Article Figures & Data
Figures
- Fig. 1.
MAP following a single subcutaneous administration of either vehicle, CNP-38 (800 µg CNP/kg), or TransCon CNP (800 µg CNP/kg) to mice. Footnote: MAP recorded up to 48 hours postdose. Means (±S.E.M.). *Significant difference from vehicle P < 0.05. **Significant difference from vehicle P < 0.01. William’s test comparing treatment groups with vehicle control at each time point.
- Fig. 2.
SAP following a single subcutaneous administration of TransCon CNP and daily CNP-39 molecule to cynomolgus monkeys compared with vehicle control. Footnote: SAP recorded up to 48 hours postdose. (A) Means. (B) Baseline-adjusted means (±S.E.M.).
- Fig. 3.
Growth from baseline of body, tail, tibia, and ulna following weekly administration of TransCon CNP to monkeys (n = 4/group) compared with the daily CNP-39 molecule (positive control) and vehicle treatment (negative control); (A) for duration of study (26 weeks), and (B) comparing relative change from baseline (±95% CI) at week 26. Footnote: Estimates and test are derived from an analysis of covariance model, including treatment as a fixed effect and baseline value as a covariate. *Significant difference in absolute growth from negative control, P < 0.05. Neg.Ctrl, negative control; Pos.Ctrl, positive control.
- Fig. 4.
Histomorphometry imaging of the proximal tibial physis following weekly administration of (A) vehicle control compared with (B) TransCon CNP (100 µg CNP/kg per week) for 26 weeks to monkeys. Footnote: PZ, proliferative zone; HZ, hypertrophic zone; PZi, increased cellularity and width of proliferative zone; HZi, increased cellularity and width of hypertrophic zone.
Tables
CNP-38 Conjugate (Linker Type, Linker Attachment Site) Description 5-kDa PEG-linker CNP-38 (permanent, Lys26) Linear 5-kDa PEG carrier conjugated to the Lys26 side chain of CNP-38 via a permanent linker 5-kDa PEG-linker CNP-38 (permanent, N-terminus) Linear 5-kDa PEG carrier conjugated to the N-terminus of CNP-38 via a permanent linker 4 × 10-kDa PEG-linker CNP-38 (permanent, Lys26) 4-Arm–branched 4 × 10-kDa PEG carrier conjugated to the Lys26 side chain of CNP-38 via a permanent linkera 2 × 20-kDa PEG-linker CNP-38 (transient, Lys26) 2-Arm–branched 2 × 20-kDa PEG carrier conjugated to the Lys26 side chain of CNP-38 via a TransCon linkera 4 × 10-kDa PEG-linker CNP-38 (transient, Lys26), TransCon CNP 4-Arm–branched 4 × 10-kDa PEG carrier conjugated to the Lys26 side chain of CNP-38 via a TransCon linkera Cb(10-kDa PEG-linker CNP-38)4 (permanent, Lys26) Four CNP-38 molecules conjugated to a 4-arm–branched 4 × 10-kDa PEG; one CNP-38 is attached via its Lys26 side chain and via a permanent linker to the distal end of each of the four PEG arms Evaluation Ulna Growth Plate Evaluation Radius Metaphysis Evaluation Radius Diaphysis Sigma 0.8 0.8 0.8 Support 1 1 1 Lower threshold 95 150 (total/cortical) and 110 (trabecular) 150 Upper threshold 1000 1000 1000 CNP-38 Conjugate NEP Resistance Activitya NPR-C Affinityb,c (Linker Type, Attachment Site) Half-Life [h] [%] [%] CNP-38 12.6 ± 3.9d 100 100 5-kDa PEG-linker CNP-38 (permanent, N-terminus) Stablee 14 199 ± 12 5-kDa PEG-linker CNP-38 (permanent, Lys26) 65.4 <1f 83 ± 7 2 × 20-kDa PEG-linker CNP-38g (transient, Lys26) NDh <1f 11 ± 4 4 × 10-kDa PEG-linker CNP-38i (permanent, Lys26) Stablee <1f <2f 4 × 10-kDa PEG-linker CNP-38i (transient, Lys26), TransCon CNP ND <1f <1f,j C(10-kDa PEG-linker CNP-38)4k (permanent, Lys26) ND ND 68 ± 11 ↵a Activity to elicit intracellular cGMP response in a NIH3T3 cell assay, relative to CNP-38.
↵b n = 2 to 3.
↵c Ratio IC50 CNP-38/IC50 CNP-38 conjugate.
↵d n = 4.
↵e Almost no degradation after 96 h.
↵f Limitation due to assay range.
↵g Branched 40-kDa PEG carrier having the CNP attachment site near the branching site of two 20-kDa arms.
↵h ND, not determined.
↵i Branched 40-kDa PEG carrier having the CNP attachment site near the branching site of four 10-kDa arms.
↵j Calculated from a 25× concentrated sample.
↵k Branched 4 × 10-kDa PEG carrier having a total of four CNPs attached. The CNP attachment site is not close to the branching site of the four 10-kDa arms, but at the distal end of each of the arms.
- TABLE 4
Mean pharmacokinetic parameters of CNP (after first dose) released from TransCon CNP following administration of TransCon CNP compared with the daily CNP-39 molecule in monkeys
Group Dose (µg CNP/kg) Tmaxa (h) Cmax (pmol/l) AUC(0-t) (h × pmol/l) T1/2 (h) Daily CNP-39 molecule 20/day 0.25 3850 2560 0.35 TransCon CNP 40/wk 48 16.5 1748 92.6 TransCon CNP 100/wk 24 39.4 4186 86.7 AUC, area under the curve; T1/2, half-life; Tmax, time to maximum plasma concentration.
