4 Committee discussion
4.1 Having noted the external assessment centre's (EAC) comments on the limited evidence, the committee concluded that there was sufficient evidence to partially support the claimed patient benefits of Memokath‑051 compared with double‑J stents. It considered, however, that the claimed patient benefits compared with other metallic stents were not fully substantiated by the limited evidence available. The clinical experts commented that although the level of evidence was disappointing for a technology that has been commercially available for over 15 years, possible explanations include both the relatively rare circumstances under which Memokath‑051 is used and the technically demanding nature of its insertion.
4.2 The clinical experts explained that double‑J stents are the most commonly used stent for ureteric obstruction. They stated that the primary objective for patients who present with acute ureteric obstruction is to stabilise the patient by relieving the obstruction and treating any infection present. This is usually done by first creating a nephrostomy or inserting a double‑J stent (or sometimes both). Once the patient is stable, a decision can be made about longer-term management. Options that are routinely considered include reconstructive surgery or inserting a metallic stent (such as Memokath‑051). Important factors that influence this decision include the nature of the underlying disease process (benign or malignant) and the patient prognosis. The clinical experts emphasised the need for careful patient selection for Memokath‑051, and the importance of the stent being inserted by specialists with sufficient expertise and experience of the different technologies and procedures.
4.3 The clinical experts explained that there is a heterogeneous group of benign conditions that may present with ureteric obstruction, for which reconstructive surgery is considered the standard of care. However, they advised that surgery may be unsuitable for some patients because of procedural risk or other co-morbidities, and that some patients may decline surgery. In these circumstances, inserting a metallic stent (such as Memokath‑051) may be a reasonable alternative. The committee heard that Memokath‑051 stents should not be used in patients with bladder stones because of an increased risk of stent encrustation, or in patients with pelvi-ureteric junction obstruction because of an increased risk of stent migration. One expert provided anecdotal evidence that they had successfully used Memokath‑051 stents in patients with vascular ureteral strictures. The committee concluded that Memokath‑051 should only be considered as a treatment option in patients with benign ureteric obstruction who cannot have or do not want reconstructive surgery.
4.4 Some ureteric obstructions result from malignancy; treatments for such malignancies may result in medium- or even sometimes long-term survival. The clinical experts explained that in these cases, the life expectancy of the patient is often the most important factor in determining how long stent treatment will be needed. The committee recalled that the evidence suggests that using Memokath‑051 reduces the need for stent replacements compared with double‑J stents, so that its use may be of particular value in patients with malignant ureteric obstruction with medium- or long-term life expectancy after adjunctive treatment. The committee also concluded that Memokath‑051 may be a useful option for people who cannot have a double‑J stent, or for people for whom repeat procedures are a particularly high risk.
4.5 The committee concluded from the published evidence and expert advice that Memokath‑051 is usually well tolerated, and associated with fewer adverse symptoms than double‑J stents.
4.6 Stent migration is the most common complication with Memokath‑051. The clinical experts explained that this may be for several reasons, including: physical changes in the ureter after inserting the stent, stents placed too close to the pelvi-ureteric junction, or the use of a stent that is too long. They suggested that migration rates may be reduced with Memokath‑051 through choosing the right stent and its being inserted only by trained and experienced clinicians.
4.7 Given the limited evidence available, the committee concluded that it would be beneficial for clinicians to routinely collect clinical and procedural outcome data on the use of ureteric stents including Memokath‑051. The committee proposed that data should ideally be collected in collaboration with a national professional society such as the British Association of Urological Surgeons.
4.8 The committee considered that the decision to use Memokath‑051 should only be made by a multidisciplinary team that includes endo-urologists, interventional radiologists and, if possible, reconstructive surgeons.
4.9 The clinical experts explained that clinicians' training and experience of inserting stents were important factors in determining success when using Memokath‑051. They stated that there are important technical challenges and decisions, such as ensuring that the correct stent size is used, ensuring that the ureter is properly dilated, and ensuring the best stent placement possible. The company confirmed that it includes the availability of training, workshops and proctorships in the acquisition cost of Memokath‑051. The clinical experts confirmed that the company's training had been helpful, but they felt that there was a need to further formalise this training process (such as defining the number of stents inserted before achieving competency).
4.10 The committee considered that any cost savings were uncertain because of the lack of good quality supportive evidence, the heterogeneous patient group and the complicated care pathway. It considered the EAC's revised cost model to provide more realistic results than the company's model. The clinical experts explained that double‑J stents may sometimes need to be replaced after only a few weeks, but the model assumed double‑J stent replacement at 6 months. Consequently, the estimated cost savings from using Memokath‑051 compared with double‑J stents may be conservative.