand largely on its own rather than against a matched comparator.
The status change
NCT07551427 moved from Not yet recruiting to Recruiting on July 15, 2026, according to the trial's ClinicalTrials.gov record. The study targets 51 adult patients with primary or secondary myelofibrosis classified as intermediate or high risk under the Dynamic International Prognostic Scoring System, and enrolls two cohorts: one defined by renal function and one by prior JAK inhibitor failure, relapse, or intolerance. Recruitment started June 18, 2026, and the trial's primary completion date is set for June 1, 2028. NCT07551427A Clinical Trial to Evaluate the Efficacy, Safety, and Pharmacokinetics of TQ05105 Tablets in Subjects With Intermediate/High-risk MyelofibrosisNCT07551427
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
The endpoint bar
The registered primary endpoints combine pharmacokinetic measures, including peak concentration, clearance, and half-life, with a clinical efficacy measure: the proportion of subjects achieving a 35% or greater reduction in spleen volume from baseline at week 24 (SVR35), assessed by independent review. Secondary endpoints track symptom burden through the MPN-SAF Total Symptom Score, along with progression-free and overall survival and transfusion dependence over roughly 48 weeks. SVR35 is the standard efficacy readout used across myelofibrosis drug development, so week-24 results will be the figure that matters most when they mature. NCT07551427A Clinical Trial to Evaluate the Efficacy, Safety, and Pharmacokinetics of TQ05105 Tablets in Subjects With Intermediate/High-risk MyelofibrosisNCT07551427
What preceded it
TQ05105 has a mixed record in myelofibrosis. A completed 107-patient Phase 2 monotherapy trial (NCT05020652) finished in October 2023, and an earlier 79-patient Phase 1 study across myeloproliferative neoplasms (NCT04339400) completed in March 2023. A more recent attempt to combine TQ05105 with a second Chia Tai Tianqing compound, TQB3909, in a 21-patient Phase 1/2 trial (NCT06245941) was terminated on December 30, 2025. A separate single-agent Phase 1 study in ruxolitinib-resistant or -intolerant patients (NCT06388759) was also terminated. This new 51-patient study returns to TQ05105 as a monotherapy, the format in which the drug's completed prior trial ran.
Trial health check
Enrollment held exactly at its anticipated target of 51 patients, a 0% change that the operational model treats as within the routine band. The protocol shows no primary-completion-date changes, no endpoint amendments, and no eligibility-criteria changes since the study was first posted, and carries a Stable protocol-stability label. Chia Tai Tianqing has completed 75 of 105 trials and terminated 30 across its broader portfolio, and across its four myelofibrosis-specific trials it has a 50% completion rate, split evenly between the two completed and two terminated studies named above.
The competitive field
No trial in the myelofibrosis field shares TQ05105's molecular target in the competitive set assembled here, though the modality, oral small molecules, is common: comparators span Novartis's BRD2-targeted pelabresib, Karyopharm Therapeutics' XPO1 inhibitor selinexor, and Kartos Therapeutics' MDM2 inhibitor navtemadlin, all in Phase 3 testing for the same indication. Momelotinib, a JAK1 inhibitor from GlaxoSmithKline, and other JAK-pathway and epigenetic agents round out a field where mechanisms are heterogeneous rather than convergent on a single validated pathway. Against that backdrop, a monotherapy readout that reproduces the SVR35 response Chia Tai Tianqing's completed 107-patient Phase 2 trial was designed to test would be the result that distinguishes TQ05105 as a viable single-agent option rather than one more entrant in a mechanistically scattered field.
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.