Enrollment is complete in the global Phase III ReSPECT study testing once‑weekly rezafungin for prophylaxis of Candida, Aspergillus, and Pneumocystis infection in adults undergoing allogeneic blood and marrow transplant. The randomized, double‑blind trial pits a 400 mg loading dose followed by 200 mg weekly for 13 weeks against a standard antimicrobial regimen, with fungal‑free survival at day 90 as the primary endpoint and secondary measures that include incidence of invasive fungal disease, discontinuation due to toxicity, and comorbidity‑adjusted mortality. Topline data are slated for 2Q 2026.
The core development is a milestone in a cross‑company arrangement: Mundipharma is sponsoring the trial globally, while CorMedix now holds U.S. commercial rights to REZZAYO through its August 2025 acquisition of Melinta Therapeutics. REZZAYO is already approved in the U.S. for candidemia and invasive candidiasis in adults. A positive ReSPECT readout would support a supplemental U.S. filing to expand into prophylaxis for allo‑BMT—a materially larger use case than salvage treatment. CorMedix has pointed to an addressable U.S. prophylaxis population of roughly 130,000 patients and an implied market opportunity of over $2 billion, with orphan exclusivity through 2035 and patents through 2038.
Strategically, this is an expansion play that leans on rezafungin’s weekly IV profile and the operational friction around azole‑based prophylaxis. Transplant centers grapple with drug‑drug interactions, hepatic toxicity, and therapeutic drug monitoring when using triazoles; an echinocandin that can hold ground on breakthrough mold and PCP events could reset protocols. The risk is obvious: echinocandins have historically been stronger against Candida than molds, and Pneumocystis prevention in this setting has been dominated by TMP‑SMX or alternatives. The study’s design—rezafungin monotherapy versus a multi‑component standard regimen with oral placebos—will test whether weekly dosing can offset spectrum concerns in a population with variable immunosuppression, GVHD, and steroid exposure. Regulatory tolerance for composite endpoints in prophylaxis is well established, but the bar on Aspergillus and Pneumocystis breakthrough rates will drive both labeling and adoption.
For sites and CROs, the operational signal is mixed. Weekly infusions are straightforward for transplant programs accustomed to frequent visits and central line access, and a single‑agent regimen simplifies adherence and monitoring. At the same time, replacing oral azoles with an IV echinocandin shifts cost and capacity to infusion suites and pharmacy compounding, with implications for scheduling and inpatient‑outpatient transitions. Vendors focused on safety adjudication, microbiology confirmation, and endpoint surveillance will watch how the study manages event attribution—particularly distinguishing colonization from invasive disease in a blinded setting. Payers and P&T committees will weigh any reduction in hepatic events or drug interactions against infusion resource utilization and acquisition cost.
The next catalyst is the day‑90 composite readout and its components by pathogen, along with subgroup analyses in patients with GVHD, high‑dose steroids, and varying conditioning regimens. Signals that matter for regulators and guideline bodies include mold and Pneumocystis breakthrough incidence, reasons for discontinuation, and mortality differences through day 180. If efficacy is balanced with lower discontinuations and fewer drug‑interaction complications, expect rapid health‑system evaluations and azole‑sparing protocols at high‑volume centers. If Aspergillus or Pneumocystis events are elevated, the label and uptake path narrow. Also watch the mechanics of a U.S. sNDA filed by the commercial rights holder off a Mundipharma‑run dataset, CMC scale‑up for a prophylaxis population, and whether European regulators engage in parallel. ReSPECT will clarify whether weekly echinocandin prophylaxis can displace entrenched azoles in allo‑BMT or remain a niche alternative.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
