- Shares of ImmuPharma plc fell more than 75% Tuesday after the U.K.-based biotech revealed its lead candidate failed a pivotal late-stage study testing it as a lupus treatment.
- Patients who received Lupuzor, including those who withdrew from the study, had a response rate of 52.5% as measured by the Systemic Lupus Erythematosus (SLE) Responder Index. The rate was higher, 61.5%, for patients who tested positive for a lupus biomarker. However, the rates weren't statistically significant due to a high response rate in the study's placebo group.
- Still, ImmuPharma has been in "ongoing discussions with a number of larger pharmaceutical companies" that have shown an interest in Lupuzor, according to an April 17 statement. The biotech intends to show this latest data to the companies, but noted that it's unclear when or how those discussions will turn out.
There's a fairly high degree of unmet medical need with lupus, a disease for which there is only one targeted therapy on the U.S. market.
Several big pharmas are looking to change that. AstraZeneca plc has one candidate, anifrolumab, in Phase 3 testing for lupus, and expects to file the drug for approval in the U.S., Europe and Japan next year. Eli Lilly & Co. is also evaluating barcitinib, its Janus kinase 1/2 inhibitor, as a treatment for the autoimmune disease.
Yet the road to approval has proven daunting. Mid- and late-stage trial busts litter the drug development landscape for lupus. ImmuPharma aside, Merck KGaA, Anthera Pharmaceuticals Inc. and newly acquired Ablynx NV have all recently chalked up clinical failures for their respective lupus treatments.
Reasons behind lupus drug failures are varied. In some cases, they appear to be problems with the patient group selected. In others, like that of ImmuPharma and Anthera, a high response rate in the placebo arm muddies the results. Research has also shown that, across the clinical setting, sponsors are still learning how to best construct trials for potential lupus therapies.
"Rather than invest in extensive and informative Phase 2 [randomized clinical trials (RCTs)], often there is rapid progression to Phase 3 or pivotal trials for regulatory approval, and typically Phase 3 RCTs have been conducted in parallel and not sequentially. Thus, the lessons learned from one RCT cannot be implemented in the second trial," researchers wrote in a study published in September in the journal Lupus.
Despite the setback, ImmuPharma maintains that the latest topline data warrant further investigation of Lupuzor in lupus. To that end, the company plans to forge ahead with a six-month, open-label extension study to the Phase 3 trial.
ImmuPharma said it will continue to evaluate the trial result and consult regulators about the next steps for Lupuzor.
The biotech's stock opened at £33.90 ($48.24) per share on Wednesday, down from the £147 ($209) per share it opened at on Tuesday.