↵a Median Tmax is presented.
- TABLE 5
Bone length [millimeters [95% confidence interval] (% change from control)] determined by X-ray after 5 wk of daily bolus injection or continuous infusion of CNP-38 or vehicle control in FVB mice
Subcutaneous Bolus Injection Subcutaneous Continuous Infusion Measurement Vehicle Control CNP-38 203 µg/kg Per Day Vehicle Control CNP-38 203 µg/kg Per Day Femur lengtha 14.2 [13.7; 14.8] 15.0 [14.5; 15.6] (5.5%)* 13.6 [13.0; 14.1] 14.6 [14.1; 15.2] (7.1%)* Tibia lengthb 17.9 [17.7; 18.1] 18.7 [18.5; 18.9] (4.0%)* 17.6 [17.4; 17.8] 19.8 [19.6; 20.0] (12.2%)*,# Spine lengthc 53.8 [52.4; 55.2] 59.8 [58.5; 61.2] (11.3%)* 53.6 [52.2; 55.0] 67.0 [65.6; 68.4] (25.0%)*,# - TABLE 6
Percent increase in bone formation markers BAP and PINP following weekly TransCon CNP or daily CNP-39 molecule administration for 26 wk to cynomolgus monkeys
TransCon CNP 40 µg CNP/kg Per Week TransCon CNP 100 µg CNP/kg Per Week Daily CNP-39 Molecule 20 µg/kg Per Day No. animals per group 4 4 4 BAP — 14a 51a PINP — 53a 144a ↵a Significantly different from control group; P < 0.05, based on statistical analysis of group means.
- TABLE 7
Estimated relative effects of CNP treatment on growth of body, tail, tibia, and ulna (relative increase in growth compared with vehicle treatment [% (95% confidence interval) in monkeys]
TransCon CNP 40 µg CNP/kg Per Week TransCon CNP 100 µg CNP/kg Per Week Daily CNP-39 Molecule 20 µg CNP/kg Per Day Body 1.0 (−2.3; 4.4) 4.8 (1.1; 8.5)* 3.3 (0.0; 6.6)* Tail 1.4 (−2.7; 5.5) 8.6 (3.7; 13.4)* 2.8 (−1.3; 6.9) Tibia 1.7 (−2.0; 5.4) 6.0 (2.1; 9.9)* 2.9 (−1.0; 6.8) Ulna 0.9 (−2.8; 4.7) 2.7 (−1.1; 6.5) 0.8 (−2.9; 4.5) ↵* P < 0.05.
- TABLE 8
Summary of XtremeCT values (mean ± S.D.) as percentage change from acclimation period (n = 4) after weekly subcutaneous administration of TransCon CNP or daily CNP-39 molecule for 26 wk
Treatment Control Daily CNP-39 Molecule TransCon CNP CNP Dose Vehicle 20 µg/kg Per Day 40 µg/kg Per Week 100 µg/kg Per Week Right Radius, Distal Metaphysis—Trabecular Region Trabecular region vBMD mg HA/cm3 19.8 ± 10.3 18.2 ± 14.9 27.0 ± 17.9 16.5 ± 10.7 Trabecular tissue BMD mg HA/cm3 −0.27 ± 2.1 0.45 ± 1.8 −0.12 ± 1.1 1.7 ± 0.83 Trabecular BV/TV % 18.2 ± 8.2 18.7 ± 15.0 29.9 ± 19.2 18.2 ± 12.4 Trabecular number 1/mm 13.2 ± 11.6 5.8 ± 6.0 12.9 ± 8.8 8.9 ± 5.3 Trabecular thickness mm 4.6 ± 3.7 8.9 ± 6.7 16.2 ± 14.5 14.0 ± 11.8 Trabecular separation mm −14.6 ± 8.4 −5.9 ± 7.0 −12.0 ± 9.0 −10.5 ± 5.0 Right Radius, Distal Metaphysis—Cortical Region Cortical region vBMD mg HA/cm3 −5.2 ± 1.2 −7.0 ± 2.2 −8.7 ± 2.9 −2.7 ± 2.3 Cortical tissue BMD mg HA/cm3 −3.8 ± 1.4 −5.9 ± 1.6 −5.9 ± 1.2 −2.4 ± 1.8 Cortical thickness mm −3.6 ± 16.0 −9.4 ± 11.2 −16.7 ± 11.5 4.5 ± 10.7 Right Radius, Distal Diaphysis—Cortical Region Cortical region vBMD mg HA/cm3 −1.8 ± 1.6 −3.3 ± 1.6 −7.8 ± 9.8 −2.4 ± 2.3 Cortical tissue BMD mg HA/cm3 −4.8 ± 1.9 −6.7 ± 1.4 −6.3 ± 3.6 −3.7 ± 1.6 Cortical thickness Mm 7.0 ± 3.0 8.2 ± 5.0 1.1 ± 8.4 8.9 ± 4.7 BMD, bone mineral density; BV, bone volume; TV, tissue volume.
- TABLE 9
Histomorphometry data of the proximal tibial growth plate following weekly administration of TransCon CNP compared with the daily CNP-39 molecule for 26 wk to monkeys (% change from vehicle control)
Treatment TransCon CNP 40 µg CNP/kg Per Week TransCon CNP 100 µg CNP/kg Per Week Daily CNP-39 Molecule 20 µg/kg Per Day No. animals per group 4 4 4 Bone, tibia (no. measured) 4 4 4 Proliferative zone width −2 37a 16a Hypertrophic zone width 7 38a 39a Epiphyseal plate thickness −4 16a 7 ↵a Significantly different from control group; P ≤ 0.05, based on statistical analysis of group means.
