aHUS Rare Disease Day 2018 Cohort – Report 2

In the first report on the aHUS Rare Diseases Day 2018 Cohort, ( click here) it was found that the participants in the video were younger than normal , with a higher than expected level of child patients, although the gender mix was not untypical for aHUS patients , with a higher proportion  of female patients.

In a rare survey of precipitating triggers viral and bacterial infections were the predominant factors; but quite a number of other triggers were also reported to demonstrate how wide ranging the “hits” can be.  A high proportion of the cohort reported no preceding illness , which is an aHUS “enigma”.

In the second report the focus will be on predisposing genetic factors , aHUS treatments and experience of renal replacement therapy.

Firstly a remarkable number of the cohort have had genetic tests for significant variants (mutations) undertaken. Nearly 95% of them have had tests done, although 4 were still awaiting results. This is very encouraging, as the more patients that are tested the safer the diagnosis ,and ,  even where no mutations are found, the better the prognosis and management of the disease , including transplant and withdrawal from eculizumab decisions.

Tested Not tested  Total
97 6 103
94.5% 5.5% 100%

Of those receiving the results of tests ( n=93)  for 40% of the cohort no evidence of a mutation was found, which is about the level to be expected. FH was the Complement component in which most mutations were found , (29%), as would be the case generally, followed by MCP/CD46 and C3. A lower number of patients with Anti Factor H Auto-antibodies than usual were reported.

Mutation  No %
None 38 40
FH 26 29
MCP/CD46 6 6
C3 6 6
Multi 7 8
Thrombomodulin 3 4
CHFR deletions 2 2
AFHA 2 2
others * 3 3
Total 93 100

* One each of FB, FI, DGKE

85 of the cohort have had eculizumab prescribed; and of these 74 remain on eculizumab treatment. 12 of the 74  patients are receiving infusions at intervals other than every 14 days ( Ecu/14), which by far the most are prescribed.

 

Current Treatment No. %
Ecu 2 2
Ecu/10 3 3
Ecu/14 62 61
Ecu/21 5 5
Ecu/28 2 2
Ecu/stop 11 10
Immunosuppressants 2 2
Plasma Exchange 5 5
No treatment 10 10
Total 102 100

About a third of the cohort did not need renal replacement therapy at all following aHUS onset. A remarkable number to have escaped the burden of dialysis treatment and something we all wish to see more of. 40% only needed dialysis for a short time when in acute renal failure.  The remaining 25% of patients  have experienced chronic dialysis ,which, prior to eculizumab, many more would have faced. Just under half of those who have needed chronic dialysis have had a transplant. So it leaves 1 in 8 of the cohort still waiting for a kidney transplant; and doing so while still having to cope with the burden of dialysis.

Dialysis No %
Acute 42 40
Chronic 13 12
Chronic + Transplant 16 16
None needed 32 32
Total 103 100

Typical HUS has marked peaks of incidence in the summer months when BBQs are prevalent. The dates of onset provided by the cohort  suggest that aHUS, although there is some increase in the Summer season, is quite evenly distributed over the seasons.

 

Season No. %
Spring 22 23
Summer 27 28
Autumn 25 26
Winter 22 23
Total 96 100

The year of first onset for patients in this cohort is predominantly since 2009, when eculizumab first became available on trial and then on prescription. Only 1 in 6 patients participating, onset before 2009.

Onset No %
2008 or earlier 17  16.5
2009 or later 85 83.5
Total 102 100

 

The above analysis concludes the high level look at the aHUS Rare Disease Day 2018 Cohort. The alliance will continue to study the results for any other insights that the cohort might give, and further reports may yet appear.