Johnson & Johnson is strengthening its stance against FDA's proposed maximum for sun protection factors on sunscreen products with a new study refuting the notion that high SPF formulas cannot be accurately and consistently measured.

“When using the same protocol and the same internal SPF reference, different labs can conduct the test for the same formulation and generate comparable SPF values to the level of SPF 90,” says study author Joseph Stanfield, Suncare Research Labs, LLC.

The study, which also involved researchers from J&J and its Neutrogena division, was published Jan. 4 in the online version of the journal Photodermatology, Photoimmunology & Photomedicine.

"The SPF testing procedure demonstrates directly that twice the UV exposure is needed for an SPF 90 versus an SPF 45 to cause the same erythema response in skin, indicating that a person in real life in sunlight [can] be exposed for twice the time (or effective UV dose) before sunburn appears," investigators say.

The team's findings come in response to concerns FDA expressed in its proposed final monograph for over-the-counter sunscreen drug products, released in August 2007.

In that document, FDA hoisted its proposed cap for SPF values appearing on product labels from 30 – the ceiling proposed in its 1999 version of the final rule – to 50+ ("Selected Proposed Changes To OTC Sunscreen Monograph," "The Rose Sheet" Aug. 27, 2007).

In explaining the 50+ maximum, FDA said it had not received data demonstrating that SPF testing produces accurate results for products with SPF values greater than 50. The agency added that it was inclined to believe that "increasing variability in test results is likely with increasing SPF values" and therefore was "concerned that variability will become an issue" for products with lofty SPFs.

FDA said it would revisit the issue of an SPF ceiling upon receipt of “adequate, validated data ... demonstrating that accurate and reproducible results can be obtained from the SPF test for sunscreen products with SPF values over 50."

The newly published study purports to supply that data.

Methods Meet FDA Criteria

FDA had recommended that “any future study to address clinical determination of SPF higher than 50 should be conducted at multiple laboratories for the same sunscreen formula and by the same protocol.”

In the controlled, randomized and evaluator-blinded study, four independent facilities tested two high-SPF sunscreen formulations, along with a standard reference formula with SPF 15, per the procedure FDA advanced in its proposed rule.

Evaluators at the four U.S.-based labs selected for the study were blinded as to the identifications of the formulas, which were randomized to different spots on participants' backs.

The first high-SPF formula contained active ingredients avobenzone, homosalate, octisalate, otocrylene and oxybenzone. The second formula contained the same ingredients, but included some in higher concentrations.

Solar simulators were used as UV sources. SPF values for the different formulas were derived by first determining the minimum erythema doses for their respective skin sites. MED was defined as "the smallest dose that produced redness reaching the borders of the test subsite" 16-24 hours post-exposure.

Five UV doses were used to get the MED for unprotected skin. Then, five doses were used to determine the MED for skin sites protected by the two high-SPF formulas and the SPF 15 comparison formula.

Individual SPF value for each formula was determined as the ratio of MED of protected skin over MED of unprotected skin. Statistical analysis compared the SPF results within each lab as well as the SPF results between different labs.

The formulas of interest were found to have overall mean SPF values of 90.5 and 70.7.

“There was no statistically significant difference between the labs for either formulation, and all four labs were able to statistically differentiate these two levels of SPF values,” the research found.

The coefficients of variance were consistent within each lab across the three different SPF levels, Stanfield, et al., found. “The CV for both SPF 15 reference and high SPF sunscreens were around 10% for labs one through three and about 20% in both its high and low SPF tests for the fourth lab," they note.

“The results obtained in this study confirm that multiple laboratories can test high SPF products and obtain virtually identical results, and are able to distinguish the difference in protection between SPF 70 and SPF 90," the investigators assert.

Researchers Defend Value Of High SPF

With debate ongoing among sunscreen stakeholders regarding the value of high SPF formulas, Stanfield et al. maintain "the SPF testing procedure demonstrates directly that twice the UV exposure is needed for an SPF 90 versus an SPF 45 to cause the same erythema response in skin, indicating that a person in real life in sunlight [can] be exposed for twice the time (or effective UV dose) before sunburn appears when wearing the higher SPF sunscreen versus the lower comparator sunscreen.

"Thus higher SPF-level protection can help prevent a faster accumulation of chronic UV damage that leads to premature skin aging and skin cancers, both phenomena well documented to be directly UV dose-dependent," the researchers say.

FDA recognized in its proposed final rule the potential advantages of high SPF sunscreens, holding that such products, if appropriately tested and labeled, "should be available for consumers who desire or need high levels of UV protection."

However, the agency has concerns outside of the testability of high SPF formulas. It acknowledges that marketing of thick, high-SPF formulas could lead to consumers wearing less protective clothing, using an insufficient amount of product and re-applying infrequently.

FDA missed its October 2010 target for release of the long-awaited final sunscreen rule. It maintained, however, that it expected to publish the rule within months (Also see "Sunscreen Rule Will Cost Four Times What FDA Predicted, Industry Tells OMB" - HBW Insight, 8 November, 2010. ).

By Eileen Francis

J&J Contests FDA-Proposed Cap With Study Championing High SPF Sunscreens

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