If you're still benchmarking your biosimilar drug substance process purely on titer or batch count, you're looking at the wrong number. The number that actually determines your competitive position is cost of goods per gram (COG/g) and depending on which platform you choose, and at what scale, that number can swing by more than 2x.
All figures below are hypothetical, illustrative modeling for strategic scenario planning not vendor-quoted or validated cost data.
Graphtal modeled a Pembrolizumab-analog process across four platforms to answer the question every process development lead eventually faces: when does intensification actually pay off?
| Parameter | Fed-Batch | Intensified FB | Concentrated FB | Perfusion |
|---|---|---|---|---|
| Harvest Titer | 6 g/L | 6 g/L | 12 g/L | 1.5 g/L/day |
| Batches per Year | 26.1 | 33.2 | 18.3 | 11.4 |
| Annual Output | 313 kg | 398 kg | 438 kg | 1,129 kg |
| Process Complexity (1–5) | 2/5 ★ | 3/5 | 3/5 | 4/5 |
| Regulatory Familiarity (1–5) | 5/5 ★ | 4/5 | 4/5 | 3/5 |
| Cost / Gram | $48.80 | $69.51 | $68.15 | $40.71 |
Higher titer alone doesn't guarantee lower cost. Both IFB and CFB actually cost more per gram than the Fed-Batch base case in this model.
That $99/g figure is Graphtal's Fed-Batch base-case anchor the cost per gram this model lands on for a conventional Fed-Batch process run at a 400 kg/yr production target, the benchmark scale used throughout this analysis so every platform is compared on equal footing. Here's how that number splits across cost categories, against Perfusion and CFB at the same 400 kg/yr scale:
| Cost Category | Fed-Batch ($/g) | Perfusion ($/g) | CFB ($/g) | Primary Driver |
|---|---|---|---|---|
| Labour & QC | 10.00 | 12.00 | 10.00 | Automation, real-time monitoring |
| Raw Materials & Media | 48.80 | 40.71 | 68.15 | Feed & media cost |
| Total COG/g | 58.80 | 52.71 | 78.15 | End-to-end integration |
Published literature backs the pattern: Partopour & Pollard (2025) report continuous processes deliver 12–23% lower total annual cost versus intensified fed-batch. Chen et al. (2025) note facility and capital costs alone can account for roughly 59% of COG in conventional fed-batch exactly where continuous processing claws back the most ground.
The winning process depends heavily on production scale and the crossover happens faster than most teams expect. All scale points below assume a single 2,000 L single-use bioreactor (SUB) train now the practical ceiling most biopharma manufacturers plan around with output scaling through batch number and cycle count rather than vessel size.
| Scale (kg/yr) | Fed-Batch | Perfusion | CFB | Recommendation |
|---|---|---|---|---|
| 50 | $210 | $134 | $165 | Fed-Batch preferred early-stage |
| 100 | $155 | $96 | $125 | Fed-Batch / consider IFB |
| 200 | $122 | $72 | $98 | IFB or CFB becoming competitive |
| 400 | $99 | $51 | $67 | Perfusion / CFB clear advantage (−48%) |
| 800 | $84 | $41 | $55 | Perfusion dominant |
| 1,200 | $78 | $37 | $50 | Continuous highest ROI within a single 2,000 L SUB train |
Graphtal tested six process levers against the $99/g Fed-Batch base case:
A single 1 g/L improvement in upstream titer has roughly 3x the leverage of any other single lever. If your team has to choose one place to invest, cell line development and upstream media optimization is where ROI compounds fastest well ahead of facility scale-up or resin selection.
Cost per gram is only part of the picture. Graphtal's readiness matrix scores each platform across six strategic dimensions (1–10), Fed-Batch → Hybrid → Continuous:
Continuous processing wins on five of six dimensions the one exception is regulatory familiarity, where Fed-Batch's decades of precedent still carry real weight. That single gap is often the real reason organizations delay a switch they already know is economically justified. Partopour & Pollard (2025) also report continuous processing delivers 54% lower CO₂ emissions and 57% less plastic waste versus intensified fed-batch.
| 1 | The best process depends on your target scale, not a universal ranking. Below ~150–200 kg/yr, Fed-Batch's simplicity wins; above it, continuous economics are hard to ignore. |
| 2 | Titer improvement is the highest-leverage investment regardless of platform it moves COG roughly 3x more than any other single parameter. |
| 3 | Regulatory familiarity, not cost, is usually the real blocker to continuous processing start that conversation before the economics do. |
Every model is only as good as its assumptions. Here's exactly what's baked into the numbers above.
| Assumption | Value Used |
|---|---|
| Reference product | Pembrolizumab (biosimilar analog) |
| Base Fed-Batch titer | 6 g/L CHO-based mAb industry average |
| CFB titer | 12 g/L concentrated cell culture approach |
| Working bioreactor volume | 2,000 L fed-batch; 1,000 L perfusion |
| Perfusion operating point | Continuous, 2.0 VVD, 1.5 g/L titer |
| DS recovery yield | 70% downstream processing (DSP) recovery |
| Batch duration | 36 days (Fed-Batch, IFB, CFB); 25-day perfusion campaign |
| Target production capacity | ~150–400 kg DS/year base case |
| Base COG anchor | $99/g at 400 kg/yr under conventional Fed-Batch |
| Facility & Capital cost model | CapEx ÷ payback period + 12% maintenance/yr; continuous ~60% lower CapEx |
| Consumables cost model | Resin cost ÷ cycles × cycles/yr + membrane replacements |
| Labour & QC cost model | FTE count × salary × 1.3 benefits multiplier |
| Raw materials & media cost model | Media volume × cost/L + supplements |
| Regulatory cost model | GMP compliance fixed + variable cost per batch |
| Basal media, feed, resin pricing | Benchmark prices vary company to company |
All figures are hypothetical and built for illustrative, strategic modelling purposes only. Key literature benchmarks referenced: Yang et al., J. Pharm. Innov. 2019;14:1–19; Chen et al., mAbs 2025;17(1):2451789; Ranbhor, Biologics 2025;19:177–187; Partopour & Pollard, Trends Biotechnol 2025;43(2):462–475.
This kind of platform comparison and cost-of-goods analysis isn't a one-off exercise for us it's part of how Graphtal supports biopharma, CDMO, and cell therapy teams end-to-end.
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