MRI in flexor tendon rupture after collagenase injection

Incidence of Tendon Rupture After Collagenase Clostridium Histolyticum Injection for Treatment of Dupuytren Contracture in Adults: A Postmarketing Safety Analysis

Purpose

Based, in part, on the clinical study reports of tendon rupture events after collagenase clostridium histolyticum (CCH) (Xiaflex, Endo Pharmaceuticals Inc) treatment for Dupuytren contracture (DC), a Risk Evaluation and Mitigation Strategy program was instituted in 2010 by Auxilium Pharmaceuticals (now Endo Pharmaceuticals Inc) to ensure that the benefits of CCH injection outweighed the risks when treating DC. Using the postmarketing surveillance data collected in this program, a retrospective analysis was conducted to evaluate the incidence of flexor tendon rupture after CCH treatment for DC in the clinical practice setting.

Methods

The Endo Pharmaceuticals Inc safety database was searched for cases of tendon rupture reported between February 2, 2010, and October 8, 2015. Total number of CCH treatments for DC and incidence of tendon rupture were estimated using CCH dosing derived from clinical trial experience (1.7 CCH vials/treatment) or clinical practice evidence (1.08 CCH vials/treatment).

Results

Over the 5.8-year surveillance period, 97,609 vials of CCH were distributed for the treatment of DC, equivalent to an estimated total of 57,416 treatments (at 1.7 CCH vials/treatment) or 90,378 treatments (at 1.08 CCH vials/treatment). Although CCH distribution increased during the surveillance period, reports of tendon rupture were infrequent (approximately 13 cases/y; total cases: flexor tendon, n = 57; ligament/pulley, n = 2), corresponding to a 0.10% (1.7 CCH vials/treatment) or 0.06% (1.08 CCH vials/treatment) mean estimated incidence of tendon rupture in patients with DC after CCH treatment.

Conclusions

This retrospective analysis showed that flexor tendon rupture occurred infrequently in patients with DC who were treated with CCH in real-world practice settings between 2010 and 2015. On the basis of these findings and other favorable safety evidence, the Risk Evaluation and Mitigation Strategy program requirement for CCH for the treatment of DC was ended by the US Food and Drug Administration in November 2016.

Type of study/level of evidence

Therapeutic IV.

Magnetic resonance imaging of diffusion characteristics following collagenase clostridium histolyticum injection in Dupuytren's contracture

PurposeWe aimed to evaluate the extent of collagenase clostridium histolyticum (CCH) diffusion in Dupuytren's contracture (DC) for tissues outside of the contracture cord using Magnetic Resonance Imaging (MRI) immediately after CCH injection. Methods: 10 male patients aged 57-79 with DC of the metacarpophalangeal (MCP) joints were examined. Extension deficits were 10-60°(mean, 34.3) and 0-60°(mean, 26.6) in the MCP and proximal interphalangeal (PIP) joints, respectively. CCH injection was performed according to the standard method. MRI was performed within 15 min of CCH injection. Results: In all 10 cases, the extended area of high-intensity signal change outside of the cord was observed on short-T1 inversion recovery images (STIRs). Continuity from the insertion site was observed in the area of signal change involving the flexor tendon and neurovascular bundle. The signal change area spanned distally and proximally beyond the injection level. The signal change area expanded along the tendon sheath but no signal changes were observed inside the flexor tendon, suggesting the tendon sheath serves as a protective barrier from the CCH solution. After 1 week of injection, the mean decrease in contracture was 32.5°(94.7%) for the MCP joint and 19.8°(74.4%) for the PIP joint. In nine out of 10 cases, the extension deficit was within five degrees of full extension in the affected finger. There was no neurovascular injury or tendon rupture at 3 months of observation. Conclusions: MRI indicated the possible leakage of the drug outside of the cord during the early phase after administration, suggesting that CCH could persistently affect healthy tissues until CCH inactivates its enzyme process.