Minghui and Qilu Pharmaceutical Unveil Promising MHB088C Data in mCRPC at ASCO 2026
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Minghui Pharmaceutical and Qilu Pharmaceutical Co. have announced updated clinical data from their Phase I/II study of MHB088C (QLC5508) in patients with heavily pretreated metastatic castration-resistant prostate cancer (mCRPC) at the 2026 ASCO Annual Meeting. The findings demonstrated encouraging anti-tumor activity and durable disease control.
Minghui Pharmaceutical and Qilu Pharmaceutical presented updated Phase 1/2 data for MHB088C (QLC5508), a B7-H3 antibody-drug conjugate, in heavily pretreated metastatic castration-resistant prostate cancer at ASCO 2026. A 12-month radiographic progression-free survival rate of 71.7% and a registered Phase 3 versus docetaxel (NCT07632690) now frame the asset’s China and global partnering story.
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Key Takeaways
- ASCO 2026 poster: updated Phase 1/2 MHB088C (QLC5508) data in heavily pretreated mCRPC (PR Newswire, 1 June 2026).
- Median rPFS not reached; 12-month rPFS rate 71.7% (95% CI 52.6–84.3%) in the disclosed analysis; 78.6% at 2.0 mg/kg Q2W (n=40).
- Qilu holds Greater China rights; Minghui retains ex-China rights and combination rights with MHB039A.
- Phase 3 NCT07632690 will randomize ~700 patients to QLC5508 versus docetaxel after novel hormonal agent progression.
What did Minghui and Qilu report for MHB088C at ASCO 2026?
On 1 June 2026 the sponsors said a Phase 1/2 poster showed durable anti-tumor activity in heavily pretreated mCRPC, including patients after androgen receptor pathway inhibitors and taxanes. Median radiographic progression-free survival was not reached (95% CI 13.1–NE), with a 12-month rPFS rate of 71.7%.
At the 2.0 mg/kg every-two-weeks dose (n=40), median rPFS was also not reached and the 12-month rPFS rate was 78.6%. Details are in the 1 June 2026 PR Newswire release.
How is the confirmatory Phase 3 designed?
NCT07632690 is a randomized, open-label Phase 3 comparing QLC5508 with docetaxel in mCRPC after novel hormonal agents. The primary endpoint is IRC-assessed radiographic PFS. Estimated enrollment is about 700 patients; status was not-yet-recruiting when last checked on ClinicalTrials.gov.
The experimental dose listed is 2.0 mg/kg intravenously every two weeks until progression or unacceptable toxicity—matching the ASCO dose cohort emphasized by the sponsors.
Why does B7-H3 ADC competition matter?
B7-H3 is a crowded ADC target across solid tumors. Durable rPFS signals in late-line mCRPC can support China Phase 3 investment and ex-China licensing talks, but cross-trial comparisons fail without matched prior therapy mixes and blinded radiology.
Minghui’s retained global rights mean BD outreach will track toxicity (especially hematologic and interstitial lung disease risks common to ADCs) alongside efficacy. FDA oncology review standards for ADCs provide context on FDA Oncology Center of Excellence pages.
What remains unproven for MHB088C?
Phase 1/2 rPFS without a randomized control cannot prove superiority to docetaxel or to other ADCs. Overall survival, confirmed objective response rates and grade ≥3 adverse event tables need the full ASCO poster and peer-reviewed paper. Phase 3 NCT07632690 results are years away.
Investors should also separate Greater China commercialization (Qilu) from global partnering optionality (Minghui) when modeling peak sales.
What due diligence should ex-China partners demand?
Before licensing MHB088C outside Greater China, partners will request patient-level listings, independent radiology reads, prior therapy matrices and full adverse-event tables—not only 12-month rPFS point estimates. ADC payload and linker chemistry drive off-tumor toxicity that poster headlines rarely quantify.
The Phase 3 versus docetaxel sets a clear bar in China after novel hormonal agents. Global development may need different comparators if docetaxel timing or ARPI sequences differ by region. Combination work with Minghui’s PD-1/VEGF bispecific MHB039A adds another strategic layer.
Manufacturing scale for ADCs and cold-chain logistics also matter for partnering. Qilu’s Greater China rights mean Minghui must keep CMC packages partner-ready for Western filings if data hold.
Until NCT07632690 reads out, treat ASCO 2026 as supportive Phase 1/2 evidence. Durable disease control in late-line mCRPC is encouraging, but randomized superiority remains unproven.
Related NovaPharma coverage
Prostate cancer physicians will compare MHB088C data against radioligand therapy sequencing and other ADCs entering mCRPC. Cross-trial hazard ratios are misleading when scan schedules differ. The Phase 3’s IRC-assessed rPFS endpoint is the right next experiment; interim looks, if any, should be pre-specified to avoid multiplicity concerns.
Frequently Asked Questions
What is MHB088C (QLC5508)?
MHB088C, also called QLC5508, is an investigational B7-H3-targeted antibody-drug conjugate co-developed by Minghui Pharmaceutical with Greater China rights held by Qilu Pharmaceutical.
What efficacy signal was highlighted at ASCO 2026?
Sponsors reported median rPFS not reached and a 12-month rPFS rate of 71.7% (95% CI 52.6–84.3%) in heavily pretreated mCRPC, with 78.6% at the 2.0 mg/kg Q2W dose among 40 patients.
Is there a Phase 3 trial of MHB088C in mCRPC?
Yes. NCT07632690 is a randomized Phase 3 of QLC5508 versus docetaxel after novel hormonal agent progression, with IRC-assessed rPFS as the primary endpoint.
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