Advancing Factor D Inhibition into Late-Stage Clinical Development

At Achillion, we are focused on advancing our clinical-stage portfolio of small molecule, orally administered factor D inhibitors into late-stage development and potential commercialization for patients with devastating rare disorders mediated by the complement alternative pathway (AP). Our first-generation, oral factor D inhibitor, danicopan (ACH-4471), has demonstrated initial proof-of-concept in paroxysmal nocturnal hemoglobinuria (PNH) and proof-of-mechanism in C3 glomerulopathy (C3G), with development expanded into global, Phase 2 clinical programs. In addition to danicopan, we have advanced next-generation, oral factor D inhibitors from our proprietary complement platform into clinical Phase 1 studies in healthy volunteers. For more information on the ongoing, global Phase 2 clinical programs for danicopan, please visit Patient and Clinicians.

Danicopan (ACH-4471)

Danicopan is an investigational, oral, factor D inhibitor that has demonstrated initial proof-of-concept in two rare diseases mediated by the complement alternative pathway – paroxysmal nocturnal hemoglobinuria (PNH) and C3 glomerulopathy (C3G). Danicopan has been granted orphan drug designation for the treatment of each condition in both the United States and European Union.

Danicopan is being assessed as a potential treatment for patients with PNH in an ongoing global, Phase 2 clinical program. The orally, administered factor D inhibitor is being studied in both treatment-naïve patients and in combination in patients treated with, but sub-optimally responding to, eculizumab.

Danicopan is also being evaluated in an ongoing global, Phase 2 clinical program as a potential treatment for patients with C3G, including patients with dense deposit disease (DDD) and C3 glomerulonephritis (C3GN). The ongoing clinical program includes a six-month blinded, placebo-controlled study, and a 12-month open label study.

For more information on the ongoing, global Phase 2 clinical programs for danicopan, please visit Patient and Clinicians.


In July 2019, Achillion announced topline results from the randomized Phase 1 multiple ascending dose (MAD) study with ACH-5228, our second-generation oral factor D inhibitor. Results from the study demonstrated that ACH-5228, when dosed at 120 mg twice a day (BID) or higher, achieved near complete and sustained AP inhibition with a mean value of >95% at steady state concentrations as measured by AP Hemolysis and AP Wieslab assays. We plan to submit an investigational new drug (IND) application to the U.S. FDA in the fourth quarter of 2019.


Achillion is developing third generation, oral factor D inhibitors which we believe will provide additional optionality and durability for our factor D development program. We plan to nominate one of the third-generation factor D inhibitors for clinical development in 2020.

Complement Factor D Platform

Achillion has leveraged its internal discovery capabilities and a novel complement-related platform to develop small molecule drug candidates that are inhibitors of complement factor D. Achillion has generated over 3,000 small-molecule compounds and a substantial subset of them are potent and specific inhibitors of complement factor D, with physicochemical properties suitable for various routes of administration. We have advanced oral, factor D inhibitors including danicopan and ACH-5228 into the clinic and are continuing preclinical development efforts for third-generation compounds. Each of the product candidates in our oral factor D portfolio were discovered in Achillion laboratories and are wholly owned.

Danicopan and ACH-5228 are investigational compounds. Their safety and efficacy have not been established.