Rallybio Corp
RLYB evidence brief
What we can confirm
- BioSniper Score:
- 7.7 / 10
- Market Cap:
- $89.6M
- Lead Asset:
- rlyb114 (Phase 1)
What it means
What to watch
Prepared research question
What matters most for RLYB—catalysts, financial risk and supporting evidence?
Traceable citations · Unknowns marked
BioSniper AI · RLYB
Rallybio Corp is a clinical-stage biotechnology company developing antibody-based therapies for complement dysregulation and iron overload, with a lead program in Phase 1 and a preclinical candidate for iron overload.
Key risk: Lead program early stage
BioSniper Score
Based on 3 of 6 signals
Limited data coverage
Market Cap
$89.6M
Cash Runway
—
Lead Asset
rlyb114 (Phase 1)
Next Catalyst
—
Tracking 4 pipeline candidates · 3 clinical trials for Rallybio Corp.
Rallybio Corp is a clinical-stage biotechnology company developing antibody-based therapies for complement dysregulation and iron overload, with a lead program in Phase 1 and a preclinical candidate for iron overload.
- Lead program RLYB116, a once-weekly subcutaneous C5 inhibitor, is in Phase 1 development for complement dysregulation [pipeline].
- Preclinical candidate RLYB332 (long-acting MTP-2 antibody) is being developed for iron overload diseases [sec_mda · as of 2026-08-06].
- In April 2025, the RLYB212 program for FNAIT was discontinued due to insufficient PK data from Phase 2 [sec_mda · as of 2026-08-06].
- In Q3 2025, Rallybio received $20.0 million from the sale of its ENPP1 inhibitor program (REV102) to Recursion, with potential for additional milestones and royalties [sec_mda · as of 2026-05-13].
- A planned merger with Candid Therapeutics was terminated in May 2026, resulting in a $50 million termination fee paid to Rallybio [sec_mda · as of 2026-05-13].
What works
- Rallybio has a novel preclinical candidate, RLYB332, which demonstrated favorable tolerability and sustained PD effects in non-clinical studies, supporting its potential as a best-in-class therapy for iron overload [sec_mda · as of 2026-08-06].
- The company generated $20.0 million in Q3 2025 from the sale of its ENPP1 program, with additional milestone payments and royalties possible [sec_mda · as of 2026-05-13].
- Rallybio received a $50 million termination fee in May 2026 after the Candid merger was terminated, providing a significant cash infusion [sec_mda · as of 2026-05-13].
What to weigh
- The RLYB212 program for FNAIT was discontinued in April 2025 after Phase 2 PK data showed the dose regimen could not achieve target concentrations, highlighting a major clinical setback [sec_mda · as of 2026-08-06].
- The company's lead program, RLYB116, is still in Phase 1, with no disclosed efficacy data, and faces competition from established C5 inhibitors like Soliris and Ultomiris [pipeline].
- The termination of the Candid merger in May 2026 introduces uncertainty about Rallybio's strategic direction and future partnerships [sec_mda · as of 2026-05-13].
From the filings
Quoted directly from source documents.
RLYB212 program discontinued due to inability to achieve target concentrations
“In April 2025, we announced the discontinuation of our RLYB212 program for the prevention of fetal and neonatal alloimmune thrombocytopenia ("FNAIT") based on PK data from the Phase 2 clinical trial that demonstrated an inability of the RLYB212 dose regimen to achieve predicted target concentrations, as well as the minimum target concentration required for efficacy.”
SEC MD&A · August 6, 2026
RLYB332 preclinical data supports continued development
“These findings, which were presented in a poster at the 66th annual meeting of the American Society of Hematology, support the continued development of RLYB332 as a potentially best-in-class therapeutic for treating diseases of iron overload.”
SEC MD&A · August 6, 2026
ENPP1 program sale generated $20 million in Q3 2025
“In the third quarter of 2025, we received a total of $20.0 million in connection with the JV Sale, including $7.5 million from an upfront payment and $12.5 million from a milestone payment related to the initiation of additional preclinical studies.”
