DOC-UP01-03 · v0.3 · Aster Biologics · Mesa UP-01
Investigation Summary: Feed Droop and Head-Pressure Exceedance, BR-UP-01
Deviation Q-DEV-031 · Batch MES-26073 · Prepared by Alex Rivera (MSAT) with Root Cause agent assistance
1. Purpose and scope
This summary documents the investigation of deviation Q-DEV-031 on Skid BR-UP-01, batch MES-26073 (AB-mAb-014, campaign CMP-26-10). It covers the feed-flow droop and PM-204 head-pressure exceedance, the evidence reviewed, the most-likely cause and proposed CAPAs. It does not constitute a batch disposition decision.
2. Event description
At T+264.4 h PM-204 discharge head pressure rose to 1.48 bar against a 1.20 bar ceiling, and delivered feed flow fell from 16.88 to 14.48 mL/min (−14.2%) within two minutes.
The operator acknowledged the deviation at eBR step 05.4 with FEED_SP 16.90 mL/min and FEED_PV 14.48 mL/min.
A 42-minute historian gap exists at T+182.0–182.7 h caused by a PI buffer overflow. No values from this window are used in any calculation in this report.
3. Investigation and evidence
Work order WO-8819, performed 48 h before the event, records an increase of the PM-204 occlusion clamp torque from 0.42 to 0.55 N·m. Dynamic slip verification was not performed because the fixture was unavailable.
SOP-UP-014 Rev 7 §7.2 requires a dynamic slip verification at operating RPM after any occlusion adjustment, with gravimetric acceptance of ±3% of setpoint.
The pump-head OEM manual states that increased occlusion shortens tubing service life (400–500 h nominal) and raises discharge pressure.
Harvest sample QC-948 returned an HPLC titer of 3.42 g/L, below the 3.80 g/L alert limit. System suitability passed. Second-person review is pending.
4. Most-likely root cause (pending QA)
The most-likely cause is over-occlusion of PM-204 tubing following WO-8819, without the required slip verification, leading to accelerated tubing fatigue, elevated discharge pressure and reduced delivered feed. This has not been confirmed by physical inspection of the removed tubing.
Alternative causes reviewed and not supported by evidence: feed media lot FM-2207 out of specification (all attributes within specification); DO probe drift (redundant probes agree within 0.6%).
5. Product impact
Titer is below the alert limit; other in-process results are within specification except osmolality, which is near its upper limit. SEC monomer has not been tested, so aggregation impact is unknown. Lot MES-26073 remains on QA hold.
6. Proposed CAPA
CAPA-01: exchange the PM-204 tubing spool and perform dynamic slip verification before return to service (owner R. Chen, due 2026-11-07). CAPA-02: amend SOP-UP-014 §7.2 so occlusion work orders cannot be closed without a slip-verification record (owner A. Rivera, due 2026-11-28). Both are proposals and have not been entered into QMS.
Appendix A · Data tables
1,474 words of tabulated historian and LIMS data. Collapsed in this demo.