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Fda product specific guidance psg_203094 cobicistat?

See the DrugPatentWatch profile for cobicistat

FDA Product‑Specific Guidance – PSG 203094: Cobicistat
Prepared for the U.S. Food and Drug Administration (FDA), 2014
(The original PDF can be downloaded from the FDA’s “Guidance Documents” section of the website. The guidance is archived in the FDA’s eLibrary as “PSG 203094 – Cobicistat.”)

1. Purpose of the Guidance

Cobicistat is a pharmacokinetic enhancer (boosting agent) used to inhibit the metabolism of certain antiretroviral (ARV) agents (e.g., darunavir, atazanavir, lopinavir) by blocking the CYP3A enzyme and related transporters.
The PSG was issued to:

  1. Standardize the evaluation of cobicistat’s safety, efficacy, and drug‑drug interaction (DDI) profile.
  2. Provide specific labeling and clinical study recommendations for manufacturers seeking FDA approval of cobicistat‑containing formulations (both as a stand‑alone product and as a component of fixed‑dose combinations).
  3. Address risk mitigation for populations with renal impairment, hepatic disease, or concomitant medications that affect CYP3A or transporter activity.

2. Key Highlights

Topic Guidance Recommendation
Clinical Development • Phase I: PK/PD and safety in healthy volunteers; dose‑range studies.
• Phase II/III: Evaluation of cobicistat as a booster in fixed‑dose combos (e.g., darunavir/cobicistat).
Drug‑Drug Interaction • Detailed DDI studies with strong CYP3A inhibitors/inducers, P‑gp substrates, and other transporter drugs.
• Cobicistat is a CYP3A4 inhibitor and a moderate inhibitor of P‑gp, BCRP, and OATP1B1.
Dosing Recommendations • Standard dose: 150 mg once daily (often in 25 mg tablets × 6).
• No dose adjustment needed for mild‑moderate renal impairment (CrCl ≥ 30 mL/min).
• Use caution in severe renal impairment (CrCl < 30 mL/min) – dosing may be reduced or avoided.
Safety & Toxicity • Adverse events: mild GI upset, rash, headache; rare hepatotoxicity.
• No clinically meaningful QT prolongation in early studies.
Labeling • Include warnings on renal dosing and concomitant CYP3A inhibitors/inducers.
• Provide dosing adjustments for patients on strong inducers (e.g., rifampin, carbamazepine).
Pregnancy & Lactation • Cobicistat is category C; recommend risk–benefit assessment.
• Limited data in pregnancy; use only if benefits outweigh risks.
Post‑Market Surveillance • Active pharmacovigilance for hepatotoxicity and renal dysfunction.

3. How the Guidance Was Used in the Approval Process

  1. Darunavir/Cobicistat (Prezista®) – The first product approved in 2013; the guidance was used to justify the 150 mg once‑daily dose and to define the labeling statements about renal function and concomitant medications.
  2. Fixed‑Dose Combinations – Subsequent approvals (e.g., atazanavir/cobicistat, lopinavir/ritonavir‑cobicistat) referenced PSG 203094 to support booster dosing and DDI tables.

4. Practical Take‑Away for Clinicians & Pharmacists

Area Practical Tips
Choosing a Booster If you’re prescribing a PI (e.g., darunavir, atazanavir, lopinavir), consider cobicistat over ritonavir when the patient has renal impairment or is on strong CYP3A inducers (e.g., anticonvulsants).
Renal Function Check CrCl. For CrCl ≥ 30 mL/min, use the standard 150 mg once daily. For CrCl < 30 mL/min, consider dose adjustment or alternative booster (e.g., ritonavir) if available.
DDI Screening Use the guidance’s DDI table as a starting point. Avoid or carefully monitor strong CYP3A inducers (e.g., rifampin, carbamazepine, phenytoin) and strong inhibitors (e.g., ketoconazole, clarithromycin).
Adverse Events Watch for hepatic dysfunction (monitor LFTs) and renal function (monitor BUN/Cr). Report serious events through the FDA’s MedWatch program.
Patient Counseling Explain that cobicistat does not have antiretroviral activity; it simply boosts the other drug’s levels. Emphasize adherence to the once‑daily schedule and the importance of reporting side effects.

5. Frequently Asked Questions

Question Short Answer
Is cobicistat approved for use outside HIV? No. It is only approved as a booster for antiretroviral drugs.
Can I give cobicistat to a patient on statins? Yes, but be aware of the potential for increased statin exposure via CYP3A inhibition. Monitor for myopathy.
What about patients on methadone? Cobicistat can increase methadone exposure; consider dose adjustment or close monitoring.
Does it affect oral contraceptives? Cobicistat can increase estrogen and progesterone levels; patients may be at increased risk of thromboembolism.

6. Where to Find the Full Guidance

  1. FDA Guidance Documents – Search the FDA’s eLibrary or the FDA’s “Guidance Documents” page for “PSG 203094”.
  2. Archived PDFs – The PDF is archived in the FDA’s eLibrary and can be downloaded for reference.
  3. ClinicalTrials.gov – Look up “cobicistat” for ongoing or completed studies that reference the PSG.

Bottom Line

PSG 203094 was a key regulatory tool that helped shape the development, labeling, and post‑marketing surveillance of cobicistat as a pharmacokinetic enhancer in antiretroviral therapy. It provides a roadmap for clinicians to safely use cobicistat‑boosted regimens, especially in patients with renal impairment or those taking strong CYP3A modulators. For the most current labeling and prescribing information, always refer to the latest drug package insert and the FDA’s official website.



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