SEC MD&A · May 13, 2026
Candid merger terminated, $50 million fee paid
“On May 3, 2026, Candid terminated the Merger Agreement concurrently with entering into a Permitted Alternative Agreement (as defined in the Merger Agreement) with UCB S.A. ("UCB"). As a result of the termination of the Merger Agreement, we were paid on May 4, 2026 a $50”
SEC MD&A · May 13, 2026
Catalyst timeline
- 2024-11-21 · Phase 2 start for RLYB212 (discontinued) — A Phase 2 study to evaluate RLYB212 in pregnant women at risk for HPA-1a alloimmunization was initiated but later discontinued.
- 2025-04-14 · Phase 1 start for RLYB116 — A multiple-dose study to evaluate safety, tolerability, PK, and PD of RLYB116 in healthy participants was initiated.
Risks & what to watch (3)›
Key risks
- Lead program early stage — RLYB116 is only in Phase 1; no efficacy data yet, and faces strong competition from approved C5 inhibitors [pipeline].
- Recent program failure — RLYB212 discontinued in April 2025 due to PK issues, raising questions about pipeline execution [sec_mda · as of 2026-08-06].
- Merger termination uncertainty — Candid merger terminated May 2026; strategic direction and future partnerships unclear [sec_mda · as of 2026-05-13].
What to watch
- Initiation of Phase 1 dosing for RLYB116, which could trigger a $5.0 million milestone from the ENPP1 sale [sec_mda · as of 2026-05-13].
- Any new partnership or strategic pivot following the Candid merger termination [sec_mda · as of 2026-05-13].
- Progress of RLYB332 toward clinical trials, given its preclinical promise [sec_mda · as of 2026-08-06].
Sources: Catalysts · Pipeline · SEC MD&A · Generated October 7, 2026 · How we verify sources →
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Evidence & data
Score breakdownBased on 3 of 6 signals · derived from public data
Cash runway data unavailable
Financial health data unavailable
Lead: Phase 2
4 candidates
No upcoming catalysts tracked
14 buys · 0 sells (180d)
Pipeline
Regulatory
Financials
Institutional Holdings
Source: SEC Form 13F · as of Mar 2026Institutional holders
38
Total value held
$41.8M
| Holder | Shares | Value |
|---|---|---|
| fmr llc | 793,451 | $7.1M |
| viking global investors lp | 524,347 | $4.7M |
| cormorant asset management, lp | 400,000 | $3.6M |
| tpg gp a, llc | 378,551 | $3.4M |
| balyasny asset management l.p. | 376,573 | $3.4M |
| laurion capital management lp | 302,756 | $2.7M |
| nantahala capital management, llc | 300,635 | $2.7M |
| pivotal bioventure partners investment advisor llc | 300,579 | $2.7M |
| 5am venture management, llc | 291,788 | $2.6M |
| almitas capital llc | 191,206 | $1.7M |
Showing top 10 of 38 institutional holders of Rallybio Corp. Open the full 13F history after sign-in.
Short Interest
as of May 22, 2026- % of float
- 35.8%
- Days to cover
- 23.9
- Shares short
- 1,572,902
- Daily short volume
- -
Short percent of float and days-to-cover reflect reported short positioning. Daily short volume is the exchange-reported short share of a single day's trading volume and is noisier. See the most-shorted biotech ranking →
RLYB short interestGovernance
Frequently asked questions
What is the AI investment thesis for Rallybio Corp?
Rallybio Corp is a clinical-stage biotechnology company developing antibody-based therapies for complement dysregulation and iron overload, with a lead program in Phase 1 and a preclinical candidate for iron overload.
What is Rallybio Corp's lead drug candidate?
Rallybio Corp's most advanced tracked candidate is rlyb114 (Phase 1) for Complement-mediated ophthalmic diseases.
Who is the CEO of Rallybio Corp?
Dr. Stephen Uden M.D., MBBS is the chief executive officer of Rallybio Corp (RLYB).
Where is Rallybio Corp headquartered?
Rallybio Corp (RLYB) is headquartered in New Haven, CT, United States.
What therapeutic areas does Rallybio Corp focus on?
Rallybio Corp develops therapies across Oncology, Rare Disease, Immunology, Ophthalmology, Hematology.
The AI overview and BioSniper Score are neutral, data-derived signals built from public SEC filings, ClinicalTrials.gov and FDA records — not investment advice.