Dicerna Pharmaceuticals: Decision Making in Clinical Trial Design and Operations Custom Case Solution & Analysis

1. Evidence Brief: Dicerna Pharmaceuticals

Financial Metrics

Cash Position: Dicerna reported approximately $303 million in cash, cash equivalents, and held-to-maturity investments as of late 2018 [Exhibit 1].
R&D Spend: Annual research and development expenses increased from $38.5 million in 2016 to $58.1 million in 2017, reflecting the transition to clinical-stage operations [Exhibit 1].
Market Opportunity: Primary Hyperoxaluria (PH) is a rare orphan disease. PH1 affects 1 in 58,000 individuals; PH2 and PH3 are even rarer, representing roughly 10% and 5% of the PH population respectively [Para 12].
Valuation Driver: The GalX platform technology is the primary source of enterprise value, with Nedosiran (DCR-PHXC) being the lead internal candidate [Para 4].

Operational Facts

Technology Platform: GalX platform utilizes RNA interference (RNAi) to silence genes in the liver. Nedosiran targets the LDHA enzyme [Para 8].
Trial Pipeline: The PHYOX program includes PHYOX1 (Phase 1 in healthy volunteers and PH patients) and the proposed PHYOX2 (pivotal trial) [Para 15].
Recruitment Constraint: Total global PH population is estimated at fewer than 5,000 patients across Western markets, making clinical trial enrollment highly competitive [Para 22].
Competitor Status: Alnylam Pharmaceuticals is approximately 12–18 months ahead with Lumasiran, which specifically targets PH1 [Para 25].

Stakeholder Positions

Douglas Fambrough (CEO): Prioritizes speed to market and the need to differentiate from Alnylam by addressing all PH types (1, 2, and 3) [Para 31].
Ralf Rosskamp (CMO): Concerned with the regulatory risks of a combined Phase 2/3 design and the statistical power required for the rarer PH2 and PH3 cohorts [Para 34].
Jim Weissman (COO): Focused on the commercial implications of being second to market and the necessity of a broad label to capture the entire PH market [Para 36].
FDA/Regulators: Have expressed openness to innovative trial designs for orphan drugs but require a primary endpoint of urinary oxalate reduction [Para 40].

Information Gaps

Comparative Efficacy: No head-to-head data exists between Nedosiran and Alnylam’s Lumasiran.
Long-term Safety: Limited data on the effects of long-term LDHA inhibition in humans.
Pricing Strategy: Exact reimbursement levels for PH therapies in European markets are not yet defined.

2. Strategic Analysis

Core Strategic Question

How should Dicerna structure the PHYOX2 pivotal trial to balance the urgency of closing the 18-month competitive gap with Alnylam against the technical risk of seeking a broad indication across PH types 1, 2, and 3?

Structural Analysis

Jobs-to-be-Done (JTBD): Patients and clinicians are not just looking for oxalate reduction; they seek the prevention of end-stage renal disease (ESRD) and the elimination of the need for combined liver-kidney transplants. Alnylam’s Lumasiran addresses PH1. Dicerna’s Nedosiran has the potential to be the only therapy for PH2 and PH3, providing a unique competitive moat in those sub-segments.

Competitive Dynamics: The rare disease market follows a winner-takes-most logic due to high switching costs and physician loyalty to the first-approved efficacious therapy. Being 18 months behind Alnylam in PH1 means Dicerna cannot win on speed alone; it must win on breadth of label or ease of administration.

Strategic Options

Option 1: The Accelerated Pan-PH Path (PHYOX2 as a Combined Phase 2/3). Include PH1, PH2, and PH3 patients in a single pivotal trial.
Rationale: Direct path to a broad label that covers the entire PH population, differentiating from Alnylam.
Trade-offs: High risk of trial failure if PH2/3 patients do not respond similarly to PH1; increased statistical complexity.

Option 2: The Sequential De-Risked Path. Conduct a dedicated Phase 2 for PH2 and PH3 while running a separate Phase 3 for PH1.
Rationale: Protects the PH1 filing by separating it from the more uncertain PH2/3 data.
Trade-offs: Extends the timeline by 12–24 months, effectively ceding the PH1 market to Alnylam.

Preliminary Recommendation

Dicerna should pursue Option 1. In orphan diseases, the scarcity of patients makes sequential trials operationally prohibitive. By including PH2 and PH3 in the pivotal PHYOX2 trial, Dicerna creates a superior clinical value proposition that Alnylam’s current candidate cannot match. The risk of being a second-place PH1-only player is greater than the risk of a complex trial design.

3. Implementation Roadmap

Critical Path

Month 1-3: Regulatory Alignment. Finalize PHYOX2 protocol with FDA and EMA, specifically focusing on the inclusion of PH2 and PH3 as a separate but integrated cohort.
Month 4-10: Global Site Activation. Prioritize nephrology centers in Europe and the US with known clusters of PH2 and PH3 patients to ensure rapid enrollment.
Month 6-18: Patient Enrollment. Execute a rolling enrollment strategy. Use initial PH1 data to maintain investor confidence while the rarer cohorts fill.
Month 24: Data Readout and NDA Submission. Target a single filing for all three PH types.

Key Constraints

Patient Scarcity: With fewer than 5,000 patients globally, the primary constraint is not capital, but the physical availability of trial participants. Every patient recruited by Alnylam is a patient unavailable to Dicerna.
Regulatory Novelty: Regulators have never approved a single drug for all three PH types simultaneously. The burden of proof for the LDHA mechanism across different genetic drivers is high.

Risk-Adjusted Implementation Strategy

To mitigate the risk of PH2/3 data dragging down the PH1 approval, Dicerna must utilize a pre-specified hierarchical testing strategy. The trial should be powered to show efficacy in PH1 independently, with PH2 and PH3 treated as supplemental indications within the same label. If the PH2/3 data is ambiguous, the company can still proceed with the PH1 filing without tainting the primary data set. This approach preserves the speed to market for the largest patient segment while maintaining the upside of the broader label.

4. Executive Review and BLUF

BLUF

Dicerna must execute the PHYOX2 trial as a combined Phase 2/3 study including PH types 1, 2, and 3. Attempting to beat Alnylam on speed in the PH1 segment is a losing proposition; Alnylam holds a 12-to-18-month lead and established clinical momentum. Dicerna’s path to leadership lies in label superiority. By targeting the LDHA enzyme, Nedosiran can treat PH2 and PH3—segments Alnylam’s Lumasiran cannot reach. This breadth justifies the operational complexity and regulatory risk. Failure to include all PH types in the pivotal trial will result in Dicerna becoming a perpetual second-best alternative in a market that rarely rewards the runner-up.

Dangerous Assumption

The analysis assumes that the LDHA inhibition mechanism will result in clinically significant urinary oxalate reduction across all three PH genotypes. While biologically plausible, PH2 and PH3 involve different metabolic pathways (GRHPR and HOGA1 mutations). If the reduction in PH2/3 is statistically inferior to PH1, the entire PHYOX2 program faces a regulatory delay that would extend Alnylam's market exclusivity indefinitely.

Unaddressed Risks

Recruitment Cannibalization (High Probability, High Consequence): Alnylam’s ongoing trials and potential early access programs may deplete the pool of PH1 patients before Dicerna can activate its global sites.
Physician Inertia (Medium Probability, Medium Consequence): If Alnylam establishes the standard of care in PH1, nephrologists may be reluctant to switch patients to Nedosiran even if the label is broader, unless Dicerna demonstrates superior ease of use or significantly lower pricing.

Unconsidered Alternative

The team has not evaluated a Geographic Sequencing Strategy. Dicerna could concede the US PH1 market to Alnylam and focus exclusively on dominating the European and emerging markets for all PH types, where Alnylam’s commercial footprint may be weaker. This would allow for a more focused clinical spend and a clearer path to becoming the primary partner for European national health systems.